Title of Invention	A PROCESS FOR THE PRODUCTION OF 9, 9-DIALKYL SUBSTITUTED FLUORENE MONOMER AND OBTAINING THE POLYFLUORENE POLYMERS (PFO) THEREOF.
Abstract	A process for the preparation of 9, 9-dialkyl fluorene derivatives via alkylation of fluorene carried out by the direct treatment of fluorene with alkyl halide in the presence of aqueous metal hydroxide solution, a cationic surfactant as the phase transfer catalyst under degassed reaction conditions in the absence of any external pressure. The process involves the reaction with thermally stable and safe reagents in water to accomplish the synthesis of 9, 9-dialkyl fluorene in -4 hours in quantitative yields thereby qualifying the process to be economical and environmentally benign. Compositions made out of these 9, 9-dialkyl fluorene derivatives are devoid of ketone defect formation on exposure to high temperature and trace amounts of oxygen.

Title of Invention

A PROCESS FOR THE PRODUCTION OF 9, 9-DIALKYL SUBSTITUTED FLUORENE MONOMER AND OBTAINING THE POLYFLUORENE POLYMERS (PFO) THEREOF.

Abstract

A process for the preparation of 9, 9-dialkyl fluorene derivatives via alkylation of fluorene carried out by the direct treatment of fluorene with alkyl halide in the presence of aqueous metal hydroxide solution, a cationic surfactant as the phase transfer catalyst under degassed reaction conditions in the absence of any external pressure. The process involves the reaction with thermally stable and safe reagents in water to accomplish the synthesis of 9, 9-dialkyl fluorene in -4 hours in quantitative yields thereby qualifying the process to be economical and environmentally benign. Compositions made out of these 9, 9-dialkyl fluorene derivatives are devoid of ketone defect formation on exposure to high temperature and trace amounts of oxygen.

Full Text	FIELD OF INVENTION This invention relates to a process for the production of 9, 9-dialkyl substituted fluorene monomer from fluorene. More specifically, the invention particularly relates to a fast reaction process for the alkylation of unsubstituted fluorene for synthesizing the same. Importantly also, the above process; of the invention favors in obtaining the dialkyl substituted fluorene monomer economically. BACKGROUND OF THE INVENTION 9H-Fluorene commonly known as Fluorene is a polycyclic aromatic hydrocarbon. It is combustible, white crystalline material. It exhibits fluorescence, due to which it is called fluorene, and as such its polymer derivatives are attractive emissive material in Organic light emitting diodes (OLEOs). Polyfluorene (PFO) is a well-known high mobility hole transporting blue-emitting polymer for practical applications such as polymer light emitting diodes (PLED). The high quantum efficiency (QE) of fluorene, and polymers and copolymers made with fluorene showed excellent luminescence properties. Fluorene molecules consist of a methylene bridge that can be substituted with varying carbon chain length anc size, without interfering with the aromatic rings. The high quantum efficiency (QE) of fluorene in comparison with various polycyclic hydrocarbons viz. benzene, naphthalene, anthracene and closely related biphenyl, has been a preference to the use of fluorene to make optoelectronic devices that have excellent luminescence properties. However, it is interesting to note that although both biphenyl and fluorene possess the same degree of conjugation, QE of fluorene is much better than bipheny s. This is primarily due to the rigidly held biphenyl rings in fluorene, by a methylene bridge, as compared to the freely rotating two aromatic rings in the biphenyl. Fluorene offers added advantage due to the presence of this methylene bridge by allowing substitution of these methylene hydrogens at the remote 9-position, without interfering with the aromatic rings. Introducing dialkyl substituents of varying carbon chain length and size onto the fluorene molecule has been found to influence the optical, thermal, electrical, electrochemical, morphological and processing parameters of the final polymer, PFO. The below mentioned Fig. 1 highlights the position 9, where substitution with alkyl functional group occurs. Various methods for making alkylated luorene have been developed. References are drawn to the prior arts, CN Pat. no. 1752084; CN Pat. no. 1587252; JP Pat. no. 04224525; JP Pat. no. 071U6541; JP Pat. no. 06234668 wherein, various methods for making alkylated fluorene have been developed that have utilized a combination of high boiling organic solvents like DMSO and DMF and bases like NaOH/ KOH. W. S. Murphy et al J. Org. Chem. 1966, 31, 85 relates to a process where alkylation reaction to obtain alkylated fluorene has been performed in good yields using butyl lithium as a reagent. Effective use of this process for industrial purposes is limited since lithium reagents are extremely moisture sensitive requiring extreme operating conditions like very low temperatures and strict inert atmosphere. References are also drawn to the follow ng prior arts, D'yachenko, N. L; Shishov, M. G.; Ob'edkova, V. A.; Sergeeva, T. . Khimicheskaya Promyshlennost (Moscow, Russian Federation) 1985, (9), 522-5 24 where fluorene is alkylated by using a combination of isopropanol / ZnCI2 catalyst; Ob'edkova, V. A.; D'yachenko, N. L; Kharlampovich, G. D.; Moskovskikh, V. V. USSR. Osnovn. Organ. Sintez i Neftekhiniya 1977, (8), 92-96 and Ob'edkova, V. A.; Plotkina, N. I.; D'yachenko, N. L.; Kha-lampovich, G. D.; Moskovskikh, V. V. Ural. Politekh. Inst., Sverdlovsk, USSR. Khimiya Tverdogo Topliva (Moscow, Russian Federation) 1978, (1), 128-132 where fluorene is alkylated using AICI3 catalyst; D'yachenko, N. L; Novoselov, V. S.; Ob'edkova, V. A.; Kharlampovich, G. D. Il'ina, L. K. Izvestiya Vysshikh Uchebnyth Zavedenii, Khimiya i Khimicheskaya used; Ob'edkova, V. A.; Plotkina, N. I.; D'yachenko, N. L; Kharlampovich, G. D.; Syshchikova, N. D. Izvestiya V/sshikh Uchebnykh Zavedenii, Khimiya i Khimicheskaya Tekhnologiya 1977, 20(8), 1128-31 where CHCI3 / HF as catalyst have been used for the alkylation at the 9-position of the fluorene molecule. Pulina, M. Sh.; Klein, A. G. USSR. Katalitich. prevrashcheniya organ, soedin. 1973, 54 From: Ref. Zh., Khim. 1974, Absti. No.21ZH219 is directed to the alkylation of olefins in presence of catalytic amount of polyphosphoric acid. Makosza, M. Tech. Univ., Warsaw, Pol. Bull, de I'Academie Polonaise des Sciences, Serie des Sciences Chimiques. 19'67, 15, 165 and Malkhasyan, A. Ts.; Dzhandzhulyan, Zh. L; Mirakyan, S. M.; Maitirosyan, G. T. Nauchno-Proizvod. Ob'edin. "Nairit", Yerevan, USSR Armyanskii Khimicheskii Zhurnal 1980, 33, 335 have illustrated the use of phase transfer catalysts like PhCH2NEt3CI for the alkylation of fluorene. Reference is drawn to the prior art, Fedorynski, M.; Wojciechowski, K.; Matacz, Z.; Makosza, M. Inst. Org. Chem. Technol., Tech. Univ. Warsaw, Warsaw, Pol., J. Org. Chem. 1978, 43, 4682 where tetraalkylammonium halides and crown ethers have been used for alkylation of fluorene in moderate to good yields. Eli Lilly and Co., USA. Austrian, 1982 9 pp; AT Patent no. 368125 demonstrates the use of Sodium amide as an effective base for the removal of acidic proton at 9- position of fluorene molecule for alkylation purposes. Several drawbacks of these methods remain in the extensive use of organic solvents and hazardous catalyst or strong acid conditions of the reaction medium. All these methods either use strong acids, costly and sensitive catalysts, strongly basic and harsh or extreme reaction conditions, making the overall reaction too expensive to be facile for practical application. However, yet the art of making dialkylated fluorene has not yet been achieved and the unsubstituted fluorene resulted in formation of ketone at 9-position that was responsible for green emission. Cho, S. Y.; Grimsdale, A. C; Jones, D. J.; Watkins, S. E.; Holmes, A. B. J. Amer. Chem. Soc. 2007, 129(39), 11910-11911 describes the preparation of dialkylated fluorene using a multistep route by using cyclization of tertiary alcohol that is reported to be efficient as compared to the other prior arts in this field, however, employing multi step route that affect the overall economy of the process for producing 9, 9-dialkylated fluorene. US Patent 7102042, 2006 is directed to the alkylation of unsubstituted fluorene at the 9-position by chloro alkanes in the presence of nitrogen atmosphere and a polar protic solvent. Moreover, the slower reaction rate of 12 hours comprising chloro alkanes and fluorene gives rise to sufficient time and possibility for the formation of fluorenone i.e. the ketone at the 9-position of the fluorene molecule. Also the above said process in US Patent 7102042, 2036, comprising chloro alkanes, makes it more suitable to academia than industry because of the cost of chloro alkanes which are not thermally stable and hence not recoverable and reusable. Various methods for making alkylated fluorene have been developed. However, most methodologies involve stringent reaction conditicns in using low temperature baths and inert atmosphere techniques that often utilize a combination of organic solvent, base, and moisture sensitive reagents tnereby making the entire process difficult to handle and expensive for industrial applications. Few of the above said methods also result in incomplete alkylation yielding a mono alkylated product giving poor yields. Polymers made with these incompletely alkylated fluorene product resulted in kestone defect formation on exposure to high temperature and under traces of oxygen Therefore the above teachings flowing from the background art are summarized to suffer from either one or many of the drawbacks, which include: a) Low yielding and slow process and thus less efficient b) Strongly basic and harsh reaction conditions c) Moisture sensitive reagent and difficult/ in handling d) Longer reaction times thereby generating fluorenone defects e) Expensive nature of the reagents cind inert gas techniques f) Unreacted reagent recovery unknown It is thus reflected from the above mentioned arts that there is a continuous need in the art for a simple, economical, practical and a high yielding process for the dialkylation of fluorene at its 9-position as is described in this embodiment. There is also a need in the art to develop a process for complete alkylation of fluorene at its 9-position that would n turn lead to the production of good quality PFO's or poly fluorene polymers with ro ketone defect formation on exposure to high temperature and under trace amounts of oxygen. In light of the above said it is apparent that there is a continuous need in the art to develop a process for the production of 9,9-dialkylated fluorene in an industrial scale, which would circumvent all the aforementioned difficulties associated with the process. OBJECTS OF THE INVENTION It is thus a basic object of the present invention to provide for a process for the production of 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene in an industrial scale that would enable an efficient, economic, environment friendly and more importantly a high yielding process associated with high product purity. Another object of the invention is to provide for a process for a large scale production of 9, 9-dialkyl fluorene from fluorene that would be economically viable, eco-friendly and would thus enable a faster production of 9, 9-dialkyl fluorene. Yet a further object of the present nvention is directed to a process for the production of 9, 9-dialkyl fluorene involving easily available and non-corrosive reagents in association with a environmentally benign solvent. A further object of the invention is to provide for a process for the production of 9, 9- dialkyl fluorene that would be simple and easy to operate and would not involve harsh reaction conditions. It is a further object of the invention to provide for a process for the production of 9, 9-dialkyl fluorene that would be economical in not requiring any inert gases or nitrogen in the reaction medium which can also be accomplished within a short time without any hazard or risk. Still another object of the invention is to provide for a process for the production of 9, 9-dialkyl fluorene that would result in highly pure product specifications. Yet another object of the invention is to provide Tor a process for the production of 9, 9-dialkyl fluorene wherein the desirec products; would be obtained in quantitative yields. Still a further object of the invention is to provide for a process for the production of 9, 9-dialkyl fluorene wherein the unreacted reagents can be recycled to further economize the said process. SUMMARY OF THE INVENTION This according to the basic aspect of the invention there is provided a process for the production of 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene of the structural formula: Where R' is an alkyl or a substituted alkyl; wherein fluorene is reacted with one desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base and an appropriate amount of the phase transfer catalyst in a polar solvent to yield the said dialkylated fluorene. In accordance with another preferrej aspect of the invention, the phase transfer catalyst is a cationic surfactant molecule of the formula R-X; where R is selected from the group of tetraethyl ammonium, tetrapropyl ammonium, tetrabutyl ammonium, tetrapentyl ammonium, tetrahexyl ammonium, tetraheptyl ammonium, tetraoctyl ammonium, tetradecyl ammonium, tetradodecyl ammonium; and X selected from the group of halogen, phosphate, carboxylate, nitrate, perchlorate. Halogen refers to fluorine, chlorine, bromine and iodine. Sulfate refers to sulfur and oxygen that are bonded to either of the R group mentioned above. Phosphate refers to phosphorous and c xygen that is bonded to either of the R group mentioned above. Carboxylate refers to carbon and oxycen that are bonded to either of the R group mentioned above. Nitrate refers to nitrogen and oxyger that are bonded to either of the R group mentioned above. Perchlorate refers to chlorine and oxycen that are bonded to either of the R group mentioned above. The above said phase transfer catalyst facilitating the production of 9, 9-dialkylated fluorene from fluorene is stable at high temperatures, at high pH and is easily soluble in water. The quantity of the above said phase transfer catalyst is minimum comprising a cationic surfactant and is in the range of 5-15 mole % but preferably only 10 mol % was found to be efficient to affect the di.ilkylation of fluorene. In accordance with yet another preferred aspect of the invention the alkyl halide of the formula R'-Y; where R' = C6-C11 is alkyl, branched alkyl and disubstituted alkyl derivatives selected from the group of 1-chlorohexane, 1-bromohexane, 1- iodohexane, 1-chlorooctane, 1-bromooctane, 1-iodooctane, 1-bromoundecane, 1- iodoundecane, 2-ethylhexylbromide, :., 6-dichlorohexane, 1, 6-dibromohexane, 1, 6- diiodohexane, 1, 8-dichlorooctane, 1, 8-dibromooctane, 1, 8-diiodohexane; and Y selected from the group of Y = fluorinu, chlorine;, bromine, iodine. The above said mono or di halogemited alkyl of the formula R'-Y is preferably a bromo or a dibromo alkane and R' can either be linear or branched or substituted alkyl chain or a carbon chain having bulky groups like bromide and iodide at both ends. The above said alkyl chain is preferable a saturated hydrocarbon with varying carbon chain length comprising of 6-11 carbor atoms. Advantageously, the solvent in the p-ocess for the production of 9, 9-dialkylated fluorene from fluorene is a polar solvent, that can dissolve the base and the above said surfactant molecule and is selected from alcohol, dimethylsulfoxide dimethylformamide, water and is prefeiably water. Advantageously again, the above said surfactan: molecule is cheap and economical which is easily soluble in water, stable inder high pH and at a temperature range of 70-100 °C and is also separated easlly from the reaction medium after product formation. Preferably the reaction takes place in an atmosphere free of oxygen, nitrogen and inert gases preferably obtained by degassing the -eaction mixture. The above said oxygen free atmosphere in the reaction vessel is created whereby there is no need for flushing the reaction mixture with any inert gases like argon or helium or nitrogen. No external pressure is needed for the reaction to proceed and there is no fear of any hazard or explosion. In accordance with an aspect of the invention the process for the production of dialkylated fluorene proceeds with a base comprising of alkali metal hydroxide of the formula; M-OH wherein M refers to either Sodium or Potassium. The above said alkali metal hydroxide with high purity that is capable of performing the dialkylation reaction. Most importantly, the unreacted alkyl halide preferably a bromo alkane is recovered from the reaction medium, recycled and reused. In another aspect of the present invention the temperature of the reaction is always maintained below 100 °C preferably 85 °C and the reaction gets completed in 4 hours more preferably in 3.5 hours time. Advantageously enough, the process of the present invention proceeds to completion in ~4 hours and has much lower possibility of ketone formation in 9-position of the fluorene molecule obtained as an undesired side product. In yet another aspect of the present invention the above said dialkylated product comprises a yield % of >80 % preferably in the range of 80-98 %. In yet a further aspect of the invention there is provided a process for the production of polyfluorene polymers (PFO) comprising the steps of: (i) Providing 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene of the structural formula: Where R' is an alkyl or a substituted alkyl; comprising reacting fluorene with one desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base and a phase transfer catalyst and in a bolar solvent to produce the said dialkylated fluorine and (ii) Obtaining the said polymer from said monomer thus obtained. Most advantageously, compositions comprising of 9, 9-dialkyl substituted conjugated fluorene monomer produced by the process of the present invention is free of ketone defect formation on exposure to high temperature and traces amounts of oxygen. Another important aspect of the process of the present invention is the complete di alkylation of fluorene molecule in which the monoalkylated product was completely absent that eventually leads to the much favoured disappearance of ketone formation at 9-position in the compositions or polymers namely poly fluorene polymers (PFO) made out of it. DETAILED DESCRIPTION OF THE INVENTION As already disclosed herein before the present invention comprises of a simple, economic and environment friendly process for the production of 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene of the structural formula: Where R' is an alkyl or a substituted alkyl, preferably a saturated hydrocarbon with varying chain length of 6-11 carbon atons. The above mentioned 9, 9-dialkyl fluorene are obtained in almost quantitative yields from the reaction involving fluorene with a desired alkyl halide, R'-Y, in a degassed atmosphere in the presence of a base and an appropriate amount of the phase transfer catalyst in a polar solvent preferably water. The environmentally green method adapted for the preparation of 9, 9-dialkylated fluorene is economical and does not employ any organic solvent in the reaction medium that uses water instead. Separation of the above said dialkylated product after the stipulated reaction time is achieved by simple separation methods, from water, and thus avoids hazardous separation steps. The above said dialkylation method is carried out in the absence of oxygen atmosphere, by a method of degassing for the removal of oxygen and carrying out the reaction in a degassed atmosphere. The reaction does not necessarily need to be performed by replacing the oxygen with other inert gases such as nitrogen, argon, helium, etc. The above said method was carried out in the presence of only one economical surfactant used as a phase transfer catalyst that are very stable under high pH, high temperature and is water soluble that can be easily separated after the formation of product from the reaction mixture. The preferred phase transfer catalysts used are tetra alkyl ammonium salts of various ralides. The phase transfer catalysts efficiently facilitated dialkylation of fluorene. The quantity of catalyst used was minimum and varied in the range of 5-15 mole percert depending on the kind of alkyl halide used. The base used in the above said method is laboratory grade sodium or potassium hydroxide. Thus, the dialkylation reaction of fluorene in the presence of phase transfer catalyst, water, degassed atmosphere and an alkyl halide were carried out under moderate temperatures ranging from 70-100°C, preferably 85 °C. The duration and temperature of the reaction were varied according to the type of alkyl halide to be inserted into the fluorene molecule. The base used in this method is laboratory grade sodium or potassium hydroxide. The dialkylation of fluorene molecule under the above conditions yielded exclusively the 9, 9-dialkylated products in isolated yields of 80-98 %. The details of the invention, its objects and advantages are explained here under in greater detail in relation to non-limiting exemplary illustrations as per the following examples: The substrate starting material Fluorene and reagent alkyl halides was bought from Aldrich Chemical Co. and used as such without any further purification. Laboratory grade sodium or potassium hydroxide (Rankem India) was used as base in the process of production of 9, 9-dialkylated Fluorene. Water was used to solubilise sodium or potassium hydroxide for the above said process. Example I: Synthesis of 9.9-dialkylated Fluorene Fluorene (0.21gm, 1.26 x 10"3 moles), 1-bromohexane (1.45_gm, 8.82 x 10'3 moles), tetrabutylammonium iodide (0.047 gm, 10 mole %) were suspended in 11 ml 50 % sodium hydroxide solution at room temperature. The reaction mixture was appropriately degassed to remove traces of oxygen and was then heated to a temperature of 80 °C for 3.5 hrs. While maintaining the temperature at 80 °C, the liquid phase was separated, wherein the solid Na-salt remained suspended in the top organic phase. The organic phase was washed three times with 50 x 3 ml water. The resulting organic phase was weighed to give 0.401 gm of the crude product, which was further purified by column chromatography (silica column) using 1-3 % of ethyl acetate/hexane as an eluent to yield 9, 9-dialkyl fluorene in 96 % yield. The above synthetic procedure followed is further briefly outlined below in Scheme 1 hereunder. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. All percentages are by weight. The above exemplary illustration of the process of the invention clearly reveals a highly efficient, economized and an environmentally green process for the production of 9, 9- dialkyl fluorene through a chemically safe route. Respective yield of the said dialkylated product is > 80 % irresoective of the kind of alkyl halide used. The dialkylation process is preferably achieved without employing any kind of organic solvent and without the use of any strong acids. Since the reaction is carried out under degassed conditions the process does not essentially need external pressure on the reaction medium and thereby does not involve any kind of hazard or the risk of explosion. The unreacted reagents that comprises of an aqueous solution of base and excess alkyl halide are easily separated from the reaction mixture thereby enabling recycle and reuse to ensure a yield of > 75 % of 9, 9- dialkyl fluorene in the next recycle. The phase transfer catalyst is recovered from the above said process in untraceable amounts. The method described herein permits to introduce dialkyl chains of varying carbon chain length, types with bulky substituents at 9, 9'-position of fluorene molecule. The above said process is fast in yielding 9, 9'-dialkyl fluorene in a short span of time ~3.5 hours in yields >80%. It is also noteworthy that the reaction proceeds in a degassed atmosphere, which further economizes the process of production in not needing nitrogen or any type of inert gases. Advantageously the process providec in this invention is environmentally green because of the use of water as a solvent in the reaction medium and the non-toxic nature of the reagents used. Accordirgly the process provided in this invention is favorable with respect to easy handling of the reagents, which are moisture insensitive. Conclusively, the drawbacks of US pa:ent 7102042, 2006 are circumvented in the present process of the invention on using bromo alkanes under degassed reaction conditions whereby the bromo alkares are obtainable in the form of various derivatives that are cheap, thermally more stable, recoverable and reusable and of more practical importance than the chloro alkanes. Also, the process of the present invention gets completed in ~4 hours and thereby has a much lower possibility of ketone formation in 9-position of the fluorene molecule obtained as an undesired side product in comparison to US patent 7102042, 2006 that takes 12 hours to proceed to completion. More advantageously, the bromo alkenes have higher boiling points and higher flash points w.r.t the chloro alkanes of comparative chain length thus making handling safer. Unlike the prior art US patent 710242, 2006, this process of the present invention for producing 9, 9-dialkyl fluorene is deemed efficient with various alkyl halides possessing linear carbon chain, brarched carbon chain and carbon chain having bulky groups like bromide and iodide at both ends. It is thus possible by way of the present invention to provide for a process for the production of 9, 9-dialkyl fluorene from fluorene on complete alkylation which is efficient in terms of the time required to accomplish high yields of the product and also in terms of recovery of the starting materials for recycle and reuse. Compositions or poly fluorene polymers like (PFO) made out of 9, 9-dialkyl substituted conjugated fluorene monomer synthesized by the above said process is free all mono substituted fluorene and s free of ketone defect formation on exposure to high temperature and traces amounts of oxygen. The process is environmentally green, most significantly for water being used as the solvent for reaction and also for the non-toxic nature of the reagents needed. It is easy to operate in terms of the moisture insensitive reagents needed for the purpose. We Claim: 1. A process for the production of 9, 9-dialkyl substituted fluorene monomer from fluorene of the structural formula: Where R' is an alkyl or a substitutec alkyl; comprising reacting fluorene with one desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base and a phase transfer catalyst in a polar solvent to produce the said dialkylated fluorene. 2. A process as claimed in any of the preceding claims wherein the phase transfer catalyst is a cationic surfactant molecule of the formula R-X; where R is selected from the group of tetraethyl amnonium, tetrapropyl ammonium, tetrabutyl ammonium, tetrapentyl ammonium, tetrahexyl ammonium, tetraheptyl ammonium, tetraoctyl ammonium, tetradecyl ammonium, tetradodecyl ammonium; and X selected from the group of halogen, phosphate, carboxylate, nitrate, perchlorate. 3. A process as claimed in any of the preceding claims wherein the alkyl halide of the formula R'-Y; where R' = C6-C11 is alkyl, branched alkyl and disubstituted alkyl derivatives selected from the group of 1-chlorohexane, 1-bromohexane, 1- iodohexane, 1-chlorooctane, 1-bromooctane, 1-iodooctane, 1-bromoundecane, 1- iodoundecane, 2-ethylhexylbromide, 1, 6-dichlorohexane, 1, 6-dibromohexane, 1, 6- diiodohexane, 1, 8-dichlorooctane, 1, 8-dibromooctane, 1, 8-diiodohexane; and Y selected from the group of Y = fluorine, chlorine, bromine, iodine. 4. A process as claimed in claim 3, wherein the mono or di halogenated alkyl of the formula R'-Y is preferably a bromo or a dibromo alkane. 5. A process as claimed in any of the preceding claims wherein the polar solvent is preferably not a polar organic solvent bit preferably water. 6. A process as claimed in any of the preceding claims wherein the surfactant is easily soluble in water, stable under high pH and at a temperature range of 70-100 °C. 7. A process as claimed in any one of the preceding claims wherein the reaction proceeds in an atmosphere free of oxygen, nitrogen and inert gases preferably obtained by degassing the reaction mixture. 8. A process as claimed in any of the preceding claims wherein the production of dialkylated fluorene proceeds with a base comprising of alkali metal hydroxide of the formula; M-OH wherein M refers to either Sodium or Potassium. 9. A process as claimed in any one of the preceding claims wherein the unreacted alkyl halide is recovered from the react on medium and recycled. 10. A process as claimed in any one of the preceding claims wherein the temperature of the reaction is always maintained below 100 ºC preferably 85 °C and the reaction gets completed in 4 hours more preferably in 3.5 hours time. 11. A process as claimed in anyone of the preceding claims wherein the product obtained comprises a yield % of >80 % preferably in the range of 80-98 %. 12. A process for the manufacture of polyfluorene polymers (PFO) comprising the steps of: Where R' is an alkyl or a substituted eIkyl; comprising reacting fluorene with one desired alkyl halide, R'-Y, in a degassec atmosphere and in the presence of a base (i) Providing 9, 9-dialkyl substituted fluorene monomer from fluorene of the structural formula: and a phase transfer catalyst and in a polar solvent to produce the said dialkylated fluorine and (ii) Obtaining the said polymer from said monomer thus obtained. 13. A process for the preparation of 9, 9-dialkylated fluorene from fluorene substantially as herein described and illustrated with reference to the accompanying examples A process for the preparation of 9, 9-dialkyl fluorene derivatives via alkylation of fluorene carried out by the direct treatment of fluorene with alkyl halide in the presence of aqueous metal hydroxide solution, a cationic surfactant as the phase transfer catalyst under degassed reaction conditions in the absence of any external pressure. The process involves the reaction with thermally stable and safe reagents in water to accomplish the synthesis of 9, 9-dialkyl fluorene in -4 hours in quantitative yields thereby qualifying the process to be economical and environmentally benign. Compositions made out of these 9, 9-dialkyl fluorene derivatives are devoid of ketone defect formation on exposure to high temperature and trace amounts of oxygen.

Full Text

FIELD OF INVENTION
This invention relates to a process for the production of 9, 9-dialkyl substituted
fluorene monomer from fluorene. More specifically, the invention particularly relates
to a fast reaction process for the alkylation of unsubstituted fluorene for synthesizing
the same. Importantly also, the above process; of the invention favors in obtaining
the dialkyl substituted fluorene monomer economically.
BACKGROUND OF THE INVENTION
9H-Fluorene commonly known as Fluorene is a polycyclic aromatic hydrocarbon. It is
combustible, white crystalline material. It exhibits fluorescence, due to which it is
called fluorene, and as such its polymer derivatives are attractive emissive material
in Organic light emitting diodes (OLEOs). Polyfluorene (PFO) is a well-known high
mobility hole transporting blue-emitting polymer for practical applications such as
polymer light emitting diodes (PLED). The high quantum efficiency (QE) of fluorene,
and polymers and copolymers made with fluorene showed excellent luminescence
properties. Fluorene molecules consist of a methylene bridge that can be substituted
with varying carbon chain length anc size, without interfering with the aromatic
rings.
The high quantum efficiency (QE) of fluorene in comparison with various polycyclic
hydrocarbons viz. benzene, naphthalene, anthracene and closely related biphenyl,
has been a preference to the use of fluorene to make optoelectronic devices that
have excellent luminescence properties. However, it is interesting to note that
although both biphenyl and fluorene possess the same degree of conjugation, QE of
fluorene is much better than bipheny s. This is primarily due to the rigidly held
biphenyl rings in fluorene, by a methylene bridge, as compared to the freely rotating
two aromatic rings in the biphenyl. Fluorene offers added advantage due to the
presence of this methylene bridge by allowing substitution of these methylene
hydrogens at the remote 9-position, without interfering with the aromatic rings.
Introducing dialkyl substituents of varying carbon chain length and size onto the
fluorene molecule has been found to influence the optical, thermal, electrical,
electrochemical, morphological and processing parameters of the final polymer, PFO.
The below mentioned Fig. 1 highlights the position 9, where substitution with alkyl
functional group occurs.

Various methods for making alkylated luorene have been developed.
References are drawn to the prior arts, CN Pat. no. 1752084; CN Pat. no. 1587252;
JP Pat. no. 04224525; JP Pat. no. 071U6541; JP Pat. no. 06234668 wherein, various
methods for making alkylated fluorene have been developed that have utilized a
combination of high boiling organic solvents like DMSO and DMF and bases like
NaOH/ KOH.
W. S. Murphy et al J. Org. Chem. 1966, 31, 85 relates to a process where alkylation
reaction to obtain alkylated fluorene has been performed in good yields using butyl
lithium as a reagent. Effective use of this process for industrial purposes is limited
since lithium reagents are extremely moisture sensitive requiring extreme operating
conditions like very low temperatures and strict inert atmosphere.
References are also drawn to the follow ng prior arts, D'yachenko, N. L; Shishov, M.
G.; Ob'edkova, V. A.; Sergeeva, T. . Khimicheskaya Promyshlennost (Moscow,
Russian Federation) 1985, (9), 522-5 24 where fluorene is alkylated by using a
combination of isopropanol / ZnCI2 catalyst;
Ob'edkova, V. A.; D'yachenko, N. L; Kharlampovich, G. D.; Moskovskikh, V. V.
USSR. Osnovn. Organ. Sintez i Neftekhiniya 1977, (8), 92-96 and Ob'edkova, V. A.;
Plotkina, N. I.; D'yachenko, N. L.; Kha-lampovich, G. D.; Moskovskikh, V. V. Ural.
Politekh. Inst., Sverdlovsk, USSR. Khimiya Tverdogo Topliva (Moscow, Russian
Federation) 1978, (1), 128-132 where fluorene is alkylated using AICI3 catalyst;
D'yachenko, N. L; Novoselov, V. S.; Ob'edkova, V. A.; Kharlampovich, G. D. Il'ina,
L. K. Izvestiya Vysshikh Uchebnyth Zavedenii, Khimiya i Khimicheskaya

used;
Ob'edkova, V. A.; Plotkina, N. I.; D'yachenko, N. L; Kharlampovich, G. D.;
Syshchikova, N. D. Izvestiya V/sshikh Uchebnykh Zavedenii, Khimiya i
Khimicheskaya Tekhnologiya 1977, 20(8), 1128-31 where CHCI3 / HF as catalyst
have been used for the alkylation at the 9-position of the fluorene molecule.
Pulina, M. Sh.; Klein, A. G. USSR. Katalitich. prevrashcheniya organ, soedin. 1973,
54 From: Ref. Zh., Khim. 1974, Absti. No.21ZH219 is directed to the alkylation of
olefins in presence of catalytic amount of polyphosphoric acid.
Makosza, M. Tech. Univ., Warsaw, Pol. Bull, de I'Academie Polonaise des Sciences,
Serie des Sciences Chimiques. 19'67, 15, 165 and Malkhasyan, A. Ts.;
Dzhandzhulyan, Zh. L; Mirakyan, S. M.; Maitirosyan, G. T. Nauchno-Proizvod.
Ob'edin. "Nairit", Yerevan, USSR Armyanskii Khimicheskii Zhurnal 1980, 33, 335
have illustrated the use of phase transfer catalysts like PhCH2NEt3CI for the alkylation
of fluorene.
Reference is drawn to the prior art, Fedorynski, M.; Wojciechowski, K.; Matacz, Z.;
Makosza, M. Inst. Org. Chem. Technol., Tech. Univ. Warsaw, Warsaw, Pol., J. Org.
Chem. 1978, 43, 4682 where tetraalkylammonium halides and crown ethers have
been used for alkylation of fluorene in moderate to good yields.
Eli Lilly and Co., USA. Austrian, 1982 9 pp; AT Patent no. 368125 demonstrates the
use of Sodium amide as an effective base for the removal of acidic proton at 9-
position of fluorene molecule for alkylation purposes.
Several drawbacks of these methods remain in the extensive use of organic solvents
and hazardous catalyst or strong acid conditions of the reaction medium.
All these methods either use strong acids, costly and sensitive catalysts, strongly
basic and harsh or extreme reaction conditions, making the overall reaction too
expensive to be facile for practical application. However, yet the art of making
dialkylated fluorene has not yet been achieved and the unsubstituted fluorene
resulted in formation of ketone at 9-position that was responsible for green emission.

Cho, S. Y.; Grimsdale, A. C; Jones, D. J.; Watkins, S. E.; Holmes, A. B. J. Amer.
Chem. Soc. 2007, 129(39), 11910-11911 describes the preparation of dialkylated
fluorene using a multistep route by using cyclization of tertiary alcohol that is
reported to be efficient as compared to the other prior arts in this field, however,
employing multi step route that affect the overall economy of the process for
producing 9, 9-dialkylated fluorene.
US Patent 7102042, 2006 is directed to the alkylation of unsubstituted fluorene at
the 9-position by chloro alkanes in the presence of nitrogen atmosphere and a polar
protic solvent. Moreover, the slower reaction rate of 12 hours comprising chloro
alkanes and fluorene gives rise to sufficient time and possibility for the formation of
fluorenone i.e. the ketone at the 9-position of the fluorene molecule. Also the above
said process in US Patent 7102042, 2036, comprising chloro alkanes, makes it more
suitable to academia than industry because of the cost of chloro alkanes which are
not thermally stable and hence not recoverable and reusable.
Various methods for making alkylated fluorene have been developed. However, most
methodologies involve stringent reaction conditicns in using low temperature baths
and inert atmosphere techniques that often utilize a combination of organic solvent,
base, and moisture sensitive reagents tnereby making the entire process difficult to
handle and expensive for industrial applications.
Few of the above said methods also result in incomplete alkylation yielding a mono
alkylated product giving poor yields. Polymers made with these incompletely
alkylated fluorene product resulted in kestone defect formation on exposure to high
temperature and under traces of oxygen
Therefore the above teachings flowing from the background art are summarized to
suffer from either one or many of the drawbacks, which include:
a) Low yielding and slow process and thus less efficient
b) Strongly basic and harsh reaction conditions
c) Moisture sensitive reagent and difficult/ in handling
d) Longer reaction times thereby generating fluorenone defects

e) Expensive nature of the reagents cind inert gas techniques
f) Unreacted reagent recovery unknown
It is thus reflected from the above mentioned arts that there is a continuous need in
the art for a simple, economical, practical and a high yielding process for the
dialkylation of fluorene at its 9-position as is described in this embodiment.
There is also a need in the art to develop a process for complete alkylation of
fluorene at its 9-position that would n turn lead to the production of good quality
PFO's or poly fluorene polymers with ro ketone defect formation on exposure to high
temperature and under trace amounts of oxygen.
In light of the above said it is apparent that there is a continuous need in the art to
develop a process for the production of 9,9-dialkylated fluorene in an industrial
scale, which would circumvent all the aforementioned difficulties associated with the
process.
OBJECTS OF THE INVENTION
It is thus a basic object of the present invention to provide for a process for the
production of 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene in
an industrial scale that would enable an efficient, economic, environment friendly
and more importantly a high yielding process associated with high product purity.
Another object of the invention is to provide for a process for a large scale
production of 9, 9-dialkyl fluorene from fluorene that would be economically viable,
eco-friendly and would thus enable a faster production of 9, 9-dialkyl fluorene.
Yet a further object of the present nvention is directed to a process for the
production of 9, 9-dialkyl fluorene involving easily available and non-corrosive
reagents in association with a environmentally benign solvent.

A further object of the invention is to provide for a process for the production of 9, 9-
dialkyl fluorene that would be simple and easy to operate and would not involve
harsh reaction conditions.
It is a further object of the invention to provide for a process for the production of 9,
9-dialkyl fluorene that would be economical in not requiring any inert gases or
nitrogen in the reaction medium which can also be accomplished within a short time
without any hazard or risk.
Still another object of the invention is to provide for a process for the production of
9, 9-dialkyl fluorene that would result in highly pure product specifications.
Yet another object of the invention is to provide Tor a process for the production of 9,
9-dialkyl fluorene wherein the desirec products; would be obtained in quantitative
yields.
Still a further object of the invention is to provide for a process for the production of
9, 9-dialkyl fluorene wherein the unreacted reagents can be recycled to further
economize the said process.
SUMMARY OF THE INVENTION
This according to the basic aspect of the invention there is provided a process for the
production of 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene of
the structural formula:

Where R' is an alkyl or a substituted alkyl; wherein fluorene is reacted with one
desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base
and an appropriate amount of the phase transfer catalyst in a polar solvent to yield
the said dialkylated fluorene.

In accordance with another preferrej aspect of the invention, the phase transfer
catalyst is a cationic surfactant molecule of the formula R-X; where R is selected
from the group of tetraethyl ammonium, tetrapropyl ammonium, tetrabutyl
ammonium, tetrapentyl ammonium, tetrahexyl ammonium, tetraheptyl ammonium,
tetraoctyl ammonium, tetradecyl ammonium, tetradodecyl ammonium; and X
selected from the group of halogen, phosphate, carboxylate, nitrate, perchlorate.
Halogen refers to fluorine, chlorine, bromine and iodine.
Sulfate refers to sulfur and oxygen that are bonded to either of the R group
mentioned above.
Phosphate refers to phosphorous and c xygen that is bonded to either of the R group
mentioned above.
Carboxylate refers to carbon and oxycen that are bonded to either of the R group
mentioned above.
Nitrate refers to nitrogen and oxyger that are bonded to either of the R group
mentioned above.
Perchlorate refers to chlorine and oxycen that are bonded to either of the R group
mentioned above.
The above said phase transfer catalyst facilitating the production of 9, 9-dialkylated
fluorene from fluorene is stable at high temperatures, at high pH and is easily soluble
in water.
The quantity of the above said phase transfer catalyst is minimum comprising a
cationic surfactant and is in the range of 5-15 mole % but preferably only 10 mol %
was found to be efficient to affect the di.ilkylation of fluorene.
In accordance with yet another preferred aspect of the invention the alkyl halide of
the formula R'-Y; where R' = C6-C11 is alkyl, branched alkyl and disubstituted alkyl
derivatives selected from the group of 1-chlorohexane, 1-bromohexane, 1-

iodohexane, 1-chlorooctane, 1-bromooctane, 1-iodooctane, 1-bromoundecane, 1-
iodoundecane, 2-ethylhexylbromide, :., 6-dichlorohexane, 1, 6-dibromohexane, 1, 6-
diiodohexane, 1, 8-dichlorooctane, 1, 8-dibromooctane, 1, 8-diiodohexane; and Y
selected from the group of Y = fluorinu, chlorine;, bromine, iodine.
The above said mono or di halogemited alkyl of the formula R'-Y is preferably a
bromo or a dibromo alkane and R' can either be linear or branched or substituted
alkyl chain or a carbon chain having bulky groups like bromide and iodide at both
ends.
The above said alkyl chain is preferable a saturated hydrocarbon with varying carbon
chain length comprising of 6-11 carbor atoms.
Advantageously, the solvent in the p-ocess for the production of 9, 9-dialkylated
fluorene from fluorene is a polar solvent, that can dissolve the base and the above
said surfactant molecule and is selected from alcohol, dimethylsulfoxide
dimethylformamide, water and is prefeiably water.
Advantageously again, the above said surfactan: molecule is cheap and economical
which is easily soluble in water, stable inder high pH and at a temperature range of
70-100 °C and is also separated easlly from the reaction medium after product
formation.
Preferably the reaction takes place in an atmosphere free of oxygen, nitrogen and
inert gases preferably obtained by degassing the -eaction mixture.
The above said oxygen free atmosphere in the reaction vessel is created whereby
there is no need for flushing the reaction mixture with any inert gases like argon or
helium or nitrogen. No external pressure is needed for the reaction to proceed and
there is no fear of any hazard or explosion.
In accordance with an aspect of the invention the process for the production of
dialkylated fluorene proceeds with a base comprising of alkali metal hydroxide of the
formula; M-OH wherein M refers to either Sodium or Potassium.

The above said alkali metal hydroxide with high purity that is capable of performing
the dialkylation reaction.
Most importantly, the unreacted alkyl halide preferably a bromo alkane is recovered
from the reaction medium, recycled and reused.
In another aspect of the present invention the temperature of the reaction is always
maintained below 100 °C preferably 85 °C and the reaction gets completed in 4 hours
more preferably in 3.5 hours time.
Advantageously enough, the process of the present invention proceeds to completion
in ~4 hours and has much lower possibility of ketone formation in 9-position of the
fluorene molecule obtained as an undesired side product.
In yet another aspect of the present invention the above said dialkylated product
comprises a yield % of >80 % preferably in the range of 80-98 %.
In yet a further aspect of the invention there is provided a process for the production
of polyfluorene polymers (PFO) comprising the steps of:
(i) Providing 9, 9-dialkyl substituted conjugated fluorene monomer from fluorene of
the structural formula:

Where R' is an alkyl or a substituted alkyl; comprising reacting fluorene with one
desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base
and a phase transfer catalyst and in a bolar solvent to produce the said dialkylated
fluorine and
(ii) Obtaining the said polymer from said monomer thus obtained.

Most advantageously, compositions comprising of 9, 9-dialkyl substituted conjugated
fluorene monomer produced by the process of the present invention is free of ketone
defect formation on exposure to high temperature and traces amounts of oxygen.
Another important aspect of the process of the present invention is the complete di
alkylation of fluorene molecule in which the monoalkylated product was completely
absent that eventually leads to the much favoured disappearance of ketone
formation at 9-position in the compositions or polymers namely poly fluorene
polymers (PFO) made out of it.
DETAILED DESCRIPTION OF THE INVENTION
As already disclosed herein before the present invention comprises of a simple,
economic and environment friendly process for the production of 9, 9-dialkyl
substituted conjugated fluorene monomer from fluorene of the structural formula:

Where R' is an alkyl or a substituted alkyl, preferably a saturated hydrocarbon with
varying chain length of 6-11 carbon atons.
The above mentioned 9, 9-dialkyl fluorene are obtained in almost quantitative yields
from the reaction involving fluorene with a desired alkyl halide, R'-Y, in a degassed
atmosphere in the presence of a base and an appropriate amount of the phase
transfer catalyst in a polar solvent preferably water.
The environmentally green method adapted for the preparation of 9, 9-dialkylated
fluorene is economical and does not employ any organic solvent in the reaction
medium that uses water instead.

Separation of the above said dialkylated product after the stipulated reaction time is
achieved by simple separation methods, from water, and thus avoids hazardous
separation steps.
The above said dialkylation method is carried out in the absence of oxygen
atmosphere, by a method of degassing for the removal of oxygen and carrying out
the reaction in a degassed atmosphere.
The reaction does not necessarily need to be performed by replacing the oxygen with
other inert gases such as nitrogen, argon, helium, etc.
The above said method was carried out in the presence of only one economical
surfactant used as a phase transfer catalyst that are very stable under high pH, high
temperature and is water soluble that can be easily separated after the formation of
product from the reaction mixture. The preferred phase transfer catalysts used are
tetra alkyl ammonium salts of various ralides. The phase transfer catalysts efficiently
facilitated dialkylation of fluorene. The quantity of catalyst used was minimum and
varied in the range of 5-15 mole percert depending on the kind of alkyl halide used.
The base used in the above said method is laboratory grade sodium or potassium
hydroxide.
Thus, the dialkylation reaction of fluorene in the presence of phase transfer catalyst,
water, degassed atmosphere and an alkyl halide were carried out under moderate
temperatures ranging from 70-100°C, preferably 85 °C. The duration and
temperature of the reaction were varied according to the type of alkyl halide to be
inserted into the fluorene molecule. The base used in this method is laboratory grade
sodium or potassium hydroxide. The dialkylation of fluorene molecule under the
above conditions yielded exclusively the 9, 9-dialkylated products in isolated yields of
80-98 %.
The details of the invention, its objects and advantages are explained here under in
greater detail in relation to non-limiting exemplary illustrations as per the following
examples:

The substrate starting material Fluorene and reagent alkyl halides was bought from
Aldrich Chemical Co. and used as such without any further purification. Laboratory
grade sodium or potassium hydroxide (Rankem India) was used as base in the
process of production of 9, 9-dialkylated Fluorene. Water was used to solubilise
sodium or potassium hydroxide for the above said process.
Example I: Synthesis of 9.9-dialkylated Fluorene
Fluorene (0.21gm, 1.26 x 10"3 moles), 1-bromohexane (1.45_gm, 8.82 x 10'3 moles),
tetrabutylammonium iodide (0.047 gm, 10 mole %) were suspended in 11 ml 50 %
sodium hydroxide solution at room temperature. The reaction mixture was
appropriately degassed to remove traces of oxygen and was then heated to a
temperature of 80 °C for 3.5 hrs. While maintaining the temperature at 80 °C, the
liquid phase was separated, wherein the solid Na-salt remained suspended in the top
organic phase. The organic phase was washed three times with 50 x 3 ml water. The
resulting organic phase was weighed to give 0.401 gm of the crude product, which
was further purified by column chromatography (silica column) using 1-3 % of ethyl
acetate/hexane as an eluent to yield 9, 9-dialkyl fluorene in 96 % yield. The above
synthetic procedure followed is further briefly outlined below in Scheme 1
hereunder.

The following examples are given by way of illustration of the present invention and
therefore should not be construed to limit the scope of the present invention. All
percentages are by weight.
The above exemplary illustration of the process of the invention clearly reveals a
highly efficient, economized and an environmentally green process for the production

of 9, 9- dialkyl fluorene through a chemically safe route. Respective yield of the said
dialkylated product is > 80 % irresoective of the kind of alkyl halide used. The
dialkylation process is preferably achieved without employing any kind of organic
solvent and without the use of any strong acids. Since the reaction is carried out
under degassed conditions the process does not essentially need external pressure
on the reaction medium and thereby does not involve any kind of hazard or the risk
of explosion. The unreacted reagents that comprises of an aqueous solution of base
and excess alkyl halide are easily separated from the reaction mixture thereby
enabling recycle and reuse to ensure a yield of > 75 % of 9, 9- dialkyl fluorene in the
next recycle. The phase transfer catalyst is recovered from the above said process in
untraceable amounts.
The method described herein permits to introduce dialkyl chains of varying carbon
chain length, types with bulky substituents at 9, 9'-position of fluorene molecule.
The above said process is fast in yielding 9, 9'-dialkyl fluorene in a short span of time
~3.5 hours in yields >80%. It is also noteworthy that the reaction proceeds in a
degassed atmosphere, which further economizes the process of production in not
needing nitrogen or any type of inert gases.
Advantageously the process providec in this invention is environmentally green
because of the use of water as a solvent in the reaction medium and the non-toxic
nature of the reagents used. Accordirgly the process provided in this invention is
favorable with respect to easy handling of the reagents, which are moisture
insensitive.
Conclusively, the drawbacks of US pa:ent 7102042, 2006 are circumvented in the
present process of the invention on using bromo alkanes under degassed reaction
conditions whereby the bromo alkares are obtainable in the form of various
derivatives that are cheap, thermally more stable, recoverable and reusable and of
more practical importance than the chloro alkanes. Also, the process of the present
invention gets completed in ~4 hours and thereby has a much lower possibility of
ketone formation in 9-position of the fluorene molecule obtained as an undesired
side product in comparison to US patent 7102042, 2006 that takes 12 hours to
proceed to completion.

More advantageously, the bromo alkenes have higher boiling points and higher flash
points w.r.t the chloro alkanes of comparative chain length thus making handling
safer.
Unlike the prior art US patent 710242, 2006, this process of the present invention
for producing 9, 9-dialkyl fluorene is deemed efficient with various alkyl halides
possessing linear carbon chain, brarched carbon chain and carbon chain having
bulky groups like bromide and iodide at both ends.
It is thus possible by way of the present invention to provide for a process for the
production of 9, 9-dialkyl fluorene from fluorene on complete alkylation which is
efficient in terms of the time required to accomplish high yields of the product and
also in terms of recovery of the starting materials for recycle and reuse.
Compositions or poly fluorene polymers like (PFO) made out of 9, 9-dialkyl
substituted conjugated fluorene monomer synthesized by the above said process is
free all mono substituted fluorene and s free of ketone defect formation on exposure
to high temperature and traces amounts of oxygen.
The process is environmentally green, most significantly for water being used as the
solvent for reaction and also for the non-toxic nature of the reagents needed. It is
easy to operate in terms of the moisture insensitive reagents needed for the
purpose.

We Claim:
1. A process for the production of 9, 9-dialkyl substituted fluorene monomer from
fluorene of the structural formula:

Where R' is an alkyl or a substitutec alkyl; comprising reacting fluorene with one
desired alkyl halide, R'-Y, in a degassed atmosphere and in the presence of a base
and a phase transfer catalyst in a polar solvent to produce the said dialkylated
fluorene.
2. A process as claimed in any of the preceding claims wherein the phase transfer
catalyst is a cationic surfactant molecule of the formula R-X; where R is selected
from the group of tetraethyl amnonium, tetrapropyl ammonium, tetrabutyl
ammonium, tetrapentyl ammonium, tetrahexyl ammonium, tetraheptyl ammonium,
tetraoctyl ammonium, tetradecyl ammonium, tetradodecyl ammonium; and X
selected from the group of halogen, phosphate, carboxylate, nitrate, perchlorate.
3. A process as claimed in any of the preceding claims wherein the alkyl halide of the
formula R'-Y; where R' = C6-C11 is alkyl, branched alkyl and disubstituted alkyl
derivatives selected from the group of 1-chlorohexane, 1-bromohexane, 1-
iodohexane, 1-chlorooctane, 1-bromooctane, 1-iodooctane, 1-bromoundecane, 1-
iodoundecane, 2-ethylhexylbromide, 1, 6-dichlorohexane, 1, 6-dibromohexane, 1, 6-
diiodohexane, 1, 8-dichlorooctane, 1, 8-dibromooctane, 1, 8-diiodohexane; and Y
selected from the group of Y = fluorine, chlorine, bromine, iodine.
4. A process as claimed in claim 3, wherein the mono or di halogenated alkyl of the
formula R'-Y is preferably a bromo or a dibromo alkane.
5. A process as claimed in any of the preceding claims wherein the polar solvent is
preferably not a polar organic solvent bit preferably water.

6. A process as claimed in any of the preceding claims wherein the surfactant is
easily soluble in water, stable under high pH and at a temperature range of 70-100
°C.
7. A process as claimed in any one of the preceding claims wherein the reaction
proceeds in an atmosphere free of oxygen, nitrogen and inert gases preferably
obtained by degassing the reaction mixture.
8. A process as claimed in any of the preceding claims wherein the production of
dialkylated fluorene proceeds with a base comprising of alkali metal hydroxide of the
formula; M-OH wherein M refers to either Sodium or Potassium.
9. A process as claimed in any one of the preceding claims wherein the unreacted
alkyl halide is recovered from the react on medium and recycled.

10. A process as claimed in any one of the preceding claims wherein the temperature
of the reaction is always maintained below 100 ºC preferably 85 °C and the reaction
gets completed in 4 hours more preferably in 3.5 hours time.
11. A process as claimed in anyone of the preceding claims wherein the product
obtained comprises a yield % of >80 % preferably in the range of 80-98 %.
12. A process for the manufacture of polyfluorene polymers (PFO) comprising the
steps of:
Where R' is an alkyl or a substituted eIkyl; comprising reacting fluorene with one
desired alkyl halide, R'-Y, in a degassec atmosphere and in the presence of a base
(i) Providing 9, 9-dialkyl substituted fluorene monomer from fluorene of the
structural formula:

and a phase transfer catalyst and in a polar solvent to produce the said dialkylated
fluorine and
(ii) Obtaining the said polymer from said monomer thus obtained.
13. A process for the preparation of 9, 9-dialkylated fluorene from fluorene
substantially as herein described and illustrated with reference to the accompanying
examples

A process for the preparation of 9, 9-dialkyl fluorene derivatives via alkylation of
fluorene carried out by the direct treatment of fluorene with alkyl halide in the presence of aqueous metal hydroxide solution, a cationic surfactant as the phase transfer catalyst under degassed reaction conditions in the absence of any external pressure. The process involves the reaction with thermally stable and safe reagents
in water to accomplish the synthesis of 9, 9-dialkyl fluorene in -4 hours in quantitative yields thereby qualifying the process to be economical and environmentally benign. Compositions made out of these 9, 9-dialkyl fluorene derivatives are devoid of ketone defect formation on exposure to high temperature
and trace amounts of oxygen.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=+mrgSmMVVwGW7NVSBIPBYA==&loc=wDBSZCsAt7zoiVrqcFJsRw==

« Previous Patent

Next Patent »

Patent Number

269149

Indian Patent Application Number

2228/KOL/2008

PG Journal Number

41/2015

Publication Date

09-Oct-2015

Grant Date

01-Oct-2015

Date of Filing

30-Dec-2008

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

INDIAN INSTITUTE OF TECHNOLOGY, GUWAHATI

Inventors:

#	Inventor's Name	Inventor's Address
1	IYER, PARAMESWAR KRISHNAN	INDIAN INSTITUTE OF TECHNOLOGY, GUWAHATI, DEPARTMENT OF CHEMISTRY, GUWAHATI-781039
2	SAIKIA, GUNIN	INDIAN INSTITUTE OF TECHNOLOGY, GUWAHATI, DEPARTMENT OF CHEMISTRY, GUWAHATI-781039
3	THAPA, PRABIN	INDIAN INSTITUTE OF TECHNOLOGY, GUWAHATI, DEPARTMENT OF CHEMISTRY, GUWAHATI-781039
4	SARMAH, PRANJOL JYOTI	INDIAN INSTITUTE OF TECHNOLOGY, GUWAHATI, DEPARTMENT OF CHEMISTRY, GUWAHATI-781039

PCT International Classification Number

CO9K11/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA