Title of Invention

"PROCESS OF PREPARATION OF DIHYDROMYRCENOL"

Abstract

A process of preparation of 2,6-dimethyl-7-octen-2-ol (di-hydromyrcenol) Comprising the steps of hydrogenating alpha pinene in the presence of Raney Nickel catalyst at pressure range of 5.0 - 25 kgs/cm2 and temperature range of 80-130 deg c to get cis pinene, subjecting the cis pinene to pyrolysis under vaccum at temperature range 800-950 deg c. to get a dihydromyrcen, distilling the dihydromyrcen under vaccum in a tall column at 600-700 mm/Hg at a temperature range of 105-117 deg c, reacting the di¬hydromyrcen with water in the presence of concentrated mineral acids and Noigen as catalyst at temperature range of 0- minus 6 degree c to form dihydromyrcenol.

Full Text

Field of Invention The present invention relates to a process of preparation of 2,6-dimethyl-7-octen-2-ol, named as Dihydromyrcenol. The molecular formula of the compound is C1oH20 O having a molecular weight of 156.27 having the structure of formula I. The compound is almost colourless clear liquid having a powerful fresh lime like citrusy floral olefactive note. The density of the compound at 25 deg c is 0.820 to 0.8360 and refractive index at 20 deg c is 1.4390 to 1.4430. The compound is sparingly soluble in water and soluble in 80% alcohol (v/v). The color of the compound in Gardner scale is (Formula Remvoved) Wherein R1 is protected group R2 is protected carboxy group n is 1 or 2, Formula I Background of the Invention Applicants know no prior art relating to the process of preparation of the compound of formula I. The present process is novel, inventive and industrially applicable. Statement of the Invention Accordingly, A process of preparation of 2,6-dimethyl-7-octen-2-ol (di-hydromyrcenol) of the formula I (Formula Removed) Wherein R1 is protected group R2 is protected carboxy group n is 1 or 2, Comprising the steps of- (a) hydrogenating alpha pinene in the presence of Raney Nickel catalyst at pressure range of 5.0 - 25 kgs/cm2 and temperature range of 80-130 deg c to get cis pinene, (b) subjecting the cis pinene to pyrolysis under vaccum at temperature range 800-950 deg c. to get a dihydromyrcen, (c) distilling the dihydromyrcen under vaccum in a tall column at 600-700 mm/Hg at a temperature range of 105-117 deg c (d) reacting the di-hydromyrcen with water in the presence of concentrated mineral acids and Noigen as catalyst at temperature range of 0- minus 6 degree c to form dihydromyrcenol. A preferred embodiment is wherein the the catalyst is recovered and reused number of times Another embodiment is wherein the di-hydromyrcenol is purified by vaccum distillation A further embodiment is wherein the product yield is 50-60%. Detailed description of the invention The following are the details of the process for the preparation of the compound of formula I. 1.1 Alpha pinene (purity 95%) from terpenoids is hydrogenated in the presence of Raney Nickel catalyst (Hicat catalyst) at pressure range of 5.0 - 25 kgs/cm2 and temperature range of 80-130 deg c. The alpha pinene is converted to cis-pinene. Certain amount of trans-pinene and high boilers are also formed. The catalyst is recovered and reused number of times with some additional catalyst added in every batch. The mass is subjected to filteration under vaccum to get 90-95% of cis-pinene. The high boilers formed during the reaction are removed. (Formula Removed)1.2 The cis-pinane is fed to pyrolysis reactor under vaccum at temperature range 800-950 deg c. The reactor is specially designed for the process. The reactor is having tube bandies of outer diameter of 15-70 mm. HSD and other fuels are used for the thermolysis. The cis-pinane is converted into di-hydromyrcen of 35-55% purity. Cis-pinene is evaporated continuously at high temperature to convert to di-hydromyrcene which is then quickly condensedto obtain di-hydromyrcene. Nitrogen is supplied to minimize the oxidation. The control of this high temperature reactor is extremely difficult as the products are thermally unstable and a number of byproducts are formed such as cyclo-pinene (10-15%), trans -pinene (5-8%), high boilers (10-15%), unconverted cis-pinene (15-45%), intermediate product containing 5 member cyclic hydrocarbons with substituted alkyl group, low boiling hydrocarbons of unknown structures, non-condensable gases formed by breakdown or oxidation of hydrocarbons which are lost during the condensation of the vapor. The product is collected after scrubbing through condenser along with water and separated in the decanter. The mass is subjected to distillation under vacuum for further process. The unconverted mass is recycled back to the process. (Formula Removed) 1.3 The di-hydromyrcen is vaccum distilled in a very tall column (25-30 metres) with very efficient structural pickings at 600-700 mm/Hg with watering vaccum pumps at a temperature range of 105-1 17 deg c for purification. All the byproducts mentioned above and dihydromyrcene have very close boiling points that make their separation by fractional distillation extremely difficult. The top product is collected as low boilers; middle product as product and the bottom left over mass is again fed in the distillation column. The product purity are as follows - Di-hydromyrcen - 80-90% Cyclopinene - 8-5% Trans pinene - 6-3% Low boilers - 6-2% 1.4 The di-hydromyrcen is reacted for 6-8 hours with water in the presence of concentrated mineral acids and Noigen as catalyst under cool conditions at temperature range of 0- minus 6 degree c to form OH-group product. At the end of the reaction, the mineral acid is diluted, separated and discarded and the crude dihydromyrcene is washed to neutral. The products formed are as follows - Di-hydromyrcenol - 70-75% Low boilers - 7-5% Cyclo pinene - 5-3% Trans pinene - 5-2% High boilers -1-2% Di-hydromyrcen- 10-13% (Formula Removed) 1.5 The di-hydromyrcenol is purified by vaccum distillation. The top product is collected a s low boilers, the middle product as product (di-hydromyrcenol) and the bottom left over mass is as residue. The product purity increases from 70 to 99.6%. The product yield is 50-60%. EXAMPLES Production process for di-hydromyrcenol Step I. Hydrogenation 136 kg of alpha pinene takes 2 kg of hydrogen and forms 138 kgs of cis pinene. Therefore, 136 kgs of alpha pinene = 138 kg of cis pinene Or 1 kg of alpha pinene (100%) = 1.0147 kg of cis pinene. But actually 0.905 kg of cis pinene is formed. Or 1 kg of alpha pinene (96%) = 1.0146*.96= 0.9741 kg of cis pinene. But in actual 0.905 kgs of cis pinene of 100% purity or 0.984 of 92% purity cis pinene is obtained. That is 0.905/0.9741 = 92.9 % of theory 1 kg of 100% cis pinene or 1.087 kg of 92% cis pinene = 1.105 kg of 96% alpha pinene During the reaction, byproducts such as trans isomer is formed which is not useful and the yield decreases. The product if fractionated to remove high boilers and hence part of the material is lost. The product is volatile and part of the material escape along with hydrogen. Step II. Pyrolysis Cis pinene (92%) is heated at high temperature and nitrogen atmosphere to breakdown the ring to form open chain ring product. By theory, 138 kgs of cis pinene gives 138 kgs of cis pinene crude. That is 1 gm cis pinene = 1 gm dihydromyrcene (dhm) crude. In actual, 1 kg of cis pinene gives 0.48 kgs of dhm crude. That is, 1 kg of dhm crude requires 2.083 kg of cis-pinene. Pyrolysis reaction is high temperature cracking of product in a fraction of second due to readjustment of atoms. Byproducts are formed which have close boiling points to dhm. Some high boiling product are formed which has tendency to convert part of dhm into residue during distillation. Step III Distillation of di-hydromyrcen To separate the byproducts, tall distillation column of 25-30 metres length is used and part quantity dhm is lost during this operation. Step IV Hydration of di-hydromyrcen In theory, 138 kgs of dhm gives 156 kgs of dihydromyrcnol That is, 1 kg of dihydromyrcnol is 1.1304 kg of dhm. In actual, 1 kg of dhm gives 0.763 kgs of dihydromyrcnol. That is 1 kg of dihydromyrcnol = 1.311 kg of dhm. The product is lost due to polymerization. The product is slighjtly soluble in waterand hence same is lost in washing. Step V Distillation of dihydromyrcnol Fractionisation reduces the yield. The product is sensitive to heat. Any small drop in vaccum during distillation increases the residue and results in lass of yield. Materal Balance Stoichiometric balance at 100% conversion (Table Removed) That is 1 kg alpha pinene gives 1.130 kg of Dihydromyrcnol That is 1 kg of Dihydromyrcnol requires 0.88 kg of alpha pinene Actual (Table Removed) We claim - 1. A process of preparation of 2,6-dimethyl-7-octen-2-ol (di-hydromyrcenol) of the formula I (Formula Removed) Wherein R1 is protected group R2 is protected carboxy group n is 1 or 2, Comprising the steps of- (e) hydrogenating alpha pinene in the presence of Raney Nickel catalyst at pressure range of 5.0 - 25 kgs/cm2 and temperature range of 80-130 deg c to get cis pinane, (f) subjecting the cis pinene to pyrolysis under vaccum at temperature range 800-950 deg c. to get a dihydromyrcen, (g) distilling the dihydromyrcen under vaccum in a tall column at 600-700 mm/Hg at a temperature range of 105-117 deg c (h) reacting the di-hydromyrcen with water in the presence of concentrated mineral acids and Noigen as catalyst at temperature range of 0- minus 6 degree c to form dihydromyrcenol. 2. A process as claimed in claim 1, wherein the catalyst is recovered and reused number of times 3 A process as claimed in claim 1, wherein di-hydromyrcenol is purified by vaccum distillation 4. A process as claimed in claim 1, wherein the product yield is 50-60%. 5. A process of preparation of 2,6 dimethyl-7-octen-2-ol (di-Hydromyreenol) of the formula I substantially as herein described.

Documents:

29-del-2005-abstract.pdf

29-del-2005-claims.pdf

29-del-2005-correspondence-others.pdf

29-del-2005-correspondence-po.pdf

29-del-2005-description (complete).pdf

29-del-2005-form-1.pdf

29-del-2005-form-18.pdf

29-del-2005-form-2.pdf

29-del-2005-form-3.pdf

29-del-2005-form-5.pdf