AU2011322203B2 - Ethyl oligo-silicates with strong acid heterogenous polymeric catalysts - Google Patents

Abstract

The present invention provides a process for the synthesis of ethyl silicate with varying silica concentration, by hydrolysing ethyl silicate in varying water concentration in the presence of sulfonated catalysts having a styrene-divinyl benzene backbone. The present invention further relates to the preparation of beaded crosslinked polymers containing sulfonic acid moieties having an interconnected pore structure and surface area up to 400 m

Description

WO 2012/056290 PCT/IB2011/002531 1 ETHYL OLIGO-SILICATES WITH STRONG ACID HETEROGENOUS POLYMERIC CATALYSTS FIELD OF INVENTION The present invention relates to the hydrolysis of ethyl silicate using sulfonated polymeric 5 bead catalysts synthesized using high internal phase emulsion methodology. The present invention further relates to the preparation of beaded crosslinked polymer having aromatic rings present in the polymer backbone and is synthesized using water-in oil-in water emulsion technique which is further modified so as to introduce sulfonic acid groups on the polymer backbone. 10 BACKGROUND OF THE INVENTION The tetraethyl ortho silicate (EtO) 4 Si possess excellent thermal stability and liquid behavior over a broad temperature range. Ethylsilicate-32 is used as binders in paints and coatings. It is also used as room temperature silicone for vulcanizing cross linking agents. Ethyl silicate 15 40 has a stable and long shelf life. It is primarily used as binders in paints, coatings, ceramic and precision casting and is also used as silicone room temperature vulcanizing agents. Ethyl silicate-28 is used as binders in paints, coatings, precision casting and ceramics. The number indicates the silica content present in the sample. Intermediate ethoxy derivatives of silicic acid and polysilicates are formed during the hydrolysis of ethyl silicate before the formation 20 of silicon dioxide. The hydrolysis can be acid or base catalyzed. The rate of acid catalyzed hydrolysis is faster as compared to base catalyzed reactions and gives rise to more linear polymers due to sol gel transformation. Depending on the applications the catalysts can be chosen. For binder preparation dilute hydrochloric acid or sulphuric acid is used as it facilitates stable silanol condensation products. Basic catalysts like ammonia, ammonium 25 carbonate are preferred when more complete condensation or gelation is preferred. Hydrolysis of ethyl silicate in the presence of acidic and alkaline catalysts have been elaborated to produce ethyl silicate hydrolysates of the desired degree of hydrolysis by CONFIRMATION

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WO 2012/056290 PCT/IB2011/002531 2 varying the reaction parameters such as catalyst concentration, water concentration, reaction temperature and time. US4393230 describes the process for having a controlled process for predetermined silica 5 content. Tetraethyl orthosilicate is prepared by reacting silicon tetrachloride and ethanol. If water is present in ethanol it forms ethyl polysilicate and if excess of ethyl silicate is present it forms polymeric products. By predetermined amounts of silicon dioxide (SiO 2 ) is meant within the range of the reaction wherein water is one of the reactants, which produces a product which contains about 28.8% SiO 2 , up to that amount where SiO 2 is precipitated out 10 of solution (about 53% SiO 2 content). Therefore the stoichiometry involved in the complete hydrolysis of (EtO) 4 Si and, complete condensation of the hydrolysate can be represented as: (EtO) 4 Si + 4HOH o 4EtOH + Si(OH) 4 Si(OH) 4 P 2 HOH + SiO 2 15 (EtO) 4 Si + 2 HOH 1 4EtOH + SiO 2 The equations indicate that 2 moles of water would be required for the complete hydrolysis of 1 mole of (EtO) 4 Si. The hydrolysis reaction is random so that an amount of water 20 equivalent to partial hydrolysis would yield initially a distribution of (EtO) 4 Si, (EtO) 3 SiOH, (EtO) 2 Si(OH) 2 , (EtO)Si(OH) 3 and Si(OH) 4 The reaction can be monitored with the disappearance of water and appearance of ethanol. 25 US4290811 describe a process for hydrolysis of ethyl silicate in presence of strong acid ion exchange resin instead of conventional acid catalyst. The conventional acids used are sulphuric acid and hydrochloric acid but the residual acidity can create problems of instability of ethyl silicate and pot life stability. The use of heterogeneous catalyst minimizes the work up procedure and problems related to removal of acid traces left behind in the 30 reaction mixture. Conventional ion exchange resins like Amberlyst 15 (trade mark of Rohm and Hass Company) have been reported for the hydrolysis of ethylsilicate.

WO 2012/056290 PCT/IB2011/002531 3 The chief disadvantage of the reactions done using homogeneous catalysts is contamination of product due to presence of catalyst such as sulfuric acid and the necessity of an additional difficult and expensive unit operation for the removal of catalysts by treating with salts that 5 may be critical during processing and applications of the resin, disposal of the waste generated by treatments. This can be circumvented using heterogeneous catalysts which may be removed easily by filtration after the reaction and reused many times without loss in catalyst activity. 10 The present invention relates to hydrolysis of tetraethyl orthosilicate using a highly porous polymeric catalyst, very much higher than Amberlyst- 15 having styrene divinyl benzene backbone. The cross-linked polymer is synthesized in beaded form using high internal phase emulsion methodology. The polymers have interconnected pore structure, variable surface area in the range of 100-400 m 2 /g depending on the synthesis strategy while the surface area 15 of commercially available macroreticular resin Amberlyst-15 is 42.5 m 2 /g as reported by R. Kunin, E. A. Meitzner, J. A. Oline, S. A. Fischer, N. Frish (Ind. Eng. Chem. Prod Res. Dev., 1962, 1 (2), pp 140-144). The aromatic ring on the polymer backbone is postmodified to adhere the sulfonic acid moieties onto it. The surface accessible sulfonic acid groups determine the catalytic efficiency of the heterogeneous catalyst. The problems like charring 20 of the reaction mixture by direct use of the strong acid are circumvented by the use of heterogeneous acid catalyst. The present inventors have surprisingly found that use of catalysts such as beaded polymers containing sulfonic acid moieties prepared by High internal phase emulsion polymer technique provides for efficient hydrolysis of ethyl silicate so as to provide catalysts with silica content in the range 32-40%. 25 Beaded polymers containing sulfonic acid moieties can be synthesised using suspension polymerization methodology to be used in chromatographic applications. The bead size, particle size distribution, surface accessible functional groups, pore structure and porosity play an important role in the efficiency of the polymer application. The properties of the 4 polymers are dependent on the reaction parameters like protective colloid type and nature, stirring speed, reactivity ratio of monomer and crossliker, The beads can be post modified to introduce ilnctional groups like sulphonic acid., amin hydroxyl, t-butyl so as to make the polymer support hydrophobic or hydrophilc to be used in chromatographic applications such as ion exchange, gel filtration, adsorption and affinity chromatography. US 5863957 describes a process for synthesis ot porous crosslinked polymeric nucrobeads having cavities joined by interconnecting pores wherein at least some of the cavities are connected to the outer surface. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field, OBJECT OF INVENTION It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful aitemative. It is the primary object of a preferred embodiment of the invention to provide a process for the synthesis of ethyl silicate with varyig silica concentration. It is an object of a preferred embodiment of the invention to provide a process fir the hydrolysis of ethyl silicate in the presence of sulfonated catalyst synthesized using high internal phase emulsion methodology. It is an object of a preferred embodiment of the invention to provide a process for the hvdrolysis of ethyl silicate in the presence of beaded crosslinked polymers oii suion acid moieties and synthesized using high intemal phase emulsion niethodology and having An interconnected pore structure It is yet another object of a preferred embodiment of the invention to provide a Process for the synthesis of beaded crosslinked polymers having an interconnected pore structure and surface area up to 400 nV/g. It is yet another object of a preferred embodiment of the invention to prepare beaded crosslinked polymers which is post modified to provide sulfonic aeid groups in the polymer backbone, SUMMARY OF THE INVENTION According to a first aspect ofthe invention there is provided a process for the hydrolysis of ethyl silicate comprising the steps of: a) adding tetraethyl orthosilicate and water in a range of 0.5 to 5,55 wt% of the amount of tetraethyl orthosilicate to a container; b) adding sulfonated polymeric beads surface area in the range of 100 ng to 400 m 2g to the reaction mixture; C) heating the reaction Mixture to u2p to 600C and maintaining it for up to 10 hours; d) analysing the reaction mixture for tetraethyl orthusilicate and ethanol; c) determining the amount of silica content; f) removing the sulfonated polyimeric beads after the reaction is complete; optionally reusing the sulfonated polymeric beads for the hydroysis process. According to a second aspect of the Invention there is provided a process for the hydrolysis of ethyl silicate as defined in. the first aspect; Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise""comprising and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to" Also described is a process for the hydrolysis of ethyl silicate comprising the steps of: 6 a) Adding tetraethyl orthosilicate and water in the range of 0.5 to 5 wt% of tetraethylorthosilicate to a container b) Adding sultonated polymeric beads having surtace area in the range of 100 n 2 /g to 400 nI/g to the reaction mixture, c) Heating the reaction mixture to up to 60C and maintaining it for up to 10 hours; d) Analysing the reaction mixture or tetraethyl orthosilicate and ethanol; e) De n the amount of silica content; ft) Removing the sulfonated poly-mric beads after the reaction is complete; g) Optionally reusing the sulfoiated polymeric beads for the hvdrolysis process. Also described is a process for the preparation of polymeric beads bearing sulfn'ic acid moieties on the polymer backbone with an interconnected pore structure and comprising the steps of a) Preparing water in oil phase emulsion by the following steps: i) combining an oil phase containing styrene as monomer, cross linker, surfatant, porogen and initiator; ii) Adding aqueous discontinuous phase to the oil phase to form a water in oil emulsion under constant stirring: b) Adding the water in oil enmlsion to an aqueous phase containing a protective colloid wider constatnt stirring at a rate of 250-500 rotations per minute; c) Polymer izirg the emulsion droplets under constant stirring at higher temperature for a period of up to 12 hours to obtain polymeric beads having a surface area of up to 400 m~.g d) Adding sulfuric acid to the polymeric beads and heating at 11O" for a period of 24 hours to obtain sulfonated polymeric beads. DETAILED DESCRIPTION OF INVENTION The present invention provides a Process for having a controlled silica concentration in ethyl silica t i.Si .ontent. This can be achieved by hydrolysis of ethyl. silicate using requisite quantity of water in presence of a sulfonated polymeric bead catalyst such as beaded crosslinked polymers containing sulfonic acid moieties 6a The hydrolysis of ethyl silicate comprises the steps of a) Adding tetraethyl rthosilnicate and water in the range of 0?5 to 5 wt% of tctraethylorthosilicate 'to a container; b) Adding sulfbnated polymeric beads ha i suface area in the range of 100 n 2 /g to 400 n// to the reaction mixture; c) Heating the reaction mixture to 60T and maintaining it for up to 10 hours; d) Analysing the reaction mixture for tetraethyl ortnosilicate and ethanol; e) Determining the amount of silica content; f) Removing the sulfonated polymeric beads after the reaction is complete; g) Optionally reusing the suifonated polymeric heads for the hydrolysis process, In an. embodiment of the invention, hydrolysis of tetraethyl ortho silicate is done by varying the concentration of water depending on the quantity of SiO2 required in the product. In yet another embodiment, the hydrolysis is carried out with variation in concentration of water and sulfonated polymeric bead catalyst. In vet another embodiment the hydrolysis is carried out in the presence of used sulfdnated polymeric bead catalyst. The inolar ratio of tetraethyl ontho silicate and water is in the range 1-: 0006 up to 1:0,64.

WO 2012/056290 PCT/IB2011/002531 7 The molar ratio of tetraethyl ortho silicate and sulfonated polymeric bead catalyst is 1:0.1. The molar ratio of water and sulfonated polymeric bead catalyst is in the range 1:0.15 upto 1:1.54. 5 The surface area of the catalyst used is in the range 100- 400 m 2/g and is preferably in the range of 100- 350 m2/g. The percentage of hydrolysis and the silica content of the hydrolysed product depend on the 10 quantity of water used which is preferably in the range of 0.5 to 5% of tetraethyl orthosilicate. The present invention further relates to the synthesis of beaded crosslinked porous polymers having interconnected pore structure. The process deals with polymerization of oil in water 15 type emulsion by suspension polymerization technique to generate polymers in beaded form. The process consists of two steps. It is a water-in-oil-in-water emulsion i.e. the innermost water phase is surrounded by oil phase which in turn is surrounded by external phase. In first step, water in oil emulsion is prepared and in the second phase oil in water emulsion is 20 formed by suspending the water in oil emulsion in the form of droplets in a reactor containing protective colloid which is stirred at constant rpm. So the second phase forms oil in water emulsion and hence the polymerization is water in oil in water type of system. The process for the preparation of polymeric beads having an interconnected pore structure 25 and having sulfonic acid moieties on the polymer backbone comprising the steps of: a) Preparing water in oil phase emulsion by the following steps: i) combining an oil phase containing styrene monomer, crosslinker, surfactant, porogen and initiator; WO 2012/056290 PCT/IB2011/002531 8 ii) Adding aqueous discontinuous phase to the oil phase to form a water in oil emulsion under constant stirring at a rate of 350-1400 rotations per minute; b) Adding the water in oil emulsion to an outer aqueous phase containing a protective 5 colloid under constant stirring at a rate of 300 rotations per minute; c) Polymerizing the emulsion droplets under constant stirring at higher temperature for a period of upto 12 hours to obtain polymeric beads having a surface area of up to 400 d) Adding sulfuric acid to the polymeric beads and heating at 11 0 0 C for a period of 24 10 hours to obtain sulfonated polymeric beads. The monomer used in the present invention is styrene. The concentration of monomer in oil phase is 80% with respect to surfactant and initiator. 15 The crosslinker used in the present invention is selected from divinyl benzene, ethylene dimethacrylate. The concentration of the crosslinker to be used in the present invention varies from 0.05 to 2.0 times of the monomer concentration. 20 The concentration of monomer in oil phase is 15 wt % with respect to surfactant and initiator. The initiator used is 2,2'-azobisisobutyronitrile and is 3 mole % of monomer phase. 25 The surfactant to be used in the present invention is Span in the range of Span 20 to Span 80. The porogen to be used in the present invention is selected from chlorobenzene, toluene and heptane.

WO 2012/056290 PCT/IB2011/002531 9 The ratio of the monomer to porogen in the present invention varies from 1: 0.5 to 1: 2. The porogen concentration comprises of 50 % upto 200 % of the monomer. 5 The pore volume range depends on the porogen used and is preferably in the range of 0.2 cm 3 /g to 0.6 cm 3 /g. The surface accessible functional groups are in the range of 2.8-3.9 milli equivalents per gram. 10 In formation of water in oil phase the water can be 5:1 upto 30:1 with respect to monomer and during suspension polymerization is 10 times to 20 times of the oil phase. The stirring speed during the preparation of water in oil phase emulsion can be varied from 15 350 rotations per minute to 1400 rotations per minute. The protective colloid prevents the coalescence of the polymeric beads during the sticky period of polymerization and polymer is obtained in the form of beads at the end of the reaction. The basic function of protective colloid is to increase the viscosity of the aqueous 20 phase. The protective colloid to be used in the present invention is selected from poly vinyl (pyrrolidone), poly (vinyl alcohol), sodium chloride or calcium chloride. The concentration of protective colloid to be used in the present invention varies from 0.5 wt % up to 2 wt % of the aqueous phase. 25 WO 2012/056290 PCT/IB2011/002531 10 The stirring speed of the suspended particles in the present invention can be varied from 250 rotations per minute up to 500 rotations per minute. EXAMPLES 5 The process of the present invention is described herein below with reference to the following examples, which are only illustrative in nature and should not be construed to limit the scope of the invention in any manner. Example 1 10 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate with 28% silica content and 0.05 g (0.0028 mol) of water are taken. To the reaction mixture 1.032 g of sulfonated (poly (styrene-divinyl benzene) catalyst having surface area of 330 m 2 /g and synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 604C for a period of ten hours. The reaction mixture was then 15 analysed for tetraethyl orthosilicate and ethanol by gas Chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. 33.3% of hydrolysis was achieved with respect to ethyl silicate and silica content was determined by gravimetric method and was found to be about 30 %. 20 Example 2 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.100 g (0.0056 mol) of water are taken. To the reaction mixture 1.032 g of sulfonated (poly (styrene divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60"C for a period of ten hours. 25 The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. 46% of hydrolysis was achieved with respect to ethylsilicate and silica content was determined by gravimetric method and was found to be about 32 %.

WO 2012/056290 PCT/IB2011/002531 11 Example 3 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.201 g (0.0112 mol) of water are taken. To the reaction mixture 1.032 g of sulfonated (poly (styrene 5 divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60"C for a period of ten hours. The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. 50% of hydrolysis was achieved with 10 respect to ethylsilicate and silica content was determined by gravimetric method and was found to be about 34 %. Example 4 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.502 g 15 (0.0279 mol) of water are taken. To the reaction mixture 1.032 g of sulfonated (poly (styrene divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60 0 C for a period of ten hours. The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous 20 catalyst followed by distillation to remove ethanol. 87% of hydrolysis was achieved with respect to ethylsilicate and silica content was determined by gravimetric method and was found to be about 37 %. Example 5 25 The reaction as illustrated in Example 2 was repeated to check the reusability of the catalyst. The concentration of ethanol and tetra ethyl orthosilicate in the reaction mixture was analyzed using gas chromatography and silica content by gravimetric analysis, is as follows: WO 2012/056290 PCT/IB2011/002531 12 Cycle % Ethanol % tetraethyl % Silica content orthosilicate 1 60.4 12.8 42 2 13.1 52.2 33 3 12.2 69.7 30 The silica content in the starting tertaethylorthosilicate is 28%. The amount of water used is 0.1 g (0.0056 mol). 5 Example 6 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.05 g (0.028 mol) of water are taken. To the reaction mixture 0.516 g of sulfonated (poly (styrene divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60*C for a period of ten hours. 10 The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. The silica content was determined by gravimetric method and was found to be about 30 %. 15 Example 7 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.05 g (0.028 mol) of water are taken. To the reaction mixture 1.548 g of sulfonated (poly (styrene divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60 0 C for a period of ten hours. 20 The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. The silica content was determined by gravimetric method and was found to be about 34 %.

WO 2012/056290 PCT/IB2011/002531 13 Example 8 The reaction as illustrated in Example 2 was repeated with varying reaction time and reaction temperature keeping the other parameters same. The silica content was analyzed by gravimetric analysis: 5 When the reaction was run for two and half hours, the silica content obtained was 30% and when the reaction was run for five hours, the silica content obtained was 36%. When the reaction was run for ten hours at 40 0 C, the silica content obtained was 38% and 10 when the reaction was run for ten hours at 80 0 C, the silica content obtained was 45%. Example 9 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.05 g (0.0028 mol) of water are taken. To the reaction mixture 0.516 g of sulfonated (poly (styrene 15 divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 60C for a period of five hours. The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas Chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. The silica content was determined by 20 gravimetric method and was found to be about 32 %. Example 10 In a stoppered plastic container 9.020 g (0.0433 mol) tetraethyl orthosilicate and 0.05 g (0.0028 mol) of water are taken. To the reaction mixture 0.516 g of sulfonated (poly (styrene 25 divinyl benzene) synthesized using high internal phase emulsion polymerization methodology was added. The reaction mixture was heated at 40 0 C for a period of five hours. The reaction mixture was then analysed for tetraethyl orthosilicate and ethanol by gas Chromatography (GC). The reaction mixture is then filtered to remove the heterogeneous catalyst followed by distillation to remove ethanol. The silica content was determined by 30 gravimetric method and was found to be about 32 %.

WO 2012/056290 PCT/IB2011/002531 14 Example 11 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 80 surfactant and 5 0.15 g (9.34x10 4 mole) of azobisisobutyronitrile, 4.5 mL chlorobenzene as porogen (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a 10 double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the 15 temperature of reactor is increased upto 70 0 C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 298 m 2 /g. 20 Sulphonation of beads: All the polymers synthesized as illustrated in Examples 1 to 5 are subjected to post modification reaction to introduce sulphonic acid groups on the polymer backbone. For 8.96 g (100 % CLD) poly(styrene-divinyl benzene) beads, 45 mL (98 %) sulphuric acid (0.449 mol) is added. The reaction mixture is heated at 11 0*C for a period of 24 hours. After 25 the reaction is completed the reaction mixture is poured in water. The beads are filtered and washed several times with water. The beads are dried overnight in a vacuum oven at 80 0

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WO 2012/056290 PCT/IB2011/002531 15 Example 12 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 80 surfactant, 0.15 g (9.34x104 mole) of azobisisobutyronitrile and 4.5 mL toluene as porogen (continuous 5 phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a 10 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70'C and maintained for a period of 12 hours. After 15 the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 293 m 2 /g. The sulfonation step is carried out in the same manner as described in example 11. 20 Example 13 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 80 surfactant, 0.15 g (9.34x10Q4 mole) of azobisisobutyronitrile and 4.5 mL heptane as porogen (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil 25 phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a WO 2012/056290 PCT/IB2011/002531 16 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the 5 temperature of reactor is increased upto 70 0 C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 357 m 2 /g. The sulfonation step is carried out in the same manner as described in example 11. 10 Example 14 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 1.116 g Span 80 surfactant, 0.15 g ( 9

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34 x104 mole) of azobisisobutyronitrile and 4.5 mL chlorobenzene as porogen 15 (continuous phase) is taken. 98.16 mL of deionised water (discontinuous phase) are added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a 20 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70 0 C and maintained for a period of 12 hours. After 25 the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 333 m 2 /g.

WO 2012/056290 PCT/IB2011/002531 17 Example 15 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 1.116 g Span 80 surfactant, , 0.15 g (9.34x104 mole) of azobisisobutyronitrile and 4.5 mL toluene as porogen (continuous 5 phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a 10 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70 0 C and maintained for a period of 12 hours. After 15 the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 274 m 2 /g. Example 16 20 Preparation of water in oil phase (HIPE): In a container 1.54 g (0.0148 mol) styrene monomer, 2.94 g (0.0148 mol) crosslinker ethylene glycol dimethacrylate, 0.982 g Span 80 surfactant, 0.15 g (9.34x104 mole) of azobisisobutyronitrile and 5.4 mL toluene as porogen (continuous phase) are taken. 116.3 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 25 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil WO 2012/056290 PCT/IB2011/002531 18 emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70'C and maintained for a period of 12 hours. After 5 the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 114 m2/g. Example 17 10 Preparation of water in oil phase (HIPE): In a container 1.54 g (0.0148 mol) styrene monomer, 2.94 g (0.0148 mol) crosslinker ethylene glycol dimethacrylate, 0.982 g Span 80 surfactant, 0.15 g (9.34x10 4 mole) of azobisisobutyronitrile and 5.4 mL chlorobenzene as porogen (continuous phase) are taken. 116.3 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a 15 period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL 20 aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70*C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface 25 area of 108 m 2 /g. Example 18 Preparation of water in oil phase (HIPE): In a container 1.54 g (0.0148 mol) styrene monomer, 2.94 g (0.0148 mol) crosslinker ethylene glycol dimethacrylate, 1.346 g Span 80 WO 2012/056290 PCT/IB2011/002531 19 surfactant, 0.15 g ( 9

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3 4 xlO4 mole) of azobisisobutyronitrile and 5.4 mL chlorobenzene as porogen (continuous phase) are taken. 116.3 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. 5 Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per 10 minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70'C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 133 m 2 /g. 15 Example 19 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 20 surfactant, 0.15 g (9.34x10-4 mole) of azobisisobutyronitrile and 4.5 mL chlorobenzene as porogen 20 (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a 25 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the WO 2012/056290 PCT/IB2011/002531 20 temperature of reactor is increased upto 70"C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 275 m 2 /g. 5 Example 20 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 20 surfactant, 0.15 g (9.34x10 4 mole) of azobisisobutyronitrile and 4.5 mL toluene as porogen (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil 10 phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil 15 emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 1 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70'C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, 20 filtered, washed several times with water and then dried. The beads obtained had a surface area of 250 m 2 /g. Example 21 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 80 surfactant, 0.15 25 g (9.34x10 4 mole) of azobisisobutyronitrile and 4.5 mL toluene as porogen (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes.

WO 2012/056290 PCT/IB2011/002531 21 Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL 5 aqueous phase with 2 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70 0 C and maintained for a period of 12 hours. After the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface 10 area of 275 m 2 /g. Example 22 Preparation of water in oil phase (HIPE): In a container 1.65 g (0.0158 mol) styrene monomer, 2.07 g (0.0158 mol) crosslinker divinyl benzene, 0.818 g Span 80 surfactant, 0.15 g (9.34x1 04 mole) of azobisisobutyronitrile and 4.5 mL chlorobenzene as porogen 15 (continuous phase) are taken. 98.16 mL of deionised water (discontinuous phase) is added to the oil phase with constant stirring of 1400 rpm to obtain water in oil emulsion for a period of 10 minutes. Suspension polymerization of the oil phase: The suspension polymerization is carried out in a double walled cylindrical glass reactor maintained at a constant temperature, equipped with a 20 condenser, nitrogen inlet and overhead stirrer with constant stirring. The water in oil emulsion prepared as above is added to the suspension reactor comprising of a 200 mL aqueous phase with 0.5 wt % protective colloid at a constant stirring rate of 300 rotations per minute. After the complete addition of the water in oil phase to the outer aqueous phase the temperature of reactor is increased upto 70"C and maintained for a period of 12 hours. After 25 the completion of the reaction time the product obtained in the form of beads is cooled, filtered, washed several times with water and then dried. The beads obtained had a surface area of 290 m 2 /g.

Claims (2)

1. 2-2 CLAIMS 1. A process for the hydrolysis of ethyl silicate comprising the steps of: a) adding tetraethyl orthoslicate and water in a range of 0.5 to 5.55 wt% of the amount of tetraethvl orthosl icate to a container; b) adding sulfonated polymeric beads surface area in the range of 100 mg to 400 ng to the reaction mixture; c) heating the reaction mixture to up to 60C and maintaining it for up to 10 hours; d) analysing the reaction mixture for tetrathy orthosilicate and ethanol e) determining the amount of silica content; removing the sulfbnated polymeric beads afler the reaction is complete; g) optionally reusing the sulfonated polymeric beads for the hydrolysis process, 2, A process for the hydrolysis of ethyl silicate according to claim i, wherein the molar ratio of tetraethyl or ho silicate and water is in the range 1:0 0065 upto 1:0.64 A process for the hydrolysis of ethyl silicate according to claim I, wherein the molar ratio of tetraethy ortho silicate and sulOnated beads LS 1:0,1
2. 4. A process for the hydrolysis of ethyl silicate according to claim I wherein the molar ratio of water and sulfonated beads is in the range 1:01 5 upto l:1 54, 5, Product obtained by the process according to any one of claims I to 4. 6, A process for the hydrolysis of ethyl silicate as defined in claim I substantially as hereinbeobre described with reference to the accompanying description and examples excluding comparative examples, if any. 7, Product as defined in claim 5 substantially as hereinbefbre described with reference to the accompanying description and exam ples, excluding cmpvar e examples. if any.