FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Poly (alkyl cinnamate-co-alkylmaleimide) as pour point depressant for oils
APPLICANTS:
Crompton Greaves Limited, CG House, Dr. Annie Besant Road, Worli, Mumbai -400030, Maharashtra, India, an Indian Company
INVENTOR:
Chaudhari Sushil Ekanath of Condition Monitoring & Diagnostic Research Centre, CG Global R&D Centre, Crompton Greaves Limited, Kanjur Marg (E), Mumbai 400 042, 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:
The present invention relates to pour point depressants, poly(alkyl cinnamate -co-alkylmaleimide) having formula (I);

Formula (I) Poly(alkyl cinnamate -co-alkylmaleimide) wherein "R" represents C10 to C22 straight chain aliphatic alkyl group; "X" represents number of "-CH2-" units and "n" represents number of operating units having pour point depressant activity in oil and process for the preparation thereof.
BACKGROUND AND PRIOR ART :
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 pil precipitates 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 wax crystals formation.
In their natural state, vegetable oils have high viscosity which causes operational problems in transformers. Hence, all vegetable oils are trans-esterified 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 crude oil, 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 limited to modified carboxy containing interpolymers; acrylate polymers; nitrogen containing acrylate polymers; and, methylene linked aromatic compounds. Specific examples of pour point depressants used are Ethylene Vinyl Acetate (EVA) copolymers, polymethacrylates,

polyacrylates, alkyl esters of styrene-maleic anhydride copolymers, copolymers of olefins, acrylamides, polyacrylamides, copolymers of maleimide, maleic anhydrides, compounds of alkyl amines, alkyl ammonium salts, copolymers of mono, dicarboxylic acids with mono, dipolyhydric alcohols, branched polyalkyl methacrylates with nitrogen containing functional group, sulfone copolymers, copolymers of alpha olefins and maleic anhydride etc.
Many of these pour point depressants like polymethacrylates, polyacrylates and polyalkyl methacrylates are known to be expensive.
Cheaper and effective pour point depressant made from vegetable resources, 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 pour point depressant for oil.
Another object of the invention is to provide pour point depressant for oils which is economical.
Another object of the invention is to provide a process for the preparation of pour point depressant which is simple, easy and convenient to carry out and is economical.

DETAILED DESCRIPTION:
According to the invention, there is provided poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I);

Formula (I) Poly(alkyl cinnamate-co-alkylmaleimide) wherein "R" represents C10 to C22 straight chain aliphatic alkyl group; "X" represents number of "-CH2-" units and "n" represents number of operating units having pour point dispersant activity.
Particularly, poly(alkyl cinnamate -co-alkylmaleimide) of formula (I) are as follows:
1. Poly(decyl cinnamate -co-alkylmaleimide) of the formula (II):


Formula (II) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;
2. Poly(dodecyl cinnamate -co-alkylmaleimide) of the formula (III):

Formula (III) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;

3. Poly(tetradecyl cinnamate -co-alkylmaleimide) of the formula (IV):

Formula (IV) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;
4. Poly(hexadecyl cinnamate -co-alkylmaleimide) of the formula (V):

Formula (V) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;

5. Poly(octadecyl cinnamate -co-alkylmaleimide) of the formula (VI):

Formula (VI) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;

Formula (VII)
6. Poly(behenyl cinnamate -co-alkylmaleimide) of the formula (VII);

wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
More particularly, poly(alkyl cinnamate -co-alkylmaleimide) of formula (I) are as
follows:
1. Poly(decyl cinnamate -co-octadecylmaleimide) of the formula (VIII):

Formula (VIII) wherein "n" represents number of operating units;
2. PoIy(dodecyl cinnamate -co-octadecylmaleimide) of the formula (IX):

Formula (IX)

wherein "n" represents number of operating units; 3. Poly(tetradecyl cinnamate -co-octadecylmaleimide) of the formula (X):

Formula (X) wherein "n" represents number of operating units;
Formula (XI)
4. Poly(hexadecyl cinnamate -co-octadecylmaleimide) of the formula (XI):


wherein "n" represents number of operating units; 5. Poly(octadecyl cinnamate -co-octadecylmaleimide) of the formula (XII):

Formula (XII) wherein "n" represents number of operating units;
6. Poly(behenyl cinnamate -co-octadecylmaleimide) of the formula (XIII);

Formula (XIII)

wherein "n" represents number of operating units.
According to the invention, there is also provided process for the preparation of poly(alkyl cinnamate -co-alkylmaleimide) of formula (I):

Formula (I) Poly(alkyl cinnamate -co-alkylmaleimide) wherein "R" represents C10 to C22 straight chain aliphatic alkyl group; "X" represents number of "-CH2-" units and "n" represents number of operating units having pour point depressant activity in oil. the process comprising:
a. esterifying unsaturated cinnamic acid with C10 to C22 aliphatic alcohol in the
molar ratio of 1.5:1 to 2: 1 in the presence of acid catalyst under azeotropic
conditions to obtain an alkyl ester of cinnamic acid;
b. copolymerizing the alkyl ester of cinnamic 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 80°C to obtain
a poly(alkyl cinnamate-co-maleic anhydride) copolymer; and

c. condensing the copolymer with amine in the presence of activated 4° A molecular sieves at 90°C to 150°C.
The C10 to C22 aliphatic alcohol is selected from decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, behenyl alcohol, etc.
The organic solvent is selected from toluene, dry benzene, methanol, or xylene, etc. The inert atmosphere is provided by dry nitrogen gas. The free radical initiator is benzoyl peroxide or azobisisobutyronitrile (AIBN). The acid catalyst is para-toluene sulfonic acid or sulphuric acid or combination thereof.
The amine used is decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecyl amine, behenyl amine etc.
Preferably, the amine used is octadecyl amine.
The invention also provides oil comprising poly(alkyl cinnamate-co-alkylmaleimide) of formula (I) having pour point depressant in the oil
The oil comprises 1000 to 3000 ppm of poly(alkyl cinnamate-co-alkylmaleimide) of formula (I) to improve the pour point of oil.
The oil used is vegetable oil, crude oil or any oil.
According to another embodiment of the invention, the crude oil comprising poly(alkyl cinnamate-co-octadecylmaleimide) having general formula (I) in a concentrations of 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point up to maximum -11 °C.

Poly(alkyl cinnamate-co-alkylmaleimide) of formula (I) of the invention is very effective and efficient in improving the pour point of oil and is prepared using raw materials like decyl alcohol, dodecyl alcohol, tetradecyl, hexadecyl, octadecyl and behenyl alcohols which are easily obtainable from the naturally occurring fats and oils. Therefore, the pour point depressant of the invention is economical. 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
Excess cinnamic acid was esterified with C10, C12, C14, C16, C18 and C22 straight chain aliphatic alcohols in a molar ratio of 2:1 at 110°C for 8 to 12 hours in presence of dry toluene as a solvent and 0.2 ml of sulphuric acid as a catalyst to yield six different respective alkyl esters of cinnamic acid. Water was eliminated by azeotropic distillation. The resulting crude esters were 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. Table 1.1 illustrates the quantities of reactants used for the preparation of each of these esters.

Table 1.1 Data related to preparation of n-alkyl cinnamate
Sr.
No. Reactants Toluene ml H2S04 ml Alkyl cinnamate

Cinnamic acid mole Fatty
Alcohol
mole

1 0.060 M Decyl alcohol 0.030 M 70 0.2 Decyl cinnamate
2 0.056 M Dodecyl alcohol 0.028 M 60 0.2 Dodecyl cinnamate
3 0.052 M Tetradecyl
alcohol
0.026 M 75 0.2 Tetradecyl cinnamate
4 0.048 M Hexadecyl alcohol
0.024 M 65 0.2 Hexadecyl cinnamate
5 0.044 M Octadecyl alcohol 0.022 M 75 0.2 Octadecyl cinnamate
6 0.042 M Behenyl
alcohol
0.021 M 70 0.2 Behenyl
cinnamate
The alkyl cinnamate of the table 1 were then copolymerized with double recrystallized maleic anhydride in 1:1 molar ratio in the presence of dry benzene under dry nitrogen atmosphere with azobisisobutyronitrile as an initiator at 60°C to 65°C with constant stirring for 8 hours to give poly(alkyl cinnamate-co-maleic anhydride). The resulting

poly(alkyl cinnamate-co-maleic anhydride) were purified by repeated solvent non-solvent method (Benzene-methanol). Traces of solvent were removed by drying under reduced pressure at 50°C / 25mm Hg for 5 hours. Table 1.2 illustrates the quantities of the reactants used in the copolymerization reaction.
Tablel.2 Data related to preparation of poly (alkyl cinnamate-co-maleic anhydride)

Reactants Benzene (ml) Copolymer
Alkyl cinnamate (mole) Maleic anhydride
(mole) Azobisisobu -tyronitrile gm (% wt.
of total monomers)


Decyl cinnamate 0.020 M 0.020 M 0.1 gm 50 Poly(decyl cinnamate -co-maleic anhydride)
Dodecyl cinnamate 0.028 M 0.028 M 0.1 gm 50 Poly(dodecyl cinnamate-co-maleic
anhydride)
Tetradecyl
cinnamate
0.035 M 0.035 M 0.1 gm 50 Poly(tetradecyl
cinnamate-co-maleic
anhydride)
Hexadecyl
cinnamate 0.030 M 0.030 M 0.1 gm 55 Poly(hexadecyl cinnamate -co-maleic anhydride)
Octadecyl
cinnamate 0.025 M 0.025 M 0.1 gm 60 Poly(octadecyl cinnamate -co-maleic anhydride)

Behenyl
Poly(behenyl cinnamate
cinnamate . 0.026 M 0.1 gm 60 -co-maleic anhydride)
0.026 M
The anhydride copolymers were condensed to octadecyl amine in a molar ratio of
1:1 in the presence of activated 4° A molecular sieves at 100°C to 150°C to produce
amides namely; poly(decyl cinnamate-co-octadecylmaleimide), poly(dodecyl
cinnamate-co-octadecylmaleimide), poly(tetradecyl cinnamate-co-
octadecylmaleimide), poly(hexadecyl cinnamate-co-octadecylmaleimide),
poly(octadecyl cinnamate-co-octadecylmaleimide) and poly(behenyl cinnamate-co-octadecylmaleimide).
Table 1.3 illustrates the quantities of the reactants used in the condensation reaction.
Table 1.3 Data related to preparation of poly(alkyl cinnamate-co-octadecylamide)

Reactants Solvent
(ml) Pour Point
Copolymer Amine Activated 4°

(mole) (mole) A molecular
sieves Depressants
Poly(decyl cinnamate- 0.028 M 3.0 30 Poly(decyl cinnamate-
co-maleic anhydride) co-octadecylmaleimide)
0.028 M
Poly(dodecyl 0.035 M 3.0 35 Poly(dodecyl
cinnamate-co-maleic cinnamate-co-octadecyl
anhydride) maleimide)
0.035 M

Poly(tetradecyl 0.031 M 3.0 25 Poly(tetradecyl
cinnamate-co-maleic cinnamate-co-octadecyl
anhydride) maleimide)
0.031 M
Poly(hexadecyl 0.037 M 3.0 35 Poly(hexadecyl
cinnamate-co-maleic cinnamate-co-octadecyl
anhydride) maleimide)
0.037 M
Poly(octadecyl 0.028 M 3.0 35 Poly(octadecyl
cinnamate-co-maleic cinnamate-co-octadecyl
anhydride) maleimide)
0.028 M
Poly(behenyl 0.025 M 3.2 35 Poly(behenyl
cinnamate-co-maleic cinnamate-co-
anhydride) octadecylmaleimide)
0.025 M
Pour Point Depressants (additives) prepared according to table 1.3 of the invention were tested for its pour point depressant activity by standard method as prescribed by the ASTM D97.
1000 ppm, 2000 ppm and 3000 ppm of various pour point depressant additives of Table 1.3 were added to crude oil and tested for their pour point depressant activity. The results of the pour point of the crude oil on addition of 1000 ppm, 2000 ppm and 3000 ppm of various pour point depressant additives of the invention were shown in the Table 1.4.

Table 1.4 : Pour point depressant of crude oil after adding varying amount of pour point depressant additives of the invention in the oil.

Pour Extent of
Pour Point Depressants point Pour point of PPD depression in pour
of
crude
oil treated crude oil (°C) point
(°C)

1000 2000 3000 1000 2000 3000
(°C) ppm ppm ppm ppm ppm ppm
Poly (decyl cinnamate-
co-octadecylmaleimide) 39 20 18 12 19 22 27
[Alkyl chain length=C10]
Poly (dodecyl cinnamate
-co-octadecylmaleimide) 39 21 16 6 18 23 33
[Alkyl chain length=C12]
Poly (tetradecyl
cinnamate -co- 39 18 15 9 21 24 30
octadecylmaleimide)
[Alkyl chain length=C14]
Poly (heaxadecyl
cinnamate -co- 39 12 9 9 27 30 30
octadecylmaleimide)
[Alkyl chain length=C16]
Poly (octadecyl
cinnamate -co- 39 10 5 1 29 34 38
octadecylmaleimide)
[Alkyl chain length=C18]

Poly (behenyl cinnamate
-co-octadecylmaleimide) 39 -5 -8 -11 44 44 47
[Alkyl chain length=C22]
According to the results of Table 1.4, the pour point depressant additives of the invention namely; poly (decyl cinnamate-co-octadecylmaleimide), poly (dodecyl cinnamate-co-octadecylmaleimide), poly (tetradecyl cinnamate-co-octadecyl maleimide), poly (heaxadecyl cinnamate-co-octadecyl maleimide), poly (octadecyl cinnamate-co-octadecyl maleimide), poly (behenyl cinnamate-co-octadecylmaleimide) has excellent pour point depressant activity in crude oil in range of concentration from 1000 ppm to 3000 ppm which will reduce the pour point up to maximum -11°C as shown in the above table.
The present invention as described above, it is to be understood that this invention is not limited to particular methodologies and materials described, as these may vary as per the person skilled in the art. It is also to be understood that the terminology used in the description is for the purpose of describing the particular embodiments only, and is not intended to limit the scope of the present invention.

WE CLAIM:
1. Poly (alkyl cinnamate -co-alkylmaleimide) having general formula (I);

Formula (I) Poly(alkyl cinnamate -co-alkylmaleimide) wherein "R" represents C10 to C22 straight chain aliphatic alkyl group; "X" represents number of "-CH2-" units and "n" represents number of operating units, having pour point dispersant activity.
2. The poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(decyl cinnamate -co-alkylmaleimide) of the formula (II);


Formula (II) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.

Formula (III)
3. The poly(alkyl cinnamate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(dodecyl cinnamate -co-alkylmaleimide) of the formula (III);

wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
4. The poly(aIkyl cinnamate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(tetradecyl cinnamate -co-alkylmaleimide) of the formula (IV);

Formula (IV)
wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
5. The poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(hexadecyl cinnamate -co-alkylmaleimide) of the formula (V);


Formula (V)
wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
6. The poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(octadecyl cinnamate -co-alkylmaleimide) of the formula (VI);

Formula (VI)
wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.

7. The poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(behenyl cinnamate -co-alkylmaleimide) of the formula (VII);

Formula (VII)
wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
8. A process for the preparation of poly(alkyl cinnamate -co-alkylmaleimide) of formula (I):

Formula (I) Poly(alkyl cinnamate -co-alky;maleimide)

wherein "R" represents C10 to C22 straight chain aliphatic alkyl group; "X"
represents number of "-CH2-" units and "n" represents number of operating
units,
having pour point dispersant activity;
the process comprising:
a. esterifying unsaturated cinnamic acid with C10 to C22 aliphatic alcohol in
the molar ratio of 1.5:1 to 2: 1 in the presence of acid catalyst under
azeotropic conditions to obtain an alkyl ester of cinnamic acid;
b. copolymerizing the alkyl ester of cinnamic 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
80°C to obtain a poly(alkyl cinnam ate-co-maleic anhydride) copolymer;
and
c. condensing the copolymer with amine in the presence of activated 4° A
molecular sieves at 90°C to 150°C.
9. The process as claimed in claim 8, wherein the C10 to C22aliphatic alcohol used is selected from decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol or behenyl alcohol.
10. The process as claimed in claim 8, wherein the organic solvent is selected from toluene, dry benzene, methanol, or xylene.
11. The process as claimed in claim 8, wherein the amine used is decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecyl amine or behenyl amine.

12. A crude oil comprising poly(alkyl cinnamate-co-alkylmaleimide) having general formula (I) in concentrations of 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point up to maximum -11°C.