DESC:FIELD OF THE INVENTION:
The present invention relates to an improved and efficient process for derivatization of natural polysaccharides or gums. More preferably, these polysaccharides or gums are derivatized directly in form of endosperm occurring in seeds of various plants, mainly from Leguminosae seeds. The said process provides maximum and efficient derivatization in less time and also provides derivatized natural polymers with excellent polymeric properties useful in textiles, paints, construction and oil drilling industries.
BACKGROUND AND PRIOR ART:
Galactomannans are reserve polysaccharides consisting mainly of the monosaccharides, mannose and galactose units present in plant seed sources such as locust bean, guar, tara and tamarind. The majority of galactomannans originate from Leguminosae family.
Around 90-100 thousand tons of polygalactomannan (a class of natural polymer) is consumed per year throughout the world and it differs according to different sources.
The biggest consumption is of guar gum with 70-80 thousand tons followed by locust bean gum with 12-14 thousand tons.
Guar gum is procured from the endosperm part of Guar seed (Cyamopsistetragonoloba) which are principally grown in India, Pakistan, USA, Australia and Africa. Initially guar gum was most abundantly used in oil drilling industries as a rheology modifier in proppant formulation. Guar gum is a polysaccharide composed of galactose and mannose. The backbone is a linear chain of ß 1,4-linked mannose residues to which galactose residues are 1,6-linked at every second mannose, forming short side-branches and the ratio of mannose to galactose is 2:1. The average molecular weight of guar gum is 220000 to 300000 Daltons. On average 3 hydroxyl groups are available for derivatization on mannose or galactose sugar units in guar gum. The maximum theoretical degree of substitution (DS) in guar monomer is 3.
When Guar gum is used, it hydrates in cold water, but concerns about thermal stability, susceptibility to bacterial, enzymatic degradation and alcohol solubility. Solution to these problems led to the development of derivatized guar gum, wherein reactions of various derivatizing agent with hydroxyl groups has yielded wide range of modified/derivatized guar gums.
But later on, because of its cold water solubility, versatile chemistry and better thixotropic and stabilizing properties than other poly galactomannan like locust bean gum, guar gum and its derivatives found applications in textiles, paints and construction industries as an economic thickening and stabilizing agent.
One such category of derivatized guar is Hydroxyalkyl Guar which is basically hydroxyalkyl ether of guar gum. They are primarily synthesized by reacting alkyleneoxide with the guar gum. Hydroxypropyl Guar is used as a thickening, thixotropic, binding and water retaining agent in textiles, paints, construction and oil drilling industries. The dispersion in water or solvent and rheology properties of derivatized guar gum are highly dependent upon molar substitution and method of synthesis. There are numerous methods which are employed to increase the molar substitution of guar gum.
US 3,912,713 disclose a method for producing non-lumping derivatives of guar gum. The degree of substitution of acetyl groups is 0.08. The product gives a clear solution with no lumps or clots on stirring with water.
WO 2012159972 A1 discloses a method to produce Hydroxypropyl guar having molar substitution between 1.5 and 2.3, characterized by an unsubstituted mannose/galactose ratio higher than 5 and process for producing it.
However, such known Hydroxypropyl guar and related methods are not generally suitable for use in different formulation with wide pH range or formulation containing organic solvents due to its insolubility.
Other class of derivatives consists of cationic and anionic guar gums (charged guar gums) which are primarily synthesized by reacting etherifying agents such as halogen fatty acids (eg. Sodium monochloroacetic acid, etc), haloalkylsulphonic acids, cationic reagents (eg. 3-chloro-2- hydroxypropyltrimethylammonium chloride, etc.) and epoxy group containing compounds, usually referred to as epoxides (eg. 2,3-epoxypropyltrimethylammonium chloride, etc.). US3,912,713 and US,2003/0044479 describe the process for derivatizing guar with derivatizing agents stated above. US20100036114A1 describe the method for synthesis of cationic guar using 3-chloro-2- hydroxypropyl-trimethylammoniumchloride.
Different derivatives of guar, but also of Cassia and locust bean gum like anionic, cationic and nonionic need to develop very high viscosity in aqueous solution. In the textile industry they are used to thicken the dye baths in printing and dyeing of fibers, fabrics and carpets. The gums control the flow characteristics of the dye formulations, so that sharp, bright patterns can be achieved. For different types of cloth and dyestuff, different types of thickener with different type of viscosity-rheological properties are used.
Hence, the present inventors of present invention has developed an improved process of a derivatization wherein a controlled hydration steps to open maximum micro-pores and provides more active sites for further derivatization resulting into higher substituted, fast hydrating derivatized polysaccharides polymer having solubility in solution from pH 2 to pH 14. It is one of the object of the present invention to provide a process for derivatization of natural polymer which will produce maximum yield and provide a product having a wide range of pH stability and compatibility in organic solvents and excellent rheological properties. And also the said process is economic with reduced reaction time.
The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

SUMMARY OF INVENTION:
The present invention provides an improved process for derivatization of Polygalactomannan. The said improvement in process provides maximum and efficient derivatization in less time and also provides derivatized natural polymers with excellent polymeric properties useful in textiles, paints, construction and oil drilling industries. Wherein, as per inventive step of present invention, a controlled hydration steps to open maximum micro-pores and provides more active sites for further derivatization resulting into higher substituted, fast hydrating derivatized polysaccharides polymer having solubility in solution from pH 2 to pH 14.
The present invention provides a process for preparing higher substituted and fast hydrating derivatized Galactomannans, said process comprising of following steps:
a) Hydration of splits by addition of water at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
b) Hydration by addition of alkali at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
c) Addition of phase transfer catalyst for time ranging from 15 to 45 minutes,
d) Derivatization by addition of derivatizing agent at temperature range between 65-90oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 60 to 200 minutes under nitrogen gas environment,
e) Neutralization and Flaking,
f) Drying;

DETAILED DESCRIPTION OF INVENTION:
It should be noted that while the making and using of various embodiments of the present invention as discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as "a", "an" and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims.
Embodiments described herein relates to process for derivatization of galactomannans directly in form of endosperm of seeds, mainly from Leguminosae seeds
The present invention provides an improved process for derivatization of Polygalactomannan. The said improvement in process provides maximum and efficient derivatization in less time and also provides derivatized natural polymers with excellent polymeric properties useful in textiles, paints, construction and oil drilling industries.
According to a first aspect of the invention, a process for preparing higher substituted and fast hydrating derivatized Galactomannans, said process comprising of following steps:
a) Hydration of splits by addition of water at temperature range between 50-70ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
b) Hydration by addition of alkali at temperature range between 50-70ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
c) Addition of phase transfer catalyst for time ranging from 15 to 45 minutes,
d) Derivatization by addition of derivatizing agent at temperature range between 65-90ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 60 to 200 minutes under nitrogen gas environment,
e) Neutralization and Flaking,
f) Drying;
Wherein, the controlled hydration steps open maximum micro-pores and provides more active sites for further derivatization resulting into higher substituted, fast hydrating derivatized polysaccharides polymer having solubility in solution from pH 2 to pH 14.
The both said hydration and derivatization steps are conducted under inert gas environment.
Accordingly, to the present invention, the process for preparing higher substituted and fast hydrating derivatized Galactomannans, wherein the splits are selected from family Leguminosae seeds having atleast one cell wall storage polysaccharides selected from mannans, glucomannans and galactomannans. The alkali is sodium hydroxide, potassium hydroxide and the concentration of alkali in step b) is ranging from 40 to 80 % w/w total weight of reaction mass.
The derivatizing agent is selected from the group of 3-chloro-2-hydroxypropyltrimethylammonium chloride, ethylene oxide, propylene oxide, higher alkylene oxides and Sodium mono-chloro acetic acid, whereas the concentration of derivatizing agent is ranging from 50 to 80% of total weight of reaction mass.
The phase transfer catalyst is selected from group of quaternary ammonium salt, more preferably selected from cetyltrimethylammonium bromide, cetyltrimethylammonium chloride and Tertiarybutylammoium bromide, whereas the concentration of catalyst is ranging from 0.5 to 2.0% w/w by weight of total reaction mass.
The cross-linking agent is selected from sodium tetra borate in a concertation ranging from 0.1 to 0.5% w/w total reaction mass.
The dertivatizing agent is selected from range of 3-chloro-2-hydroxypropyltrimethylammonium chloride, ethylene oxide, propylene oxide or higher alkylene oxides and Sodium mono-chloro acetic acid (SMCA). The present invention is not limiting to process for preparation of semi-synthetic natural polymer derivative such as Hydroxypropyl guar, Cationic Guar (Hydroxypropyltrimethyl ammonium chloride guar)and Hydroxypropyl-Cationic guar.
According to a second aspect of the invention, an improved process for derivatizing a guar gum to produce cationic guar is provided. The said method comprises of steps:
a) Hydration of splits by addition of water at temperature range between 50-70ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
b) Hydration by addition of alkali at temperature range between 50-70ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
c) Cooling reaction mass to temperature between 10 to 30ºC and addition of alkali at pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment
d) Addition of phase transfer catalyst for time ranging from 15 to 45 minutes,
e) Derivatization by addition of derivatizing agent at temperature range between 45-90ºC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 60 to 200 minutes under nitrogen gas environment,
f) Cross-linking by addition of 0.1 to 0.5% w/w crosslinking agent
g) Neutralization and Flaking,
h) Drying.
The both said hydration and derivatization steps are conducted under inert gas environment and the said derivatizing agent is selected from ethylene oxide, propylene oxide or higher alkylene oxides, more preferably propylene oxide.
In this process, the higher substituted and fast hydrating hydroxypropyl guar having molar substitution from 0.5 to 2.5 is obtained. The resulting Hydroxypropyl Guar is stable across a wide pH range of 2-14, viscosity in water (2% w/w aqueous solution) ranging from 4000 to 23000 cps and viscosity in alcohol-water mixtures between 400 to 15000 cps.
One of the important aspects of the said process is method of hydration of guar split at elevated temperature and pressure before subsequent derivatization. The hydration scheme as per present invention helps to open up micro-pores in the splits and provide more active sites for derivatizing agent to react.
Second important aspect of the present invention is that, the said process favors the desired reaction of derivatization and reduces formation of glycol as a by-product.
The said process utilizes a Heterogeneous catalyst which is basically a quaternary ammonium salt (viz. cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), Tertiarybutylammoium bromide (TBAB), etc.) in concentration range from 0.5-2% by weight.
Finally flaking of derivatized guar is done using flaking rollers followed by grinding and drying to get high viscosity and fast hydrating guar derivative product.
The present invention is further described with the help of the following examples, which are given by way of illustration and therefore should not be construed to limit the scope of the invention in any manner.

EXAMPLES:
Example 1: Synthesis of Hydroxypropyl Guar:
1) The guar splits were kept in 100% wt of water for 1 hr. While water hydration step, the solution temperature was maintained between 50-70oC and Nitrogen pressure between 1.5-2.5 Kg/cm2.
2) Added 10% alkali sodium hydroxide maintaining the temperature between 50-70oC, and nitrogen pressure between 1.5-2.5 Kg/cm2 for 1 hr.
3) 2% by wt of Cetyltrimethylammonium bromide was added and mixed for15-45 minutes.
4) 80 %by wt of propylene oxide was added in above reaction mixture maintained at nitrogen pressure of 1.5-2.0 Kg/cm2andat temperature of 65-90oC.The said Reaction is carried out for 3 hr.
5) The product was neutralized and then flaked using flaking rollers, ground in a French mill (at 1200-1400 RPM) and then dried in a flash dryer (inlet air temperature being 120-140oC and average residence time of product being 3-5 seconds).
The Hydroxypropyl Guar thus obtained has molar substitution (MS) of 0.5 to 2.5. The moisture content is 2-10% (Wt% respect to final product, w/w). The Hydroxypropyl Guar obtained from the process has viscosity ranging from 4000 to 23000 cps in water (2% w/w aqueous solution), measured using Brookfield RVT viscometer at 20 RPM and 20oC. The Hydroxypropyl Guar obtained has excellent alcohol solubility, exhibiting viscosity between 400 to 15000 cps in alcohol-water mixtures of varying strengths. The Hydroxypropyl Guar is stable across a wide pH range of 2-14.

Example 2: Synthesis of Cationic Guar
1) The guar splits were kept in 100% wt of water for 1 hr. While water hydration step, the solution temperature was maintained between 50-70oC and Nitrogen pressure between 1.5-2.5 Kg/cm2.
2) Cooled the reaction mass below 300C and added excess 9% by wt of sodium hydroxide. Maintaining the nitrogen pressure between 1.5-2.5 Kg/cm2 for 1 hr.
3) Added certain amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride in above reaction mixture depending on required DS and maintained at nitrogen pressure of 1.5-2.0 Kg/cm2andat temperature of 45-60oC. The said Reaction is carried out for 3 hr.
4) 0.5% by wt of borax was added after derivatization to crosslink the polymer and washed with water.
5) The product was neutralized and then flaked using flaking rollers, ground in a French mill (at 1200-1400 RPM) and then dried in a flash dryer (inlet air temperature being 120-140oC and average residence time of product being 3-5 seconds).
The product thus obtained has a nitrogen content of 0.8-1.6% (Wt% respect to final product, w/w). Degree of substitution (DS) thus obtained is 0.15-0.2. Viscosity of cationic guar thus obtained can be 1000-4000cps in water (1% w/w aqueous solution), measured using Brookfield RVT viscometer at 20 RPM and 200C. Ash content of cationic guar obtained after washing is between 1-5% (Wt% respect to final product, w/w). Moisture content ranges between 5-10% (Wt% respect to final product, w/w).

Example 3: Synthesis of Hydroxypropyl Guar:
1) Guar used in the process is in the form of guar splits which are referred to as de-husked endosperms of guar seeds.
2) Before the derivatization step, splits are hydrated in two steps. First step of hydration is carried out by letting splits swell in presence of 40-100% (% respect to guar splits, w/w) water. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2(guage). Hydration time of 0.5-1 hour is provided.
3) Second step of hydration is carried out in presence of 1-10% alkali (viz. sodium or potassium hydroxide is used). Normally diluted alkali solution is preferred over concentrated alkali to avoid hydrolysis of guar. 8-10% w/waqueous solutions of alkali can be used in this step. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2(guage). Hydration time of 0.5-1 hour is provided.
4) After 2 steps of hydration and before derivatization, 0.5-2% phase transfer catalyst is added in form of solid or 15-30% w/w aqueous solution. Catalyst is added in small quantities just enough to coat the splits. Phase transfer catalyst can be any quaternary ammonium salt having formula R4N+X- salt (viz. Cetyltrimethylammonium bromide (CTAB), Cetyltrimethylammonium chloride (CTAC), Tertiarybutylammoium bromide (TBAB), etc.), where –R refers to alkyl/aryl group and X refers to halogen atom. All –R’s can be same or different. Mixing time of normally 15-45 minutes is provided for the catalyst to mix and coat the splits properly.
5) Before the addition of propylene oxide, a nitrogen blanket is maintained by keeping the nitrogen pressure of 1.5-2.0 Kg/cm2 in the reactor. The temperature during derivateization step is 65-90ºC. Now 10-80% propylene oxide is added step wise so as to maintain the reactor pressure between 2.0-2.5Kg/cm2 as at prevailing temperature and pressure the propylene oxide will be in gaseous state. Normally it takes about 0.5-3 hours for the added amount of propylene oxide to react.
6) The derivatization step is followed by neutralization or acidification based on the desired pH of the final product. Around 0.5-1% glyoxal can be added to improve the dispersibility of final product. The product is then flaked using flaking rollers, ground in a French mill (at 1200-1400 RPM) and then dried in a flash dryer (inlet air temperature being 120-140ºC and average residence time of product being 3-5 seconds).
The Hydroxypropyl Guar thus obtained has molar substitution (MS) of 0.5 to 2.5. The moisture content is 2-10% (% respect to final product, w/w). The Hydroxypropyl Guar obtained from the process has viscosity ranging from 4000 to 23000 cps in water (2% w/w aqueous solution), measured using Brookfield RVT viscometer at 20 RPM and 20ºC. The Hydroxypropyl Guar obtained has excellent alcohol solubility, exhibiting viscosity between 400 to 15000 cps in alcohol-water mixtures of varying strengths. The Hydroxypropyl Guar is stable across a wide pH range of 2-14.

Example 4:Synthesis of Cationic Guar:
1) Guar used in the process is in the form of guar splits which are referred to as de-husked endosperms of guar seeds.
2) Before the derivatization step, splits are hydrated in two steps. First step of hydration is carried out by letting splits swell in presence of 40-100% (with respect to guar) water. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2 (guage). Hydration time of 0.5-1 hours is provided.
3) Second step of hydration is carried out in presence of 1-10% alkali (viz. sodium or potassium hydroxide is used). Normally diluted alkali solution is preferred over concentrated alkali to avoid hydrolysis of guar. 8-10% w/w aqueous solutions of alkali can be used in this step. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2 (guage). Hydration time of 0.5-1 hours is provided.
4) After second step of hydration, the reaction mass is cooled to 10-30ºC and then excess 5-9 % alkali (sodium and potassium hydroxide) is added for the activation of guar. The reaction mass is cooled to10-30ºC to decrease the rate of hydrolysis in presence of excess alkali. Activation of guar is very important in the process of synthesizing cationic guar as it involves Williamson’s etherification reaction. Activation is referred to the formation of alkoxide (-ONa, -OK) group following reaction between the hydroxyl group of guar and alkali. Nitrogen pressure of 1.5-2.5 Kg/cm2 is maintained in the reactor. Activation time of 0.5-1 hour is given.
5) Following the activation step, activated guar is treated with cationic reagent viz. 3-chloro-2-hydroxypropyltrimethylammonium chloride at elevated temperature of 45-60oCand under nitrogen pressure of 1.5-2.5 Kg/cm2 for 1-3 hours. The desired degree of substitution (DS) decides the quantity of cationic reagent to be used. Normally 10-50% cationic reagent is used. The reaction is an exothermic reaction. Salts are formed as a byproduct.
6) 0.1-0.5% borax is added after derivatization to crosslink the polymer and decrease the product loss in the washing step. The obtained product is washed with water in 3 stages, the ratio of “water to product” being1.5 to 3 at each stage. Washing removes the unreacted cationic reagent and the byproduct salts.
The product thus obtained has a nitrogen content of 0.8-1.6% (% respect to final product, w/w). Degree of substitution (DS) thus obtained is 0.15-0.2. Viscosity of cationic guar thus obtained can be 1000-4000cps in water (1% w/w aqueous solution), measured using Brookfield RVT viscometer at 20 RPM and 20ºC. Ash content of cationic guar obtained after washing is between 1-5% (% respect to final product, w/w). Moisture content ranges between 5-10% (% respect to final product, w/w).

Example 5:Synthesis of Hydroxypropyl-hydroxypropyltrimethylammonium chloride guar):
1) Guar used in the process is in the form of guar splits which are referred to as de-husked endosperms of guar seeds.
2) Before the derivatization step, splits are hydrated in two steps. First step of hydration is carried out by letting splits swell in presence of 40-100% (with respect to guar) water. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2 (gauge). Hydration time of 0.5-1 hours is provided.
3) Second step of hydration is carried out in presence of 1-10% alkali (viz. sodium or potassium hydroxide is used). Normally diluted alkali solution is preferred over concentrated alkali to avoid hydrolysis of guar. 8-10% w/w aqueous solutions of alkali can be used in this step. Temperature is maintained between 50-70ºC, but generally should not exceed 65ºC to avoid de-polymerization by hydrolysis. Nitrogen pressure is maintained between 1.5-2.5 Kg/cm2 (gauge). Hydration time of 0.5-1 hours is provided.
4) After 2 steps of hydration and before derivatization, 0.5-2% phase transfer catalyst is added in form of solid or 15-30% w/w aqueous solution. Catalyst is added in small quantities just enough to coat the splits. Catalyst can be any quaternary ammonium salt having formula R4N+X- salt (viz. Cetyltrimethylammonium bromide (CTAB), Cetyltrimethylammonium chloride (CTAC), Tertiarybutylammoium bromide (TBAB), etc.), where –R refers to alkyl/aryl group and X refers to halogen atom. All –R’s can be same or different. Mixing time of normally 15-45 minutes is provided for the catalyst to mix and coat the splits properly.
5) Before the addition of propylene oxide, a nitrogen blanket is maintained by keeping the nitrogen pressure of 1.5-2.0 Kg/cm2in the reactor. The temperature during derivatization step is 65-90oC. Now 10-80% propylene oxide is added step wise so as to maintain the reactor pressure between 2.0-2.5Kg/cm2 as at prevailing temperature and pressure the propylene oxide will be in gaseous state. Normally it takes about 0.5-3 hours for the added amount of propylene oxide to react.
6) After the propylene oxide reacts with the guar to form Hydroxypropyl guar, the reaction mass is cooled to 10-30ºC and then excess 5-9% alkali (viz. sodium and potassium hydroxide) is added for the activation of Hydroxypropyl guar. The reaction mass is cooled to 10-30ºC to decrease the rate of hydrolysis in presence of excess alkali. Activation of guar is very important in the process of synthesizing cationic guar as it involves williamson’s etherification reaction. Activation is referred to the formation of alkoxide (-ONa, -OK) group following reaction between the hydroxyl group of guar and alkali. Nitrogen pressure of 1.5-2.5 Kg/cm2 is maintained in the reactor. Activation time of 0.5-1 hour is given.
7) Following the activation step, activated Hydroxypropyl guar is treated with the cationic reagent viz. 3-chloro-2-hydroxypropyltrimethylammonium chloride at elevated temperature of 45-60ºC and under nitrogen pressure of 1.5-2.5 Kg/cm2 for 1-3 hours. The desired degree of substitution (DS) decides the quantity of cationic reagent to be used. Normally 10-50% cationic reagent is used. The reaction is an exothermic reaction. Salts are formed as a byproduct.
8) 0.1-0.5% borax is added after double derivatization of guar to crosslink the polymer and decrease the product loss in the washing step. The obtained product is washed in 3 stages with water, the ratio of “water to product” being 1.5 to 3 in each stage. Washing removes the phase transfer catalyst, unreacted cationic reagent and the byproduct salts.
The double derivative thus obtained has better solution transparency(1% w/w aqueous solution) compared to simple cationic guar. It has higher nitrogen content of 1.5-2.0% (% respect to final product, w/w). Degree of substitution (DS) thus obtained is 0.15-0.3. Viscosity of the double derivative thus obtained can be 1000-2000cps in water (1% w/w aqueous solution), measured using Brookfield RVT viscometer at 20 RPM and 20ºC.
Dated this 03rd Day of January 2018.
,CLAIMS:CLAIMS
We claim,
1. A process for preparing higher substituted and fast hydrating derivatized Galactomannans, said process comprising of following steps:
a) Hydration of splits by addition of water at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
b) Hydration by addition of alkali at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
c) Addition of phase transfer catalyst for time ranging from 15 to 45 minutes,
d) Derivatization by addition of derivatizing agent at temperature range between 65-90oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 60 to 200 minutes under nitrogen gas environment,
e) Neutralization and Flaking,
f) Drying;
Wherein, the controlled hydration steps open maximum micro-pores and provides more active sites for further derivatization resulting into higher substituted, fast hydrating derivatized polysaccharides polymer having solubility in solution from pH 2 to pH 14.
2. The process as claimed in claim 1, wherein the said process further comprising of following steps:
a) Hydration of splits by addition of water at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
b) Hydration by addition of alkali at temperature range between 50-70oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
c) Cooling reaction mass to temperature between 10 to 30oC and addition of alkali at pressure range between 1.5-2.5 Kg/cm2 for time ranging from 30 to 60 minutes under nitrogen gas environment,
d) Addition of phase transfer catalyst for time ranging from 15 to 45 minutes,
e) Derivatization by addition of derivatizing agent at temperature range between 45-90oC and pressure range between 1.5-2.5 Kg/cm2 for time ranging from 60 to 200 minutes under nitrogen gas environment,
f) Cross-linking by addition of 0.1 to 0.5% w/w crosslinking agent,
g) Neutralization and Flaking,
h) Drying.

3. The process as claimed in claim 1, wherein the splits are selected from family Leguminosae seeds having atleast one cell wall storage polysaccharides selected from mannans, glucomannans and galactomannans.

4. The process as claimed in claim 1, wherein the alkali is sodium hydroxide and potassium hydroxide.
5. The process as claimed in claim 1, wherein the concentration of alkali in step b) is ranging from 40 to 80 % w/w total weight of reaction mass.
6. The process as claimed in claim 1, wherein the derivatizing agent is selected from the group of 3-chloro-2-hydroxypropyltrimethylammonium chloride, ethylene oxide, propylene oxide, higher alkylene oxides and Sodium mono-chloro acetic acid.
7. The process as claimed in claim 1, wherein the concentration of derivatizing agent is ranging from 50 to 80% of total weight of reaction mass.
8. The process as claimed in claim 1, wherein the phase transfer catalyst is selected from group of quaternary ammonium salt, more preferably selected from cetyltrimethylammonium bromide, cetyltrimethylammonium chloride and Tertiarybutylammoium bromide.
9. The process as claimed in claim 1, wherein the concentration of catalyst is ranging from 0.5 to 2.0% w/w by weight of total reaction mass.
10. The process as claimed in claim 2, wherein the cross-linking agent is selected from sodium tetra borate in a concertation ranging from 0.1 to 0.5% w/w total reaction mass.

Dated this 03rd Day of January 2018.