Title of Invention	ALKYL PYRIDINIUM DICYANAMIDES AND METHOD FOR THE PRODUCTION THEREOF
Abstract	The inventiofc relates to alkylpyridinium dicyanamides of the •formula (Figure Remove) in which R,,1 jis cyano orCuB-alM and. o is an integer from Oto 3 and any R1 radicals present are the same or different, and in which R2 U d-jb-alkyl. It further relates to their preparation Ejiom alkylpyridinium halides and alkali metal dicyanamkjcs, and to thoir use as polar solvents.

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The invention relates to aDcylpyridinium dicyanaraides of the formula (Figure Remove) in which R,,1 u| cyano or Ci^o-alkyl and n is an integer from 0 to 3 and any ft1 radicals present are the same or different, and in which R3 is Ci-ao-alkyl. It further relates to their preparation from alkylpyridinium halides and alkali metal dicyanamides, and to their use as polar solvents, ! Alkylpyridintu m dicyanamides of the formula I are ionic liquids. Ionic liquids are commonly unc erstood to mean salts which contain organic cations and are liquid at room temperature. The temperature range within which ionic liquids can be used as a solvent covers temperatures from -6QQC to over 300°C. As a result of their good solvatipn properties and {their low volatility, they have become known in the last few years as environmentally friendly solvents for "green chemistry11. Typically, the factions in ionic liquids are monbvslent quaternary ammonium or phosphoniura bases, or cations of aromatic nitrogen bases, which nave optionally been substituted by jdkyl groups, halogen atoms or cyano groups and may contain further heteroatoms sijeh as O or S. Examples of nitrogen-containing cations are knidazolium, oxazolium, pyrazinium, pyrazblium, pyridaziniura, pyridinium, pyrrolidinfum, pyruniduuum.jtbiazolium and triazolhun ions, fmidazolium and pyrroltdinium ions are the most frequent!^ used. In structural formulae, the charge is shown localized on the heteroatom (usually on the nitrogen) or delocalized in the middle of the ring. The two illustrations arfc equivalent Typical aniottfi in ionic liquids are acetate, AIGU", AsF6", BF4~ bromide, CFjSCb, (CF&PFr, (pFafePFf, (CFj)4PF2-, (CF3),PF. (CF&F, chloride, CN% FeClf, NOf, PFa~, pyruva^c, trifluoromethanesulphonate, oxalate or SCN~. The most frequently used are AKV, AsFjf, BFTandPFfi". Starting raatdriaJs for the preparation of ionic liquids can be purchased, for example, from Merck KGaA, Darmstadt or loLiTcc, A. Bosmann, Dr T. Schubert G.b.R., Freiburg. Ionic liquids with pyridinium ions and their use are disclosed, inter alia, in US-A-24SS331, WO-A1-02/34863, WO-A2-03/004727.US-A 1-2004/003 8031 and US-Al-2004/0031685. Further known applications of ionic liquids based on pyridinium are disclosed in A. Ikeda et al. Chemistry Letter* 2001,1154-1155; M, Grilteel etal. J. Phys. Chem. B 107,2003, 13280-13285; G.L. Rebeiro and B.M. Kh&dik&r Synthesis 3,21901,370-372; AJ. Carmiehael and M.J. Earle Organic Letters 1,1999,997-1000; A. Boesmann et al. Angew. Chem. Int. Ed 40,2001,2697-2699 and A. Eteuteri and D. Capaldi Org. Proc. Res. Dev. 4, 2000, 182-189. Ionic liquids Which contain a dieyanamide ion (WV-dialkylimidazoIium dicyanamide, A^AT-dialkylpyrrolidmiuni dicyanamide and tctraalkylammonium dicyanamide) are disclosed in 0.R. MacFarlane, et al. Chem. Commun. 2001,1430-1431; S.A. Forsyth etal. Chem. Commun. 2002,714-715 and D.R, MacFarlane, et al. Green Chemistry. 4,2002, 444-448. All A^-dialkylimidazoliurti dicyanamides, ^.AT-dialkylpyrrolidinium dicyanamides and tetraalkylammonium dicyanamides disclosed are prepared from the corresponding imidazolium, pyrrolidinium and tetraalkylammonium iodides with silver dicyanamide (AgCCjNj)). Other preparation methods are not disclosed, nor are any examples for the preparation of the dicyanamides mentioned from other haiides. It is an object of the present invention to provide novel ionic liquids and inexpensive processes for their preparation. The new compounds should be disposable in an environmentally harmless manner after use. This object i? achieved in accordance with Claim 1. The compounds claimed are alkylpyridinium dicyanamides of the formula (Figure Remove) in which R,1 jis cyano or C|.20-alkyl and n is an integer from 0 to 3 and any Rl radicals present are the same or different, and in which R? is Ci-jo-alkyl. Here and hereinafter, the expression "Ci^-alkyl" means an unbranched or branched alky! group having I to n carbon atoms. Ci-w-alkyl represents, for example, methyl, ethyl, propyl, isopripyl, butyl, isobutyi, see-butyl, iwf-butyl, pentyl, 1,4-dimethylpentyl, hexyl, heptyl, octyl. 1,5-dimethylhexyl, nonyl, decyl and 4-ethyl-l,5-dimethylhexyl, undecyl, dodecyl, trid^cyl, tetradecyl or eicosyl. Preferred alkylpyridinium dicyanamides are compounds of the formula I where R*1 is cyano or Ci^talkyl, preferably methyl or ethyl, and n is an integer from 0 to 2 and any R1 radicals present are the same or different, and hi which R2 is C2^-alkyl. Particular preference is jgiven to alkylpyridinium dicyanamides according to the formula (Figure Remove) in which R2 ii C+4-alkyl. The anions used customarily in ionic liquids have the disadvantage mat their thermal disposal offenj gives rise to halogenated and metallic residues. When the inventive alkylpyridiniijm dicyanamides are disposed of thermally, these wastes do not arise. By virtue of the aromatic structure, the inventive ionic liquids having optionally substituted pyridirie-based cations open up a wider polarity range than, for example, those formed from quaternary ammonium ioiis. Hie water solubility of itbe inventive alkylpyridinium dtcyanamides can be adjusted by virtue of the humber and chain length of the substituents R,,' and R1 in the inventive compounds Within a range from "completely water-miscible' up to "water-immiscible". For example #-butylpyridinium dicyanamide and AT-butyl-3-methylpyrklinium dicyanamide are water-miseible, while tfK>ctyl-3-methylpyridhiium dicyanamide and .Af-octylpyrid nium dieyanaraide are water-immiscible. The miscibilhy with solvents, for example acetone, acetonttrile, DMSO, ethyl acetate, hexane, methylenc chloride, organic acids, propyljsne carbonate, carbon disulphide, TUP, toluene or other ionic liquids is likewise determined significantly by the side groups Rg1 and R2. A process for preparing the inventive alkylpyridinium dtcyanamides of the formula (Figure Remove) in which Rn1 is cyano or Cuo-allcyl and h is an integer from 0 to 3 and any R1 radicals present are the same or different, and in which R2 is Ci.io-alkyl, comprises the reaction of a compound of the formula (Figure Remove) where Rg1 and R3 are each as defined above and X is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine, with an alkali metal dicyanamide, preferably in the presence of water. Here and her jinafter, alkali metal dicyanamides are understood to mean dicyanamides of the alkali metals lithium, sodium, potassium, and die mixtures and hydrates thereof. The alkali metal preferably usjed as an aqueous solution or suspension. i In a preferred embodiment, the molar ratio of the reaetants alkylpyridinhim halide: alkali metal dicyan^mide is within a range of 0*2:1 to 5:1, more preferably in the ratio of 1:1. Unconverted starting materials can be removed in a simple manner from the aikylpyridinijim dicyanamide formed. In a preferred process variant, the reaction of alkylpyridinium halide and alkali metal dicyanamide is, performed in the presence of water in a molar ratio of the sum of the reaetants to water of 2:0 to 2 :100, preferably of 2:10 to 2:30, more preferably of 2: IS to 2:25. Compared tojthe known process for preparing ionic liquids win dicyanamide ions, the process according to the invention is notable in that the preparation of Ag(CjNj) as an intermediate compound can be dispensed with. As a result of the high concentration of the starting compounds in the process according to the inventionj alkylpyridinium dicyanaffiides can be prepared in a surprisingly simple and inexpensive manner directly from alkylpyridinium halides and alkali metal dicyanamides. The expensive workup of the silver-containing wastes which occur is thus also dispensed with. Moreover, it is possible in the process according to the invention to use not just iodides but a]so the far more favourable other halides without yield losses. In a further preferred process variant, depending on the number and properties of the R»' and R2 radicals, in addition to water, further solvents, for example acetone, acetonftrilc, Ci-t-alcoholsj chloroform, dichloroethane, diethyl ether, DMSO, ethyl acetate, hexane, methylene chloride, propylene carbonate, carbon dtsulphide, THF, toluene and/or xylene are also used as solubilizers. In a preferred embodiment, the alkylpyridinium dicyanamides are purified by an extraction process. Mori; preferably, alkylpyridinium dicyanamides and alkali metal halides which form can be solated in the presence of water by phase separation. When water is already present in thi •> reaction solution, even aftylpyridinium dicyanamides which are, otherwise entirely wate r-miscible, as a result of alkali metal haltde formed during the reaction, form a phase interface (salting-out effect). This salting-out effect can be enhanced by salt addition, for example {luring the extraction. Moreover, itjhas bent found that, surprisingly, even readily water-soluble alkylpyridinium dicyanamides can be extracted from aqueous solutions with water-immiscible organic solvents of l Pyridine andjvarious alkylpyridines occur in natural sources, tor example hi coal tar, and are isolated there in a technically simple manner and hi large amounts. Since imidazoies are not natur illy occurring, the inventive alkylpyridinium dicyanamides have a cost advantage o\ cr known imidazolium dicyanamides. Substituted pyridinest can be prepared by a multitude of methods. Hiti Atalkylation of the pyridines is likewise effected by known processes, foj- example with alky 1 halides. Since pyridines have only one alkylatable nitrogen aton) in the ring, homogeneous products are obtained specifically in the tf-eJkylation, while the W-alkylation of substituted imidazole derivatives can often lead to inhomogeneous products which are difficult to separate. The inventiv* alkylpyridinium dicyanamides of the formula (Figure Remove) I, in which R»' \& cyano or Ct-io-alkyl and n is an integer from 0 to 3 and any R1 radicals present are the same or different, and in which R7 is Ci-io-alkyl, are ionic liquids and can be used if appropriate in a mixture with one or more other ionic liquids, water or organic solvents. Possible uses of the inventive alkylpyridinium dicyanamides are, for example, as a constituent pf polar solvents, as electrolytes in electrolysis or in electrical components or for the production of liquid crystals for LCDs or of conductive gels, tor example for applications ifi phqtovoltaics. It has also tx «n found that, in Suzuki reactions (C-C bond formation of haloaromatics with aromatic boi Lc esters), a smalkir amount of by-products are generated in the inventive ionic liquids than when ionic liquids based on the known imidazolium dicyanamides are used. The example's which follow are intended to illustrate the invention but without constituting a restriction. Examples: Example 1:' 3-Methyl-l-butylpyridini«m chloride (formula n, R! - 3-methyl, R* - batyl, X = CI) 3-Methylpyrfdine (2142 g, 23 mol) and 1-chlorobutane (2129 g, 23 mol) are initially charged in a 51 jacketed stirred apparatus and stirred under reflux. The temperature in the stirred apparatus is approx. ?2-95°C. The initially clear solution forms initially 2 phases, of which the louver comprises the product After full conversion, only one phase is present The product pan be separated from the starting materials in a simple manner batchwise or continuously! by phase separation. After 33 h, 1042 g of crude 3-methyl-l-butyIpyridinium chloride are obtained. Residues of 3-methylpyridine and I-chlorobutane ( 98%. Example 2: 3-Methyl-l-burylpyridinium dicyanamide (formula I, R1 - 3-raethyl, R2 - butyl) An aqueous solution Of 3-methyH-butylpyridinium chloride (1686 g, 9 mol) in water (2S50 ml, 140 mel) is admixed at room temperature fat portions with solid sodium dicyanamide (808 % 9 mol) and then stirred until all solids dissolve. This forms a clear beige solution. The solution is admixed with 85 g of activated carbon and stirred for 30 min and men filtered. The clear yellowish solution is then extracted with diehlorometnane each time (2 x 1000 ml). The extracts arc then washed with water (3 x 500 ml) and then concentrated jto constant weight first at 50°C and 500 mbar, later at 20 rabar. In this way, 1708 g of 3-methyl-l-butylpyridinium dieyanarnide are obtained in the form of a light beige liquid, Corresponding to 87% yield and with a purity of > 98 % by 'H NMR. Example 3: 3-MethyUl-qctylpyridinium chloride (formula H» R1 - 3-methyl, R2 - octyl, X = CI) 3-MethylpyiSdine (1676 g, 18 mol) and 1-chlordOctane (2676 g, 18 mol) are initially charged in aiS 1 jacketed Stirred apparatus and stirred at a temperature of 13Q-I35°C. The initially clear solution forms 2 phases, of which the lower contains the 3-methyl-l-ocryl-pyridinium dhloride. In the course of the reaction, die tipper phase decreases ever further until the reaction mixture in turn consists only of one phase after full conversion. After 24 h, 4370 gj Of crude product are obtained. The resulting beige to brownish reaction product solidifies gradually in the course of cooling to room temperature. Purity by 'H NMR > 9J8%, melting range 63-70*C. Example 4: 3-MethyU-betylpyrldiniBm dicyaaamide (formula I, R1 - 3-methyl, R* - octyl) A mixture ofJ3-methyl-I-octylpyridiniura chloride (242 g* 1 mot) and a little water (25 ml, 1.4 mol) is animated with a saturated solution of sodium dicyanamide (89 g, 1 mol) in water (340 ml, 18.9 mol) at room temperature within 30 rain. After completion of metered addition, the reaction mixture is stirred for a further 20 rain. This forms two phases. The (lower) organic phase is removed and the aqueous phase is extracted with dichloromethane (2 * 300 ml), The dichloromethane extracts and the organic phase removed beforehand are combined and washed with water (3 x 250 ml). The organic phase is concentrated to constant weight initially at 500 mbar and 50°C, later at 20 mbar and 50*G. In this way, 218 g of a light beige clear liquid (corresponding to 90% yield) of 3-methyl-1-octylpyridinium dicyanamide are obtained with a purity of > 98% by *H NMR. I. Alkybyridiniura dicyanamides of the formula (Figure Remove) We Claim: 1. Alkylpyridinium dicyanamides of the formula (Formula Removed) in which Rn1 is cyano or C1-20-alkyl and n is an integer from 0 to 3 and any R1 radicals present are the same or different, and in which R2 is C1-20-alkyl. 2. Alkylpyridinium dicyanamides according to Claim 1, in which Rn1 is cyano or C1-8-alkyl, preferably methyl or ethyl, and n is an integer from 0 to 2 and any R1 radicals present are the same or different, and in which R2 is C2-8-alkyl. 3. Alkylpyridinium dicyanamides of the formula (Formula Removed) characterized in that R2 is C4-8-alkyl. 4. Process for preparing alkylpyridinium dicyanamides according to Claim 1, characterized in that an alkylpyridinium halide of the formula (Formula Removed) where Rn1 is cyano or C1-20-alkyl and n is an integer from 0 to 3 and any R1 radicals present are the same or different, and in which R2 is C1-20-alkyl, and in which X- is a halogen ion, is reacted with an alkali metal dicyanamide, preferably in the presence of water. 5. Process according to Claim 4, characterized in that X" is chloride or bromide. 6. Process according to Claim 4 or 5, characterized in that the molar ratio of alkylpyridinium halide:alkali metal dicyanamide is within a range of 0.2:1 to 5:1, more preferably in the ratio of 1:1. 7. Process according to at least one of Claims 4 to 6, characterized in that the reaction of alkylpyridinium halide and alkali metal dicyanamide is performed in the presence of water in a molar ratio of the sum of the reactants to water of 2:0 to 2:100, preferably of 2:10 to 2:30, more preferably of 2:15 to 2:25. 8. Process according to at least one of Claims 4 to 7, characterized in that the alkali metal dicyanamide is used in the form of a solution or suspension. 9. The alkylpyridinium dicyanamides according to Claim 1, for use as a polar aprotic solvent, as an electrolyte in electrolysis or in electrical components, as a solvent in Suzuki reactions, and for the production of liquid crystals for LCDs or of conductive gels.

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