Title of Invention A PROCESS FOR PREPARATION OF SULFATED ZIRCONIA CATALYST.
Abstract A process for the preparation of sulfated zirconia catalyst comprising the steps of hydrolyzing zirconium alkoxide and sulfating with sulfuric acid to obtain sulfated zirconia; drying the sulfated zirconia followed by calcining the dried sulfated zirconia to obtain nano-crystalline sulfated zirconia catalyst, activating the dried and sulfated zirconia catalyst in the range of 400-450°C for 2-4 hrs to get sulfated zirconia catalyst.
Full Text A process for preparation of sulfated zirconia catalyst Field of the invention
The present invention relates to a process for preparation of sulfated zirconia catalyst. Catalyt prepared is useful for the preparation of isolongifolene using nanocrystalline solid super acid. This process is an eco-friendly, single step, solvent free catalytic process for the preparation of a tricyclic sesqui-terpene hydrocarbon, isolongifolene..
More particularly, the present invention provides a process for the catalytic isomerisation of longifolene to iso-longifolene using nano-crystalline sulfated zirconia as a solid super acid catalyst. Background of the invention
Longifolene, CisH^ (decahydro-4,8,8-trimethyl- 9-methylene-l-4-methanoazulene), is present in the Indian turpentine oil obtained from Chirpine (Pinus longifolia) to the extent of 5-7V This is the largest tonnage sesquiterpene hydrocarbon available anywhere in the world.
The economical utilization of this terpene hydrocarbon involves its transformation into isomeric product iso-longifolene and its derivatives, which have extensively used in perfumery industry due to their woody and floral odor. The acid catalysed and hydroformylated products of this isomerized iso-longifolene (2, 2, 7, 7-tetramethyltricyclo undec-5-ene) have also woody amber odor and are used as a flavor in many pharmaceutical industries.
This isomerized aromatic compound is of commercial importance in pharmaceutical industries as a flavor. Presently, iso-longifolene, CisF^, is mainly produced by a rearrangement of longifolene involving a number of steps catalysed by mineral acids like sulfuric acid/ acetic acid. Currently used processes using mineral acids is a multi-step process which results into a large quantity of unwanted waste chemicals as by-products that requires further treatment before disposal.
The use of hazardous mineral acid is not safe from handling point of view, as they are corrosive, irritant and also required in more than stoichiometric amount. Furthermore, isomerized product obtained using mineral acid possesses some colour due to impurities generated, which needs further purification.
Therefore, research efforts to prepare iso-longifolene from longifolene to overcome the above-mentioned disadvantages and to find an eco-friendly and safer catalyst are needed.
(Figure Removed)
Reference is made to Sobti, R. R.and Dev, S.(Tetrahedron, Volume 26, 649,1970) who have reported synthesis of isolongifolene from camphene-1-carboxylic acid using multi-step process. Besides involving many steps, this route has a drawback in producing a by-product ( n-keto acid, which is produced due to degradation of isolongifolene and uses reagents in sioichiometric amounts.
Prahlad, J. R. et al.(Tetrahedron Letters, Volume 60, 417, 1964), who have reported the synthesis of isolongifolene from acid catalysed hydration of longifolene using acid treated silica gel. This synthesis strategy has a major drawback in the stability of the catalysts used as leaching of acid occurs from silica gel with prolonged use.
Beyler, R. E. and Ourisson, G. (J. Org. Chem. Volume 30, 2838, 1965) who have reported the synthesis of isolongifolene by treating longifolene with boron trifluoride etherate. In a typical reaction, longifolene is taken in sodium-dried ether to which boron trifluoride etherate is added and the mixture is refluxed on a steam bath for 60 minutes. Resultant dark brown mixture is added cautiously to excess of potassium hydroxide and ice. The mixture is stirred at ambient temperature for 90 minutes at the end of which the ether phase becomes straw yellow in colour. Separation and further extraction, water wash and, evaporation of ether result into light yellow isolongifolene. This route has drawback of using multi step synthesis of isolongifolene using hazardous chemicals like KOH, BF_i and sodium metal. Separation of the
product from the reaction mixture imbibes several chemical treatments and is additionally time consuming before product can be obtained.
Bisarya S, C. et al. (Tetrahedron Letters Volume 28, 2323, 1969) reports the synthesis of isolongifolene by treating longifolene with amberlyst-15 (Rohm and Haas) or acid treated silica gel at 95°C for 36 hours with 95% yield of isolongifolene. This process has drawback in using amberlyst, ion exchange resin, which have poor thermal stability and also swell with prolonged use. Furthermore, the process takes 36 hours for completion.
Ramesha A.R. ct al. (Organic Preparation Procedure International, Volume 31, 227, 1999) have reported the isomerization of longifolene using montmorillonite clay K10 at 120°C with 100 % selectivity and more than 90% conversion. However, the process has drawback in using natural clays which have lot of impurities and difficult to reproduce with the requisite surface acidity. Furthermore, the thermal stability of the clays is low and these get deactivated with use and regeneration and re-usability of the clay catalyst is not known.
Kula J., and Masarweh A. (Flavour and Fragrance Journal, Volume 13, 277, 1998) have reported acid catalyzed rearrangement of longifolene to isolongifolene using bromoacetic acid. This process has drawback in using liquid bromoacetic acid for isomerization, which is not safe to handle. Moreover, the separation of the product from the reaction mixture is difficult.
Nayak, U. R. and Dev S. (Tetrahedron, 8, 42, 1960) have reported the preparation of isolongifolene by hydration of longifolene using acetic acid and sulphuric acid in dioxane. Alongwith isolongifolene, 3-sesquiterpene alcohols were also obtained as by-products. Typically, 200 g of longifolene in 500 mL acetic acid and 40mL 50% sulphuric was stirred with 475mL dioxane. The mixture was kept at 22-24°C for 60h followed by warming at 52°C for I Oh and then poured into 600 mL water. The aqueous layer was treated with ammonium sulphates then extracted three times with 50mL petroleum ether. The combined organic product was washed with water and dried to evaporate the solvent. This dried product has around 66% isolongifolene. The process has drawback of using many steps and large number of reagents, which are hazardous and toxic. This also has problem of disposal of spent reagent.
Wang, Hui, et.al., Jilin daxue Ziran Kexue Xuebao, 1,88-90,2001, (Chinese) wherein the isolation and identification of iso-longifolene alongwith other products from the volatile oil in the stems and leaves of panax ginseng have been reported. However, this is time-consuming process and it cannot meet the demand of large production, thereby necessitates the development of a synthetic route.
Objects of the invention
The main object of the present invention is to provide a catalytic process for the preparation of iso-longifolene, which obviates the drawbacks as detailed above.
Another object of the present invention is to prepare isolongifolene by the isomerization of longifolene.
Yet another object of the present invention is to provide a single step and solvent free process for the isomerisation of longifolene.
Yet another object of the present invention is to provide a process wherein nano-crystalline sulfated zirconia solid super acid is used as a catalyst.
Yet another object of the present invention is to provide a process wherein isomerization of longifolene with high conversion (>90%) and 100% selectivity for iso-longifolene.
Yet another object of the present invention is to provide a process wherein isomerization of longifolene with high conversion and selectivity for iso-longifolene at atmospheric pressure and moderate temperature may be achieved.
Yet another object of the present invention is to provide a process wherein isomerization of longifolene is carried out catalytically with high atom utilization and low E-factor.
Summary of the invention
Accordingly, the present invention comprises of a catalytic process for the preparation of sulfated zirconia catalyst comprising the steps :
(i). hydrolyzing zirconium alkoxide and sulfating with sulfuric acid to obtain sulfated zirconia;
(ii) drying the sulfated zirconia followed by calcining the dried sulfated zirconia to obtain nano-crystalline sulfated zirconia catalyst,
(iii) activating the dried and sulfated zirconia catalyst obtained in step (ii) above in the range of 400-450°C for 2-4 hrs to get sulfated zirconia catalyst.
obtained in step (iii) in a solvent free medium,
while maintaining the reactant to catalyst ratio in the range of 2-10 weight percent to
obtain an isomerised product; (iv) separating the isomerised product iso-longifolene from the reaction mixture;
(v) washing the catalyst to remove adhering materials and
(vi) drying the catalyst at 110°C for 2-4h followed by air calcination at 550°C for a period
between 4-8h.
In one embodiment of the invention, the hydrolysis and sulfation in step (i) above is carried out by one-step or two-step sol-gel technique and in a medium selected from the group consisting of acid, basic or neutral medium, and at ambient temperature
In another embodiment of the invention the sulfated zirconia is dried at a temperature of 110°C for 8-12 hours followed by calcination at 550 to 650°C for 2-6 hours.
In another embodiment of the invention, the dried and sulfated zirconia catalyst is activated prior to reaction at a temperature in the range of 400-450°C for 2-4 hours
In another embodiment of the invention the reaction of longifolene is carried out while maintaining the temperature of the reaction in the range of 120 to 200°C and at atmospheric pressure and for a period selected from 0.5 to 6h.
In another embodiment of the invention, the separation of the isomerised product iso-longifolene is carried out by filtration.
In yet another embodiment of the invention, the catalyst is washed with ethyl acetate to remove the adherent materials.
In another embodiment of the invention, the catalyst comprises nano-crystalline sulfated zirconia having (i) crystallite size; (ii) BET surface area; (iii) pore volume and (iv) pore size in the range of 10-100 nm; 80-120m2g"'; 0.08-0.2cm3g"' and 35-60 A" respectively with catalytic active predominantly tetragonal crystalline phase. Detailed description of the invention
Nano-crystallite zirconia having sulphates as chelating bidentate species on the surface is used for catalytic conversion at atmospheric pressure. The hydrolysis of zirconium alkoxide or zirconium salts can be carried out in acidic, basic or neutral medium. The sulfation of /irconia with sulfuric acid can be carried by sol-gel technique using one-step as well as two-step procedures at ambient temperature. The solid acid catalyst has sulfur in the range of 0.5 to 25 weight % after calcination of the catalyst at the temperature of 600 °C. The ratio of the reactant to solid acid catalyst ratio can be varied in the range of 2 to 10 weight by percent.
The temperature for the catalytic conversion can be in the range of 120 to 200 °C and the time period can be in the range of 0.5 to 6h. The reaction is preferably carried out in a solvent free condition and in a single step procedure.
In a typical procedure for the preparation of the catalyst, zirconium iso-propoxide is hydrolysed into ZrCh and sulfated with sulfuric acid to sulfated zirconia. The hydrolysis and sulfation was carried out simultaneously during one-step procedure. In two-step procedure hydrolysis was carried out in first step followed by sulfation in second step. The hydrolysis was carried out in basic and neutral medium. The sample in all the cases was dried overnight at 110°C and then calcined at 550-650°C for 2 to 6 h. The catalyst thus obtained was cooled at ambient temperature. Activation of these prepared catalysts was done at 450°C for 4h prior to catalytic studies.
Catalytic studies were done in a stirred tank reactor of 50ml capacity having attached temperature controller, water circulator, magnetic stirrer and moisture trap. Typically, longifolene (2g) was taken in a 50ml capacity round bottom flask to which the activated catalyst (0.2g) was added so as the ratio of longifolene /catalysts is in the range of 2 to 10. The activation of the catalysts was done at 450 ° C for 4 h. The round bottom flask was fitted with a condenser through which constant temperature water was circulated. Moisture trap was attached at the end of the condenser. The contents of the flask were constantly stirred using a magnetic stirrer. The flask was kept in an oil bath whose temperature was slowly raised to desired reaction temperature in the range of 120 to 200 °C. The content of the flask were analyzed at different time intervals ranging from 0.5 to 6h by Gas Chromatography, HP model 6890, using capillary column HP-5. Percent conversion of longifolene was calculated using following equation Percent conversion = [n0- nr /no] X 100
Where, no " Number of moles of longifolene introduced before reaction.
nf- Number of moles of longifolene remaining in the reaction mixture after reaction.
Structural characterization of above synthesized catalysts was done by FT-IR spectroscopy and X-ray powder diffraction techniques. The crystallite size was determined from X-ray diffraction data. Textural characterization for surface area, pore volume and pore st/.e was carried out by nitrogen adsorption at 77K.
In the present invention nano-crystalline sulfated zirconia based catalysts are developed for the single step isomerisation of longifolene to produce selectively iso-longifolene product. These catalysts evinced highest activity (>90% conversion with 100% selectivity) in a solvent free condition.
Sulfated zirconia possesses surface acidity in super acidity range (Hammett indicator Inventive steps adopted with respect to prior art are (i) a novel synthetic route based on solid acid catalysts for the preparation of Isolongifolene; (ii) synthesis of nano-crystalline sulfated zirconia by one- step and two-steps sol-gel technique; in acid, basic as well as neutral medium for catalytical activity for the isomerisation of longifolene to isolongifolene with very higher conversion (>90%) and selectivity (100%) for isomerised product; (iii) the synthesis of isolongifolene in a single step and solvent free medium; (iv) relatively moderate conditions of temperature at atmospheric pressure for synthesis of isolongifolene in a less than an hour which makes the process energy efficient; (v) high atom utilization of the process as no by-products are produced and catalysts can be easily separated and re-used.
The following examples are given by the way of illustrations and therefore should not be constructed to limit the scope of the present invention. EXAMPLE-1
1.02mL of cone. H2SO4, diluted with 6.4mL of H2O was added drop-wise to 30% solution of Zr(OCMT7)4 in propanol or zirconium salt like zirconium nitrate. The hydrolysed sol was continuously stirred by magnetic stirrer for 3h. The formed gel was first dried at ambient temperature for 3h and then at 110° C for 12h. The dried gel was powdered to 170 mesh and calcined at 600 °C for 2h. The prepared sample had crystallite size of 13 nm as determined from X-ray diffraction. Sulfur loaded on the catalysts as measured by elemental analysis was 1.2 wt%. 2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to

120°C. 0.2 gm of catalyst, pre-activated 450°C in muffle furnace for 2 h was added to the reactant. The sample were taken out periodically by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 72 to75% with 100 % selectivity after 3 to 6 h. EXAMPLE-2
2 g of longifolene was taken in two- necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., 140 °C. 0.2 gm of catalyst prepared as described in Example-1, pre-activated at 450°C in muffle furnace for 2h was added to the reactant. The sample was taken out after 6h by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 85 % wuh 100 % selectivity after 6h. EXAMPLE-3
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., 160 °C. 0.2 gm of catalyst prepared as described in Example-1, pre-activated at 450°C in muffle furnace for 2h was added to the reactant. The sample was periodically taken out after 2 to 6h by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 84 to 86% with 100 % selectivity after 2 to 6h. EXAMPLE-4
2 g of longifolene was taken in two- necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., 180 °C. 0.2 gm of catalyst prepared as described in Example-1, pre-activated at 450°C in muffle furnace for 2h was added to the reactant. The sample was periodically taken out from 0.5 to 6h by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 91 to 92% with 100 % selectivity after 0.5 to 6h. EXAMPLE-5
2 g of longifolene was taken in two- necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The
temperature of the oil bath was then slowly raised to the desired one, i.e., 190 °C. 0.2 gm of catalyst prepared as described in Example-1, pre-activated at 450°C in muffle furnace for 2h was added to the reactant. The sample was periodically taken out after 0.5 to 4h by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 90 to 92% with 100 % selectivity 0.5 to 4h. EXAMPLE-6
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., 200 °C. 0.2 gm of catalyst prepared as described in Example-1, pre-activated at 450°C in muffle furnace for 2h was added to the reactant. The sample was periodically taken out after 0.5 to 4h by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 91 to 92% with 100 % selectivity after 1 to 4h. EXAMPLE-7
1.02mL of cone. HiSCU, was added to 30% solution of Zr(OC3H7)4 in propanol and then 6.4mL of HiO was added drop-wise to this solution. The hydrolysed sol was continuously stirred by magnetic stirrer. The gel was immediately solidified. The formed gel was first dried at room temperature for 3h and then at 110 °C for 12h. The dried gel was powdered to 170 niesh and calcined at 600 °C for 2h. The prepared sample had crystallite size of 11 nm as determined from X-ray diffraction. Sulfur loaded on the catalysts as measured by elemental analysis was 1.6 wt%. 2 g of longifolene was taken in two- necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 14()°C. 0.2 gm of the catalyst, pre-activated at 450°C in muffle furnace for 2 h was added to the reactant. The sample were periodically taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 92% with 100% selectivity after 2 h. EXAMPLE-8
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.2 gm of
the catalyst prepared as described in Example-7 pre-activated at 450°C in muffle furnace for 2 h was added to the reactant. The sample were periodically taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 93% with 85% selectivity after 2 h. EXAMPLE-9
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 200°C. 0.2 gm of the catalyst prepared as described in Example-7, pre-activated at 450°C in muffle furnace for 2 h was added to the reactant. The sample were periodically taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 93% with 80% selectivity after 2 h. EXAMPLE-10
Aqueous ammonia (25%) was added drop-wise to 30% solution of Zr(OC3H7)4 in propanol until the pH of the mixture becomes 9-10. The hydrolysed sol was continuously stirred by magnetic stirrer for 3h. The formed gel was first dried at room temperature for 3h and then at 110°C for 12h. The dried gel was powdered to 170mesh and stirred with IN HiSC^ (!5mL/g) for 30min. After filtration, it was first dried at room temperature for 3h and then at HOT for 12h. The dried gel was powdered to 170mesh and calcined at 600 °C for 2h. The prepared sample had crystallite size of llnm as determined from X-ray diffraction. Sulfur loaded on the catalysts as measured by elemental analysis was 1.4wt%. 2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.2 gm of catalyst, pre-activated at 450°C in muffle furnace for 2 h was added to the reactant. The sample were taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 90% with 100% selectivity after 2 h. EXAMPLE-11
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 200°C. 0.2 gm of
catalyst prepared as described in Example-10, pre-activated at 450°C in muffle furnace for 2 h was added to the reactant, The sample were taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 90% with 100% selectivity after 2 h. EXAMPLE-12
6.4mL of HaO was added drop-wise to 30% solution of Zr(OC3H7)4 in propanol. The hvdrolysed sol was continuously stirred by magnetic stirrer for 3h. The formed gel was first dried at room temperature for 3h and then at 1 IOC for 12h. The dried gel was powdered to 170 mesh and stirred with of IN H^SC^ ( 15mL/g) for 30min. After filtration, it was first dried at room temperature for 3h and then at 110 °C for 12h. The dried gel was powdered to 170 mesh and calcined at 600 °C for 2h. The prepared sample had crystallite size of 1 OOnm as determined from X-ray diffraction. Sulfur loaded on the catalysts as measured by elemental analysis was 1.3 vvt%. 2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.2 gm of catalyst, pre-activated at 450°C in muffle furnace for 2 h was added to the reactant. The sample were taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 92% with 100% selectivity after 2 h. KXAMPLE-13
2 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 200°C. 0.2 gm of catalyst prepared as described in Example-12, pre-activated at 450°C in muffle furnace for 2h was added to the reactant taken in the flask. The sample were taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 92% with 100% selectivity after 2 h. EXAMPLE-14
The catalyst, prepared as described in Example-!, after the completion of the reaction as described in Example-4 was separated from the reaction mixture by filtration and washed with lOmL of ethyl acetate solution at ambient temperature. Catalyst was dried in oven at 11()°C for 2-4h followed by air calcination in muffle furnace at 550°C for 4-8h. The catalyst
was cooled to ambient temperature) and labelled as Ex.1-recycle. 1 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.1 gm of catalyst, Ex.1-recycle was added to the reactant taken in the flask. The sample were taken out by means of syringe and analysed by gas chromatography using HP-5 column. The percent conversion of longifolene was 36% with 100% selectivity after 2 h. EXAMPLE-15
The catalyst, prepared as described in Example-7, after the completion of the reaction as described in Example-8 was separated from the reaction mixture by filtration and washed with 1 OmL of ethyl acetate solution at ambient temperature. Catalyst was dried in oven at 11()°C for 2-4h followed by air calcination in muffle furnace at 550°C for 4-8h. The catalyst was cooled to ambient temperature) and labelled as Ex.2-recycle. 1 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.1 gm of catalyst, Ex.7-recycle was added to the reactant taken in the flask. The sample were taken out by means of syringe and analyzed by gas chromatography using HP-5 column. The percent conversion of longifolene was 90% with 100% selectivity after 2 h. EXAMPLE-16
The catalyst, prepared as described in Example-10, after the completion of the reaction as described in Example-10 was separated from the reaction mixture by filtration and washed with lOmL of ethyl acetate solution at ambient temperature. Catalyst was dried in oven at 110°C for 2-4h followed by air calcination in muffle furnace at 550°C for 4-8h. The catalyst was cooled to ambient temperature) and labelled as Ex.lO-recycle. 1 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.1 gm of catalyst, Ex.lO-recycle was added to the reactant taken in the flask. The sample were taken out by means of syringe and analyzed by gas chromatography using HP-5 column. The percent conversion of longifolene was 90% with 100% selectivity after 2 h.
EXAMPLE-17
The catalyst, prepared as described in Example-12, after the completion of the reaction as described in Example-12 was separated from the reaction mixture by filtration and washed with lOmL of ethyl acetate solution at ambient temperature. Catalyst was dried in oven at 110"C for 2-4h followed by air calcination in muffle furnace at 550°C for 4-8h. The catalysts was cooled to ambient temperature) and labelled as Ex.l2-recycle. 1 g of longifolene was taken in two-necked round bottom flask, which was put in an oil bath equipped with temperature controller, magnetic stirrer, condenser and circulator. The temperature of the oil bath was then slowly raised to the desired one, i.e., to 180°C. 0.1 gm of catalyst, Ex.l2-recycle was added to the reactant taken in the flask. The sample were taken out by means of syringe and analyzed by gas chromatography using HP-5 column. The percent conversion of longifolene was 91% with 100% selectivity after 2 h.
The main advantages of this process over conventional process include: 1 The present process employs solid acid catalyst, which are environment friendly, safe in
handling and do not generate any waste or by-product. 2, The reaction process is a single step process without use of any solvent.
3 Furthermore, this process is carried at moderate conditions of pressure and temperature.
4 Catalysts being solid in nature can be easily separated from the liquid reaction mixture by
means of filtration or centrifugation.
5 Catalysts being highly crystalline and thermally stable can be regenerated by thermal
treatment and can be re-used.
6. Sulfated zirconia based solid acid catalysts are easy in transforming, handling etc. in comparison to conventional catalysts like H2SCO4, CHsCOOH, and BF3.OEt2.






We claim :
1. A process for preparation of sulfated zirconia catalyst comprising the steps :
(i) hydrolyzing zirconium alkoxide and sulfating with sulfuric acid to obtain sulfated zirconia;
(ii) drying the sulfated zirconia followed by calcining the dried sulfated zirconia to obtain nano-crystalline sulfated zirconia catalyst,
(iii) activating the dried and sulfated zirconia catalyst obtained in step (ii) above in the range of 400-450 C for 2-4 hrs to get sulfated zirconia catalyst.
2. A process as claimed in claim 1 wherein the hydrolysis and sulfation in step (i) above is carried out by one-step or two-step sol-gel technique and in a medium selected from the group consisting of acid, basic or neutral medium, and at ambient temperature.
3. A process as claimed in claim 1 wherein the sulfated zirconia is dried at a temperature of 110°C for 8-12 hours followed by calcinations at 550 to 650°C for 2-6 hours.
4. A process for preparation of sulfated zirconia catalyst substantially as herein described with reference to examples accompanying this specification.

Documents:

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-DEL-2004-Abstract-(13-09-2010).pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-abstract.pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-DEL-2004-Claims-(13-09-2010).pdf

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http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-DEL-2004-Correspondence-Others-(01-10-2010).pdf

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http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-correspondence-others.pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-DEL-2004-Description%20(Complete)-(01-10-2010).pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-description%20(complete).pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-DEL-2004-Form-1-(13-09-2010).pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-form-1.pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-form-18.pdf

http://ipindiaservices.gov.in/documents/1530-DEL-2004/1530-del-2004-form-2.pdf

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Patent Number 243879
Indian Patent Application Number 1530/DEL/2004
PG Journal Number 46/2010
Publication Date 12-Nov-2010
Grant Date 10-Nov-2010
Date of Filing 17-Aug-2004
Name of Patentee COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 RAKSH VIR JASRA, BEENA TYAGI AND MANISH KUMAR MISHRA CENTRAL SALT AND MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-3640002, GUJARAT, INDIA.
PCT International Classification Number B01J 27/033
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA