Indian Patents. 213816:IMPROVED FRIDEL-CRAFTS PROCESS FOR ACYLATION AND ALKYLATION OF SUBSTITUTED AROMATICS USING SOLID ACID CATALYST UDCAT-1

Title of Invention	IMPROVED FRIDEL-CRAFTS PROCESS FOR ACYLATION AND ALKYLATION OF SUBSTITUTED AROMATICS USING SOLID ACID CATALYST UDCAT-1
Abstract	An improved Friedel-Crafts acylation process comprising the steps of: i. contacting aromatic compounds with acylating/alkylating agent in presence of highly acidic mesoporous solid catalyst; ii. maintaining the reaction under stirring at the reaction temp 50-100 °C from 30 min to 6 hours; and iii. recovering the reaction product by conventional methods.

Full Text	This invention relates to improvements in Friedel-Crafts process and in particular to Friedel-Crafts acylation process and to a process for vapour phase alkylation of aniline using solid acid catalyst. The most common method of introducing an alkyl or acyl group in to an organic compound is via the Friedel-Crafts reaction, by using either aluminium chloride in nitrobenzene or boron trifluride in liquid HF. Recently, M. Masahiro et. al., have reported the Friedel-Crafts acylation reaction using the forgoing catalysts on these and various other Lewis acids such as FeCI3, ZnCI2, SnCI2, TiCl4, InCl4 and SbCls and Bronstead acids such as H2S04 and HCI. These Friedel-Crafts acylation methods suffer from numerous drawbacks including unpredictable regioselectivity, the extremely hazardous solvent system and requirements of large amounts of the acid. The homogeneous catalysed Friedel-Crafts acylations require at least 2 moles of a Lewis acid to generate 1 mole of the product, posing an enormous catalyst disposal problem. Investigation & study on industrially importance Friedel-Crafts reaction involving acylation of benzene with 4-chlorobenzoyl chloride to give 4-chlorobenzophenone an important intermediate in the formation of cytrazin - a well known pharmaceutical drug, related thai inuse of various known acidic heterogeneous catalysts, so that the problem of disposal of waste catalyst, after completion of the Friedel-Crafts reactions could be avoided. Since the solid catalysts could be separated and reused, thereby making the process clean and more economic. However, in use of such known heterogeneous catalysts for acylation of benzene with 4-chlorobenzoyl chloride, it was found that most of these catalysts were not at all active for this reaction. Use of sulphated zirconia has been reported in such reactions but it could not give yields better than those obtained with classical aluminium chloride. Aniline is known to be used as a building block for the manufacture of several products useful to the chemical industry. Aniline and its alkylated products are highly useful in fine chemical industry especially for the preparation of Pharmaceuticals, drugs, pesticides, plastics, additives and dyes. Conventionally, Friedel-Crafts alkylation reactions are carried out with homogeneous acid catalysts used in stochiometric quantities or in excess. The economics associated in the separation processes and the present day's stringent environmental concerns on the disposal of spent homogeneous catalysts make it difficult to proceed with them anymore. Heterogeneous acid catalysts have been employed in the synthesis of tert-butyl aromatic amines. They are usually prepared by reacting aniline over the acid catalysts with pure isobutylene or C4 fraction from naphtha crackers, which contains isobutylene, under pressures ranging from 300 -950 psig. (Burgoyne W.F. and Dixon D.D., Applied Catalysis, 63, (1990), 117.; Burgoyne W.F. and Dixon D.D., Eur. Pat. 336, 134, (Oct.1989), C.A,113 (1990): 171653w.; Frederick Harold H., Eur. Pat., 69, 065, (Jan.1983), C.A., 99 (1983) : 38176u.; Lobanova N.S. and Popov M.A., Zh. Prinkl. Khim. (Leningrade), 43(4), (1970), 938. (Russ) C.A., 73 (1970): 25032g.). Reactions were performed by either co-feeding the arylamine and alkene over the solid catalyst in a fixed - bed reactor or by reacting the reagents and catalyst in a stirred autoclave. There are not many reported studies on the use of alcohols other than methanol and ethanol for the alkylation of aniline using heterogeneous acid catalysts. The studies on higher alkylation of aniline over heterogeneous solid acid catalysts have been restricted to the use of alkenes rather than alcohols as the alkylating agent. Table A gives the different catalyst used in the alkylation of aniline with isobutylene. In the presenqe of acid catalyst, tert-butano! cracks into isobutylene and water. Isobutylene thus produced reacts in situ with aniline giving different mono-alkylated products likn-tert-butylaniline, 2-tert-butylaniline, 4-tert-butylaniline and dialkylated products. Table A Different Catalysts used for Alkylation of Aniline (Table Removed) Bernard Herstein (U.S. Pat. 2, 092, 973, (Sep. 14, 1937), C.A., 31 (1937). 789345) prepared 4-tert butylaniline by reacting acetanilidc with tert butyl chloride in the presence of anhydrous AICl3 and the resulting 4-tert-butyl acetanilide is separated from the reaction mixture and is deacetylated Alternatively it was also prepared by hydrogenation of the 4-nitro-tert-butyl benzene at atmospheric pressure at 20°C over 20% Pt-C.(Mazitova F.N and Paushkin Ya.M Doklady Akad. Nauk S.S.S.R. 125, (1959), 1033-6.) It is thus the basic objective of the present invention is to provide a process for carrying out Friedel-Crafts reactions using solid acidic catalysts which would avoid the drawbacks associated with presently known strongly corrosive acidic catalysts used in such reactions discussed hereinbefore. Another object of the present invention is to provide a process for carrying out Friedel-Crafts reaction using solid acidic catalysts which would be free of catalyst disposed problems associated with the known art. Yet further object of the present invention is directed to a process for Friedel-Crafts acylation reaction which would provide for better yield as compared to known processes of Friedel-Crafts reaction. Yet further objective of the present invention is to provide a process for carrying out vapour phase alkylation of aniline using solid acid catalyst which would avoid the drawbacks associated with presently known strongly corrosive acidic catalysts used in such reactions discussed hereinbefore. Another objective of the present invention is directed to a process for vapour phase alkylation of aniline which would provide selectively better monoalkylated product as against prior art processes which give a mixture of ortho alkylated, N alkylated, dialkylated along with para-alkylated compounds. Another objective of the present invention is directed to a process for vapour phase alkylation of aniline which would provide better para selectivity as compared to process of aniline alkylation reaction. Thus according to one aspect of the present invention there is provided a process for Friedel-Crafts reactions comprising : i. contacting aromatic compounds with acylating/alkylating in presence of highly acidic mesoporous solid catalyst such as hereindescribed ; ii. maintaining the reaction under stirring at the reaction temp 50-100°C from 30 mins to 6 hours ; and iii. recovering the reaction product by conventional methods. In the process of the invention the catalyst used was UDCaT-1 discussed and defined in our co-pending Ind.Pat. Appln. entitled "A process for preparation of a highly acidic mesoporous solid catalyst." The said catalyst comprised a synergistic combination of sulfated metal oxide and mesoporous geotypes having surface area of 200-500 m2/g pore volume of 0.1 to 0.3 m3/g pore diameter of 25-35°A XRD (20) of 0-3° and Elemental Si in an amount of 50-60% by wt. S in an amount of 5-10% by wt. and Zr in an amount of 40-50% by wt. According to another aspect of the present invention there is provided a process for vapour phase alkylation reaction for selectively forming monoalkylated arylamine, alkylated at para- position, products comprising : i) contacting arylamines with alkylating agent both in vapour phase in presence of highly acidic mesoporous solid catalyst such as hereindescribed ; ii) maintaining the reaction temperature between 150 - 400 °C in the tubular down flow reactor. iii) recovering the reaction product by conventional methods. iv) using a ratio of the arylamine to alkylating agent between 4 : 1 to 1 : 10. In this process arylamine is selected from the group .comprising, aniline, alkylated anilines, halogenated anilines, hydroxylated anilines. In this process alkylating agent is selected from a group comprising alkanols with Carbon number from C2 to C16, cylic alcohols such as cyclohexanol and olefins such as ethylene, propylenes, butylenes, isoamylene, cyclohexene, and other cx-olefines. In the process of the invention the catalyst used is UDCaT-1 discussed and defined in pur co-pending Indian Patent "Applicationentitled "A process for preparation of a highly acidic mesoporous solid catalyst". The said catalyst comprised a synergistic combination of metal oxide and mesoporous zeotype having surface area of 200-500 m2/g pore volume of 0.1 to 0.3 m3/g pore diameter of 25-35 °A XRD(20) of 0-3° and Elemental Si in an amount of 50-60% by wt. S in an amount of 5-10% by wt. and Zr in an amount of 40-50% by wt. EXAMPLES The invention will now be illustrated with the help of Examples. The examples are by way of illustration only and not to restrict the invention. Example 1: Acylation of benzene with 4-chloro benzoyl chloride in presence of Aluminium chloride. i. Acylation of benzene with 4-chloro benzoyl chloride in presence of Aluminium chloride. The current industrial process empoly Aluminium chloride. The reaction has a drawback of being homogeneous and hence the problem of recovery of the catalyst. Beside, the amount of the catalyst used is equimolar to the amount of reactant which is very high. 90% conversion of 4-chlorobenzoyl chloride to 4-chlorobenzophenone takes place in 4 h at 65-70°C. Reported reaction yield is 70%. ii. Tanabe K., Yamaguch et al., have reported the reaction by using heterogeneous catalyst such as sulphated zirconia to overcome the difficulty in disposal of used catalyst in this reaction In this case, though the catalyst could be separated out after the reaction its regeneration for reuse was difficult. Catalysts and Chemicals Aluminium chloride and benzene was obtained from S.D. Fine Chem Ltd. 4-chlorobenzoyl chloride was obtained from Merck Ltd. All the chemicals were analytical grade and were used without further purification. Preparation of UDCaT-1 : 5g Dodecyl amine was dissolved in 41.8g of ethanol and 29.6g of distilled water. 20.8g of tetraethyl orthosilicate was added under vigorous stirring to it. The addition of ethanol improved the solubility of the template. The reaction mixture was kept for aging for 18 hours at 30°C. The clear liquid above the white coloured precipitate was decanted and the prcipitate HMS, was dried on a glass plate. The template was removed either by calcining the resulting material at 550°C in air for 3h or by refluxing the dried HMS material twice in 150 ml ethanol for 1h and drying it at 80°C in an oven for2h. 2.5g Zirconium oxychloride dissolved in 10ml of distilled water was added in drops to the 5g of calcined HMS with vigorous mixing, special precaution was taken during the said procedure of adition aqueous solution of zirconium oxychloride in calcined HMS. After every little addition of the solution, the solid was partially dried over a boiling water bath. Ultimately, after all the addition was over, the solids were dried in an oven at 120°C for 1h. The dried material was loaded in a reactor and ammonia gas was passed through it for 3h. The ammoniated sample was washed with distilled water to remove the chloride ions and dried in oven at 120°C for 2h. The sulfation was done by passing 1N sulfuric acid (15ml/g) through the filter paper containing the dried ammoniated solid material. It was then dried in an oven for 1h at 120°C and calcined at 550°C for 3h to give the active catalyst UDCaT-1. Experimental setup The reactor consisted of a flat glass vessel of 5 cm i.d , 10 cm height and 150ml of capacity equipped with baffles and a six blade impeller. The assembly was kept in an oil bath at 65-70°C The reaction mixture could be agitated at the required speed with the help of a variable motor. Reaction procedure 4-chloro benzoyl chloride ( 0.02 moles) and benzene ( 0.2 moles) were fed into the reactor. Catalyst ( 0.02 moles ) was added to the reaction mixture and the reaction mixture was heated at reflux temperature. An initial sample was then drawn and the agitation started. The reaction was monitored by periodic withdrawal of samples. The samples were analysed on HPLC (Model : Toscho, UV-8010) by using C18 supported on silica column. Mobile phase methanol : water (60 :40) were used for analysis of the samples. The quantitative analysis was done by comparison with standard synthetic mixtures. After 5 hrs, benzene was removed by distillation and reaction mixture were poured into water which contained dil.hydrochloric acid to neutralise the mixture. Results Conversion and yield are given in Table 1. Examples 2-10 : Acylation of benzene with 4-chloro benzoyl chloride using catalysts other than aluminium chloride. Catalysts and Chemicals Amberlyst-15 and Amberlite IR 120 were obtained from Rohm and Mass. K 10 was a montmorillinite clay obtained from Fluka and Filtrol-24 clay was obtained from Engelhart. Indion 130 was obtained from Ion Exchange (India) Ltd Dodecatungstophosphoric acid and benzene was obtained from M/S. S.D.Fine chemicals Ltd. Sulphated zirconia was prepared in our lab. UDCaT-1 as described in Example 1. (See also co-pending Ind.PAt. Appln. entitled "A process for preparation of a highly acidic mesoporous solid catalyst.") 4 chlorobenzoyl chloride were obtained from Merck Ltd. The catalysts used for the reaction were dried at 100°C under vacuum for 6 hr. before use. All the chemicals were analytical grade and were used without further purification Experimental setup The reactor consisted of a flat glass vessel of 5 cm i.d., 10 cm height and 150ml of capacity equipped with baffles and a six blade impeller. The assembly was kept in a oil bath at 65-70°C. The reaction mixture could be agitated at the required speed with the help of a controllable motor. Reaction procedure 4-chloro benzoyi chloride ( 0.02 moles) and benzene ( 0.2 moles) were fed into the reactor. A catalyst (10% w/w) as shown in Table 1, was added to the reaction mixture and the reactor was heated to 70°C and maintained at 70 ± 1°C. An initial sample was then withdrawn and the agitation started. The reaction was monitored by periodic withdrawal of samples. The samples were analysed on HPLC (Model : Toscho, UV-8010) by using C18 supported on silica column. A mobile phase methanol : water (60 .40) were used for analysis of the samples. The quantitative analysis was done by comparison with standard synthetic mixtures. After 4 hrs, when the reaction was complete and the product was isolated by distilling the excess quantity of benzene. Results : The conversion of 4-chlorobenzoyl chloride and the yields of the reaction in each of the examples using different catalysts are given in Table 1. Table 1 Acylation of benzene with 4-chlorobenzoyl chloride Activity of various catalysts (Table Removed) It will be seen that none of these catalysts of examples 2-8 were active for this reaction. The catalyst of example 9 did not give yields better than that of AICI3 while example 10, using UDCaT-1 gave yield higher than the of AICI3 even though conversion was poor. That shows less wastage. It will be seen that the acylation reaction is very efficently carried out with UDCaT-1 catalyst. Product were identified by IR spectra, 1H NMR, Melting point and purity also checked by HPLC method. The repeated runs were carried out by decanting the original contents of the reactor and later adding fresh reactants into the reactor. Care was taken that there was no loss of catalysts while the repeat experiments were carried out using the same used catalysts. The results of these repeat experiments are given in Table 2. Table 2 Acylation of benzene with 4-Chlorobenzoyl chloride Repeat use of catalyst - UDCaT-1 (Table Removed) Examples 11-16 Alkylation of p-cresol with Methyl tert-butyl ether (MTBE). It is well known that apart from its being a fuel oxygenate, MTBE has been employed as an excellent alkylating agent whereby only methanol would be a byproduct of reaction. Butylated hydroxy toluenes (BHT) are among the well known industrial antioxidants and the basic raw materials for the manufacture of oil-soluble phenol formaldehyde resins that are conventionally prepared by the alkylation of p-cresol with isbbutylene. BHT are the usual source of isobutylene is the C4 cut from the refineries. On cracking, MTBE gives high purity isobutylene. Further MTBE forms a homogeneous phase with p-cresol and thus monitoring the reaction becomes easier. The alkylation of p-cresol with MTBE has been studied with UDCaT-1 and has been found to give good activity. Catalysts: Filtrol-24, K-10, Indion 130 and HPA/K-10 were used. Filtrol 24 was obtained from Engelhardt. K-10 was obtained from fluka. lndion-130 used was a product of Ion Exchange (I) Ltd. Chemicals : p-Cresol was obtained from s.d. fine Chem(l) Ltd. MTBE was obtained from Texas Petrochemicals, USA. Other chemicals used were obtained from firms of repute. Reaction procedure: All experiments were carried out in a Parr Autoclave of 100 ml capacity equipped with a four blade pitched turbine impellar. The temperature was maintained at + 0.5°C of the desired temperature. The intrument was also equippped with a spped regulator that could maintain the speed at +5 rpm of the desired speed. A predetermined quantity of reactants and the catalysts was charged into the autoclave and the temperature was raised to the desired value. Once the temperature was attained the initial sample was withdrawn ahich was the zero time sample. Further samples were drawn st periodic intervals. A typical standard experiment contained 0.22 mole (19.61g) of MTBE, 0.22 moles (24.31 g) of p-cresol and 3.5% w/w catalyst, based on reaction mixture. The temperature was maintained at 100°C and the speed of agitation was 700 rpm. Analysis : The samples were analysed on a gas chromatograph (Perkin Elmer Model 8500 ) equipped with a flame ionisation detector. A 2m x 0.003m column was used. The stationary phase was 10% OV-17 supported on chromosorb WHP. The GC conditions were as follows; Carrier gas: Nitrogen Carrier Flow: 20ml/min Inj. temperature : 300°C Del. Temperature : 300°C Oven conditions (Table Removed) The quantitative analysis was done by comparison with standard synthetic mixtures. Results : Table 3 gives the % conversion of p-Cresol and selectivity to BHT with different types of catalysts. As from Table 3 UDCaT-1 is giving better conversion of p-cresol and selectively forming 2-tert-butyl-p-cresol. Table 3 Activity of various catalysts for the alkylation of p-cresol with MTBE (Table Removed) Examples 17-22 Friedel-Crafts alkylation benzene / toluene with benzyl chloride In these examples, Friedel-Crafts alkylation of benzyl chloride with benzene and toluene were carried out with classical AlCl3, different bi-transition metals and UDCaT-1 as catalyst. Supported clays are the recent of the Friedel-Crafts alkylation catalysts reported to have exceptionally high activity for the reaction of benzyl chloride with benzene to give diphenylmethane. Diphenyl methane & diphenyl toluene are useful drug & pesticide intermediates, the reaction which uses the conventional AICI3 as the catalysts has several pollution problems & the reaction proceeds vigorously and is dangerous. Chemicals : Aluminium chloride and ferric chloride were obtained from s.d. Fine Chem Ltd. K-10 was obtained from Fluka. Benzene, benzyl chloride and toluene were products of s.d. Fine Chem Ltd. Catalysts: A bitransitional metal halide constituting of ferric chloride and aluminium chloride, HPA supported on K-10 were prepared as per our Ind. Pat. . Aluminium chloride and ferric chloride supported in the ratios of 0:1, 1:3, 3:1, 1:0 were also prepared by the process described. UDCaT-1 was prepared as des+cribed under Example 1. Experimental: -The reactor consisted of a flat glass vessel of 5 cm i.d. amd 10 cm height equipped with baffles and a six blade impeller located at a height of 0.5 cm from the bottom. The assembly was kept in a water bath to maintain constant temperature. The reaction mixture could be agitated at the required speed with the help of a variable motor. Reaction procedure : All experiments were carried out by charging 39.50 mmol of benzyl chloride and 197 mmol each of benzene and toluene into the reaction vessel. Catalyst loading was 0.55gm. The reaction was carried out at 45°C. Under such conditions 100% conversion was observed in 40min. The reaction products are recovered by distillation. The products were diphenylmethane and benzyltoluene The reaction was highly selective and no side products were formed Analysis: Samples were analysed on a Chemito Gas Chromatography by using a ionisation detector and a spectrophysics integrator. For the analysis a S.S. column 94x3 mm) packed with OV-17 on chromosorb was used. The column conditions were maintained as follows. The quanitative analysis was done by calibrating with synthetic mixtures. Results : Conversion and Selectivity were shown in Table 4. Table 4 Comparitive activities of the supported catalysts. (Table Removed) The results show that between these catalyst UDCaT-1 is only the ecofriendly catalyst that gives conversion and selectivity similar to other non-ecofriendly catalysts. Examples 23-27 : The invention will now be illustrated with the help of Examples. The Examples are by way of illustration only and in no way restrict the scope of the invention Examples 23-27: Chemicals: All chemicals were procured from firms of repute. Tetraethyl orthosilicate (TEOS) (Fluka) was taken as the neutral silica source and dodecyl amine (Spectrochem Ltd.) as the neutral amine surfactant for the templates. Zirconium oxychloride, ammonia solution (AR grade), ammonium sulfate (AR grade), aniline (AR grade) and tert-butanol (AR grade) were procured from M/s, Loba Chemie and s.d. Fine Chemicals Ltd. respectively. Ethanol was purified by distillation and treatment with calcium oxide. Catalysts: SO42" - ZrO2 was prepared by the method given by Hino and Arata (Hino, M.; Arata, K. J. Chem.Soc., Chem. Commun., 24, (1980), 851-852). HMS and UDCaT-1 were prepared as follows. Preparation of UDCaT-1: The hexagonal mesoporous silicate (HMS) was prepared with following procedure. 5g dodecyl amine was dissolved in 41.8g of ethanol and 29.6g of distilled water. 20.8g of tetraethyl orthosilicate was added under vigorous stirring to it. The addition of ethanol improve the solubility of the template. The reaction mixture was aged for 18 hours at 30°C. The clear liquid above the white coloured precipitate was decanted and the prepitate HMS, was dried on a glass plate. The template was removed either by calcining the resulting material at 550°C in air for 3h or by reflexing the dried HMS material twice in 150 ml ethanol for 1h and drying it at 80°C in an oven for 2h. 2.5g zirconium oxychloride dissolved in 10ml of distilled water was added in drops to the 5g of calcined HMS with vigorous mixing. Special pecaution was taken during the said procedure of addition aqueous solution of zirconium oxychloride in calcined HMS After very little addition of the solution, the solid was partially dried over a boiling water bath. Ultimately, after all the addition was over, the solides were dried in an oven at 120°C for 1h. The dried material was loaded in a reactor and ammonia gas was passed through it for 3h. The ammoniated sample was washed with distilled water to remove the chloride ions and dried in oven at 120°C for 2h. The sulfation was done by passing 1N sufuric acid (15 ml/g) through the filter paper containing the dried ammoniated solid material. It was dried in oven foMh at 120°C and calcined at 550°C for 3h to give the active catalyst UDCaT-1. Reaction Procedure The tert-butylation of aniline was carried out in a vapour phase fixed bed catalytic reactor at atmospheric pressure. 1.0 g of catalyst sample was placed in a tubular down flow glass reactor (40 cm x 1.5 cm) and the catalyst section was packed between two sections of glass wool. The reactants mixed in a proper ratio were fed from the top by using a calibrated motorised syringe pump. Glass beads loaded at the top of the catalyst bed were used as pre-heating zone. Nitrogen was used as the carrier gas and the flow rate was controlled by a rotameter at a range of 15 ml/min and 30 ml/min. It was calibrated carefully with a soap film meter in every run. Examples 35-39 were carried out using different catalyst at feed rates and temperature region as given below in the Table 2. The liquid products were obtained by circulating cold water through the condenser. Aniline was separated by distillation and the product 4-tert-butylaniline was obtained. In example 39, a run of 3 hrs gave 10 g of aniline and 4-te/?-butylaniline mixture. On distillation it gave 2.5 g of 4-terf-butylaniline. Analysis of Reaction Mixture The products were analysed by gas chromatography (Model Chemito 8510) using 4 m x 3 mm i.d., stainless steel column packed either with 5 % SE -30 or OV - 17 on chromosorb WHP, coupled with a flame ionisation detector Synthetic mixtures of reactants and products were used to calibrate the G.C. results for quantification A typical mass spectral fragmentation pattern of alkylated product proves that the product obtained is mono alkylated product. The 1H NMR (500 MHz) spectra shows that the product formed is 4-te/t-butyl aniline . The mass spectral fragmentation pattern of aniline alkylation reaction mixture confirming the mono alkylation. The separated product was then further analysed by 1H NMR for its mono alkylation. 1H NMR (500 MHz) using CDCI3, 6 7.25 (d, J= 8.514 Hz, 2H), 6 6.7 (d, J=8.483, 2H), 6 3.78 (s, 2H), 5 1.35 (s, 9H) spectra shows that the product formed is 4-tert-butyl aniline. Thus N- alkylation was totally absent using UDCaT-1 whereas it was a major product in the case of DTP/ K-10 as a catalyst as reported elsewhere (Doshi N.S., Ph.D. Thesis, University of Mumbai., 1998). The reaction results are summarised in Table 2. Results: Table 10 gives the % conversion of aniline and selectivity to 4-tert-butyl aniline with different types of catalysts. As from Table 5 UDCaT-1 is giving better conversion of aniline and selectivity forming 4 - tert - butyl aniline. Table 5 Alkylation of aniline with tert-butanol (Table Removed) Reaction Conditions =Anilline and tert-butanol were taken in 1 : 4 mole ratio, Catalyst loading = 1 g., Reaction temperature = 250 °C, Reactanl feed rate = 6.5 ml/ h. a : Nitrogen flow rate = 30 ml/ min. b : Nitrogen flow rate = 15 ml/ min. c 4-tert- butylanilino Examples 4 and 5 show high conversion and high selectivity In continuous processes the isobutylenc vapours can be rccirculated and yields should be high. WE CLAIM : 1. An improved Friedel-Crafts acylation process comprising the steps of: i. contacting aromatic compounds with acylating/alkylating agent in presence of highly acidic mesoporous solid catalyst; ii. maintaining the reaction under stirring at the reaction temp 50-100 °C from 30 min to 6 hours; and iii. recovering the reaction product by conventional methods. 2. Process as claimed in claim 1 wherein said aromatic compound used is the following formula (Formula Removed) 1. Process as claimed in anyone of claims I or 2, wherein said acylating agent used is 4- chlorobenzoyl chloride. 2. Process as claimed in anyone of claims 1 or 2 wherein said alkylating agent used is selected from methyl tert-butyl ether (MTBE) and benzyl chloride. 3. Process as claimed in anyone of claims 1 to 4 wherein the catalyst used is sulfated metal oxide molecular sieve catalyst having synergistic combination of sulfated metal oxide and mesoporous geotypes having surface area of 200-500 m2/g pore volume of 0.1 to 0.3 m3/g pore diameter of 25-35°A XRD (20) of 0-3° and Elemental Si in an amount of 50-60% by wt. S in an amount of 5-10% by wt. And Zr in an amount of 40-50% by wt. 6. Process as claimed in anyone of claims 1 to 5 wherein said catalyst is used in an amount of 1.5% - 15% w/w of the reaction mixture. 7. Process as claimed in anyone of claims 1 to 6 wherein said catalyst is reused for carrying out the next batch of the same reaction. 8. An improved Friedel-Crafts acylation process substantially as herein described and illustrated with reference to the accompanying examples.

Full Text

This invention relates to improvements in Friedel-Crafts process and in particular to Friedel-Crafts acylation process and to a process for vapour phase alkylation of aniline using solid acid catalyst. The most common method of introducing an alkyl or acyl group in to an organic compound is via the Friedel-Crafts reaction, by using either aluminium chloride in nitrobenzene or boron trifluride in liquid HF. Recently, M. Masahiro et. al., have reported the Friedel-Crafts acylation reaction using the forgoing catalysts on these and various other Lewis acids such as FeCI3, ZnCI2, SnCI2, TiCl4, InCl4 and SbCls and Bronstead acids such as H2S04 and HCI. These Friedel-Crafts acylation methods suffer from numerous drawbacks including unpredictable regioselectivity, the extremely hazardous solvent system and requirements of large amounts of the acid. The homogeneous catalysed Friedel-Crafts acylations require at least 2 moles of a Lewis acid to generate 1 mole of the product, posing an enormous catalyst disposal problem.
Investigation & study on industrially importance Friedel-Crafts reaction involving acylation of benzene with 4-chlorobenzoyl chloride to give 4-chlorobenzophenone an important intermediate in the formation of cytrazin - a well known pharmaceutical drug, related thai inuse of various known acidic heterogeneous catalysts, so that the problem of disposal of waste catalyst, after completion of the Friedel-Crafts reactions could be avoided. Since the solid catalysts could be separated and reused, thereby making the process clean and more economic. However, in use of such known heterogeneous catalysts for acylation of benzene with 4-chlorobenzoyl chloride, it was found that most of these catalysts were not at all active for this reaction.
Use of sulphated zirconia has been reported in such reactions but it could not give yields better than those obtained with classical aluminium chloride.
Aniline is known to be used as a building block for the manufacture of several products useful to the chemical industry. Aniline and its alkylated products are highly useful in fine chemical industry especially for the preparation of Pharmaceuticals, drugs, pesticides, plastics, additives and dyes. Conventionally, Friedel-Crafts alkylation reactions are carried out with homogeneous acid catalysts used in stochiometric quantities or in excess. The economics associated in the separation processes and the
present day's stringent environmental concerns on the disposal of spent homogeneous catalysts make it difficult to proceed with them anymore. Heterogeneous acid catalysts have been employed in the synthesis of tert-butyl aromatic amines. They are usually prepared by reacting aniline over the acid catalysts with pure isobutylene or C4 fraction from naphtha crackers, which contains isobutylene, under pressures ranging from 300 -950 psig. (Burgoyne W.F. and Dixon D.D., Applied Catalysis, 63, (1990), 117.; Burgoyne W.F. and Dixon D.D., Eur. Pat. 336, 134, (Oct.1989), C.A,113 (1990): 171653w.; Frederick Harold H., Eur. Pat., 69, 065, (Jan.1983), C.A., 99 (1983) : 38176u.; Lobanova N.S. and Popov M.A., Zh. Prinkl. Khim. (Leningrade), 43(4), (1970), 938. (Russ) C.A., 73 (1970): 25032g.). Reactions were performed by either co-feeding the arylamine and alkene over the solid catalyst in a fixed - bed reactor or by reacting the reagents and catalyst in a stirred autoclave.
There are not many reported studies on the use of alcohols other than methanol and ethanol for the alkylation of aniline using heterogeneous acid catalysts. The studies on higher alkylation of aniline over heterogeneous solid acid catalysts have been restricted to the use of alkenes rather than alcohols as the alkylating agent. Table A gives the different catalyst used in the alkylation of aniline with isobutylene. In the presenqe of acid catalyst, tert-butano! cracks into isobutylene and water. Isobutylene thus produced reacts in situ with aniline giving different mono-alkylated products likn-tert-butylaniline, 2-tert-butylaniline, 4-tert-butylaniline and dialkylated products.
Table A Different Catalysts used for Alkylation of Aniline

(Table Removed)
Bernard Herstein (U.S. Pat. 2, 092, 973, (Sep. 14, 1937), C.A., 31 (1937). 789345) prepared 4-tert butylaniline by reacting acetanilidc with tert butyl chloride in the presence of anhydrous AICl3 and the resulting 4-tert-butyl acetanilide is separated from the reaction mixture and is deacetylated Alternatively it was also prepared by hydrogenation of the 4-nitro-tert-butyl benzene at atmospheric pressure at 20°C over
20% Pt-C.(Mazitova F.N and Paushkin Ya.M Doklady Akad. Nauk S.S.S.R. 125, (1959), 1033-6.)
It is thus the basic objective of the present invention is to provide a process for carrying out Friedel-Crafts reactions using solid acidic catalysts which would avoid the drawbacks associated with presently known strongly corrosive acidic catalysts used in such reactions discussed hereinbefore.
Another object of the present invention is to provide a process for carrying out Friedel-Crafts reaction using solid acidic catalysts which would be free of catalyst disposed problems associated with the known art.
Yet further object of the present invention is directed to a process for Friedel-Crafts acylation reaction which would provide for better yield as compared to known processes of Friedel-Crafts reaction.
Yet further objective of the present invention is to provide a process for carrying out vapour phase alkylation of aniline using solid acid catalyst which would avoid the drawbacks associated with presently known strongly corrosive acidic catalysts used in such reactions discussed hereinbefore.
Another objective of the present invention is directed to a process for vapour phase alkylation of aniline which would provide selectively better monoalkylated product as against prior art processes which give a mixture of ortho alkylated, N alkylated, dialkylated along with para-alkylated compounds.
Another objective of the present invention is directed to a process for vapour phase alkylation of aniline which would provide better para selectivity as compared to process of aniline alkylation reaction.
Thus according to one aspect of the present invention there is provided a process for Friedel-Crafts reactions comprising :
i. contacting aromatic compounds with acylating/alkylating in presence of highly acidic mesoporous solid catalyst such as hereindescribed ;
ii. maintaining the reaction under stirring at the reaction temp 50-100°C
from 30 mins to 6 hours ; and iii. recovering the reaction product by conventional methods.
In the process of the invention the catalyst used was UDCaT-1 discussed and defined in our co-pending Ind.Pat. Appln. entitled "A process for preparation of a highly acidic mesoporous solid catalyst." The said catalyst comprised a synergistic combination of sulfated metal oxide and mesoporous geotypes having
surface area of 200-500 m2/g
pore volume of 0.1 to 0.3 m3/g
pore diameter of 25-35°A
XRD (20) of 0-3° and Elemental Si in an amount of 50-60% by wt.
S in an amount of 5-10% by wt. and
Zr in an amount of 40-50% by wt.
According to another aspect of the present invention there is provided a process for vapour phase alkylation reaction for selectively forming monoalkylated arylamine, alkylated at para- position, products comprising :
i) contacting arylamines with alkylating agent both in vapour phase in presence of highly acidic mesoporous solid catalyst such as hereindescribed ;
ii) maintaining the reaction temperature between 150 - 400 °C in the tubular down flow reactor.
iii) recovering the reaction product by conventional methods.
iv) using a ratio of the arylamine to alkylating agent between 4 : 1 to 1 : 10.
In this process arylamine is selected from the group .comprising, aniline, alkylated anilines, halogenated anilines, hydroxylated anilines.
In this process alkylating agent is selected from a group comprising alkanols with Carbon number from C2 to C16, cylic alcohols such as cyclohexanol and olefins such as ethylene, propylenes, butylenes, isoamylene, cyclohexene, and other cx-olefines.
In the process of the invention the catalyst used is UDCaT-1 discussed and defined in pur co-pending Indian Patent "Applicationentitled "A process for preparation of a highly acidic mesoporous solid catalyst". The said catalyst comprised a synergistic combination of metal oxide and mesoporous zeotype having surface area of 200-500 m2/g
pore volume of 0.1 to 0.3 m3/g
pore diameter of 25-35 °A
XRD(20) of 0-3° and
Elemental Si in an amount of 50-60% by wt.
S in an amount of 5-10% by wt. and
Zr in an amount of 40-50% by wt.
EXAMPLES
The invention will now be illustrated with the help of Examples. The examples are by way of illustration only and not to restrict the invention.
Example 1: Acylation of benzene with 4-chloro benzoyl chloride in presence of Aluminium chloride.
i. Acylation of benzene with 4-chloro benzoyl chloride in presence of Aluminium chloride.
The current industrial process empoly Aluminium chloride. The reaction has a drawback of being homogeneous and hence the problem of recovery of the catalyst. Beside, the amount of the catalyst used is equimolar to the amount of reactant which is very high. 90% conversion of 4-chlorobenzoyl chloride to 4-chlorobenzophenone takes place in 4 h at 65-70°C. Reported reaction yield is 70%.
ii. Tanabe K., Yamaguch et al., have reported the reaction by using
heterogeneous catalyst such as sulphated zirconia to overcome the
difficulty in disposal of used catalyst in this reaction
In this case, though the catalyst could be separated out after the reaction its regeneration for reuse was difficult.
Catalysts and Chemicals
Aluminium chloride and benzene was obtained from S.D. Fine Chem Ltd. 4-chlorobenzoyl chloride was obtained from Merck Ltd. All the chemicals were analytical grade and were used without further purification.
Preparation of UDCaT-1 :
5g Dodecyl amine was dissolved in 41.8g of ethanol and 29.6g of distilled water. 20.8g of tetraethyl orthosilicate was added under vigorous stirring to it. The addition of ethanol improved the solubility of the template. The reaction mixture was kept for aging for 18 hours at 30°C. The clear liquid above the white coloured precipitate was decanted and the prcipitate HMS, was dried on a glass plate. The template was removed either by calcining the resulting material at 550°C in air for 3h or by refluxing the dried HMS material twice in 150 ml ethanol for 1h and drying it at 80°C in an oven for2h.
2.5g Zirconium oxychloride dissolved in 10ml of distilled water was added in drops to the 5g of calcined HMS with vigorous mixing, special precaution was taken during the said procedure of adition aqueous solution of zirconium oxychloride in calcined HMS. After every little addition of the solution, the solid was partially dried over a boiling water bath. Ultimately, after all the addition was over, the solids were dried in an oven at 120°C for 1h. The dried material was loaded in a reactor and ammonia gas was passed through it for 3h. The ammoniated sample was washed with distilled water to remove the chloride ions and dried in oven at 120°C for 2h. The sulfation was done by passing 1N sulfuric acid (15ml/g) through the filter paper containing the dried ammoniated solid material. It was then dried in an oven for 1h at 120°C and calcined at 550°C for 3h to give the active catalyst UDCaT-1.
Experimental setup
The reactor consisted of a flat glass vessel of 5 cm i.d , 10 cm height and 150ml of capacity equipped with baffles and a six blade impeller. The assembly was kept in an oil bath at 65-70°C The reaction mixture could be agitated at the required speed with the help of a variable motor.
Reaction procedure
4-chloro benzoyl chloride ( 0.02 moles) and benzene ( 0.2 moles) were fed into the reactor. Catalyst ( 0.02 moles ) was added to the reaction mixture and the reaction mixture was heated at reflux temperature. An initial sample was then drawn and the agitation started. The reaction was monitored by periodic withdrawal of samples.
The samples were analysed on HPLC (Model : Toscho, UV-8010) by using C18 supported on silica column. Mobile phase methanol : water (60 :40) were used for analysis of the samples. The quantitative analysis was done by comparison with standard synthetic mixtures.
After 5 hrs, benzene was removed by distillation and reaction mixture were poured into water which contained dil.hydrochloric acid to neutralise the mixture.
Results
Conversion and yield are given in Table 1.
Examples 2-10 : Acylation of benzene with 4-chloro benzoyl chloride using catalysts other than aluminium chloride.
Catalysts and Chemicals
Amberlyst-15 and Amberlite IR 120 were obtained from Rohm and Mass. K 10 was a montmorillinite clay obtained from Fluka and Filtrol-24 clay was obtained from Engelhart. Indion 130 was obtained from Ion Exchange (India) Ltd Dodecatungstophosphoric acid and benzene was obtained from M/S. S.D.Fine chemicals Ltd. Sulphated zirconia was prepared in our lab. UDCaT-1 as described in Example 1. (See also co-pending Ind.PAt. Appln. entitled "A process for preparation of a highly acidic mesoporous solid catalyst.") 4 chlorobenzoyl chloride were obtained from Merck Ltd. The catalysts used for the reaction were dried at 100°C under vacuum for 6 hr. before use.
All the chemicals were analytical grade and were used without further purification
Experimental setup
The reactor consisted of a flat glass vessel of 5 cm i.d., 10 cm height and 150ml of capacity equipped with baffles and a six blade impeller. The assembly was kept in a oil bath at 65-70°C. The reaction mixture could be agitated at the required speed with the help of a controllable motor.
Reaction procedure
4-chloro benzoyi chloride ( 0.02 moles) and benzene ( 0.2 moles) were fed into the

reactor. A catalyst (10% w/w) as shown in Table 1, was added to the reaction mixture and the reactor was heated to 70°C and maintained at 70 ± 1°C. An initial sample was then withdrawn and the agitation started. The reaction was monitored by periodic withdrawal of samples.
The samples were analysed on HPLC (Model : Toscho, UV-8010) by using C18 supported on silica column. A mobile phase methanol : water (60 .40) were used for analysis of the samples. The quantitative analysis was done by comparison with standard synthetic mixtures.
After 4 hrs, when the reaction was complete and the product was isolated by distilling the excess quantity of benzene.
Results :
The conversion of 4-chlorobenzoyl chloride and the yields of the reaction in each of the examples using different catalysts are given in Table 1.
Table 1 Acylation of benzene with 4-chlorobenzoyl chloride
Activity of various catalysts

(Table Removed)
It will be seen that none of these catalysts of examples 2-8 were active for this reaction. The catalyst of example 9 did not give yields better than that of AICI3 while example 10, using UDCaT-1 gave yield higher than the of AICI3 even though conversion was poor. That shows less wastage.
It will be seen that the acylation reaction is very efficently carried out with UDCaT-1 catalyst. Product were identified by IR spectra, 1H NMR, Melting point and purity also checked by HPLC method.

The repeated runs were carried out by decanting the original contents of the reactor and later adding fresh reactants into the reactor. Care was taken that there was no loss of catalysts while the repeat experiments were carried out using the same used catalysts.
The results of these repeat experiments are given in Table 2.
Table 2 Acylation of benzene with 4-Chlorobenzoyl chloride
Repeat use of catalyst - UDCaT-1

(Table Removed)
Examples 11-16
Alkylation of p-cresol with Methyl tert-butyl ether (MTBE).
It is well known that apart from its being a fuel oxygenate, MTBE has been employed as an excellent alkylating agent whereby only methanol would be a byproduct of reaction. Butylated hydroxy toluenes (BHT) are among the well known industrial antioxidants and the basic raw materials for the manufacture of oil-soluble phenol formaldehyde resins that are conventionally prepared by the alkylation of p-cresol with isbbutylene. BHT are the usual source of isobutylene is the C4 cut from the refineries. On cracking, MTBE gives high purity isobutylene. Further MTBE forms a homogeneous phase with p-cresol and thus monitoring the reaction becomes easier. The alkylation of p-cresol with MTBE has been studied with UDCaT-1 and has been found to give good activity.
Catalysts:
Filtrol-24, K-10, Indion 130 and HPA/K-10 were used. Filtrol 24 was obtained from Engelhardt. K-10 was obtained from fluka. lndion-130 used was a product of Ion Exchange (I) Ltd.

Chemicals :
p-Cresol was obtained from s.d. fine Chem(l) Ltd. MTBE was obtained from Texas Petrochemicals, USA. Other chemicals used were obtained from firms of repute.
Reaction procedure:
All experiments were carried out in a Parr Autoclave of 100 ml capacity equipped with a four blade pitched turbine impellar. The temperature was maintained at + 0.5°C of the desired temperature. The intrument was also equippped with a spped regulator that could maintain the speed at +5 rpm of the desired speed.
A predetermined quantity of reactants and the catalysts was charged into the autoclave and the temperature was raised to the desired value. Once the temperature was attained the initial sample was withdrawn ahich was the zero time sample. Further samples were drawn st periodic intervals.
A typical standard experiment contained 0.22 mole (19.61g) of MTBE, 0.22 moles (24.31 g) of p-cresol and 3.5% w/w catalyst, based on reaction mixture. The temperature was maintained at 100°C and the speed of agitation was 700 rpm.
Analysis :
The samples were analysed on a gas chromatograph (Perkin Elmer Model 8500 ) equipped with a flame ionisation detector. A 2m x 0.003m column was used. The stationary phase was 10% OV-17 supported on chromosorb WHP. The GC conditions were as follows; Carrier gas: Nitrogen Carrier Flow: 20ml/min Inj. temperature : 300°C Del. Temperature : 300°C
Oven conditions

(Table Removed)
The quantitative analysis was done by comparison with standard synthetic mixtures. Results :
Table 3 gives the % conversion of p-Cresol and selectivity to BHT with different types of catalysts. As from Table 3 UDCaT-1 is giving better conversion of p-cresol and selectively forming 2-tert-butyl-p-cresol.
Table 3 Activity of various catalysts for the alkylation of p-cresol with MTBE

(Table Removed)
Examples 17-22
Friedel-Crafts alkylation benzene / toluene with benzyl chloride
In these examples, Friedel-Crafts alkylation of benzyl chloride with benzene and
toluene were carried out with classical AlCl3, different bi-transition metals and UDCaT-1 as catalyst. Supported clays are the recent of the Friedel-Crafts alkylation catalysts
reported to have exceptionally high activity for the reaction of benzyl chloride with benzene to give diphenylmethane. Diphenyl methane & diphenyl toluene are useful drug & pesticide intermediates, the reaction which uses the conventional AICI3 as the catalysts has several pollution problems & the reaction proceeds vigorously and is dangerous.
Chemicals :
Aluminium chloride and ferric chloride were obtained from s.d. Fine Chem Ltd. K-10 was obtained from Fluka. Benzene, benzyl chloride and toluene were products of s.d. Fine Chem Ltd.
Catalysts:
A bitransitional metal halide constituting of ferric chloride and aluminium chloride, HPA
supported on K-10 were prepared as per our Ind. Pat. . Aluminium chloride
and ferric chloride supported in the ratios of 0:1, 1:3, 3:1, 1:0 were also prepared by the process described. UDCaT-1 was prepared as des+cribed under Example 1.
Experimental:
-The reactor consisted of a flat glass vessel of 5 cm i.d. amd 10 cm height equipped with baffles and a six blade impeller located at a height of 0.5 cm from the bottom. The assembly was kept in a water bath to maintain constant temperature. The reaction mixture could be agitated at the required speed with the help of a variable motor.
Reaction procedure :
All experiments were carried out by charging 39.50 mmol of benzyl chloride and 197 mmol each of benzene and toluene into the reaction vessel. Catalyst loading was 0.55gm. The reaction was carried out at 45°C. Under such conditions 100% conversion was observed in 40min. The reaction products are recovered by distillation. The products were diphenylmethane and benzyltoluene The reaction was highly selective and no side products were formed
Analysis:
Samples were analysed on a Chemito Gas Chromatography by using a ionisation detector and a spectrophysics integrator. For the analysis a S.S. column 94x3 mm) packed with OV-17 on chromosorb was used. The column conditions were maintained as follows. The quanitative analysis was done by calibrating with synthetic mixtures.
Results :
Conversion and Selectivity were shown in Table 4.
Table 4 Comparitive activities of the supported catalysts.

(Table Removed)
The results show that between these catalyst UDCaT-1 is only the ecofriendly catalyst that gives conversion and selectivity similar to other non-ecofriendly catalysts.
Examples 23-27 :
The invention will now be illustrated with the help of Examples. The Examples are by way of illustration only and in no way restrict the scope of the invention
Examples 23-27: Chemicals:
All chemicals were procured from firms of repute. Tetraethyl orthosilicate (TEOS) (Fluka) was taken as the neutral silica source and dodecyl amine (Spectrochem Ltd.) as the neutral amine surfactant for the templates. Zirconium oxychloride, ammonia solution (AR grade), ammonium sulfate (AR grade), aniline (AR grade) and tert-butanol (AR grade) were procured from M/s, Loba Chemie and s.d. Fine Chemicals Ltd. respectively. Ethanol was purified by distillation and treatment with calcium oxide.
Catalysts:
SO42" - ZrO2 was prepared by the method given by Hino and Arata (Hino, M.; Arata, K. J. Chem.Soc., Chem. Commun., 24, (1980), 851-852). HMS and UDCaT-1 were prepared as follows.
Preparation of UDCaT-1:
The hexagonal mesoporous silicate (HMS) was prepared with following procedure. 5g dodecyl amine was dissolved in 41.8g of ethanol and 29.6g of distilled water. 20.8g of tetraethyl orthosilicate was added under vigorous stirring to it. The addition of ethanol improve the solubility of the template. The reaction mixture was aged for 18 hours at 30°C. The clear liquid above the white coloured precipitate was decanted and the prepitate HMS, was dried on a glass plate. The template was removed either by calcining the resulting material at 550°C in air for 3h or by reflexing the dried HMS material twice in 150 ml ethanol for 1h and drying it at 80°C in an oven for 2h.
2.5g zirconium oxychloride dissolved in 10ml of distilled water was added in drops to the 5g of calcined HMS with vigorous mixing. Special pecaution was taken during the said procedure of addition aqueous solution of zirconium oxychloride in calcined HMS After very little addition of the solution, the solid was partially dried over a boiling water bath. Ultimately, after all the addition was over, the solides were dried in an oven at 120°C for 1h. The dried material was loaded in a reactor and ammonia gas was passed
through it for 3h. The ammoniated sample was washed with distilled water to remove the chloride ions and dried in oven at 120°C for 2h. The sulfation was done by passing 1N sufuric acid (15 ml/g) through the filter paper containing the dried ammoniated solid material. It was dried in oven foMh at 120°C and calcined at 550°C for 3h to give the active catalyst UDCaT-1.
Reaction Procedure
The tert-butylation of aniline was carried out in a vapour phase fixed bed catalytic reactor at atmospheric pressure. 1.0 g of catalyst sample was placed in a tubular down flow glass reactor (40 cm x 1.5 cm) and the catalyst section was packed between two sections of glass wool. The reactants mixed in a proper ratio were fed from the top by using a calibrated motorised syringe pump. Glass beads loaded at the top of the catalyst bed were used as pre-heating zone. Nitrogen was used as the carrier gas and the flow rate was controlled by a rotameter at a range of 15 ml/min and 30 ml/min. It was calibrated carefully with a soap film meter in every run. Examples 35-39 were carried out using different catalyst at feed rates and temperature region as given below in the Table 2. The liquid products were obtained by circulating cold water through the condenser. Aniline was separated by distillation and the product 4-tert-butylaniline was obtained.
In example 39, a run of 3 hrs gave 10 g of aniline and 4-te/?-butylaniline mixture. On distillation it gave 2.5 g of 4-terf-butylaniline.
Analysis of Reaction Mixture
The products were analysed by gas chromatography (Model Chemito 8510) using 4 m x 3 mm i.d., stainless steel column packed either with 5 % SE -30 or OV - 17 on chromosorb WHP, coupled with a flame ionisation detector Synthetic mixtures of reactants and products were used to calibrate the G.C. results for quantification A typical mass spectral fragmentation pattern of alkylated product proves that the product obtained is mono alkylated product. The 1H NMR (500 MHz) spectra shows that the product formed is 4-te/t-butyl aniline .
The mass spectral fragmentation pattern of aniline alkylation reaction mixture confirming the mono alkylation. The separated product was then further analysed by 1H NMR for its mono alkylation. 1H NMR (500 MHz) using CDCI3, 6 7.25 (d, J= 8.514 Hz, 2H), 6 6.7 (d, J=8.483, 2H), 6 3.78 (s, 2H), 5 1.35 (s, 9H) spectra shows that the product formed is 4-tert-butyl aniline. Thus N- alkylation was totally absent using UDCaT-1 whereas it was a major product in the case of DTP/ K-10 as a catalyst as reported elsewhere (Doshi N.S., Ph.D. Thesis, University of Mumbai., 1998). The reaction results are summarised in Table 2.
Results:
Table 10 gives the % conversion of aniline and selectivity to 4-tert-butyl aniline with different types of catalysts. As from Table 5 UDCaT-1 is giving better conversion of aniline and selectivity forming 4 - tert - butyl aniline.
Table 5 Alkylation of aniline with tert-butanol

(Table Removed)
Reaction Conditions =Anilline and tert-butanol were taken in 1 : 4 mole ratio, Catalyst loading = 1 g., Reaction temperature = 250 °C, Reactanl feed rate = 6.5 ml/ h. a : Nitrogen flow rate = 30 ml/ min. b : Nitrogen flow rate = 15 ml/ min. c 4-tert- butylanilino Examples 4 and 5 show high conversion and high selectivity
In continuous processes the isobutylenc vapours can be rccirculated and yields should be high.

WE CLAIM :
1. An improved Friedel-Crafts acylation process comprising the steps of:
i. contacting aromatic compounds with acylating/alkylating agent in
presence of highly acidic mesoporous solid catalyst;
ii. maintaining the reaction under stirring at the reaction temp 50-100 °C from 30 min to 6 hours; and
iii. recovering the reaction product by conventional methods.
2. Process as claimed in claim 1 wherein said aromatic compound used is the following
formula
(Formula Removed)

1. Process as claimed in anyone of claims I or 2, wherein said acylating agent used is 4-
chlorobenzoyl chloride.
2. Process as claimed in anyone of claims 1 or 2 wherein said alkylating agent used is
selected from methyl tert-butyl ether (MTBE) and benzyl chloride.
3. Process as claimed in anyone of claims 1 to 4 wherein the catalyst used is sulfated
metal oxide molecular sieve catalyst having synergistic combination of sulfated metal
oxide and mesoporous geotypes having
surface area of 200-500 m2/g pore volume of 0.1 to 0.3 m3/g pore diameter of 25-35°A
XRD (20) of 0-3° and
Elemental Si in an amount of 50-60% by wt.
S in an amount of 5-10% by wt. And Zr in an amount of 40-50% by wt.
6. Process as claimed in anyone of claims 1 to 5 wherein said catalyst is used in an
amount of 1.5% - 15% w/w of the reaction mixture.
7. Process as claimed in anyone of claims 1 to 6 wherein said catalyst is reused for
carrying out the next batch of the same reaction.
8. An improved Friedel-Crafts acylation process substantially as herein described and
illustrated with reference to the accompanying examples.

Documents:

3594-del-1997-abstract.pdf

3594-del-1997-claims.pdf

3594-del-1997-correspondence-others.pdf

3594-del-1997-correspondence-po.pdf

3594-del-1997-description (complete).pdf

3594-del-1997-form-1.pdf

3594-del-1997-form-19.pdf

3594-del-1997-form-2.pdf

3594-del-1997-form-4.pdf

3594-del-1997-gpa.pdf

3594-del-1997-petition-138.pdf

« Previous Patent

Next Patent »

Patent Number

213816

Indian Patent Application Number

3594/DEL/1997

PG Journal Number

04/2008

Publication Date

25-Jan-2008

Grant Date

17-Jan-2008

Date of Filing

12-Dec-1997

Name of Patentee

DEPARTMENT OF SCIENCE AND TECHNOLOGY (DST)

Applicant Address

TECHNOLOGY BHAVAN, NEW MEHRAULI ROAD, NEW DELHI-110016

Inventors:

#	Inventor's Name	Inventor's Address
1	GANAPATI DADASAHEB YADAV	FLAT NO.7, UNIVERSITY STAFF OTRS.,U.D.C.T. CAMPUS, R.A.KIDWAI ROAD, MATUNAGA, MUMBAI-400019.
2	M.S.KRISHNAN	SOLAMPATTU- P.O. SANKARAPURAM - T.K. VILLUPURAM-DT., TAMIL NADU, PIN-606 208.
3	AJIT ATMARAM PUJARI	A-302, BEST SWASADAN CO.OP. HUG. SOC., 13-B, UDYOG NAGAR, S.V. ROAD, GOREGAON(W), MUMBAI -400 062.

PCT International Classification Number

C07C 002/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA