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 oleate-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 particularly, poly(alkyl oleate-co-alkylmaleimide) having formula (I);

Formula (I) Poly(alkyl oleate-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 coJd 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 PPDs 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, polyacryl^tes, 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 depressants for oil.
Another object of the invention is to provide pour point depressants for oils, which are economical.
Another object of the invention is to provide a process for the preparation of pour point depressants which is simple, easy, convenient to carry out and economical.
DETAILED DESCRIPTION:

Formula (I) Poly(alkyl oleate-co-alkylmaleimide)
According to the invention, there is provided poly(alkyl oleate -co-alkylmaleimide) having general formula (I):

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.
Particularly, poly(alkyl oleate-co-alkylmaleimide) of formula (I) are as follows: 1. Poly(decyl oleate-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 oleate -co-alkylmaleimide) of the formiila (III):


Formula (III) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;
Formula (IV)
3. Poly(tetradecyl oleate -co-alkylmaleimide) of the formula (IV):


wherein "X" represents number of "-CH2-" units and "n" represents number of operating units:
4. Poly(hexadecyI oleate -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 oleate -co-alkylmaleimide) of the formula (VI):


Formula (VI) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units; and 6. Poly(behenyl oleate -co-alkylmaleimide) of the formula (VII):

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

More particularly, poly(alkyl oleate-co-alkylmaleimide) of formula (I) are as follows: 1. Poly(decyl oleate-co-decylmaleimide) of the formula (VIII):

Formula (VIII) wherein "n" represents number of operating units;
2. Poly(dodecyl oleate -co-decylmaleimide) of the formula (IX):


Formula (IX) wherein "n" represents number of operating units;
3. PoIy(tetradecyl oleate -co-decylmaleimide) of the formula (X):

Formula (X) wherein "n" represents number of operating units;

4. Poly(hexadecyl oleate -co-decylmaleimide) of the formula (XT):

Formula (XI) wherein "n" represents number of operating units;
5. Poly(octadecyl oleate -co-decylmaleimide) of the formula (XII):

Formula (XII) wherein "n" represents number of operating units; and


6. Poly(behenyl oleate-co-decylmaleimide) 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 oleate-co-alkylmaleimide) of formula (I):

Formula (I) Poly(alkyl oleate-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 oleic 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 oleic acid;
b. co-polymerizing the alkyl ester of oleic 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 to obtain a poly(alkyl oleate-co-maleic
anhydride) co-polymer; and
c. condensing the co-polymer with amine in the presence of activated 4° A molecular sieves
at90°C to 150°C to obtain poly(alkyl oleate-co-alkylmaleimide) of formula (I).
TheC10 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.
The invention also provides oil comprising poly(aIkyI oleate-co-alkylmaleimide) of formula (I) having pour point depressant activity in the oil.
The oil comprises 100 to 3000 ppm of po!y(alkyl oleate-co-alkylmaleimide) of formula (I) to improve the pour point of oil.

Oil used is vegetable oil, crude oil or any other oil.
The crude oil comprises 1000 to 3000 ppm of poly(alkyl oleate-co-alkylmaleimide) of formula (I) to improve the pour point of oil.
The vegetable oil comprises 100 to 500 ppm of poly(alkyl oleate-co-alkylmaleimide) of formula (I) to improve the pour point of oil.
Preferably, crude oil comprises 1000 to 3000 ppm of poly(alkyl oleate-co-alkylmaleimide) of formula (I) to improve the pour point of oil which will reduce the pour point of the oil up to maximum-15°C.
Preferably, Indian Beech/Karanj (Millettia pinnata) oil comprises 100 to 500 ppm of poly(alkyl oleate-co-alkylmaleimide) of formula (I) to improve the pour point of 0n which will reduce the pour point of the oil up to maximum -18°C.
Poly(alkyl oleate-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 behenyl alcohol, decyl alcohol, dodecyl alcohol and oleic acid 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 oleic 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 alkyl esters of oleic 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 alkyl oleate

Sr.
No. Reactants Toluene ml H2S04 ml

Oleic acid mole Fatty Alcohol mole

Alkyl oleate
I 0.052 M Decyl alcohol 0.026 M 50 0.2 Decyl oleate
2 0.052 M Dodecyl alcohol 0.026 M 50 0.2 Dodecyl oleate
3 0.052 M Tetradecyl
alcohol
0.026 M 70 0.2 Tetradecyl oleate
4 0.052 M Hexadecyl alcohol 0.026 M 80 0.2 Hexadecyl oleate
5 0.044 M Octadecyl alcohol 0.022 M 70 0.2 Octadecyl oleate
6 0.040 M Behenyl alcohol 0.020 M 70 0.2 Behenyl
oleate
The alkyl oleate 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 55° C to 60° C with constant stirring for 8 hours to give poly(alkyl oleate-co-maleic anhydride). The resulting poly(alkyl oleate-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 polyfalkyl oleate-co-maleic anhydride)

Reactants Benzene
ml
Alkyl oleate (mole) Maleic anhydride
(mole) Azobisisobu tyronitrile
gm (% wt. of total
monomers)
Copolymer
Decyl oleate
0.024 M 0.024 M 0.1 35 poly(decyl oleate -co-maleic anhydride)
Do decyl oleate 0.020 M 0.020 M 0.1 40 poly(dodecyl oleate-co-maleic anhydride)
Tetradecyl Oleate 0.021 M 0.021 M 0.1 40 poly(tetradecyl oleate-co-maleic anhydride)
Hexadecyl oleate 0.020 M 0.020 M 0.1 48 poly(hexadecyl oleate -co-maleic anhydride)
Octadecyl oleate 0.019 M 0.019 M 0.1 42 poly(octadecyl oleate -co-maleic anhydride)
Behenyl Oleate 0.018 M 0.018 M 0.1 50 poly(behenyl oleate -co-maleic anhydride)
The anhydride copolymers were condensed with the decyl amine in a molar ratio of 1:1 in the
presence of 1 gm of activated 4° A molecular sieves at 100°C to 150°C to produce amides;
poly(decyl oleate-co-decylmaleimide); poly(dodecyl oleate-co-decyl maleimide);
poly(tetradecyl oleate-co-decyl maleimide); poly(hexadecyl oleate-co-decyl maleimide); poly(octadecyl oleate-co-decyl maleimide); and poly(behenyl oleate-co-decyl maleimide).

Table 1.3 illustrates the quantities of the reactants used in the condensation reaction. Table 1.3 Data related to preparation of poly(a!kyl oleate--co- decylmaleimide)

Reactants Solvent (ml) Pour Point Depressants
Copolymer
(mole) Decyl amine (mole) | Activated 4° A molecular
sieves

Poly (decyl oleate-co-
maleic anhydride)
0.030 M 0.030 M 3gm 25 Poly(decyl oleate-co-decylmaieimide)
Poly(dodecyl oleate-co-
maleic anhydride)
0.032 M 0.032 M 3gra 22 Poly(dodecyl oleate-co-decylmaleimide)
Poly(tetradecyI oleate-co-
maleic anhydride)
0.029 M 0.029 M 3 gm 25 Poly(tetradecyl oleate-co-
decylmaleimide)
Poly(hexadecyl oleate-co-maleic anhydride)
0.029 M 0.029 M 3gm 22 Poly(hexadecyl oleate-co-decylmaleimide)
Poly(octadecyl oleate-co-
maleic anhydride)
0.028 M 0.028 M 3gm 24 PoIy(octadecyl oleate-co-decylmaleimide)
Poly(behenyI oleate-co-
maleic anhydride)
0.038 M 0.038 M 3.2 gm 22 Poly(behenyl oleate-co-decyl maleimide)

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 depressants 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 depressants of the invention were shown in the Table 1.4.
Table 1.4 : Pour point of crude oil after adding varying amount of pour point depressants of the invention in the oil.

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

1000 ppm 2000p pm 3000 ppm 1000 ppm 2000 ppm 3000 ppm
Poly(decyl oleate-co-decylmaleimide) [Alkyl chain length=C10] 39 15 15 12 24 24 27
Poly(dodecyl oleate -co-decylmaleimide) [Alkyl chain length=C12] 39 12 12 12 27 27 27
Poly(tetradecyl oleate -co-decylmaleimide) [Alkyl chain length=C14] 39 09 09 09 30 30 30
Poly(hexadecyl oleate -co-decylmaleimide) [Alkyl chain length=C16] 39 -3 -3 -6 42 42 45
PoIy(octadecyl oleate -co-decylmaleimide) [Alkyl chain length=C18] 39 -6 -12 -12 45 51 51

Poly(behenyl oleate -co-
decylmaleimide) 39 -15 -15 -09 54 54 48
[Alkyl chain length=C22]
According to the results of Table 1.4. the pour point depressants of the invention namely; poly(decyl oleate-co-decylmaleimide), poly(dodecyl oleate-co-decylmaleimide), poly(tetradecyl oleate-co-decylmaleimide), poly(hexadecyl oleate-co-decylmaleimide), poly(octadecyl oleate-co-decylmaleimide), poly(behenyl oleate-co-decylmaleimide) 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 -15° C as shown in the above table.
100 ppm and 500 ppm of various pour point depressants of Table 1.5 were added to Indian Beech/ Karanj {Millettia pinnata) and tested for their pour point depressant activity. The results of the pour point of the Indian Beech/ Karanj {Millettia pinnata) on addition of 100 ppm, and 500 ppm of various pour point depressants of the invention were shown in the Table 1.5.
Table 1.5 : Pour point of Indian Beech/ Karanj {Millettia pinnata) oil after adding varying amount of pour point depressant additives of the invention in the oil.

Pour Point Depressant Pour point of
Indian Beech/
Karanj {Millettia
pinnata) oil
(°0 Pour point of
PPD treated
Indian Beech/
Karanj {Millettia
pinnata) oil (°C) Extent of
depression in pour
point
(°C)

100 ppm 500 ppm 100 PPm 500 ppm
PoIy(decyl oleate-co-decylmaleimide) [Alkyl chain length=C10] 21 6 6 15 15
Poly(dodecyl oleate -co-
decylmaleimide)
[Alkyl chain length=C12] 21 6 3 15 18

Poly(tetradecyl oleate -co-
decylmaleimide) 21 3 3 18 18
[Alkyl chain length=C14]
Poly (hex adecyl oleate -co-
decylmaleimide) 21 -6 -9 27 30
[Alkyl chain length=C16]
Poly(octadecyl oleate -co-
decylmaleimide) 21 -9 -9 30 30
[Alkyl chain length=C18]
Poly(behenyl oleate -co-
decylmaleimide) 21 -15 -18 36 39
[Alkyl chain length=C22]
According to the results of Table 1.5, the pour point depressants of the invention namely; poly(decyl oleate-co-decylmaleimide), polyfdodecyl oleate-co-decylmaleimide), poIy(tetradecyl oleate-co-decylmaleimide), poly(hexadecyl oleate-co-decylmaleimide), poly(octadecyl oleate-co-decylmaleimide), and poly(behenyl oleate-co-decylmaleimide) has excellent pour point depressant activity in Indian Beech/ Karanj (Millettia pinnata) oil in range of concentration from 100 ppm to 500 ppm which will reduce the pour point up to maximum -18°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 oleate -co-alkylmaleimide) having general formula (I):

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


Formula (II) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
3. The poly(aikyl oleate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(dodecyl oleate -co-alkylmaleimide) of the formula (III):


wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
4. The poly(alkyl oleate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poJy(tetradecyl oleate -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 oleate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(hexadecyl oleate -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 oleate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(octadecyl oleate -co-alkylmaleimide) of the formula (VI):

wherein "X" represents number of "-CH2-" units and "n" represents number of operating units.
7. The poly(alkyl oleate -co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(behenyl oleate -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 oleate -co-alkylmaleimide) of formula (I):


Formula (I) Poly (alky 1 oleate-co-alkylmaleimide) wherein "R" represents do 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 oleic 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 oleic acid;
b. co-polymerizing the alkyl ester of oleic 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 to obtain a poly(alkyl
oleate-co-maleic anhydride) co-polymer; and
c. condensing the co-polymer with amine in the presence of activated 4° A molecular
sieves at 30°C to 150°C to obtain poly(alkyl oleate-co-alkylmaleimide) of formula
(I)-
9. The process as claimed in claim 8, wherein the C10 to C22 aliphatic 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 is selected from decyl amine, dodecyl amine, tetradecyl amine, hexadecyl amine, octadecyl amine or behenyl amine.
12. A crude oil comprising poly(alkyl oleate -co-alkylmaleimide) of formula (I) in range of concentration from 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point of the oil up to maximum -15° C.
13. Indian Beech/ Karanj {Millettia pinnata) oil comprising poly(alkyl oleate -co-alkylmaleimide) of formula (I) in range of concentration from 100 ppm to 500 ppm has excellent pour point depressant activity which will reduce the pour point of the oil up to maximum -18° C.