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 undecylenate-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 undecylenate-co-alkylmaleimide) having formula (I):

Formula (I) poly(alkyl undecylenate-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 :
In transformers the oil provides two major functions; the first as an insulator and the second as a heat transfer medium to dissipate 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, mineral and synthetic 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 oil at lower temperatures, i.e., the PPDs lower the pour point of the 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 depressants for oil.
Another object of the invention is to provide pour point depressants for oil which is economical.

Another object of the invention is to provide a process for the preparation of pour point depressants which is simple, easy and convenient to carry out and is economical.
DETAILED DESCRIPTION OF THE INVENTION:
According to one of the embodiment of the invention, there is provided poly(alkyl undecylenate-co-alkylmaleimide) having general formula (I):

Formula (I) poly(alkylundecylenate-co-alkylmaieimide) wherein "R" represents C10o 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 undecylenate-co-alkylmaleimide) of formula (I) are as follows:
1. Poly(decyI undecylenate-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 undecylenate-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 undecylenate-co-alkylmaleimide) of the formula (IV):


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

Formula (VI) wherein "X" represents number of "-CH2-" units and "n" represents number of operating units;
and
6. PoIy(behenyl undecylenate-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 undecylenate-co-alkylmaleimide) of formula (I) are as follows: 1. Poly(decyl undecylenate-co-octadecylmaleimide) of the formula (VIII);

Formula (VIII) wherein "n" represents number of operating units;
2. Poly(dodecyI undecylenate -co-octadecylmaleimide) of the formula (IX):

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

3. PoIy(tetradecyl undecylenate -co-octadecylmaleimide) of the formula (X):

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

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


5. Poly(octadecyl undecylenate -co-octadecylmaleimide) of the formula (XII):
Formula (XII) wherein "n" rdepresents number of operating units;
and
6. Poly(behenyl undecylenate -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 undecylenate-co-alkylmaleimide) having formula (I):
Formula (I)
poly(alkyl undecylenate -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 undecylenic 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 undecylenic acid;
b. copolymerizing the alkyl 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 to obtain a poly(alkyl undecylenate-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 to obtain poly(alkyl undecylenate-co-alkylmaleimide).
The C10 to C22 aliphatic alcohol is selected from decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, behenyl alcohol, etc.

Preferably, the organic solvent is selected from dry toluene, dry benzene, methanol, or dry 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 any suitable aliphatic or aromatic amine including decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecyl amine, behenylamine etc.
Preferably, the amine used is octadecyl amine.
The invention also provides oil comprising poly(alkyI undecylenate-co-alkylmaleimide) of formula (I) having pour point depressant in the oil.
The oil comprises 1000 to 3000 ppm of poly(alkyl undecylenate-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 undecylenate-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 -3°C.
According to another embodiment of the invention, the rapeseed oil comprising poly(alkyl undecylenate-co-octadecylmaleimide) having general formula (I) in range of concentration from 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point up to maximum -12°C.
Poly(alkyl undecylenate-co-alkyimaleimide) 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, behenyl alcohols and undecylenic 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 undecylenic acid was esterified with C10, C12, C14, C16, C18 and C22 straight chain aliphatic alcohols (i.e. decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol andbehenyl alcohol) 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 undecylenic 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 alkvl undecylenate

Reactants Toluene ml H2SO4 ml
Undecylenic acid mole Fatty Alcohol mole

Alkyl undecylenate
0.052 M Decyl alcohol 0.026 M 70 0.2 Decyl undecylenate
0.052 M Dodecyl alcohol 0.026 M 60 0.2 Dodecyl undecylenate
0.052 M Tetradecyl alcohol 0.026 M 70 0.2 Tetradecyl undecylenate

0.052 M Hexadecyl alcohol 0.026 M 80 0.2 Hexadecyl undecylenate
0.064 M Octadecyl alcohol 0.032 M 80 0.2 Octadecyl undecylenate
0.040 M Behenyl alcohol 0.020 M 70 0.2 Behenyl
undecylenate
The alkyl undecylenate 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 10 hours to give poly(alkyl undecylenate-co-maleic anhydride). The resulting poly(aIkyl undecylenate-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 125mm Hg for 5 hours. Table 1.2 illustrates the quantities of the reactants used in the copolymerization reaction.
Table 1.2 : Data related to preparation of po!y(alkyl undecylenate-co-maleic anhydride)

Reactants
Alkyl undecylenate Maleic Azobisisobuty-

(mole) anhydride ronitrile gm Benzene Copolymer
(mole) (%wt. of total monomers) ml
Decyl undecylenate 0.020 M 0.020 M 0.1% 50 poly(decyl undecylenate -co-maleic anhydride)
Dodecyl undecylenate 0.021 M 0.1% 50 poly(dodecyl undecylenate-
0.021 M co-maleic anhydride)
Tetradecyl 0.020 M poly(tetradecyl
Undecylenate
0.1% 50 undecylenate-co-maleic
0.020 M anhydride)

Hexadecyl 0.019 M poIy(hexadecyI
undecylenate
0.1% 50 undecylenate -co-maleic
0.019 M anhydride)
Octadecyl
undecylenate 0.018 M 0.1% 50 poly(octadecyl undecylenate -co-maleic
0.018 M anhydride)
Behenyl 0.013 M poly(behenyl undecylenate -
Undecylenate
0.1% 20 co-maleic anhydride)
0.013 M
The anhydride copolymers were condensed with the 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 undecylenate-co-octadecylmaleimide), poly(dodecyl undecylenate-co-
octadecylmaleimide), poly(tetradecyl undecylenate-co-octadecylmaleimide), poly(hexadecyl undecylenate-co-octadecylmaleimide), poly(octadecy] undecylenate-co-octadecylmaleimide) and poly(behenyl undecylenate-co-octadecylmaleimide).
Table 1.3 : Data related to preparation of poly(a!kyl undecylenate-eo-octadecylmaleimide)

Reactants Solvent (ml)
Copolymer (mole) Octadecyl Amine
(mole) Activated 4° A molecular sieves
Pour Point Depressants
Poly(decyl undecylenate-co-maleic anhydride) 0.013 M 0.013 M 3gm 40 Poly(decyl undecylenate-co-octadecylmaleimide)
PoIy(dodecyl
undecylenate-co-maleic
anhydride)
0.011 M 0.011 M 3 gm 30 Poly(dodecyl
undecylenate -co-
octadecylmaleimide)
Poly(tetradecyl
undecylenate-co-maleic
anhydride)
0.011 M 0.011 M 3gm 40 Poly(tetradecyl
undecylenate -co-
octadecylmaleimide)

Poly(hexadecyl
undecylenate-co-maleic
anhydride)
0.012 M 0.012 M 3gm 30 Poly(hexadecyl
undecylenate -co-
octadecylmaleimide)
Poly(octadecyl
undecylenate-co-maleic
anhydride)
0.011 M 0.011 M 3gm 30 Poly(octadecyl
undecylenate -co-
octadecylmaleimide)
PoIy(behenyI
undecylenate-co-maleic
anhydride)
0.0075 M 0.0075 M 3gm 30 Poly(behenyI
undecylenate -co-
octadecylmaleimide)
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 virgin 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 of PPD 2000 ppm of PPD 3000 ppm of PPD 1000 ppm of PPD 2000 ppm of PPD 3000 ppm of PPD
Pofy(decyl undecylenate-co-octadecylmaleimide) [Alkyl chain length=Cio] 39 30 30 30 9 9 9

Poly(dodecyl undecylenate -
co-octadecylmaleimide) 39 30 29 29 9 10 10
[Alkyl chain length=C12]
Poly(tetradecyl undecylenate -
co-octadecylmaleimide) 39 24 27 30 15 12 10
[Alkyl chain length-C14]
Poly(hexadecyl undecylenate
-co-octadecylmaleimide) 39 18 15 15 21 24 24
[Alkyl chain fength=C16]
Poly(octadecyl undecylenate -
co-octadecylmaleimide) 39 09 09 03 30 30 36
[Alkyl chain length=C18]
Poly(behenyl undecylenate -
co-octadecylmaleimide) 39 3 -3 -3 36 42 42
[Alkyl chain length=C22]
According to the results of Table 1.4, the pour point depressant additives of the invention namely;
poly(decyl undecylenate-co-octadecylmaleimide), poly(dodecyl undecylenate-co-
octadecylmaleimide), poly(tetradecyl undecylenate-co-octadecylmaleimide), poly(hexadecyl undecylenate-co-octadecylmaleimide), poly(octadecyl undecylenate-co-octadecylmaleimide), poly(behenyl undecylenate-co-octadecylmaleimide) has 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 -3°C as shown in the above table. Particularly; poly(behenyl undecylenate-co-octadecylmaleimide) have excellent pour point depressant activity in crude oil
1000 ppm, 2000 ppm and 3000 ppm of various pour point depressants of Table 1.5 were added to Rapeseed Oil and tested for their pour point depressant activity. The results of the pour point of the Rapeseed Oil on addition of 1000 ppm, 2000 ppm and 3000 ppm of various pour point depressants of the invention were shown in the Table 1.5.

Table 1.5 : Pour point of Rapeseed oil after adding varying amount of pour point depressants of the invention in the oil.

Pour Point Depressant Pour point
of
Rapeseed
oil(°C) Pour point of PPD treated Rapeseed oil
(°C) Extent of depression in pour point
(°C)

1000 ppm of PPD 2000 ppm of PPD 3000 ppm of PPD 1000 ppm of PPD 2000 ppm of PPD 3000 ppm of PPD
Poly(decyl undecylenate-co-
octadecylmaleimide)
[Alkyl chain length=Cio-] 7 -3 -3 -3 10 10 10
Poly(dodecyl undecylenate -
co-octadecylmaleimide)
[Alkyl chain length=C|2-] 7 -3 -3 -3 10 10 10
Poly(tetradecyl undecylenate -
co-octadecylmaleimide)
[Alkyl chain length=Ci4-] 7 -9 -9 -9 16 16 16
Poly(hexadecyl undecylenate -
co-octadecylmaleimide)
[Alkyl chain length=C}6-] V -12 -9 -9 19 16 16
PoIy(octadecyl undecylenate -
co-octadecylmaleimide)
[Alkyl chain length=Ci8-] 7 -3 -3 3 10 10 4
Poly(behenyl undecylenate -
co-octadecylmaleimide)
[Alkyl chain length=C22-] 7 -3 -3 -3 10 10 10
According to the results of Table 1.5, the pour point depressants of the invention namely;
poly(decyl undecylenate-co-octadecylmaleimide), poly(dodecyl undecylenate-co-
octadecylmaleimide), poIy(tetradecyl undecylenate-co-octadecylmaleimide), poIy(hexadecyl undecylenate-co-octadecylmaleimide), poly(octadecyl undecylenate-co-octadecylmaleimide) and po!y(behenyl undecylenate-co-octadecylmaleimide) has pour point depressant activity in rapeseed oil in range of concentration from 1000 ppm to 3000 ppm which will reduce the pour point up to maximum -12°C as shown in the above table. Particularly, poly(tetradecyl undecylenate-co-octadecylmaleimide) and poly(hexadecyl undecylenate-co-octadecylmaleimide) have excellent pour point depressant activity in rapeseed oil

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. A poly(alkyl undecylenate-co-alkylmaleimide) having general formula (I);

Formula (I) poly(alkyl undecylenate -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.
2. The poly(alkyl undecylenate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(decyl undecylenate-co-alkylmaleimide) of the formula (II);


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

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

4. The poly(alkyl undecylenate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(tetradecyl undecylenate-co-alkylmaleimide) of the formula (IV);

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

Formula (V)
5. The poly(alkyl undecylenate-co-alkylmaleimide) having general formula (I) as claimed in claim 1, which is poly(hexadecyl undecylenate-co-alkylmaleimide) of the formula (V);

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

Formula (I) poly(alkyl undecylenate -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 undecylenic 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 undecylenic acid;
b. copolymerizing the alkyl 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 to obtain a po!y(alkyl undecylenate-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 to obtain poly(alkyl undecylenate-co-maleic anhydride) of formula (I).
9. The process as claimed in claim 9, 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 used in step (b) is selected from dry toluene, benzene, methanol or xylene.
11. The process as claimed in claim 8, wherein amine used in step (c) is selected from aliphatic or aromatic amine including decylamine, dodecylamine, tetradecylamine, hexadecyl amine, octadecyl amine or behenyl amine.
12. A crude oil comprising poly(alkyl undecylenate-co-octadecylmaleimide) having general formula (I) in a of concentrations of 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point up to maximum -3°C.

13. Rapeseed oil comprising poly(alkyl undecylenate-co-octadecylmaleimide) having general formula (I) in range of concentration from 1000 ppm to 3000 ppm has excellent pour point depressant activity which will reduce the pour point up to maximum -12°C.