Title of Invention

SORBATE MALEATE COPOLYMER, PREPARATION AND USE AS AN ANTISCALANT

Abstract The present invention relates to a copolymer comprising a monocarboxyiic acid and a dicarboxylic acid and a process for producing the same. The monocarboxyiic acid in the copolymer of the present invention is sorbic acid and the dicarboxylic acid is maleic anhydride. The sorbic-maleic copolymer of the present invention may further include a monocarboxyiic acid or a dicarboxylic acid to increase the efficiency of the copolymer. The sorbic-maleic copolymer of the present invention has good antiscalant properties. The present invention also provides a process for producing sorbic-maleic copolymer.
Full Text FORM 2
THE PATENTS ACT. 1970 (39 of 1970)
COMPLETE SPECIFICATION [See section 10; Rule 13]
SORBATE MALEATE COPOLYMER, PREPARATION AND USE AS AN ANTISCALANT;




THE GODAVARI SUGAR MILLS
LTD., A COMPANY
INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS FAZALBHOY BLDG., 45/47, MAHATMA GANDHI ROAD, FORT, MUMBAI - 400 001, MAHARASHTRA, INDIA.


103 2
24 SEP 2004THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFOMED.

TITLE
SORBATE/MALEATE COPOLYMER, PREPARATION AND USE AS AN ANTISCALANT
TECHNICAL FIELD
The present invention relates to a copolymer for use such as for example an antiscalant in industries.
BACKGROUND
In industries such as chemical and biochemical industries, reactors and boilers are used to carryout the reaction. Specially, when chemicals like calcium, magnesium, phosphates, silicates and the like are used in a reaction, more often the salts of calcium, phosphates get deposited on the reactors or boilers. It is found to be difficult to remove the deposits from the reactors or boilers during cleaning processes.It is known in the art to use antiscalants to prevent the deposition of salts of calcium, phosphate and the like on the wall of the reactors. Different polymers are used to control different types of scale. Maleate-based polymers, along with phosphonates are used to control calcium carbonate scale. US Patent No. 4,711,725 discloses sulphonate-based polymers to control calcium phosphate, iron and other particulates.US4390670 entitled "Acrylate/maleate copolymers, their preparation and use as antiscalants" discloses substantially homogeneous acrylate/maleate copolymers of number average molecular weight of 500 to 5000 are prepared by copolymerizing 35 to 65 mole percent

acrylic or methacrylic acid with 65 to 35 mole percent maleic anhydride at 80° to 150° C. in the presence of a polymerization initiator and a chain-transfer solvent such that both the monomers and the formed polymer remain in solution and the mole ratio of the acrylic or methacrylic acid monomer to the maleic anhydride monomer in the solvent is maintained below about 0.2 throughout the polymerization. The copolymers in hydrolyzed form are employed at a level of from about 0.1 to 100 ppm for prevention of alkaline calcium and magnesium scale formation, such as during seawater evaporative desalination. However, this polymer is much suitable as an antiscalant for water treatment processes and other related processes only. Moreover, this polymer contains around 35 to 65 mole percent of acrylic acid and hence may not be suitable for use in food industries.
Therefore, there is a need for an antiscalant that can be widely used in all the industries and has good antiscalant properties.
It is the object of the present invention to provide a copolymer with better antiscalant properties suitable for various industries. It is also another object of the present invention to provide copolymers with antiscalant properties for food industries.
SUMMARY OF INVENTION
The present invention relates to a copolymer and a process for preparing the same. The copolymer of the present invention comprises a monocarboxylic acid and a dicarboxylic acid. One of the preferred embodiment of the present invention for monocarboxylic

acid is sorbic acid and the dicarboxylic acid is maleic anhydride. The sorbic-maleic copolymer of the present invention has good antiscalant properties.
The sorbic-maleic copolymer of the present invention may further include a monocarboxylic acid or a dicarboxylic acid. The monocarboxylic acid may be acrylic acid, methacrylic acid, crotonic acid or mixtures thereof. The dicarboxylic acid may be fumaric acid, itaconic acid or maleic acid or mixtures thereof.
The process for preparing said sorbic-maleic copolymer of the present invention comprising :
(a) reacting a mixture of monocarboxylic acid and dicarboxylic acid in the presence of polymerization initiator and a solvent at a temperature between 80 °C and 140 °C purging dry nitrogen for 2 to 20 hrs.;
(b) cooling the reaction mixture to room temperature;
(c ) filtering the copolymer from the unreacted monomers;
(d) washing the copolymer with excess of solvent;
(e) drying the copolymer at 80°C for 2 hours
(f) neutralizing the copolymer using an alkali.
The sequestering value of the sorbate-maleate copolymer is between 100 to 360 mg of Calcium carbonate per gm of polymer (100% solids basis).

The sorbate-maleate copolymer of present invention has good antiscalant properties. The sequestering values range from 100 to 360mg of Calcium carbonate per gm of polymer. Therefore, the copolymer is best suitable as an antiscalant for various industries including food industries.
DETAILED DESCRIPTION OF INVENTION
The present invention relates to a copolymer comprising a monocarboxylic acid and a dicarboxylic acid and a process for producing the same.
The copolymer according to the present invention comprises sorbic acid as the monocarboxylic acid and maleic anhydride as the dicarboxylic acid. The sorbate-maleate copolymer of the present invention comprises 45 to 65 mole percent of sorbic acid; 55 to 35 mole percent of maleic anhydride; preferably in the range of 50 to 60 mole percent of sorbic acid and 50 to 40 mole percent of maleic anhydride. The number average molecular weight of the copolymer is in the range of 500 to 5000. The sequestering value of the sorbate-maleate copolymer is between 100 to 360 mg of Calcium carbonate per gm of polymer (100% solids basis).
The sorbic-maleic copolymer of the present invention is a bioproduct and shall be used in food industries also.The sorbate-maleate copolymer of the present invention may further include another a monocarboxylic acid and/ or dicarboxylic acid to improve the efficiency of the copolymer of the present invention.

The further monocarboxylic acid may be selected from the group comprising acrylic acid, methacrylic acid, crotonic acid, or mixtures thereof.
The further dicarboxylic acid may be selected from the group comprising fumaric acid, itaconic acid or maleic acid or mixtures thereof.
The preferred embodiment of the present invention includes the sorbate-maleate copolymer further comprising a monocarboxylic acid selected from the group comprising acrylic acid, methacrylic acid, crotonic acid, or mixtures thereof and/ or dicarboxylic acid selected from the group comprising fumaric acid, itaconic acid or maleic acid or mixtures thereof. 0-40 mole percent of monocarboxylic acid and/ or dicarboxylic acid is added to the sorbate-maleate copolymer, which shows to increase the efficiency of sorbate-maleate copolymer of the present invention.
The process for preparing sorbate-maleate copolymer comprising:
(a) reacting a mixture of monocarboxylic acid and dicarboxylic acid in the presence of polymerization initiator and a solvent at a temperature between 80 °C and 140 °C purging dry nitrogen for 2 to 20 hrs.;
(b) cooling the reaction mixture to room temperature,
(c) filtering the copolymer from the unreacted monomers,
(d) washing the copolymer with excess of solvent to remove unreacted monomers, .

(e) drying the copolymer at 80 °C for 2 hours,
(f) neutralizing the copolymer using an alkali to make an aqueous solution.
The preferred embodiment of the process includes reacting 45 to 65 mole percent of sorbic acid and 55 to 35 mole percent of maleic anhydride in the presence of benzoyl peroxide as a polymerization initiator and methyl ethyl ketone as a solvent at 85°C for 16 hours, filtering the copolymer from the unreacted monomer and washing the copolymer with methyl ethyl ketone. The copolymer is dried at 80 °C for 2 hours and neutralized with sodium hydroxide.The polymerization initiator is preferably selected from dialkyl peroxides peroxides such as di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 and from diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide and succinic acid peroxide. The initiator is utilized at a level of from about 0.1-10 percent by weight of the combined monomers and is either added in its entirety at the start of the polymerization or over a period of time as a solution in the solvent. The preferred initiator is benzoyl peroxide at a level of about 0.1-5 weight percent of the monomer charged.
The solvents used for washing the copolymer is preferably selected from Methyl ethyl ketone, xylene, toluene, methyl isobutyl ketone, n-pentanone, and n-hexanone. The dried copolymer is neutralized to form an aqueous solution of the alkali metal, ammonium or amine salt. Alkali metal bases suitable for

the neutralization include sodium hydroxide, potassium hydroxide and lithium hydroxide, while suitable ammonium and amine bases include ammonia, ammonium hydroxide, mono-, di- and trialkyl amines having 1 to 5 carbon atoms in each alkyl group, pyridine, morpholine and lutidine.
Sorbate maleate copolymer according to present invention is prepared as below:
To a round bottom flask equipped with a reflux condenser, thermometer, nitrogen inlet and a mechanical stirrer were charged sorbic acid, maleic anhydride, methyl ethyl ketone, and benzoyl peroxide. The reaction mixture was agitated to ensure proper mixing of the raw materials. The flask was purged with dry nitrogen while the resulting solution was heated under agitation to reflux the system being maintained thereafter under a static nitrogen pressure. The polymerization solution was refluxed for 16 hours and methyl ethyl ketone was distilled out. The reaction mixture was cooled till room temperature when a solid mass separated. The solid mass was filtered out and washed with of methyl ethyl ketone and dried at 80. degree. C for 2 hours. The resulting copolymer was neutralized using sodium hydroxide to make an aqueous solution.
The sorbate-maleate copolymer according to present invention has good antiscalant properties. The sequestering values range from 100 to 360 mg of Calcium carbonate per gm of polymer (100% solids basis).

Therefore, the copolymer is best suitable for aqueous systems in various industries which involve the use chemicals that form scales on reactors, boilers etc.Further, the sorbate-maleate copolymer is also suitable for food industries such as sugar industries as sorbic acid and maleic acid are of food grade. Even with the addition of a further monocarboxylic acid such as acrylic acid, the quantity of acrylic acid is only 0 to 40 mole percent and is still suitable for food industries. Further, sorbic acid is a by-product of sugar industry, and the polymer may be produced in the sugar industry at a very low cost of production.Further, the copolymer may also be used as a dispersant in paints and as a water reducing agent in cement and clay industries.
The invention will be further clarified by use of the following example, which are not intended to restrict the scope of the invention.
EXAMPLE 1
To a 4-neck, 500 ml round flask equipped with a reflux condenser, thermometer, nitrogen inlet and a mechanical stirrer, 33.6g sorbic acid, 29.4g maleic anhydride, 147.Og methyl ethyl ketone, 0.063g benzoyl peroxide were added. The reaction mixture was agitated to ensure proper mixing of the raw materials. The flask was purged with dry nitrogen while the resulting solution was heated under agitation to reflux (about 85. degree. C), the system being maintained thereafter under a static nitrogen pressure. The polymerization solution was refluxed for 16 hours and 90.Og of methyl ethyl ketone was distilled out. The reaction mixture was cooled till room temperature (about 27.

degree. C.) when a solid mass separated. The solid mass was filtered out and washed with 50.Og of methyl ethyl ketone and dried at 80. degree. C for 2 hours. The resulting copolymer was neutralized using 36.Og sodium hydroxide to make an aqueous solution.
The sequestration value of the polymer was found by the following method
Test method for determination of sequestration value.
Sequestration.
0.5 N Calcium acetate solution was prepared and standardized . Accurately 2.0 ±0.1 g of the sample was weighed in a weighing bottle and transferred it quantitatively into a 250 ml beaker with the help of DM water. The pH of the solution was adjusted to 8.0 with dropwise addition of 1N NaOH. To this solution 10 ml of 2% Na2C03 solution was added and pH was adjusted to 11.0 using 1N NaOH. The volume of the solution was adjusted to 150 ml with DM water and titrated with 0.5N Calcium acetate solution. 1 ml of titrant was added at a time on continuous stirring till the precipitate dissolves. Smaller increments of titrant was added towards the end point. The pH of the solution was kept constant at 11.0 throughout the titration. Appearance of a permanent faint turbidity as viewed against a black background indicated the endpoint. The sequestration value , expressed as the milligrams of CaCO3 per gram of sample was calculated using the formula:Sequestration value = 50 X R X N / W Where, R = volume of Ca acetate solution consumed in ml

N =normality of Ca acetate solution as determined by titration with EDTA, and W = weight of the sample in grams.
Threshold inhibition of calcium carbonate and calcium sulfate
This test was performed by mixing solutions of sodium carbonate or sodium sulfate with enough calcium chloride to yield a supersaturated solution. The inhibition effectiveness was measured by calcium analysis of the inhibited, or treated, solution and the uninhibited, or untreated solution. More calcium was present in the inhibited solution because calcium precipitation was reduced.
CALCIUM CARBONATE TEST
In order of mixing to a 500 ml Erlenmeyer flask, 490 ml distilled water (minus inhibitor solution volume), 5 ml 0.1 M sodium carbonate solution, 0.1% of inhibitor (sorbate maleate copolymer) solution (usually 0.5 to 2.5 ppm inhibitor on 500 ml volume), 5 ml 0.1 M calcium chloride solution were added. The flask was stoppered loosely and stored at 66. degree C. in an oven for 24 hours. After ageing 24 hours at 66. degree C, 50 ml of the clear supernatant liquid was pipetted into the flask, taking care not to get any of the floating calcium scale into the sample. Then 2ml of 1 N caustic, three drops of Murexide (Ammonium purpurate) indicator solution was added , and titrated with standard EDTA from pink to blue. Two blanks were prepared without inhibitor and one blank was titrated immediately and produced about 100 ppm CaCO3 before precipitation occurred. The other blank was stored at 66 degree C for 24 hours and produced

about 24 ppm CaC03. The inhibited samples produced an intermediate level of carbonate.
The inhibition efficiency was calculated as described below:
ppm CaC03 = (ml EDTA ,0.01 N) (1000) / sample weight = (ml EDTA , 0.01 N) (20)
Inhibitor efficiency, % = ppm, inhibited - ppm, precipitated blank
ppm, unprecipitated blank - ppm, precipitated blank
All the samples were run in duplicate and titration agreed with 0.1 ml.
CALCIUM SULFATE TEST.
To a 500 ml Erienmeyer flask, 450 ml distilled water (minus inhibitor solution volume), 25 ml 1M sodium sulfate solution, 0.1% inhibitor sorbate maleate copolymer solution (usually 2 to 25 ppm inhibitor on 500 ml volume), 25 ml 1M calcium chloride solution were added and stoppered loosely and stored at 66. degree C in a oven for 24 hours. After ageing 24 hours at 66. degree C, 2 ml of the clear supernatant liquid was pipetted out into 50ml distilled water in a flask, taking care not to get any of the floating scale into the sample. To the solution, 2ml of 1 N caustic, three drops of Murexide (Ammonium purpurate) indicator solution was added and titrated with standard EDTA (0.01 N) solution from salmon to red.
Two blanks were prepared without inhibitor and one blank was titrated immediately and produced about 6800 ppm calcium sulfate before precipitation occurs. The other blank was stored at 66. degree C for

24 hours and produced about 2800 ppm calcium sulfate. The inhibited samples produced an intermediate level of sulfate.
The inhibitor efficiency was then calculated as described below:
ppm CaS04 = (ml EDTA , 0.01 N) (1360) / Sample weight = (ml EDTA, 0.01 N) (680)
Inhibitor efficiency, % = ppm, inhibited - ppm, precipitated blank
ppm, unprecipitated blank - ppm, precipitated blank
All the samples were run in duplicate and titration agreed with 0.1 ml.
Table 1 shows the inhibitor efficiency.
Table 1

Mole percent of Sequestration Threshold inhibition Threshold inhibition
monomers value mg of of calcium carbonate of calcium sulfate
Sorbic acid / maleic Calcium carbonate per



anhydride / gm of
acrylic acid polymer
Method of
polymerization
as per example 1 ppm Inhibitor ppm Inhibitor
used efficiency used efficiency

50/50/0 198 01 0.50 02 0.788





02 0.31 04 0.788

45/50/5 165 01 0.31 02 0.89





02 0.77 04 0.67

40/50/10 107.5 01 0.62 02 0.91





02 0.35 04 0.85

25 / 50 / 25 150 01 0.31 02 0.83





02 0.62 04 0.85

WE CLAIM
1. A copolymer comprising a monocarboxylic acid and a dicarboxylic acid.
2. A copolymer as claimed in claim 1 wherein said copolymer comprises 45 to 65 mole percent of monocarboxylic acid and 55 to 35 mole percent of dicarboxylic acid.
3. A copolymer as claimed in claims 1 or 2 wherein comprises 50 to 60 mole percent of monocarboxylic acid and 40 to 50 mole percent of dicarboxylic acid.
4. A copolymer as claimed in claims 1 to 3 wherein the monocarboxylic acid is sorbic acid.
5. A copolymer as claimed in claims 1 to 4 wherein the dicarboxylic acid is maleic anhydride.
6. A copolymer as claimed in claims 1 to 5 wherein the number average molecular weight of the copolymer is in the range of 500 to 5000.
7. A copolymer as claimed in any of the preceding claims wherein further comprises 0 to 40 mole percent of, monocarboxylic acid and /or dicarboxylic acid. 8.A copolymer as claimed in claim 7 wherein the monocarboxylic acid is from a group comprising of acrylic acid, methacrylic acid, crotonic acid or mixtures thereof and the dicarboxylic acid is from a group comprising of fumaric acid, itaconic acid maleic acid or mixtures thereof.

9. A process for producing copolymer as claimed in claims 1 to 8
comprising the steps of:
(a) reacting a mixture of monocarboxylic acid and dicarboxylic
acid in the presence of polymerization initiator and a solvent
at a temperature between 80 °C and 140 °C purging dry
nitrogen for 2 to 20 hrs.;
(b) cooling the reaction mixture to room temperature;
(c) filtering the copolymer from the unreacted monomers;
(d) washing the copolymer with excess of solvent;
(e) drying the copolymer at 80°C for 2 hours;
(f) neutralizing the copolymer using an alkali.

10 A process as claimed in claim 9 wherein the polymerization initiator is selected from the group comprising dialkyl peroxides peroxides such as di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 and from diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide and succinic acid peroxide.
11 A process as claimed in claim 9 & 10 wherein the solvent used for washing the copolymer is selected from the group comprising methyl ethyl ketone, xylene, toluene, methyl isobutyl ketone, n-pentanone, and n-hexanone.

12 A process as claimed in claims 9 to 10 wherein alkali used for neutralization of copolymer is selected from the group comprising
sodium hydroxide, potassium hydroxide and lithium hydroxide, while suitable ammonium and amine bases include ammonia, ammonium hydroxide, mono-, di- and trialkyi amines having 1 to 5 carbon atoms in each alkyl group, pyridine, morpholine and lutidine.
13 A copolymer as claimed in claims 1-9 wherein the sequestering value is 100 to 360mg of CaC03 per 100 gram.
14 A copolymer as claimed in claims 1 to 11 wherein the copolymer is an antiscalant.
15 A copolymer as claimed in claims 1 to 12 wherein the copolymer is a dispersant.
16 A copolymer as claimed in claims 1 to 13 wherein the copolymer is a water reducing agent for cement and clays.
Dated this 24th day of September, 2004.
FOR THE GODAVARI SUGAR MILLS LTD. By their Agent
(UMA BASKARAN) KRISHNA & SAURASTRI

Documents:

1032-mum-2004-abstract(24-09-2004).doc

1032-mum-2004-abstract(24-09-2004).pdf

1032-MUM-2004-ABSTRACT(GRANTED)-(24-5-2012).pdf

1032-MUM-2004-CANCELLED PAGES(17-4-2012).pdf

1032-mum-2004-claims(24-09-2004).doc

1032-mum-2004-claims(24-09-2004).pdf

1032-MUM-2004-CLAIMS(AMENDED)-(10-4-2012).pdf

1032-MUM-2004-CLAIMS(AMENDED)-(17-8-2011).pdf

1032-MUM-2004-CLAIMS(AMENDED)-(18-5-2012).pdf

1032-MUM-2004-CLAIMS(GRANTED)-(24-5-2012).pdf

1032-MUM-2004-CLAIMS(MARKED COPY)-(17-8-2011).pdf

1032-MUM-2004-CLAIMS(MARKED COPY)-(18-5-2012).pdf

1032-MUM-2004-CORRESPONDENCE(10-09-2008).pdf

1032-MUM-2004-CORRESPONDENCE(18-5-2012).pdf

1032-mum-2004-correspondence(24-04-2004).pdf

1032-MUM-2004-CORRESPONDENCE(9-3-2010).pdf

1032-MUM-2004-CORRESPONDENCE(IPO)-(24-5-2012).pdf

1032-MUM-2004-DESCRIPTION(GRANTED)-(24-5-2012).pdf

1032-mum-2004-form 1(24-09-2004).pdf

1032-mum-2004-form 13(17-8-2011).pdf

1032-MUM-2004-FORM 18(10-09-2008).pdf

1032-mum-2004-form 2(complete)-(24-09-2004).doc

1032-mum-2004-form 2(complete)-(24-09-2004).pdf

1032-MUM-2004-FORM 2(GRANTED)-(24-5-2012).pdf

1032-MUM-2004-FORM 2(TITLE PAGE)-(GRANTED)-(24-5-2012).pdf

1032-mum-2004-form 3(24-09-2004).pdf

1032-mum-2004-form 5(24-09-2004).pdf

1032-mum-2004-form 6(9-3-2010).pdf

1032-MUM-2004-GENERAL POWER OF ATTORNEY(9-3-2010).pdf

1032-MUM-2004-MARKED COPY(10-4-2012).pdf

1032-MUM-2004-OTHER DOCUMENT(9-3-2010).pdf

1032-MUM-2004-REPLY TO EXAMINATION REPORT(17-8-2011).pdf

1032-MUM-2004-REPLY TO HEARING(10-4-2012).pdf

1032-MUM-2004-SPECIFICATION(AMENDED)-(10-4-2012).pdf


Patent Number 252624
Indian Patent Application Number 1032/MUM/2004
PG Journal Number 22/2012
Publication Date 01-Jun-2012
Grant Date 24-May-2012
Date of Filing 24-Sep-2004
Name of Patentee GODAVARI BIOREFINERIES LTD
Applicant Address SOMAIY BHAVAN, 45/47, MAHATMA GANDHI ROAD, FORT,MUMBAI-400 001, MAHARASHTRA,INDIA
Inventors:
# Inventor's Name Inventor's Address
1 JYOTI P PHADKE 3/78, PRATIRAKSHANAGAR, CO.HSG.SOC. LTD. VACOLA BRIDGE, SANTACRUZ (E), MUMBAI - 400055,
2 VINOD C. MALSHE OLD HOSTEL, 3RD FLOOR, MUMBAI UNIVERSITY INSTITUTE OF CHEMICAL TECHNOLOGY, MATUNGA, MUMBAI - 400 019,
3 SANGEETA SRIVASTAVA 1001, BHASKARA, TIFR COLONY, COLABA, MUMBAI - 400 005
PCT International Classification Number C07D305/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA