DESC:AN IMPROVED PROCESS FOR THE SYNTHESIS OF ORDERED MESOPOROUS MATERIALS WITH IONIC LIQUIDS AND THE PRODUCT THEREOF
TECHNICAL FIELD
[0001]Embodiments are generally related to the field of chemistry. Embodiments are also related to ordered mesoporous materials.. Embodiments are further related to the process of synthesis of ordered mesoporous aluminosilicates. Embodiments are particularly related to developing an ordered mesoporous materials with ionic liquids.
Background of the Invention
[0002]Ordered mesoporous materials (OMS) such as MCM-41 and MCM-48 with long range ordered pores and high surface areas have opened various possibilities for potential applications in the field of heterogeneous catalysis. These materials possess good crystallinity, large pores and high surface area which makes them one of the best catalyst supports or the metal ion-modified analogues which finds application in the transformation of bulky molecules in to useful products. For instance, MCM-41 consists of uniform 2D hexagonal arrangement of mesopores which arrange themselves as honey comb like structure whereas MCM-48 comprises of 3D cubic gyroid pore structure. In general, the synthesis of such OMS materials involves sol-gel technique using amphiphilic surfactants as templates. In particular, both MCM-41 and MCM-48 hydrothermally synthesized by cooperative self-assembly between ionic surfactant (cetyltrimethylammonium cation, CTA+) and silica precursors in basic medium.
[0003]However, the synthesis of these materials involves some difficulties, especially for MCM-48, due to the narrow phase region of the surfactant. The synthesis of cubic gyroid structure, viz., MCM-48 involves peculiar conditions and can only be obtained by a limited number of surfactants. In addition, these materials possess thin- wall structure which poses problems for its use due to low thermal and hydrothermal stability. Hence, there is need to look for alternative structure directing agents which can yield well-ordered mesoporous analogues to both MCM-41 and MCM-48 with improves structural and textural properties.
[0004]Moreover, in AlMCM-41 and AlMCM-48 materials, the amount of aluminium incorporated into the framework is less than the expected amount and also there is a significant leaching of aluminum from the framework after calcination. Therefore, there is a need of stable tetrahedral trivalent aluminium in the framework to serve the purpose.
[0005]Therefore the current invention fills this gap in the prior art, by developing a new method, by using long chain ionic liquids as templates to synthesize OMS materials.
summary of the Invention
[0006]The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiment and is not intended to be a full description. A full appreciation of the various aspects of the embodiments disclosed herein can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
[0007]One aspect of the disclosed embodiments is to provide an improved method for efficient synthesis for the preparation of ordered mesoporous material with ionic liquids.
[0008]Another aspect of the disclosed embodiments to is to provide an improved ordered mesoporous material with with high surface area and thicker pore walls .

[0009]The aforementioned aspects and other objectives and advantages can now be achieved as described herein. The preparation of HDmimCl (1-hexadecyl-3-methylimidazolium chloride) was achived by the following process disclosed herein. 1-hexadecyl-3-methylimidazolium chloride (HDmimCl) was synthesized by stirring N-methyl imidazole and 1-hexadecylchloride with a mole ratio of 1: 1.1 at 90C in an inert atmosphere for 48 h and then cooled to room temperature. The product was recrystallized with ethyl acetate, washed several times with ethyl acetate and dried under vacuum for 12 h. Similar or enhanced results for synthesis of HDmimCl can be achieved by a person skilled in the art, by modifications of the above method.
[0010]The synthesis of synthesis of hexagonal mesoporous silicate, was achieved as disclosed herein. A solution of A was prepared by mixing 3.49 g of HDmimCl in 20 mL distilled water and 0.35 g NaOH in 8.5 mL distilled water under constant stirring for 30 min. Another solution of B was prepared by mixing 0.8 mL TMAOH, and 0.66 g fumed silica in 7.5 mL water under constant stirring for 30 min. Both the solutions A and B were then added together and stirred for 1 h. To this homogeneous solution, 1.34 g of fumed silica was added and stirred for 1 h. The resulting gel has the following (molar) composition: 1.00 SiO2 : 0.54 HDmimCl : 0.52 NaOH : 0.52 TMAOH : 120 H2O. The final gel pH was adjusted to 11.5 and hydrothermally treated in a stainless steel autoclave at 373 K for 24 h. The solid product thus obtained was washed with distilled water, filtered and dried overnight at 373 K. The resulting as-synthesized sample was then calcined at 823 K for 6 h in air with a heating rate of 1°C min1 so as to remove the surfactant. Similar or enhanced results for synthesis of synthesis mesoporous silicate, can be achieved by a person skilled in the art, by modifications of the above method.
[0011]All the materials under study were systematically characterized by various analytical, spectroscopic and imaging techniques, viz., XRD, TEM, SEM, 29Si and 27Al MAS-NMR, XRF and NH3-TPD.
[0012]The process proposed herein is an exemplary demonstration of working of the proposed concept of an improved process for acid mediated synthesis of ordered mesoporous materials and the product thereof. The standards and operating protocol for acid mediated synthesis of OMS of the use of the resultant product thereof can be standardized and adapted by a person skilled in the art to achieve the same or enhanced results.

Brief description of drawings

[0013]The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.
[0014]FIG. 1 illustrates low-angle XRD patterns of calcined A1IITM-41 (A) and A1IITM-48 (B) with varying silica-to-alumina ratio: (a) 8; (b) 30; (c) 10, in accordance with the disclosed embodiments
[0015]FIG. 2 illustrates a table of the structural and textiral properties of hexagonal and cubic materials, in accordance with the disclosed embodiments.
[0016]FIG. 3 illustrates 27Al MAS-NMR spectra of calcined samples: (a) AlIITM-41(30); (b) AlIITM-41(10); (c) AIITM-48(30), in accordance with the disclosed embodiments.
[0017]FIG. 4 illustrates tertiary butyl alkylation of phenol over hexagonal and cubic OMAS, in accordance with the disclosed embodiments.
[0018]FIG. 5 illustrates low-angle XRD patterns of calcined (a) HMA-41 (b) CoHMA-41(100); (c) CoHMA-41(25), in accordance with the disclosed embodiments.
[0019]FIG.6 illustrates structural and textural properties of HMA-41 and CoHMA-41(n), in accordance with the disclosed embodiments.
[0020]FIG.7 illustrates 27Al MAS-NMR (A) and 31P MAS-NMR (B) spectra of calcined HMA-41 and CoHMA-41(50), in accordance with the disclosed embodiments.
detailed description
[0021]The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
[0022]The embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. The embodiments disclosed herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
[0023]The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0024]Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0025]The synthesis of synthesis of hexagonal mesoporous silicate, IITM-41 was achieved as disclosed herein. A solution of A was prepared by mixing 3.49 g of HDmimCl in 20 mL distilled water and 0.35 g NaOH in 8.5 mL distilled water under constant stirring for 30 min. Another solution of B was prepared by mixing 0.8 mL TMAOH, and 0.66 g fumed silica in 7.5 mL water under constant stirring for 30 min. Both the solutions A and B were then added together and stirred for 1 h. To this homogeneous solution, 1.34 g of fumed silica was added and stirred for 1 h. The resulting gel has the following (molar) composition: 1.00 SiO2 : 0.54 HDmimCl : 0.52 NaOH : 0.52 TMAOH : 120 H2O. The final gel pH was adjusted to 11.5 and hydrothermally treated in a stainless steel autoclave at 373 K for 24 h. The solid product thus obtained was washed with distilled water, filtered and dried overnight at 373 K. The resulting as-synthesized sample was then calcined at 823 K for 6 h in air with a heating rate of 1°C min1 so as to remove the surfactant, and the sample is designated as IITM-41. Similar or enhanced results for synthesis of synthesis of hexagonal mesoporous silicate, IITM-41 can be achieved by a person skilled in the art, by modifications of the above method.
[0026]The synthesis of synthesis cubic mesoporous silicate, IITM-48 was achieved as disclosed herein. 0.4 g of NaOH and 4.46 mL of tetraethyl orthosilicate (TEOS) mixed in 5 mL distilled water under constant stirring for 10 min to get solution A. Likewise, 3.7 g of HDmimCl was dissolved in 15 mL distilled water and stirred for 20 min to get a solution B. Finally, a homogeneous transparent gel having a molar gel composition of 1 TEOS: 0.272 HDmimCl: 0.512 NaOH: 56 H2O was obtained by mixing both the solutions A and B under constant stirring for 25 min. The resulting gel was maintained at a pH of 11.3 and hydrothermally treated in Teflon-lined stainless steel autoclave at 373 K for 72 h. The solid product thus obtained was washed repeatedly with distilled water and then filtered, and dried at 353 K for 12 h. The resulting as-synthesized sample was calcined at 823 K for 6 h in air with a heating rate of 1°C min1 in order to remove the surfactant which is then referred as IITM-48. Similar or enhanced results for synthesis of synthesis of cubic mesoporous silicate, IITM-48 can be achieved by a person skilled in the art, by modifications of the above method.
[0027]The synthesis of hexagonal mesoporous aluminosilicates (AlIITM-41) and ferrisilicates (FeIITM-41) was achieved as disclosed herein. A solution of A was prepared by mixing 3.49 g of C16mimCl in 20 mL distilled water and 0.35 g NaOH in 8.5 mL distilled water under constant stirring for 30 min. Another solution of B was prepared by mixing 0.78 mL TMAOH, and 0.66 g fumed silica in 7.5 mL water under constant stirring for 30 min. Both the solutions A and B were then added together and stirred for 1 h. To this homogeneous solution, 1.34 g of fumed silica was added and stirred for 1 h. In this resulting gel, required amount of aluminium sulphate was added and stirred for an hour for homogenization. The resulting gel has the following (molar) composition: 1.00 SiO2: 0.54 C16mimCl : 0.52 NaOH : 0.52 TMAOH : x Al2O3 : 120 H2O (x = 0.033, 0.0167 and 0.011). The final gel pH was adjusted to 11.5 and hydrothermally treated in a Teflon lined stainless steel autoclave at 373 K for 24 h. The solid product thus obtained was washed with distilled water, filtered and dried overnight at 373 K. The resulting as-synthesized sample was then calcined at 823 K for 6 h in air with a heating rate of 1°C min1 so as to remove the surfactant. All the calcined aluminosilicate samples were protonated by repeated ion-exchange using 1 M ammonium nitrate solution at 353 K for 6 h. The ammonium exchanged aluminosilicate samples were recalcined at 823 K for 6 h in air. The silicate and aluminosilicate samples were designated as AlIITM-41(n); n = Si/Al ratio = 8, 90, 60, 30 & 10.
[0028]A solution of A was prepared by mixing 3.49 g of C16mimCl in 20 mL distilled water and 0.35 g NaOH in 8.5 mL distilled water under constant stirring for 30 min. Another solution of B was prepared by mixing 0.78 mL TMAOH, and 0.66 g fumed silica in 7.5 mL water under constant stirring for 30 min. Both the solutions A and B were then added together and stirred for 1 h. To this homogeneous solution, 1.34 g of fumed silica was added and stirred for 1 h. In this resulting gel, required amount of iron nitrate, Fe(NO3)3.9H2O was added and stirred for an hour for homogenization. The resulting gel has the following (molar) composition: 1.00 SiO2: 0.54 C16mimCl : 0.52 NaOH : 0.52 TMAOH : x FeO : 120 H2O (x = 0.033, 0.0167 and 0.011). The final gel pH was adjusted to 11.5 and hydrothermally treated in a Teflon lined stainless steel autoclave at 373 K for 24 h. The solid product thus obtained was washed with distilled water, filtered and dried overnight at 373 K. The resulting as-synthesized sample was then calcined at 823 K for 6 h in air with a heating rate of 1°C min1 so as to remove the surfactant. All the calcined aluminosilicate samples were protonated by repeated ion-exchange using 1 M ammonium nitrate solution at 353 K for 6 h. The ammonium exchanged aluminosilicate samples were recalcined at 823 K for 6 h in air. The silicate and aluminosilicate samples were designated as FeIITM-41(n); n = Si/Al ratio = 90, 60, and 30. Similar or enhanced results for synthesis of hexagonal mesoporous aluminosilicates (AlIITM-41) and ferrisilicates (FeIITM-41) can be achieved by a person skilled in the art, by modifications of the above method.
[0029]The synthesis of synthesis of cubic mesoporpous aluminosilicates, A1IITM-48 was achieved as disclosed herein. 0.4 g of NaOH and 4.46 mL of tetraethyl orthosilicate (TEOS) mixed in 5 mL distilled water under constant stirring for 10 min to get solution A. Likewise, 3.7 g of C16mimCl was dissolved in 15 mL distilled water and stirred for 20 min to get a solution B. Finally, a homogeneous transparent gel having a molar gel composition of 1 TEOS: 0.272 C16mimCl: 0.512 NaOH: x Al2O3: 56 H2O (x = 0.033, 0.0167 and 0.011) was obtained by mixing both the solutions A and B under constant stirring for 25 min. A required amount of aluminium sulphate was added and stirred for an hour for homogenization. The resulting gel was maintained at a pH of 11.3 and hydrothermally treated in Teflon-lined stainless steel autoclave at 373 K for 72 h. The solid product thus obtained was washed repeatedly with distilled water and then filtered, and dried at 353 K for 12 h. The resulting as-synthesized sample was calcined at 823 K for 6 h in air with a heating rate of 1°C min1 in order to remove the surfactant. All the calcined aluminosilicate samples were protonated by repeated ion-exchange using 1 M ammonium nitrate solution at 353 K for 6 h. The ammonium exchanged aluminosilicate samples were recalcined at 823 K for 6 h in air. The samples were designated as AlIITM-48(n); n = Si/Al ratio = 8, 90, 60 and 30. Similar or enhanced results for synthesis of cubic mesoporous aluminosilicates, AlIITM-48 can be achieved by a person skilled in the art, by modifications of the above method.
[0030]The incorporation of suitable hetero atoms into the tetrahedral framework of mesoporous aluminophosphates can generate Bronsted acidity and/or redox sites useful for catlytic applications. Among other transition metal ions, cobalt containing materials have widely studied as they found various applications as catalysts for oxidation reactions. However, the oxidation of cyclohexane has been of particular interest in recent years due to the importance of their reaction products. We have attempted to to synthesize hexagonal mesoprous aluminophosphates (HMA-41) and cobalt containing aluminophosphates (CoHMA-41) using ionic liquid HDmimCl as surfactant. The catalytic activity was tested for oxidation of cyclohexane using environmentally benign H2O2 as oxidant under mild reaction conditions. The synthesis of hexagonal mesoporous aluminophosphates (HMA-41) and Cobalt-aluminophosphates (CoHMA-41) was achieved as disclosed herein. 1.4 mL of phosphoric acid was diluted with 11.7 mL of distilled water to get a clear solution. To this, 4.08 g of aluminium isopropoxide was added with vigorous stirring for 1 hour at 343 K until all the aluminium precursor gets dispersed in phosphoric acid solution. Then, 7.3 mL of tetramethylammonium hydroxide (TMAOH) solution (25%) was added to the obtained sol dropwise to get a colorless precipitate of aluminophosphate. To the obtained mixture, 1.75 g of ionic liquid surfactant (HDmimCl) was added slowly and stirred for 12 h. The final molar gel composition is (1 - x) Al2O3: P2O5: 0.5 (CTA)2O: 1.25 (TMA)2O: 70 H2O. The pH of the mixture was maintained at 10 and was transferred to Teflon lined autoclave and undergoes crystallization by heating the mixture at 373 K for 3 days. The resultant mesoporous aluminophosphate was washed repeatedly with water and then dried at 343 K for 12 h. The as synthesized sample was calcined to remove the template at 823 K for 1 h under N2 followed by 5 h in air atmosphere and the obtained sample was designated as HMA-41.
[0031]1.4 mL of phosphoric acid was diluted with 11.7 mL of distilled water to get a clear solution. To this, 4.08 g of aluminium isopropoxide was added with vigorous stirring for 1 hour at 343 K until all the aluminium precursor gets dispersed in phosphoric acid solution. Then, 7.3 mL of tetramethylammonium hydroxide (TMAOH) solution (25%) was added to the obtained sol dropwise to get a colorless precipitate of aluminophosphate. To the obtained mixture, 1.75 g of ionic liquid surfactant (HDmimCl) was added slowly and stirred for 12 h. The required amount of cobalt acetate solution was added to the reaction mixture with [Al+P]/Co molar ratio of 100, 50 and 25. The final molar gel composition is (1 - x) Al2O3: P2O5: 2x CoO: 0.5 (CTA)2O: 1.25 (TMA)2O: 70 H2O. The pH of the mixture was maintained at 10 and was transferred to Teflon lined autoclave and undergoes crystallization by heating the mixture at 373 K for 3 days. The resultant mesoporous aluminophosphate was washed repeatedly with water and then dried at 343 K for 12 h. The as synthesized sample was calcined to remove the template at 823 K for 1 h under N2 followed by 5 h in air atmosphere and the obtained samples were designated as CoHMA-41 (100), CoHMA-41 (50) and CoHMA-41 (25). Similar or enhanced results for synthesis of hexagonal mesoporous aluminophosphates (HMA-41) and Cobalt-aluminophosphates (CoHMA-41) can be achieved by a person skilled in the art, by modifications of the above method.
[0032]Long chain ionic liquid, 1-hexadecyl-3-methyl imidazolium chloride (HDmimCl) is a promising surfactant/template to synthesize ordered mesoporous materials with improved structural and textural properties such as high surface area, well ordered structures and thicker pore walls in comparison to conventional surfactants. Unlike MCM-48, which requires large amount of surfactant, the HDmimCl-templated IITM-48 requires very low concentration owing to its high bonding strength with silicate oligomer. The unique templating behavior of ionic liquids may lead to incorporate more amount of metal ions in the framework structure during synthesis by virtue of the formation of thicker walls. In mesoporous aluminosilicates (AlIITM-41 and AlIITM-48), the even dispersion of silicate oligomers and aluminium hydroxide species leads to formation of stable –Al-O-Si- bond with exclusive tetrahedral framework aluminium even at high aluminium content.
[0033]All the materials showed an improved catalytic activity with high conversion and selectivity towards desired product (4-t-BP). The catalytic activity increases with increase in aluminium content. AlIITM-48 (60) showed a high conversion of phenol (65%) and good selectivity towards 4-t-BP (75%). Ionic liquid templated synthesis of ordered hexagonal mesoporous aluminophosphate (HMA-41) with improved textural properties compared to the reported mesoporous aluminophosphates in prior art. Divalent cobalt ions substituted HMA-41 with high loadings of cobalt, and that CoHMA-41 catalyst showed excellent activity for the oxidation of cyclohexane reaction using H2O2 as oxidant. CoHMA (25) catalyst showed excellent conversion (98.5%) and selectivity (90.4%) towards cyclohexanol.
[0034]The process proposed herein is an exemplary demonstration of working of the proposed concept of a process for ionic liquid templated synthesis of ordered mesoporous materials, the product thereof and the utility of the product as a catalyst exhibiting excellent catalytic activity with high conversion and selectivity towards desired product (4-t-BP). The synthesis of OMAS and the use of such product as catalyst can be standardized and adapted by a person skilled in the art to achieve the same or enhanced results.
[0035]It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the field. ,CLAIMS:I/We claim
1. A process for the synthesis of hexagonal mesoporous silicate comprising steps of;
preparing a first solution by mixing 3.49g of HDmimCl in 20ml deionised water and 0.35g NaOH in 8.5 ml deionised water under continuous stirring for 30 min,
preparing a second solution by mixing 0.8 mL TMAOH, and 0.66 g fumed silica in 7.5 mL deionised water under continuous stirring for 30 min,
adding the first solution and second solution and stirring for 1 h, and
adding 1.34 g of fumed silica to the resultant solution and stiring for 1 h to obtain a gel with molar composition of  1.00 SiO2 : 0.54 HDmimCl : 0.52 NaOH : 0.52 TMAOH : 120 H2O.
2. The method as claimed in claim 1 further comprising steps of;
 adjusting the pH of the gel to 11.5 and hydrothermally treated in a stainless steel autoclave at 373 K for 24 h, to obtain a solid product which is washed with deionised water, filtered and dried overnight at 373 K, and
the above product was then calcined at 823 K for 6 h in air with a heating rate of 1°C min-1 to remove the surfactant, to obtain the hexagonal mesoporous silicate.
3. A process for the synthesis of cubic mesoporous silicate comprising steps of;
preparing a first solution by mixing 0.4 g of NaOH and 4.46 mL of tetraethyl orthosilicate (TEOS) mixed in 5 mL deionised water under continuous stirring for 10 min,
preparing a second solution by dissolving 3.7 g of HDmimCl in 15 mL deionised water and stirred for 20 min,
mixing the first solution and second solution under continuous stirring for 25 min, to obtain a homogeneous transparent gel having a molar gel composition of 1 TEOS: 0.272 HDmimCl: 0.512 NaOH: 56 H2O.
4. The process as claimed in claim 3 further comprising steps of;
maintaining the pH of the gel at 11.3 and hydrothermally treated in Teflon-lined stainless steel autoclave at 373 K for 72 h, to obtain a solid product which is washed repeatedly with deionised water and then filtered, and dried at 353 K for 12 h’
the product obtained thereof is further calcined at 823 K for 6 h in air with a heating rate of 1°C min-1 to remove the surfactant, to obtain the cubic mesoporous silicate.
5. A process for the synthesis of hexagonal mesoporous aluminosilicate comprising steps of;
preparing a first solution by mixing 3.49 g of C16mimCl in 20 mL deionised water and 0.35 g NaOH in 8.5 mL deionised water under continuous stirring for 30 min,
preparing a second solution by mixing 0.78 mL TMAOH, and 0.66 g fumed silica in 7.5 mL deionised water under continuous stirring for 30 min,
adding the first solution and second solution and stirring for 1 h,
adding 1.34 g of fumed silica in to the resultant solution and stirred for 1 h, to obtain a gel,
further adding aluminium sulphate to the gel and stirred for an hour for homogenization, to obtain a gel having a molar composition of composition:  1.00 SiO2: 0.54 C16mimCl : 0.52 NaOH : 0.52 TMAOH : x Al2O3 : 120 H2O (x = 0.033, 0.0167 and 0.011.
6. The method as claimed in claim 5 further comprising steps of;
adjusting the pH of the gel to 11.5 and hydrothermally treated in a Teflon lined stainless steel autoclave at 373 K for 24 h, to obtain a solid product which is washed with deionised water, filtered and dried overnight at 373 K, further calcined at 823 K for 6 h in air with a heating rate of 1°C min-1 so as to remove the surfactant, to obtain
calcined aluminosilicate, which is protonated by ion-exchange using 1 M ammonium nitrate solution at 353 K for 6 h and recalcined at 823 K for 6 h in air to obtain hexagonal mesoporous aluminosilicate.
7. A process for the synthesis hexagonal mesoporous ferrisilicate, steps comprising;
preparing a first solution by mixing 3.49 g of C16mimCl in 20 mL deionised water and 0.35 g NaOH in 8.5 mL deionised water under continuous stirring for 30 min,
preparing a second solution by mixing 0.78 mL TMAOH, and 0.66 g fumed silica in 7.5 mL water under constant stirring for 30 min,
adding the first solution and second solution and stirring for 1 h,
further adding 1.34 g of fumed silica to the resultant solution and stirred for 1 h, to obtain a gel to which iron nitrate, Fe(NO3)3.9H2O was added and stirred for an hour for homogenization to obtain a gel having molar composition 1.00 SiO2: 0.54 C16mimCl : 0.52 NaOH : 0.52 TMAOH : x FeO : 120 H2O (x = 0.033, 0.0167 and 0.011.
8. The process as claimed in claim 7 further comprising steps of;
adjusting the pH of the gel to 11.5 and hydrothermally treating in a Teflon lined stainless steel autoclave at 373 K for 24 h, to obtain a solid product which is washed with deionised water, filtered and dried overnight at 373 K, and further calcined at 823 K for 6 h in air with a heating rate of 1°C min-1 to remove the surfactant, to obtain hexagonal mesoporous ferrisilicate.
9. A process for the synthesis cubic mesoporous aluminosilicate, steps comprising;
preparing a first solution by mixing 0.4 g of NaOH and 4.46 mL of tetraethyl orthosilicate (TEOS) in 5 mL deionised water under continuous stirring for 10 min,
preparing a second solution by dissolving 3.7 g of C16mimCl was in 15 mL deionised water and stiring for 20 min,
mixing the first solution and second solution under continuous stirring for 25 min, to obtain a homogeneous transparent gel having a molar gel composition of 1 TEOS: 0.272 C16mimCl: 0.512 NaOH: x Al2O3: 56 H2O (x = 0.033, 0.0167 and 0.011,
further adding aluminium sulphate and stirred for an hour for homogenization, the solid product thus obtained is washed repeatedly with deionised water and then filtered, and dried at 353 K for 12 h.
10. The method as claimed in claim 9 further comprising steps of ; calcining tat 823 K for 6 h in air with a heating rate of 1°C min-1 in order to remove the surfactant,
protonated by repeated ion-exchange using 1 M ammonium nitrate solution at 353 K for 6 h,
ammonium exchanged aluminosilicate samples were recalcined at 823 K for 6 h in air, to obtain cubic mesoporous aluminosilicate.
11. A method for the synthesis of hexagonal mesoporous aluminophosphates, comprising steps of ;
1.4 mL of phosphoric acid was diluted with 11.7 mL of distilled water to get a clear solution,
4.08 g of aluminium isopropoxide was added with vigorous stirring for 1 hour at 343 K until all the aluminium precursor gets dispersed in phosphoric acid solution,
7.3 mL of tetramethylammonium hydroxide (TMAOH) solution (25%) was added to the obtained sol drop wise to get a colorless precipitate of aluminophosphate,
to the resultant mixture 1.75 g of ionic liquid surfactant (HDmimCl) was added slowly and stirred for 12 h, to obtain a gel of molar composition of (1 - x) Al2O3: P2O5: 0.5 (CTA)2O: 1.25 (TMA)2O: 70 H2O,
pH of the gel was maintained at 10 and was transferred to Teflon lined autoclave to undergo crystallization by heating the mixture at 373 K for 72 hours,
further it is washed repeatedly with water and then dried at 343 K for 12 h, and calcined to remove the template at 823 K for 1 h under N2 followed by 5 h in air atmosphere, to obtain hexagonal mesoporous aluminophosphates.
12. A method for the synthesis of Cobalt-aluminophosphates, comprising steps of;
1.4 mL of phosphoric acid was diluted with 11.7 mL of distilled water to get a clear solution,
4.08 g of aluminium isopropoxide was added with vigorous stirring for 1 hour at 343 K until all the aluminium precursor gets dispersed in phosphoric acid solution,
7.3 mL of tetramethylammonium hydroxide (TMAOH) solution (25%) was added to the obtained sol dropwise to get a colorless precipitate of aluminophosphate,
7.3 mL of tetramethylammonium hydroxide (TMAOH) solution (25%) was added to the obtained sol drop wise to get a colorless precipitate of aluminophosphate,
Further 1.75 g of ionic liquid surfactant (HDmimCl) was added slowly and stirred for 12 h,
cobalt acetate solution was added to the reaction mixture with [Al+P]/Co molar ratio of 100, 50 and 25,
to obtain a gel with molar composition of (1 - x) Al2O3: P2O5: 2x CoO: 0.5 (CTA)2O: 1.25 (TMA)2O: 70 H2O.
13. The method as claimed in claim 12, further comprising steps of;
Maintaining the pH of the mixture at 10,
further transferred to Teflon lined autoclave to undergoes crystallization by heating the mixture at 373 K for 72 hours, to obtain a product which is washed repeatedly with water and then dried at 343 K for 12 h, and
calcined to remove the template at 823 K for 1 h under N2 followed by 5 h in air to obtain Cobalt-aluminophosphates.