FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act- 2005
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005 COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Biodegradable, non-carcinogenic, vegetable oil pour point depressants and processes for the preparation thereof
APPLICANTS
Crorapton Greaves Limited, CG House, Dr Annie Besant Road,
Worli, Mumbai 400 030, Maharashtra, India, an Indian
Company
INVENTOR
Chaudhari Sushi) Ekanath of Crompton Greaves Ltd, Conition Monitoring & Diagnostic Centre, CG Global R&D Centre, Kanjur (E), Mumbai 400042, Maharashtra, India, an Indian National
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

TECHNICAL FIELD OF THE INVENTION:
This invention relates to biodegradable, non-carcinogenic, vegetable oil pour point depressants,, Poly-(behenyl undecylenate-co-maleic anhydride)dibehenate of formula (I):

Formula (I)
wherein 'n' represents the number of repeating units
and processes for the preparation thereof. BACKGROUND OF THE INVENTION
Unfortunately, oils, hydraulic fluids, and other petroleum-based products have tendency to inevitably leak onto ground surfaces, eventually resulting in contamination of the environment. Much effort has been directed to avoiding such contamination. One promising approach has been to replace the base fluid typically, a petroleum-derived hydrocarbon

with a vegetable oil, such as a naturally occurring or synthetic triglyceride or ester thereof. Vegetable oils are biodegradable, and thus environmentally friendly.
Unfortunately, triglycerides have poor low temperature viscometrics. and tend to congeal at temperatures below about -10° C. Many industrial fluids must have a pour point of less than -25° C and a Brookfield viscosity of 7500 to 110,000 centiPoise (cP) at -25° C. In order for triglycerides to be used successfully as industrial base fluids, their low temperature viscometry must be improved.
The paraffin/wax of the oil also starts to crystallize in the form of thin plates, needles or mal-crystals in cold condition. At low temperatures, the plate shaped wax crystals coil on their edges forming needle shaped wax crystals which compact into a 3-dimensional network to form cage like structures. Thus, in cold conditions, when the paraffin from the oil begins to precipitate out, it gets deposited on the wall of the transformer and causes operational problems in the transformers. The storage of oil is also adversely affected in cold conditions due to the wax crystal formation.

In their natural state, vegetable oils have high viscosity which causes operational problems in transformers. Hence, all vegetable oils are transesterified prior to use as insulating fluids which also increases the cost.
In transformers the oil provides two major functions; the first is as an insulator and the second is as a heat transfer medium to carry heat from the coils to the cooling surfaces of the transformer. These oils must be low in corrosive agents such as acid, alkali and sulfur and resistant to oxidation and sludge formation. In addition to possessing relatively low viscosity, high electric strength and a relatively high flash point, these oils are further characterized in that they must have a relatively low pour point. This is particularly necessary when the oils are used in transformers in colder climates.
A number of compounds are known to improve the low temperature viscometrics of vegetable oils. These compounds are known as "pour point depressants"(PPD's). Pour point depressants are designed to control wax crystal formation in crude oil resulting in improved flow performance of the vegetable oil at lower temperatures, i.e, the PPDs lower the pour point of the vegetable oil. Pour point depressants, when

added to the crude oil, hinder the crystallization of the wax molecules by incorporation of the PPD molecules on the fastest growing edge of the wax crystals thereby forming an imperfection on the crystal face and sterically hindering further growth in that direction and thus preventing wax crystallization and deposition. This reduces the pour point of the oil.
Known PPD's for triglycerides include, but are not limited to: modified carboxy containing interpolymers; acrylate polymers; nitrogen containing acrylate polymers; and, methylene linked aromatic compounds. Unfortunately, known PPDs are not biodegradable. Therefore, the advantage in low temperature performance that is gained by using these PPD's is largely offset by the decrease in biodegradability of the resulting product.
Many of these pour point depressants like polymethacrylates, polyacrylates and polyalkyl methacrylates are known to be expensive and even carcinogenic,
Biodegradable and non-carcinogenic PPDs, which would meet the applicable specifications and not compromise the overall biodegradability of industrial fluids are sorely needed.

OBJECTS OF THE INVENTION
An object of the invention is to provide a bio-degradable. non-carcinogenic pour point depressant for vegetable oil.
Another object of the invention is to provide a bio-degradable, non-carcinogenic pour point depressant for vegetable oil which is economical.
Another object of the invention is to provide a process for the preparation of a bio-degradable, non-carcinogenic pour point depressant for vegetable oil.
Another object of the invention is to provide a process for the preparation of a bio-degradable, non-carcinogenic pour point depressant for vegetable oil which is simple, easy and convenient to carry out and is economical.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided Poly-(behenyi undecylenate-co-maleic anhydride)dibehenate having general formula (1) :


Formula (I)
wherein 'n' represents the number of repeating units
having pour point depressant activity in vegetable oil.
According to the invention there is also provided process for the
preparation of Poly-(behenyl undecylenate-co-maleic
anhydride)dibehenate of formula (I):

Formula (I)
wherein 'n' represents the number of repeating units

having pour point depressant activity in vegetable oil,
the process comprising:
a) esterifying undecylenic acid with behenyl alcohol in the molar ratio of 2:1 in the presence of an organic solvent and sulphuric acid catalyst at 110°C to 140°C under azeotropic conditions to obtain behenyl ester of undecylenic acid;
b) co-polymerizing the behenyl ester of undecylenic acid with a double re-crystallized maleic anhydride in the 1:1 molar ratio under inert atmosphere and in the presence an organic solvent and a free radical initiator at 50°C to 75°C under inert atmosphere of nitrogen to obtain a poly-(behenyl undecylenate-co-maleic anhydride) copolymer; and
c) diesterifying the co-polymer with behenyl alcohol in the molar ratio of 1:2 at 110° C to 140° C in the presence of an organic solvent and an acid catalyst.
Preferably, the solvent is selected from dry toluene, dry benzene or dry xylene. Preferably, the inert atmosphere is provided by dry nitrogen gas. Preferably, the free radical initiator is benzoyl peroxide or azobisisobutyronitrile (AIBN). Preferably, the acid catalyst is para-toluene sulfonic acid or sulphuric acid or combination thereof.

The molecular weight of the above-mentioned co-polymer is in the range of 20.000 to 50,000 depends upon the initiator concentration, temperature and stirring.
Oil used is non-edible oil such as vegetable oil, crude oil or a combination of vegetable oil and crude oil. Preferably, oil used is vegetable oil. More preferably, vegetable oil used is rapeseed oil.
Formula (I)
wherein 'n' represents the number of repeating units
The invention also provides a vegetable oil comprising poly-(behenyl undecylenate-co-maleic anhydride)dibehenate of formula (I):


The oil comprises 100 to 500 ppm of Poly-(behenyl undecylenate-co-maleic anhydride)dibehenate to improve the pour point of oil.
The copolymer, poly-(behenyl undecylenate-co-maleic
anhydride)dibehenate, of the invention is very effective and efficient in improving the pour point of vegetable oil and is prepared using raw materials like behenyl alcohol and undecylenic acid which are easily obtainable from the naturally occurring fats and oils. These pour point depressants are easily biodegradable and non-carcinogenic. Therefore, the pour point depressant of the invention is non-carcinogenic, economical and bio-degradable. The process of the invention is also simple, easy and convenient to carry out and economical.
The following experimental examples are illustrative of the invention but not limitative of the scope thereof:
Example 1
Undecylenic acid (0.051 M, 9.58 g) was esterified with behenyl alcohol (0.025 M, 8.491 g) at 110o-lll°C for 12 hours in the presence of toluene (75 ml) and sulphuric acid (0.2 ml) to obtain behenyl undecylenate.

Water was eliminated from the reaction mixture by azeotropic distillation. The resulting crude ester was neutralized with sodium bicarbonate. The organic layer was separated and washed with water to remove traces of sodium bicarbonate and finally dried over anhydrous sodium sulphate. Solvent recovery was achieved by vacuum distillation.
The behenyl undecylenate (0.025 M. 12.332 g) was copolymerized with double re-crystallized maleic anhydride (0.025 M, 2.451 g) in the presence of dry benzene under dry nitrogen atmosphere with azobisisobutyronitrile at 55 to 60°C with constant stirring for 5 hours to give poly(behenyl undecylenate-co-maleic anhydride) which was purified by repeated solvent non-solvent precipitation (benzene-methanol) method. Traces of the solvent were removed by drying under reduced pressure at 50°C / 25mm Hg for 5 hours.
The poly(behenyl undecylenate-co-maleic anhydride) (0.019 M, 11.22 gm) was diesterified with 2 moles of behenyl alcohol (0.038 M, 12.41 gm) in the presence of dry xylene (60 ml) and para-toluene sulfonic acid (0.1 gm) and sulphuric acid (0.2 ml) at 140°C to produce poly(behenyl undecylenate-co-maleic anhydride)dibehenate which was neutralized with sodium bicarbonate and separated and dried over anhydrous sodium

sulfate. Some part of the solvent was recovered by vacuum distillation. The crude diester was purified by repeated precipitation in excess acetone and dried under vacuum at 40°C/25mm Hg for 5 hours. The poly(behenyl undecylenate-co-maleic anhydride)dibehenate obtained in this example had a molecular weight up to 50,000.
Example 2
100 ppm and 500 ppm of poly(behenyI undecylenate-co-maleic anhydride)dibehenate prepared according to Example 1 was added to rapeseed oil and tested for its pour point depressant activity. The pour point depressant additive of the invention was tested for its pour point depressant activity by standard method as prescribed by the ASTM D97. The results of the pour point of the rapeseed oil on addition of varying amounts of poly(behenyl undecylenate-co-maleic anhydride)dibehenate were shown in the Table 1.

Table 1 : Pour point depressant of rapeseed oil after adding varying
amount of poly(behenyl undecylenate-co-maleic
anhydride)dibehenate in the oil.

Pour Pour point of Extent of Pour point of Extent of
point of rapeseed oil after depression in rapeseed oil depression in pour
virgin addition of 100 pour point after after addition point after addition
rapeseed ppm addition of 100 of 500 ppm of 500 ppm
oil Poly(behenyl ppm Poly(behenyl Poly(behenyl
undecylenate-co- Poly(behenyl undecylenate- undecylenate-co-
maleic undecylenate- co-maleic maleic anhydride)
anhydride) co-maleic anhydride) dibehenate
dibehenate anhydride) dibehenate dibehenate
-12°C -18°C 6°C -21°C 9°C
Table 1 clearly shows that the rapeseed oil comprising poly(behenyl undecylenate-co-maleic anhydride)behenate has excellent pour point depressant activity,

We claim :
1. Poly-(behenyl undecylenate-co-maleic anhydride)dibehenate having general formula (I):

Formula (I) wherein 'rr represents the number of repeating units
having pour point depressant activity in vegetable oil.
2. A process for the preparation of Poly-(behenyi undecylenate-co-maleic anhydride)dibehenate of formula (1):

Formula (I) wherein 'n' represents the number of repeating units

having pour point depressant activity in vegetable oil; the process comprising:
a) esterifying undecylenic acid with behenyl alcohol in the molar ratio of 2:1 in the presence of an organic solvent and sulphuric acid catalyst at 110°C to 140°C under azeotropic conditions to obtain behenyl ester of undecylenic acid;
b) co-polymerizing the behenyl ester of undecylenic acid with a double re-crystallized maleic anhydride in the 1:1 molar ratio under inert atmosphere and in the presence an organic solvent and a free radical initiator at 50°C to 75°C under inert atmosphere of nitrogen to obtain a poly-(behenyl undecylenate-co-maleic anhydride) copolymer; and
c) diesterifying the co-polymer with behenyl alcohol in the molar ratio of 1:2 at 110° C to 140° C in the presence of an organic solvent and an acid catalyst.
3. The process as claimed in claim 2, wherein the solvent used is selected from dry toluene, dry benzene or dry xylene.

4. The process as claimed in claim 3, wherein the free radical initiator used is benzoyl peroxide or azobisisobutyronitrile (AIBN).
5. The process as claimed in claim 3, wherein the acid catalyst used is para-toluene sulfonic acid or sulphuric acid or combination thereof.
6. A vegetable oil comprising poly-(behenyl undecylenate-co-maleic anhydride)dibehenate of formula (I):

Formula (I) wherein 'n' represents the number of repeating units having pour point depressant activity.