FORM 2
THE PATENT ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13) l.TITLE OF THE INVENTION:
A NOVEL PROCESS FOR THE PREPARATION OF 2-CYANO- 3,3-DIARYLACRYLATES"
2. APPLICANT
(a) NAME: GALAXY SURFACTANTS LTD.
(b) NATIONALITY: An Indian Company incorporated under the Indian
Companies ACT, 1956
(c) ADDRESS: C-49/2, TTC Industrial Area, Pawne,
Navi Mumbai-400703 Maharashtra, India
3.PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention relates to a novel process for the preparation of 2-Cyano-3,3-diarylacrylates. In particular, the present invention relates to a cost effective preparation of 2-Cyano-3,3-diarylacrylates using acetic acid with a very good conversion and control of unwanted impurities.
BACKGROUND OF INVENTION
2-Cyano-3,3-diarylacrylates,, with structural Formula I, is widely used in creams and lotions as a Sun protection factor (SPF) booster. The extended conjugation of the acrylate portion of the molecule absorbs UVB and short-wave UVA (ultraviolet) rays with wavelengths from 280 to 320 nm.

2-Cyano-3,3-diarylacrylates are generally prepared by the Knoevenagel condensation of either 1) Cyanoacetic ester with Arylketone or 2) Alkyl cyanoacetate with Arylketone followed by transesterification with alcohol.
Compounds of Formula I were first disclosed in US3215725 wherein the process for preparation is also disclosed. This process involves reaction of Arylketone with ethylene glycol di-(a-cyanoacetate) in the presence of ammonium acetate, glacial acetic acid in benzene. However, the drawback of this process is that the product formed is discolored and therefore the purification is extremely laborious.

US5047571 describes a process for preparation of 2-Cyano-3,3-diarylacrylates by transesterification with alcohol at 130 C in presence of basic catalyst with continuous removal of resulting alcohol. The resulting product was purified by film evaporation process.
Most of the patents describe the use of organic solvents for the removal of water of reaction azeotropically. US2623060 discloses use of aromatic solvents for the removal of water of reaction azeotropically. Patents US3337357, 3544466 and 4207523 disclose a general method for making substituted phenylcinnamates wherein the reactants are combined with an aromatic solvent and catalyst, heated to reflux, wherein water is removed and the product is recovered from the solvent. These patents generally give a yield of 60 percent to 70 percent product.
EP0430023 discloses the preparation of 2-Cyano-3,3-diarylacrylates by reaction of Arylketone with cyanoacetic acid ester in the presence of ammonium acetate and glacial acetic acid using heptane for the removal of water of reaction azeotropically. The process involves long reaction time and use of metering pump to add the catalyst periodically through the course of the reaction.
US5451694 discloses the process of making 2-Cyanocinnamic esters in organic solvent such as Propanoic acid. However, comparative example I conducted as per the process given in this patent, indicates significant generation of Biphenyl cyanoacrylamide (BPCA). Further, the process is not economical due to cost and availability of C3-C6 monocarboxylic acids.
Patent application 2831/MUM/2010 discloses the preparation of substituted Diphenylcyanoacrylate compounds using cyclohexane, hexane or toluene as solvent.

All the processes of the prior art require long reaction times for obtaining high yields, thereby leading to more formation of unwanted impurities like Diaryl cyanoacrylamide. Besides this, the use of aromatic solvent puts restriction on commercial proposition of these routes due to carcinogenicity of aromatic solvents, in addition to increase in the cost.
Hence, there is a need to develop a novel, efficient and industrially viable process for the preparation of 2-Cyano-3,3-diarylacrylates.
The inventors of present invention have found out a novel process to obtain 2-Cyano-3,3-diaryIacrylates using acetic acid and ammonium compound. Further, the process does not involve any organic solvent for removal of water of reaction. The process is cost effective, operationally simple, exploits cheap and commercially available raw material, acetic acid, with very good conversion under reduced pressure and a control over impurities.
OBJECT OF INVENTION
i) An object of the present invention is to provide a novel process for the preparation of 2-Cyano-3,3-diarylacrylates from Arylketone and Cyanoacetic ester in acetic acid without using any organic solvent.
ii) Another object of the present invention is to provide an efficient process for preparation of 2-Cyano-3,3-diarylacrylates with high yields and purity.
iii) Another object of the present invention is to provide an efficient process for the preparation of 2-Cyano-3,3-diarylacrylates by recycling acetic acid.
iv) Another object of the present invention is to provide a novel process for the preparation of 2-Ethylhexyl-3,3-biphenylcyanoacrylate from benzophenone

and 2-Ethylhexyl cyanoacetate in acetic acid without using any organic solvent.
v) Another object of the present invention is to provide an efficient process for the preparation of 2-Cyano-3,3-diarylacrylates with very good control over Diary1 cyanoacrylamide (<0.2%) in reaction mass.
vi) Yet another object of the present invention is to provide simple, economic and industrially viable processes for the preparation of 2-Cyano-3,3-diarylacrylates.
SUMMARY OF INVENTION
According to an aspect of the present invention, there is provided a novel process for the preparation of 2-Cyano-3,3-diarylacrylates of Formula I

in which
Ar =Ar' = Phenyl or substituted phenyl
R = C1-C12alkyl
comprising, reacting Cyanoacetic ester of Formula II


with Arylketone of Formula III

in presence of ammonium compound and acetic acid and without the use of organic solvent.
In particular, the present invention relates to the novel and improved process for the preparation of 2-Cyano-3,3-diaryIacrylates.
DETAILED DESCRIPTION OF INVENTION
The present invention provides the novel and improved processes for the preparation of 2-Cyano-3,3-diarylacrylates of Formula I.


According to an embodiment of the present invention, there is provided a novel process for the preparation of 2-Cyano-3,3-diarylacrylates of Formula (I), comprising, reacting Cyanoacetic ester of Formula II with Arylketone of Formula III in presence of ammonium compound and acetic acid and without the use of organic solvent.
The process of the present invention for preparation of 2-Cyano-3,3-diarylacrylates of Formula I is depicted in following Scheme 1

According to yet another embodiment of the present invention, the ammonium compound is ammonia and ammonium salts, preferably ammonium acetate is used. The amount of ammonium acetate is preferably 0.05-0.4 mol per mole of Arylketone. The ratio can be maintained low and is not very critical if the acetic acid is recovered and recycled to maintain the ratio of Arylketone to acetic acid between 0.2- 0.7 for

the generation of ammonium acetate during the reaction and the temperature maintained below 100° C, preferably between 80-90° C.
According to another e mbodiment of the present invention, acetic acid is added portion wise to make up the losses.
In yet another embodiment, the recovered acetic acid can be either recycled to reaction vessel continuously after fractional distillation of acetic acid to remove water or used in next run either without removal of water or after fractional distillation of acetic acid.
In another embodiment of the present invention, the reaction is carried out at temperature ranging from 70° C to 100° C, preferably the reaction temperature ranges from 80-90° C.
In another embodiment of the present invention, the reaction water formed can be distilled off at reduced pressure of 100 - 600 mm of Hg A, preferably 100 - 450 mm of Hg A during reaction.
The Cyanoacetic ester of Formula II can be prepared by using conventional methods known in the art.
The reaction is stopped when no significant drop in Arylketone is observed by Gas chromatographic analysis.
The inventors of the present invention have observed that keeping the reaction temperature below 100° C, in particular below 90° C, under reduced pressure, preferably 100-450 mm of Hg A with acetic acid as a solvent, lowers the generation of diaryl cyanoacrylamide. The process of the invention ensures the availability of

acetic acid (which is made available by making up the losses of acetic acid as distillate, either by adding fresh acetic acid or by recycling the acetic acid as is or after spot distillation) which lowers the chances of generation of Diaryl cyanoacrylamide and also generates the catalyst from liberated ammonia effectively.
Thus, in all processes for the manufacture of 2-Cyano-3,3-diarylacrylates of Formula I, according to the invention, it is necessary to maintain acetic acid level to such an extent that the ratio of Arylketone to acetic acid is always maintained between 0.2-0.7 and without using any other organic solvent. The invention also relates to a process for the manufacture of 2-Cyano-3,3-diarylacrylates maintaining temperature of reaction preferably below 90° C, under reduced pressure preferably between 100- 450 mm of Hg A. Further, it has been found that it is not necessary to add catalyst in either higher molar ratio or in dosage, as the catalyst is continuously generated in the presence of acetic acid. Thus, it provides the added advantage of using lower mole of ammonium acetate and thus lowers the effluent generation.
In another embodiment, the invention relates to a composition comprising 2-Cyano-3,3-diarylacrylates of Formula I

Wherein, the invention relates to a composition of the product, where in the 2-Cyano-3,3-diarylacrylate is in the range of about 98 to 99.5% and Diaryl cyanoacrylamide <0.2%.

The detail of the invention provided in the following example is given by the way of illustration only and should not be construed to limit the scope of the present invention.
EXAMPLES AND COMPARATIVE EXAMPLES
Comparative Example 1
Preparation of 2-Ethylhexyl-3.3-biphenyl cyanoacrvlate according to patent US7985870
A 1000 mL four neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a condenser, was charged with 2-ethylhexyl cyanoacetate (347 g, 1.76 gmol), benzophenone (200 g, 1.1 gmol), propanoic acid (165 g, 2.23 gmol) and ammonium acetate (3 lg, 0.4 gmol). The stirred reaction mass was then heated to 85-90 °C. Azeotrope of propanoic acid/water mixture was distilled off over a period of 16 h under reduced pressure from 110-160 mm of Hg A (213-146 mbar) till the Gas chromatographic analysis showed no further significant decrease in benzophenone concentration in reaction mass. The loss of propanoic acid was continuously adjusted by adding the corresponding loss of propanoic acid every half an hour. The propanoic acid was then recovered under reduced pressure (20-40 mm of Hg A) at temperature 100-110 °C. The HPLC analysis of reaction mass showed Biphenyl cyanoacrylamide (BPCA) content of 1.2%. The crude reaction mixture was cooled and washed twice with 300 g portion of water and subsequently distilled to yield pale yellow colored viscous liquid (302g, Yield 76%) which was found to be of 98.31% purity by Gas chromatographic analysis.

Experimental Example 1
Preparation of 2-Ethylhexyl-3,3-biphenyl cyanoacrylate according to present invention in acetic acid and using ammonium acetate
A 1000 mL four neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a condenser, was charged with 2-ethylhexyl cyanoacetate (347 g, 1.76 gmol), benzophenone (200 g, 1.1 gmol), acetic acid (165 g, 2.75 gmol) and ammonium acetate (31g, 0.4 gmol). The stirred reaction mass was then heated to 85-90°C. Azeotrope of acetic acid/water mixture was distilled'off over a period of 16 h. under reduced pressure from 400-420 mm of Hg A till the Gas chromatographic analysis showed no further decrease in benzophenone concentration in reaction mass. The loss of acetic acid was continuously adjusted by adding the corresponding acetic acid. The acetic acid was then recovered under reduced pressure (30-60 mm of Hg A). The HPLC analysis of reaction mass showed BPCA content of 0.16%.
The crude reaction mixture was cooled and washed twice with 300 g portion of water and subsequently distilled to yield pale yellow colored viscous liquid of APHA<5.0 (301 g, Yield 75.8%) which was found to be of 99.46% purity by Gas chromatographic analysis.
Experimental Example 2
Preparation of 2-Ethylhexyl-3.3-biphenyl cyanoacrvlate according to present invention in acetic acid and using ammonium acetate
A 1000 mL four neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a condenser was charged with 2-ethylhexyl cyanoacetate (236 g, 1.2 gmol), benzophenone (200 g, 1.1 gmol), acetic acid (165 g, 2.75 gmol) and ammonium acetate (34g, 0.44 gmol). The stirred reaction mass was then heated to 85-

90° C. Azeotrope of acetic acid/water mixture was distilled off over a period of 16 h under reduced pressure from 400-420 mm of Hg A, till the Gas chromatographic analysis showed no further significant decrease in benzophenone concentration in reaction mass. The loss of acetic acid was continuously adjusted by adding the corresponding acetic acid. The acetic acid was then recovered under reduced pressure of 30-60 mm of Hg A. The HPLC analysis of reaction mass showed BPCA content 0.18%. The crude reaction mixture was then cooled and washed twice with 300 g portion of water and subsequently distilled to yield pale yellow colored viscous liquid with APHA<7.0 ( 261 g, Yield 65.66 %) which was found to be of 99.56% purity by Gas chromatographic analysis.
Experimental Example 3
Preparation of 2-Ethvlhexyl-3,3-biphenylcyanoacrvlate according to present invention using recovered acetic acid.
A 1000 mL four neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a condenser, was charged with 2-ethylhexyl cyanoacetate (347 g, 1.76 gmol), benzophenone (200 g, 1.1 gmol) , recovered acetic acid (168.3 g containing 2% water, 2.75 gmol) and ammonium acetate (31g, 0.4 gmol). The stirred reaction mass was then heated to 85-90°C. Azeotrope of acetic acid/water mixture was distilled off over a period of 16 h. under reduced pressure from 400-420 mm of Hg A till the Gas chromatographic analysis showed no further decrease in benzophenone concentration in reaction mass. The loss of acetic acid was continuously adjusted by adding the corresponding recovered acetic acid. The acetic acid was then recovered under reduced pressure (30-60 mm of Hg A). The HPLC analysis of reaction mass showed BPCA content of 0.19%. The crude reaction mixture was cooled and washed twice with 300 g portion of water and subsequently distilled to yield pale yellow colored viscous liquid (303 g, Yield 76.3%) which was

found to be of 99.48% purity by Gas chromatographic analysis.
Experimental Example 4
Preparation of Amyl-3,3-biphenvlcyanoacrylate
A 1000 mL four neck round bottom flask, equipped with a mechanical stirrer, a thermometer and a condenser, was charged with amyl cyanoacetate (248 g, 1.6 gmol), benzophenone (182 g, 1.0 gmol) , acetic acid (150 g, 2.5 gmol) and ammonium acetate (31g, 0.4 gmol). The stirred reaction mass was then heated to 85-90°C. Azeotrope of acetic acid/water mixture was distilled off over a period of 16 h. under reduced pressure from 400-420 mm of Hg A till the Gas chromatographic analysis showed no further decrease in benzophenone concentration in reaction mass. The loss of acetic acid was continuously adjusted by adding the corresponding recovered acetic acid. The acetic acid was then recovered under reduced pressure (30-60 mm of Hg A). The HPLC analysis of reaction mass showed BPCA content of 0.17%. The crude reaction mixture was cooled and washed twice with 300 g portion of water and subsequently distilled to yield pale yellow colored viscous liquid (236.4 g, Yield 74.1%) which was found to be of 99.48% purity by Gas chromatographic analysis.

We claim
1. A novel process for the preparation of 2-Cyano-3,3-diarylacrylates of Formula

in which
AT =Ar'1 = Phenyl or substituted phenyl
R = C1-C12alkyl
comprising, reacting Cyanoacetic ester of Formula II

with Arylketone of Formula III

in presence of ammonium compound and acetic acid and without the use of organic solvent.

2. The process for preparation of 2-Cyano-3,3-diarylacrylates as claimed in claim 1, wherein ammonium compound is ammonium acetate.
3. The process according to Claim 1, wherein the molar ratio of Arylketone to Cyanoacetic ester is 0.1-0.9, preferably 0.6-0.75.
4. The process as claimed in claim 1 wherein the reaction is carried out between 70-100° C, preferably between 80- 90° C.
5. The process according to claim 1, wherein the reaction is carried out under reduced pressure from 100-600 mm Hg, preferably between 100- 450 mm Hg.
6. The process as claimed in claim 1, wherein the ratio of Arylketone: Acetic acid is maintained between 0.1-1.0, preferably between 0.2-0.7.
7. The process as claimed in claim 1, wherein the ratio of Ammonium acetate: Arylketone is between 0.05-0.4, preferably between 0.2-0.4.
8. The process according to claim 1, wherein the acetic acid is recovered with continuous distillation under reduced pressure.
9. The process according to claim 1, wherein the recovered acetic acid is
recycled.
10. The process according to any one of claim 1 to 9, wherein the Cyanoacetic
ester is 2-Ethylhexyl cyanoacetate and the Arylketone is Benzophenone.
11. A composition comprising 2-Cyano-3,3-diarylacrylates of Formula I


in Which
AR =Ar' = phenyl or substituted phenyl
R= C1 - C12 alkyl
where in the 2-cyano-3,3-diarylacrylate is in the range of about 98 to 99.5% and Diarylcyanoacrylamide <0.2%.