Title of Invention	A PROCESS OF PREPARING PARA ETHOXY ETHYL BENZOATE
Abstract	The present invention relates to a process of preparation of Para Ethoxy Ethyl Benzoate comprising of i) reacting Para Hydroxy Benzoic Acid with diethyl sulphate and a quaternary ammonium salt in the presence of an alkali hydroxide solution and ii) reacting the resultant with diethyl sulphate in the presence of an alkaline bi-carbonate or alkaline carbonate.

Full Text

FORM 2 THE PATENTS ACT. 1970 (39 OF 1970) & THE PATENT RULES, 2003 COMPLETE SPECIFICATION [SECTION 10 AND RULE 13] "A PROCESS OF PREPARING PARA ETHOXY ETHYL BENZOATE" APPLICANT: GUJARAT ORGANICS LIMITED NATIONALITY: AN INDIAN COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956. ADDRESS: PLOT NO. 127/1, GIDC ESTATE, ANKLESHWAR 393002, DIST. BHARUCH, GUJARAT STATE, INDIA. THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED: - Field of Invention The present invention relates to a process of preparing Para Ethoxy Ethyl Benzoate (PEEB). The invention described herein discloses a process for preparing PEEB devoid of Diethyl Sulfate, which is useful for manufacture of food grade polypropylene. Background of the invention In the prior art Para Ethoxy Ethyl Benzoate is prepared in two steps: 1) Etherification of Para Hydroxy Benzoic Acid 2) Esterification of the said Para Hydroxy Benzoic Acid Briefly, the first step requires etherification of potassium salt of Para Hydroxy Benzoic Acid by heating potassium salt of P-hydroxy benzoic acid and Ethyl Iodide to yield Para Ethoxy Benzoic Acid. The second step involves esterification of the said para Ethoxy Benzoic Acid with Ethyl Alcohol in the presence of sulfuric acid to produce para Ethoxy ethyl benzoate. The esterification is accompanied by a side reaction of ethyl alcohol and sulfuric acid, resulting in the formation of undesirec Diethyl Sulfate as impurity. The literature also provides a one-pot reaction to prepare Para Ethoxy Ethyl Benzoate wherein etherification of phenolic OH and esterification of carboxylic group are achieved in one pot. In this procedure, anhydrous reaction mixture containing para hydroxy benzoic acid, sodium carbonate, tetra butyl ammonium 2 bromide in solvent xylene is treated drop-wise with Diethyl Sulfate at 80°C and stirred for 60 minutes at 120°C to give Para Ethoxy Ethyl Benzoate with a yield of 92.5% having gas liquid chromatography (GC) purity >99%. The PEEB obtained by this procedure has residual diethyl sulphate content as high as >2000 parts per million. Our Patent Application No. 257/MUM/03 describes the processes of manufacture of Para Ethoxy Ethyl Benzoate by reacting p-Hydroxy Benzoic Acid with Diethyl sulphate in presence of sodium carbonate, Benzyl Chloride and Triethyl amine in xylene medium. The rssidual Diethyl Sulphate content in commercial Para Ethoxy Ethyl Benzoate is typically within a range of 5 to 10 parts per million. Another Patent Application No. 259/MUM03 describes the processes of manufacture of Para Ethoxy Ethyl Benzoate by esterifying Para Ethoxy Benzoic Acid with Ethyl alcohol in the presence of Para toluene sulphonic acid to yield Para Ethoxy Ethyl Benzoate which is free from Diethyl sulphate. The prior art also involves large amounts of solvent and calls for rigorous maintenance of anhyd -ous conditions. Para Ethoxy Ethyl benzoate is used along with Zieglar Nata Catalyst in the polymerization of Propylene to Polypropylene. Diethyl Sulfate, an impurity in Para Ethoxy Ethyl benzoate is carried over to Polypropylene. The presence of Diethyl Sulfate in Polypropy ene is objectionable more so when it is used for food 3 packaging. Para Ethcxy Ethyl Benzoate free of Diethyl sulfate or low diethyl sulfate content is the desired catalyst for the manufacturing of Polypropylene. Purification of Para Ethoxy Ethyl Benzoate is needed to free it from the undesired by-product viz Diethyl Sulfate. Furthermore, the known processes of PEEB preparation involves hrge amounts of solvent use thus increasing the raw material cost of PEEB. The present invention obviates the aforesaid drawbacks by economically manufacturing Para Ethoxy Ethyl Benzoate with a very low residual diethyl sulfate ( Summary The present inventior relates to a process of preparation of Para Ethoxy Ethyl Benzoate comprising of i) reacting Para Hydroxy Benzoic Acid with diethyl sulphate and a quaternary ammonium salt in the presence of an alkali hydroxide solution and ii) reacting the resultant with diethyl sulphate in the presence of an alkaline bi-carbonate or alkaline carbonate. Description of the invention The present invention involves the reaction of p-Hydroxy Benzoic Acid with Diethyl Sulphate and Quaternary ammonium salt at controlled pH. This single pot synthesis takes place in two steps: 4 (I) Phenolic OH is etherified and (II) Carboxylic acid (functional group) is esterified. The Phenolic OH group of p-Hydroxy Benzoic Acid is etherified with Diethyl Sulphate in presence of alkali hydroxide solution in the presence of Benzyl chloride and tri ethyl amine (TEA) i.e. Quaternary ammonium salt. The reaction is monitored on thin layer chromatography and continued till p-Hydroxy Benzoic Acid is absent. The pH range maintained is 10 to 11. The Esterification of 4-Ethoxy Benzoic Acid is achieved by reacting with Diethyl Sulphate. The pH of the reaction medium is maintained in the range of 6 to 9, preferably 8 to 9 by dosing alkaline carbonate/alkaline bi-carbonate. After completion of the reaction, water is added. The oily layer is separated and washed with water. The water traces are removed as toluene water azeotrope and the product is purified and isolated by high vacuum distillation (130°C/1 mmHg). CHEMICAL REACTIONS OF PARA ETHOXY ETHYL BENZOATE COOH "^1 Water ■h (C2H5)2S04 + R-OH + TEA / Benzyl chloride 7 S" 50 U OH Para Hydroxy Benzoic £cid Di Ethyl Sulphate alkali Hydroxide COOC2H5 COOH f ^^s Alkaline Carbonate / \ ^^ -^ J Alkaline Bi Carbonate I s, ^^f 50°C ^^1 OC2H5 OC2H5 The alkali hydroxide used in the etherification reaction can be selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The alkaline carbonate used in the esterification reaction can be selected from the group consisting of sodium carbonate, potassium carbonate, lithium carbonate or magnesium carbonate. 6 The alkaline bicarbonate used in the esterification reaction can be selected from the group consisting of sodium bicarbonate or potassium bicarbonate. The quaternary ammonium salt is either tri ethyl benzyl ammonium chloride, Benzyl tributyl ammonium bromide, Benzyl tributyl ammonium chloride, Benzyl trimethyl ammonium iodide, Benzyl trimethyl ammonium chloride, Benzyl triethyl ammonium bromide, Methyl tributyl ammonium chloride, Phenyl trimethyl ammonium chloride, Phenyl trimethyl ammonium iodide, Tetrabutyl ammonium chloride, Tetrabutyl ammonium fluoride or Tetrabutyl ammonium hydrogen sulphate. Particularly, the quaternary ammonium salt generated in situ by reacting benzyl chloride and tri ethyl amine can be benzyl tri ethyl ammonium chloride or tetra butyl ammonium bromide generated similarly insitu. The present invention will now be described with reference to the following examples. However, the said examples in no way limit the present invention. EXPERIMENT-1 Charge Benzyl chloride (26 gm) and Tri ethyl amine (20.2 gm) in situ warm to 50°C and cool to room temp, and add Para Hydroxy Benzoic Acid (1000 gm) in water (1500 ml). Charge Sodium Hydroxide (580 gm), Di Ethyl Sulphate (2400 gm), stir the content a1. 20-35°C for 20 - 24 hrs.Progress of reaction is monitored over thin layer chromatography (TLC). When there is no p-Hydroxy Benzoic Acid, start addition of sodium carbonate and maintain the pH 6.8 to 7.2 by slowly 7 adding the Sodium carbonate 70 gm. Monitor reaction over TLC. When (4- Ethoxy Benzoic Acid is absent, the reaction is complete. Settle the content at 25 - 36°C. Separate the lower aqueous layer containing 4-Ethoxy Benzoic Acid. Recover the 4-Ethoxy Benzoic Acid by acidifying the aqueous layer. Wash the Para Ethoxy Ethyl Benzoate layer with 10 % Sodium Hydroxide solution till it is Di Ethyl Sulphate free by Gas Liquid chromatography. Finally wash the Para Ethoxy Ethyl Benzoate layer with water and take for distillation. Add toluene in Para Ethoxy Ethyl Benzoate to remove the trace of water azeotropiclly. During distillation first collect the solvent (atmospheric distillation up to 150°C). Then under vacuum (130°C/lmmHg). Distilled PEEB =1297 gms % Age yield main cut = 96.6 % (Theory) GC Purity >99.4% Diethyl Sulfate: Nil EXPERIMENT-2 Charge Para Hydroxy Benzoic Acid (1000 gm) in water (1500 ml). Charge Sodium Hydroxide (530 gm), TEA and Benzyl chloride (46 gm) Diethyl sulfate (2400 gm). Stirrer the contents at 50°C for 20-24 hrs. Progress of the reaction is monitored over thin layer chromatography. (PHBA absent). Start addition of sodium carbonate and maintain the pH 8 to 9 by slowly adding the sodium carbonate - 70gm. Again monitor the progress of the reaction over thin layer 8 chromatography (4-Elhoxy benzoic acid absent). Settle the contents at 25-30°C. Wash the top Para Ethoxy Ethyl benzoate layer with water and take for distillation. Add toluene in Para Ethoxy Ethyl Benzoate to remove the traces of water azeotropiclly. During distillation first collect the solvent (atmospheric distillation upto 150°C). Then collect the main fraction by distilling under vacuum (130°C/lmmHg). Distilled PEEB = 129C gms % Age yield based on ;he theory = 96% GC Purity >99.25% Diethyl sulphate: Nil EXPERIMENT-3 Charge Para Hydroxy Benzoic Acid (1000 gm) in water. Charge Sodium Hydroxide (580 gm), Tetra butyl Ammonium Bromide (40 gm) Diethyl sulfate (2400 gm). Stir the contents at 20-35°C for 20-24 hrs. Progress of the reaction is monitored over thin layer chromatography. When there is no P-hydroxy benzoic acid left start addition of sodium carbonate and maintain the pH 6.8 to 7.2 by slowly adding the (soc ium carbonate 70gm). Again monitor the progress of the reaction over thin lay;r chromatography till total 4-Ethoxy Benzoic Acid gets converted into Para Ethoxy Ethyl Benzoate. Settle the contents at 25-30°C. Separate the lower aqueous layer containing 4-Ethoxy benzoic Acid. Recover the 4-Ethoxy Benzoic Acid by acidifying the aqueous layer. Wash the Para Ethoxy 9 Ethyl Benzoate layer with 10% sodium Hydroxide solution till its Diethyl sulfate is NIL by Gas Liquid chromatography. Finally wash the Para Ethoxy Ethyl benzoate layer with water and take for distillation. Add toluene in Para Ethoxy Ethyl Benzoate to remove ihe traces of water azeotropically. During distillation first collect the solvent (aimospheric distillation upto 150°C). Then collect the main fraction by distilling uider vacuum (130°C/lmm Hg) Distilled PEEB = 1297 gm % Age yield based on theory = 96.6%. GC Purity >99.25% Diethyl Sulfate Nil We claim: 1. A process of preparation of Para Ethoxy Ethyl Benzoate comprising of i) reacting Para Fydroxy Benzoic Acid with diethyl sulphate and a quaternary ammonium salt in the presence of an alkali hydroxide solution and ii) reacting the resultant with diethyl sulphate in the presence of an alkaline bicarbonate or al kaline carbonate. 2. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein the quaternary ammonium salt is either tri ethyl benzyl ammonium chloride, Benzyl tributyl ammonium bromide, Benzyl tributyl ammonium chloride, Benzyl trimethyl ammonium iodide, Benzyl trimethyl ammonium chloride, Benzyl triethyl ammonium bromide, Methyl tributyl ammonium chloride, Phenyl trimethyl ammonium chloride, Phenyl trimethyl ammonium iodide, Tetrabutyl ammonium chloride, Tetrabutyl ammonium fluoride , Tetrabutyl ammonium hydrogen sulphate or Tetra butyl ammonium bromide . 3. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1 wherein said quaternary ammonium salt is prepared in situ. 4. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein said alkali hydroxide in step (i) is selected from sodium hydroxide, potassium hydroxide or lithium hydroxide. 11 5. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein said alkaline bi-carbonate in step (ii) is sodium bicarbonate or potassium bicarbonate. 6. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein alkalins carbonate in step (ii) is sodium carbonate, potassium carbonate, lithium carbonate or magnesium carbonate. 7. A process of preparation of Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein the pH of said reaction at step (i) is maintained in the range of 10-11. 8. A process of preparation of Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein the pH of said reaction at step (ii) is maintained in the range of 6-9. 9. A process of preparation of Para Ethoxy Ethyl Benzoate as claimed in Claim 8, wherein the pH of said reaction at step (ii) is maintained in the range of 8-9. 10. A process of preparation of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein step (i) is carried out at 20 to 35°C for 20 to 24 hours. 12 11. A process of preparing Para Ethoxy Ethyl Benzoate as claimed in Claim 1, wherein said Pz ra Ethoxy Ethyl Benzoate is free from diethyl sulphate. 12. A process of preparing Para Ethoxy Ethyl Benzoate as herein described with reference lo the examples accompanying the specification. ABSTRACT The present invention relates to a process of preparation of Para Ethoxy Ethyl Benzoate comprising of i) reacting Para Hydroxy Benzoic Acid with diethyl sulphate and a quaternary ammonium salt in the presence of an alkali hydroxide solution and ii) reactirg the resultant with diethyl sulphate in the presence of an alkaline bi-carbonate or alkaline carbonate. S-3/PATENT/GUJRAT0RGANl|cS/PEEB_AQUE0US_CS_FINAL

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