FORM 2
THE PATENTS ACT, 1970
(Act 39 of 1970)
COMPLETE SPECIFICATION
(See Section 10)
Title "An improved process for manufacturing high purity Vanillin"
Name M/s. Gujarat Alkalies and Chemicals Limited.
Address P.O.: Petrochemicals : 391 346,
Dist: Vadodara, Gujarat-India.
Nationality Indian
The following specification particularly describes the invention and the manner in which it is to be performed.
Title of the present Invention :
An improved process for manufacturing high purity Vanillin.
Field of the Present Invention:
This invention relates to an improved process for manufacturing at least 99% purity Vanillin suitable for Industrial applications.

Background of the Present Invention:
Vanillin is one of the highest selling products as an aroma chemical in terms of value. Vanillin occurs in nature as glucoside, and the best known source of vanillin is the plant Vanilla plansfolia. Natural vanilla is more expensive than vanillin. Until recently, the main source of synthetic vanillin was lignins; however, using such natural resources for its manufacturing is not encouraged and vanillin is now primarily produced from phenols. Over the years, vanillin has not only found use as aromatic or flavoring agent, but it is being used in formulations for personal care, detergents and pharmaceutical applications. The importance of vanillin has increased as a chemical intermediate in the manufacturing of drugs like Methyl Dopa, L - Dopa, Veraparmil & Trimethoprim. Vanillin has also found its use as a ripening agent to increase the yield of sucrose in sugarcane before harvest. Other uses of vanillin include masking of the unpleasant odor of many manufactured goods like wearing apparel, rubber goods, paper products and plastics, and preventing the formation of foams in the lubricating oils, etc.
There are various synthetic processes for producing Vanillin. In general, the literature reports the manufacturing process of Vanillin by introduction of aldehyde functional group into the benzene ring. Generally, the manufacturing process of Vanillin involves the formation of Hydroxy Methoxy Mandelic Acid by the condensation of Glyoxalic Acid and Guaiacol followed by the Oxidative Decarboxylation, isolation and purification of the crude product.
It is known that Glyoxalic Acid in alkaline aqueous medium undergoes Cannizzaro reaction. French Patent bearing No. 2,132,364 has reported condensation of Glyoxalic Acid with Phenol at 15°C - 25°C in 36 hrs.

German Patent No. 621,567 has reported formation of Para Hydroxy Mandelic Acid at room temperature by keeping the alkaline aqueous solution of Phenol and Glyoxalic Acid for several days at room temperature.
Belgian Patent No. 867,287 has revealed the preparation of Para - Hydroxy Mandelic Acid by the condensation of Glyoxalic Acid with Phenol under alkaline conditions at 30 - 35°C in 8 - 18 hrs.
Japan Kokai Tokkyo Koho 7,961,142 has reported the preparation of Hydroxymonomandelic Acids by reaction of Phenol / Alkoxyphenol with Glyoxalic Acid in the basic medium at 0 - 50°C in presence of Cyclodextrin or Starch as catalyst.
US Patent 4,165,341 has reported the preparation of Vanillin by the condensation of Glyoxalic Acid with Guaiacol in presence of a catalyst like Aluminium Oxide, Silicon Oxide, Hydrated Aluminium Oxide at 0 - 50 °C followed by the oxidation of the reaction mixture in presence of a Metal Oxide under the basic conditions.
German Patent No. DD 289, 516 has reported the preparation of aromatic aldehydes by oxidation of aryl glycolic acid in a stream of air & presence of copper compound like Copper Sulphate & Sodium Hydroxide at 100CC followed by sequential Acidolytic Decarboxylation.
The major constrains in the above mentioned processes for synthesizing Vanillin is the formation of by-products due to the Cannizzaro reaction during the condensation of Glyoxalic Acid with Guaiacol to obtain Para - Hydroxy Methoxy Mandelic Acid. The formation of Ortho & Di-derivatives eventually affects the

purity of Vanillin. Some of the reported processes have used catalyst in the condensation of Glyoxalic Acid with Guaiacol. The selective removal of Glycolic Acid from the reaction mixture after the completion of the condensation step is also important in the process. The reported methods are not very clear on the regeneration of the Metal Oxide used in the oxidation step. The selective removal of Ortho Vanillin in the final stages decides the final purity of the product.
Summary of the Present Invention:
The present invention alleviates the above mentioned disadvantages and shortcomings of the prior manufacturing process for Vanillin.
An improved process for manufacturing Vanillin in accordance with the present invention comprises of the step of reacting Guaiacol with Sodium Hydroxide solution and preparing Hydroxy Methoxy Mandelic Acid by the condensation of resultant Sodium salt of Guaiacol with Glyoxalic Acid in presence of aqueous Sodium Hydroxide. This is followed by the steps of recovering un-reacted Guaiacol, the step of Oxidative Decarboxylation of Hydroxy Methoxy Mandelic Acid and the steps of neutralization, extraction and isolation of Crude Vanillin. An improved process for manufacturing Vanillin in accordance with the present invention finally comprises of the steps of purification and crystallization to yield Vanillin having purity > 99%.
The objectives of the present invention are to produce Vanillin having £ 99 % purity and to make the process more economical.
An improved process for manufacturing Vanillin in accordance with the present invention has high selectivity of Para isomer during the condensation of Glyoxalic Acid with Guaiacol which is achieved by separate formation of Guaiacol Sodium Salt followed by the simultaneous addition of Glyoxalic Acid & alkali, reaction

temperature & time profile, concentration of the alkali / base, reaction dilution and reactant ratios. The Guaiacol on reaction with Sodium Hydroxide forms Guaiacol - Sodium Guaicolate complex, whose solubility depends on the temperature & dilution.
The minimization of the Cannizzaro reaction could be achieved in accordance with the present invention, by the particular mode of addition followed, temperature & concentration of alkali. It may also be noted that no catalyst has been used during the condensation of Guaiacol & Glyoxalic Acid. The certain excess quantity of Guaiacol could ensure the minimum formation of Di -derivative. The excess Guaiacol is recovered and recycled in the subsequent batches.
The Copper Oxide has been used directly in the process for manufacturing Vanillin in accordance with the present invention for carrying out the oxidation of Para - Hydroxy Methoxy Mandelic Acid. The catalyst is recovered, reactivated & recycled In the process making the process more economical.
The oxidation conditions have been standardized in such a way that only the partial positive pressure is required. Therefore the reactions can be performed easily in the glass reactors. The Decarboxylation has been carried out using the mineral acid like Hydrochloric Acid.
An improved process for manufacturing Vanillin in accordance with the present invention is able to give Crude Vanillin having more than 90% purity & less than 4% Ortho content. The selective removal of the Ortho - Vanillin could be

achieved by washing the Crude product with Toluene at low temperatures. The colored impurities are further removed by the treatment with activated charcoal and the final crystallization of the product was carried out using alcohol - water mixture giving Vanillin with > 99% purity.
Detail Description of the Present Invention:
The present invention is an improved economical process to manufacture high purity Vanillin. The process to manufacture high purity Vanillin ensures the minimization of Cannizzaro reaction, enhanced Para selectivity to yield Para -Hydroxy Methoxy Mandelic Acid, selective removal of Glycolic Acid, recovery & recycling of un-reacted Guaiacol, recovery, reactivation & recycling of Copper Oxide used as catalyst in the oxidation step, selective removal of Ortho Vanillin from the Crude product to yield the Vanillin having more than 99% purity.
Equipments required: Glass Reactor with agitator, condenser, solid charging port, addition funnel, temperature indicator, pressure gauge, Gas purging system and heating / cooling system, distillation unit and filtration unit.
Chemicals required: Quantities of Guaiacol, DM Water, aqueous Sodium Hydroxide, 50% Glyoxalic Acid, 20% w/w Hydrochloric Acid, Methylene Chloride, Copper oxide, Toluene, alcohol-water mixture.
Step-1:
The required quantities of Guaiacol, DM Water & aqueous Sodium Hydroxide solution are taken and the addition of the reactants as well as the reaction is performed under Nitrogen atmosphere at 15 - 25°C for 2 - 4 hrs.

Step - 2:
The required quantities of 50% Glyoxalic Acid & Sodium Hydroxide solution of desired concentration are taken & added simultaneously in the reactor having Guaiacol Sodium Salt at 15 - 25°C for 6-28 hrs.
Step - 3:
In order to recover the un-reacted Guaiacol & to remove the Glycolic Acid selectively, the pH of the reaction mixture is brought down to 6.5 by adding 20% w/w Hydrochloric Acid followed by the extraction of the aqueous phase with Methylene Chloride. The Methylene Chloride, which contains both Guaiacol & Glycolic Acid, is collected separately. This in turn is washed sequentially with 2% Sodium Carbonate and D M water to make the pH neutral. The Methylene Chloride after the said washing is distilled separately to recover Guaiacol, which is further distilled under vacuum to yield pure Guaiacol for recycling purpose.
Step - 4:
The aqueous layer obtained from step - 3 is taken in the reactor & requisite quantities of Copper Oxide and Sodium Hydroxide are added under Nitrogen atmosphere. The marginal positive pressure is maintained in the reactor by purging the air. The reaction is carried out at 95-105 °C for 1.5-6 hrs. The used catalyst after filtration in the process is washed several times with D M Water, Dried & activated at 300 - 350°C for 10 - 11 hrs. in air circulating dryer. The oxidation conditions have been standardized in such a way that only the partial positive pressure is required. Therefore the reactions have been performed in the glass reactors only.

Step - 5:
The reaction mixture obtained after the filtration of catalyst is acidified by 20% w/w Hydrochloric Acid and the pH is brought down to 4.0 & is subsequently extracted with organic solvent like Methylene Chloride leaving behind the aqueous phase.
Step - 6:
The Methylene Chloride is distilled to yield the Crude Vanillin, which is washed with required quantity of Toluene at 10 - 15°C. The selective removal of the Ortho - Vanillin could be achieved by washing the Crude product with Toluene at low temperatures.
Step-7:
The washed product is dissolved in alcohol - water mixture & treated with activated charcoal to further remove the colored impurities. The charcoal is removed by filtration & the product is crystallized by gradually cooling the mother liquor.
The crystallized product is filtered and the final product shows £ 99% purity.
The present invention will be described in terms of specific examples and examples should be considered as illustrative of the invention and not as limiting the same. The examples described herein will substantiate our claims.

Example-1
75 ml D M Water is initially taken in 1 Itr. flask followed by the simultaneous addition of 40 gm of Guaiacol & 138 gms 9.42% w/w Sodium Hydroxide aqueous solution at 18 - 20°C for 2 hrs. under Nitrogen atmosphere. Further 30 gms 50% w/w Glyoxalic Acid & 85 gms 11.76% w/w Sodium Hydroxide aqueous solution are simultaneously added for a period of 17 hrs. at 18 - 20°C. The reaction mixture is further stirred for another 6 hrs. to ensure the completion of reaction. The total reaction time including the addition is 24 hrs.
The pH of the reaction mixture is brought down to 6.5 by adding 50 - 55 gms. of 20% Hydrochloric Acid (w/w). The un-reacted Guaiacol is recovered by extracting the aqueous layer with the organic solvent like Methylene Chloride, which in turn is given alkaline (2% Sodium Carbonate solution) & D M water wash to make the pH neutral. The solvent is finally distilled off to yield the un-reacted Guaiacol. The recovered Guaiacol is further distilled under vacuum to yield the pure Guaiacol, which can be used in the subsequent batches. The quantity of the recovered Guaiacol is 16.20 gms.
Now the aqueous layer having Hydroxy Methoxy Mandelic Acid is treated with 42 gms of Sodium Hydroxide maintaining the temperature 35 - 40°C under the Nitrogen atmosphere. 50 gm Copper Oxide is also added and the reaction is carried out at 100 - 102 °C temperature keeping the positive pressure in the reactor by the air. The reaction is continued for 2.5 hrs.
After the completion of the reaction, the catalyst is filtered. The filtrate (aqueous layer) is neutralized by adding 225 - 230 gms 20% Hydrochloric Acid (w/w) keeping the temperature 35 - 40°C. The product is extracted from the aqueous layer by the organic solvent like Methylene Chloride. The Methylene Chloride

layer is washed several times with D M water before subjecting the same for the distillation. The Crude Vanillin thus obtained (20.70 gms.) shows 90.70% purity with ortho content 4%.
The Crude Vanillin is treated with 100 ml Toluene at 10 - 15 °C and further treated with activated charcoal at 60 - 70°C with alcohol - water mixture as a media. The activated charcoal is filtered out and the mother liquor is slowly cooled below 20°C to crystallize the Vanillin.
The crystallized product is filtered, dried at 50°C in air circulating dryer. The final product shows £ 99% purity.
Example - 2
18.75 itr. D M Water is initially taken in 200 Itr. reactor followed by the simultaneous addition of 10 kg. of Guaiacol & 34.5 kg 9.42% w/w Sodium Hydroxide aqueous solution at 15 - 17°C for 4 hrs. under Nitrogen atmosphere. Further 7.5 kg 50% w/w Glyoxalic Acid & 21.25 kg. 11.76% w/w Sodium Hydroxide aqueous solution are simultaneously added for a period of 22 hrs. at 15 - 17°C. The reaction mixture is further stirred for another 6 hrs. to ensure the completion of reaction. The total reaction time including the addition is 28 hrs.
The pH of the reaction mixture is brought down to 6.5 by adding 14 - 15 kg. 20% Hydrochloric Acid (w/w). The un-reacted Guaiacol is recovered by extracting the aqueous layer with the organic solvent like Methylene Chloride, which in turn is given alkaline (2% Sodium Carbonate solution) & D M water wash to make the pH neutral. The solvent is finally distilled off to yield the un-reacted Guaiacol.

The recovered Guaiacol is further distilled under vacuum to yield the pure Guaiacol, which can be used in the subsequent batches. The quantity of the recovered Guaiacol is 3.95 kg.
Now the aqueous layer having Hydroxy Methoxy Mandelic Acid is treated with 11 kg. of Sodium Hydroxide maintaining the temperature 35 - 40°C under the Nitrogen atmosphere. 7.5 kg. Copper Oxide is also added and the reaction is carried out at 95 - 97 °C temperature keeping the positive pressure in the reactor by the air. The reaction is continued for 6 hrs.
After the completion of the reaction, the catalyst is filtered. The filtrate (aqueous layer) is neutralized by adding 50 - 55kg. 20% Hydrochloric Acid (w/w) keeping the temperature 35 - 40°C. The product is extracted from the aqueous layer by the organic solvent like Methylene Chloride. The Methylene Chloride layer is washed several times with D M water before subjecting the same for the distillation. The Crude Vanillin thus obtained (4.60 kg.) shows 90.55% purity with ortho content 3.2%.
The Crude Vanillin is treated with 40 kg. Toluene at 10 - 15 °C and further treated with activated charcoal at 60 - 70°C with alcohol - water mixture as a media. The activated charcoal is filtered out and the mother liquor is slowly cooled below 20°C to crystallize the Vanillin.
The crystallized product is filtered, dried at 50°C in the air circulating dryer. The final product shows > 99% purity.

Example-3
75 ml D M Water is initially taken in 1 Itr. reactor followed by the simultaneous addition of 27.30 gms. of Guaiacol & 133.6 gms. 6.43% w/w Sodium Hydroxide aqueous solution at 20 - 25°C for 2 hrs. under Nitrogen atmosphere. Further 30 gms. 50% w/w Glyoxalic Acid & 83 gms. 9.63% w/w Sodium Hydroxide aqueous solution is simultaneously added for a period of 11 hrs. at 20 - 25°C. The reaction mixture is further stirred for another 1 hrs. to ensure the completion of reaction. The total reaction time including the addition is 12 hrs.
The pH of the reaction mixture is brought down to 6.5 by adding 23 - 25 gms of 20% Hydrochloric Acid (w/w). The un-reacted Guaiacol is recovered by extracting the aqueous layer with the organic solvent like Methylene Chloride, which in turn is given alkaline (2% Sodium Carbonate solution) & D M water wash to make the pH neutral. The solvent is finally distilled off to yield the un-reacted Guaiacol. The recovered Guaiacol is further distilled under vacuum to yield the pure Guaiacol, which can be used in the subsequent batches. The quantity of the recovered Guaiacol is 6.50 gms.
Now the aqueous layer having Hydroxy Methoxy Mandelic Acid is treated with 24 gms. Sodium Hydroxide maintaining the temperature 35 - 40°C under the Nitrogen atmosphere. 25 gms. Copper Oxide is also added and the reaction is carried out at 100 - 102 °C temperature keeping the positive pressure in the reactor by the air. The reaction is continued for 2.5 hrs.
After the completion of the reaction, the catalyst is filtered. The filtrate (aqueous layer) is neutralized by adding 90 - 95 gms 20% Hydrochloric Acid (w/w) keeping the temperature 35 - 40°C. The product is extracted from the aqueous layer by the organic solvent like Methylene Chloride. The Methylene Chloride layer is

washed several times with D M water before subjecting the same for the distillation. The Crude Vanillin thus obtained (7.30 gms.) shows 96.12% purity with ortho content 2.0%.
The Crude Vanillin is treated with 58 gms. Toluene at 10 - 15 °C and further treated with activated charcoal at 60 - 70°C with alcohol - water mixture as a media. The activated charcoal is filtered out and the mother liquor is slowly cooled below 20°C to crystallize the Vanillin.
The crystallized product is filtered, dried at 50°C in the air circulating dryer. The final product shows > 99% purity.
Example-4
75 ml D M Water is initially taken in 1 Itr. reactor followed by the simultaneous addition of 27.30 gms. Guaiacol & 133.60 gms. 6.43% w/w Sodium Hydroxide aqueous solution at 20 - 25°C for 2 hrs. under Nitrogen atmosphere. Further 30 gms. 50% w/w Glyoxalic Acid & 83 gms. 9.63% w/w Sodium Hydroxide aqueous solution is simultaneously added for a period of 11 hrs. at 20 - 25°C. The reaction mixture is further stirred for another 1 hrs. to ensure the completion of reaction. The total reaction time including the addition is 12 hrs.
The pH of the reaction mixture is brought down to 6.5 by adding 22 - 24 gms. of 20% Hydrochloric Acid (w/w). The un-reacted Guaiacol is recovered by extracting the aqueous layer with the organic solvent like Methylene Chloride, which in turn is given alkaline (2% Sodium Carbonate solution) & D M water wash to make the

pH neutral. The solvent is finally distilled off to yield the un-reacted Guaiacol. The recovered Guaiacol is further distilled under vacuum to yield the pure Guaiacol, which can be used in the subsequent batches. The quantity of the recovered Guaiacol is 6.60 gm.
Now the aqueous layer having Hydroxy Methoxy Mandelic Acid is treated with 48 gms. of Sodium Hydroxide maintaining the temperature 35 - 40°C under the Nitrogen atmosphere. 30 gms. Copper Oxide is also added and the reaction is carried out at 100 - 102 °C temperature keeping the positive pressure in the reactor by the air. The reaction is continued for 2.5 hrs.
After the completion of the reaction, the catalyst is filtered. The filtrate (aqueous layer) is neutralized by adding 218 - 240 gms. 20% Hydrochloric Acid (w/w) keeping the temperature 35 - 40°C. The product is extracted from the aqueous layer by the organic solvent like Methylene Chloride. The Methylene Chloride layer is washed several times with water before subjecting the same for the distillation. The Crude Vanillin thus obtained (17.10 gms.) shows 90.40% purity with ortho content 3.98%.
The Crude Vanillin is treated with 86 gms. Toluene at 10 - 15 °C and further treated with activated charcoal at 60 - 70°C with alcohol water mixture as a media. The activated charcoal is filtered out and the mother liquor is slowly cooled below 20°C to crystallize the Vanillin.
The crystallized product is filtered, dried at 50°C in the air circulating dryer. The final product shows > 99% purity.

Example-5
75 ml D M Water is initially taken in 1 Itr. reactor followed by the simultaneous addition of 40 gms. of Guaiacol & 133 gms. 6.01% w/w Sodium Hydroxide aqueous solution at 18 - 20°C for 2 hrs. under Nitrogen atmosphere. Further 30 gms. 50% w/w Glyoxalic Acid & 83 gms. 9.63% w/w Sodium Hydroxide aqueous solution is simultaneously added for a period of 17 hrs. at 18 - 20°C. The reaction mixture is further stirred for another 6 hrs. to ensure the completion of reaction. The total reaction time including the addition is 24 hrs.
The pH of the reaction mixture is brought down to 6.5 by adding 32 - 35 gms. 20% Hydrochloric Acid (w/w). The un-reacted Guaiacol is recovered by extracting the aqueous layer with the organic solvent like Methylene Chloride, which in turn is given alkaline (2% Sodium Carbonate solution) & D M water wash to make the pH neutral. The solvent is finally distilled off to yield the un-reacted Guaiacol. The recovered Guaiacol is further distilled under vacuum to yield the pure Guaiacol, which can be used in the subsequent batches. The quantity of the recovered Guaiacol is 17.10 gms.
Now the aqueous layer having Hydroxy Methoxy Mandelic Acid is treated with 35 gms. of Sodium Hydroxide maintaining the temperature 35 - 40°C under the Nitrogen atmosphere. 25 gms. Copper'Oxide is also added and the reaction is carried out at 100 - 102 °C temperature keeping the positive pressure in the reactor by the air. The reaction is continued for 2.5 hrs.
After the completion of the reaction, the catalyst is filtered. The filtrate (aqueous layer) is neutralized by adding 218 - 240 gms. 20% Hydrochloric Acid (w/w) keeping the temperature 35 - 40°C. The product is extracted from the aqueous layer by the organic solvent like Methylene Chloride. The Methylene Chloride

layer is washed several times with D M water before subjecting the same for the distillation. The Crude Vanillin thus obtained (17.50 gms) shows 96.60% purity with ortho content 2.98%.
The Crude Vanillin is treated with 141 gms. Toluene at 10 - 15 °C and further treated with activated charcoal at 60 - 70°C with alcohol water mixture as a media. The activated charcoal is filtered out and the mother liquor is slowly cooled below 20°C to crystallize the Vanillin.
The crystallized product is filtered, dried at 50°C in the air circulating dryer. The final product shows > 99% purity.
Claims:
We Claim:
1) An improved process for manufacturing Vanillin comprising
the step of reacting Guaiacol with Sodium Hydroxide solution; the step of preparing Hydroxy Methoxy Mandelic Acid by condensation of Glyoxalic Acid with Sodium Salt of Guaiacol in presence of aqueous Sodium Hydroxide;
the step of recovering unreacted Guaiacol;
the step of oxidative decarboxylation of Hydroxy Methoxy Mandelic
Acid;
the steps of neutralization, extraction and isolation of Crude Vanillin;
the steps of purification and crystallization to yield Vanillin having purity
> 99%.

2) The process as per claim - 1, wherein Guaiacol is reacted with 6 - 9.50% w/w Sodium Hydroxide solution at 15 - 25°C.
3) The process as per claim - 2, wherein Guaiacol and Sodium Hydroxide solution are added simultaneously for 2 - 4 hrs. in a reactor having D M Water and Nitrogen atmosphere.
4) The process as per claim - 2, wherein the Sodium Hydroxide, Guaiacof & D M Water are taken in the weight ratio of 1 : 3 - 5 : 9 - 25.
5) The process as per claim - 1, wherein Glyoxalic Acid is condensed with Sodium salt of Guaiacol at 15 - 25°C in presence of Sodium Hydroxide.
6) The process as per claim - 5, wherein Glyoxalic Acid and 9.60 - 11.80% w/w Sodium Hydroxide solution are added simultaneously to the solution of Guaiacol Sodium salt in 6 - 28 hrs.
7) The process as per claim - 5, wherein the weight of Glyoxalic Acid taken is 0.37 - 0.55 times that of Guaiacol taken in the reaction.
8) The process as per claim - 5, wherein Sodium Hydroxide, Glyoxalic Acid and water are taken in the weight ratio of 1 : 1.50 - 1.88 : 9.0 - 11.25.
9) The process as per claim -1, wherein the un-reacted Guaiacol is recovered by adjusting the pH of the reaction mixture to 6.5 by adding 20% w/w Hydrochloric Acid, followed by extraction with organic solvent like Methylene Chloride, sequential washing of Methylene Chloride layer with 2% Sodium Carbonate solution & D M water and subsequent distillation of Methylene Chloride.

10) The process as per claim - 1, wherein the aqueous layer containing
Hydroxy Methoxy Mandelic Acid is subjected to Oxidative
Decarboxylation in presence of Sodium Hydroxide and Copper Oxide at
95-105°Cfor 1.5-6 hrs.
11) The process as per claim - 10, wherein the Oxidative Decarboxylation is carried out at pH 12 - 13.
12) The process as per claim - 10, wherein the weight of Sodium Hydroxide and Copper Oxide are 1.15-2.32 and 1.09 - 2.10 times that of reacted Guaiacol respectively.
13) The process as per claim - 1, wherein Copper Oxide is separated and the aqueous filtrate, which is highly alkaline is neutralized with 20% w/w Hydrochloric Acid, followed by the extraction of contents with Methylene Chloride and isolation of Crude Vanillin by distilling out Methylene Chloride.
14) The process as per claim - 13, wherein the used Copper Oxide is washed several times with D M Water, dried and activated at 300 - 350 °C for 10-11 hrs. in air recalculating dryer, thereby, making the same suitable for recycling purpose in the subsequent batches.
15) The process as per claim - 13, wherein pH of the aqueous filtrate is brought down to 4.0 by gradually adding 20% w/w Hydrochloric Acid.

16) The process as per claim - 13, wherein the Crude Vanillin obtained by
distilling out Methylene Chloride has 90 - 96% purity with Ortho content
< 4 %.
17) The process as per claim - 1, wherein Crude Vanillin is further washed with Toluene at 10 - 15°C and the resultant solid is crystallized in alcohol water mixture after treating with activated charcoal to yield Vanillin having > 99% purity.
18) The process as per claim - 17, wherein the quantity of Toluene used is 4 - 8 times that of Crude Vanillin obtained.
19) The process as per claim - 17, wherein the weight ratio of alcohol, Crude Vanillin and Water in crystallization step is taken as 1:1.25:12.5.