WO2012035542A1

WO2012035542A1 - Catalyst composition (icat-3) comprising of transition metal supported on acidified anatase titania

Info

Publication number: WO2012035542A1
Application number: PCT/IN2011/000091
Authority: WO
Inventors: Ganapati Dadasaheb Yadav; Rajesh Vishnudev Sharma
Original assignee: Ganapati Dadasaheb Yadav; Rajesh Vishnudev Sharma
Priority date: 2010-09-16
Filing date: 2011-02-11
Publication date: 2012-03-22

Abstract

The heterogeneous solid acid catalyst (ICaT-3) has been disclosed herein. The catalyst of the invention comprises of iron loaded, chlrosulfonic acid treated anatase nano titania as basic metal. The said catalyst composition has the specific surface area in the range of 20 m²/g to 200 m²/g. The ICaT-3 catalyst shows very good activity and reusability for liquid phase oxidation reaction.

Description

TITLE OF THE INVENTION

"CATALYST COMPOSITION (ICaT-3) COMPRISING OF TRANSITION METAL SUPPORTED ON ACIDIFIED ANATASE TITANIA"

FIELD OF INVENTION

The present invention is related to development of heterogeneous solid acid catalyst comprising trivalent and divalent metals supported on chlorosulfonic acid treated anatase nano titania as base metal wherein said catalyst possesses high acidity due presence of sulfate linkages. The sulfated divalent and trivalent metal increases the oxidation strength of the aforesaid catalyst. A process for preparation of ICaT-3 catalyst and its application in the liquid phase oxidation reactions has been discussed in the present discloser. The aforesaid catalyst has high conversion, selectivity and also has good reusability. BACKGROUND OF THE INVENTION

The treatment and disposal of excessive toxic waste, produce during the isolation and work-up of the reaction media to get the product, is driving force for industry to consider cleaner technologies, including the use of heterogeneous catalysis. Heterogeneous catalyst is always hot area of research to design highly active and reusable catalyst.

Acid treated metal oxides are very important in the field of catalysis and their structural properties are altered through innovative recipes. Sulfated metal oxide has drown lots of attention because the chemical properties of metal increase by presence of sulfate groups. Sol-gel method gives crystalline titania in the range of nanometer. Hence sol-gel processing provides excellent chemical homogeneity and the possibility of deriving unique metastable structure at low reaction temperature. It involves the formation of metal -oxo-polymer network from molecular precursor such as metal alkoxides or metal salts. US 5182247 discloses aluminas, silica-aluminas or clays treated with sulfuric acid, metal sulfates, sulfur trioxide or organic sulfates used for skeletal isomerization without substantial cracking. US 53455028 discloses sulfated mixed oxide of titanium and nickel used for alkylation reactions.

US 6124367 discloses alumina, silica are used as binders for a titania containing support and used in Fischer-Tropsch synthesis. It is useful in slurry reactions.

According to the process in Catalysis Communication 6 (2005) 611-616, sulfated titania and chromium loaded sulfated titania were prepared and used for nitration of phenol by using nitric acid. According to the process in Journal of Molecular Catalysis A: Chemical 156, 2000, 267- 274, sulfated titania samples with varying amount of sulfate have been prepared by solid- solid kneading, as well as aqueous impregnation method.

This invention relates to the development of heterogeneous solid acid catalyst ICaT-3 (Institute of Chemical Technology, Mumbai). ICaT-3 comprising chlorosulfonic acid treated, trivalent and divalent metal supported on anatase nano titania as base metal wherein said catalyst possesses high acidity due presence of sulfate linkages.

A process for preparation of ICaT-3 catalyst and its application in liquid phase alkylation reaction and liquid phase oxidation of benzyl alcohol to benzaldehyde has been discussed in the present discloser. The aforesaid catalyst has high conversion and selectivity and also has good reusability.

OBJECTIVE OF THE INVENTION

The objective of the present invention is to prepare a heterogeneous solid catalyst with high acidity and good stability. Yet another objective of the present invention is to specific selection of divalent and trivalent metal for calcinated catalyst composition. Yet another objective of the invention is to design heterogeneous catalyst having good oxidizing strength.

Objective of the present invention is to design heterogeneous solid acid catalyst which can be easily seperable, regenerable and reusable.

According to the process of the present invention, solid acid catalyst "ICaT-3" (Institute of Chemical Technology, Mumbai) is used for the liquid phase oxidation reactions.

The heterogeneous solid acid catalyst (ICaT-3) composition comprising at least 1 to 30 mass percentage of iron or tungsten supported on chlorosulfonic acid treated anatase nano titanium and/or mixture thereof.

Another objective of the present invention is to design catalyst having specific surface are in the range of 20 to 200 m²/g.

SUMMARY OF INVENTION

In the present invention A heterogeneous solid acid catalyst (ICaT-3) is designed and developed comprising at least 1 to 30 mass percentage of iron or tungsten supported on chlorosulfonic acid treated anatase titania and/or mixture thereof. ICaT-3 has surface area in the range of 20-200 m²/g.

Process for preparation of catalyst (ICaT-3) comprising the steps of:

a) Converting titania precursor into anatase nano titania by controlled hydrolysis.

b) Incorporating iron or tungsten and/or mixture thereof by wet impregnation and/or co-precipitation method. C) Acidifying heterogeneous material by treatment with chlorosulfonic acid. d) Calcining at temperature in the range of 400-850 °C, more preferably 550 °C for a minimum of 3 hr. The catalyst shows excellent activity for liquid phase alkylation reaction and liquid phase oxidation of benzyl alcohol to bezaldehyde by using phase transfer catalyst. The catalyst is used in an amount of 0.5 to 15 % wt/wt of the reaction mixture. ICaT-3 catalyst shows good stability and reusability. BRIEF DISCRIPTION OF DRAWINGS

Drawing 1 : Infra Red (IR) spectra of the catalyst

Drawing 2: Thermogravimetric data the catalyst

Drawing 3: Temperature programmed desorption (TPD) data for N¾ desorption of the catalyst

Drawing 4: N₂- Adsorption/desorption analysis

Drawing 5: XRD image of the catalyst

DETAIL DESCRIPTION OF INVENTION

In accordance with the principle of the present invention, a heterogeneous solid catalyst (ICaT-3) having high acidity and oxidation property is prepared.

According to the process of the in the present invention, acidity is induced by treating with chlorosulfonic acid. According to the process in the present invention, heterogeneous solid acid catalyst comprises of titania metal with a crystalline size in the range of nanometer as basic backbone.

The metal incorporated in the catalyst is metal ions, selected from group consisting of Fe, Ti, W in the form of chloride or nitrate and or mixture thereof. The present invention discloses post grafting and co-condensation methods to prepare ICaT-3 catalyst.

One of the embodiments of the present invention is this ICaT-3 catalyst is characterized by several analytical techniques such as IR spectroscopy, thermogravimetric analysis, NH₃-temperature programmed desorption (NH₃-TPD), BET-surface area and pore volume measurements, elemental analysis by energy dispersive X-ray spectroscopy, X- ray diffraction analysis (XRD). The IR spectra of ICaT-3 (Drawing 1) disclose a broad peak with shoulders at around 1120-1160 cm^"1. The peak at 1128, 1141 and 1156 cm^"1 are typical for S0₄ ^"2 mode of vibration of a chelating bidentate sulfate ion coordinated to a metal cation.

Themogavimetric analysis (TGA) and Differential thermal analysis (DTA) discloses the thermal stability of the ICaT-3 catalyst (Drawing 2). This catalyst has the thermal stability up to 850 °C more preferably around 600 °C.

One more embodiments of the present invention is that the ICaT-3 catalyst, which comprises of Fe metal ion in the range of 1 to 30 mass percentage to the total mass percent of the catalyst.

NH₃-TPD profile discloses the surface acidity of ICaT-3 catalyst. ICaT-3 exhibits two peaks (Drawing 3), one in the intermediate range (128 °C) and another in the range of very strong acid strength (428 °C). The intermediate acid strength and strong acid strength of ICaT-3 catalyst are 0.332 and 0.112 mmol g^"1. The high acidity is due to the higher sulfate content in ICaT-3.

Another aspect of the present invention is to prepare the ICaT-3 catalyst having a surface area in the range of 20m /g to 200 m /g, pore volume in the rage of 0.01 ml/g to 0.5 ml/g, a pore diameter in the range of 20 to 200 A. It is found that surface area, pore volume and pore diameter of ICaT-3 was less than without chlrosulfonic acid treated ICaT-3, this is because the immobilization of sulfate linkage on it (Table A-C).

Table C

(3) Pore Diameter (A)

BJH

Average pore adsorption

diameter (4V/A average pore BJH desorption by Langmuir) diameter average pore diameter

Catalyst A (4V/A) A (4V/A) A

Without

chlrosulfonic acid 100.72 113.46 101.37

treated ICaT-3

ICaT-3 96.93 87.07 75.53

ASAP 2010 V 3.( )0, Analysis Adsorptive: N₂, Analysis Bath: 77.30 K, Low pressure Dose: 5 c m²/g STP, Equilibrium Interval : 20 sees., Sample weight:

0.2 g.

To summaries the catalyst ICaT-2 characteristics show,

The XRD pattern of ICaT-3 (Drawing 5) discloses the diffraction line at 2Θ values 25.5 , 37.4°, 48°, and 53° indicating the anatase type of Ti0₂. This is also a characteristic value for chlorosulfonic acid treated titania. Iron loading decreases the peak intensity of chlorosulfonic acid treated titania.

One more embodiment of the present invention involves checking the catalytic activity ICaT-3 catalyst by Friedel-Crafts alkylation reaction of toluene and oxidation of alcohols.

One more embodiment of the present invention is to check the catalyst activity of ICaT-3 by oxidation of benzyl alcohol to benzaldehyde. In this process, benzyl alcohol is oxidized to benzaldehyde with excellent conversion and with high efficiency and selectivity. The ICaT-3 catalyst is easily separable, regenerable and reusable.

One of the embodiment of the present invention is ICaT-3 catalyst is separated by filtration and regenerated by washing with organic solvent (methanol, ethanol) and further used for the next reaction, without any considerable loss in catalytic activity.

One of the embodiment of the present invention that the ICaT-3 has excellent catalytic activity and only 0.1 to 2 % catalyst required to oxidize benzyl alcohol to benzaldehyde in liquid phase.

Therefore, the foregoing examples are considered as illustrative in terms of principles of the invention. EXAMPLE 1: Synthesis of ICaT-3 catalyst by wet impregnation technique

A specific amount of titanium isopropoxide (Ti(OC₃H₇)₄) is dissolved in anhydrous ethanol and, then this is added to the solution of the water:ethanol. Titanium isopropoxide solution is added drop wise with rigorous stirring at room temperature under N₂ atmosphere. The precipitate is subjected to hydrothermal treatment. Iron loading (5%, 6% and 9%) is done by wet impregnation technique by using iron nitrate. The dried material is hydrolyzed by ammonia gas. It is dried in an oven for 24 h at 110 °C. Sulfation is done by immersing it in 0.5 M chlorosulfonic acid and calcined thereafter at 500 °C for 3 h to get the final solid acid catalyst called ICaT-3. EXAMPLE 2: Synthesis of ICaT-3 catalyst by co-precipitation technique

A specific amount of titanium tetrachloride is dissolved in anhydrous ethanol and, then added to the solution of the waterrethanol. Titanium isopropoxide solution is added drop wise with rigorous stirring at room temperature under N₂ atmosphere. Iron, molybdenum and tungsten loading is done by adding solution to it. The precipitate is subjected to hydrothermal treatment. The dried material is hydrolyzed by ammonia gas. Sulfation is done by immersing it in 0.5 M chlorosulfonic acid and calcined thereafter at 500 °C for 3 h to get the final solid catalyst.

EXAMPLE 3: Alkylation of toluene with benzyl chloride by using ICaT-3 catalyst The liquid phase alkylation of toluene with benzyl chloride is carried out to check the acidic strength of ICaT-3. Reaction is performed by adding toluene (0.2 mol), benzyl chloride (0.04 mol), 0.04 g/cc of ICaT-3 and undecane as internal standard. The reactor is consisted of a flat glass vessel of 5 cm i.d., 10 cm height and 150 ml of capacity equipped with baffles and a six blade impeller. The assembly is kept in an oil bath at 90 °C. The reaction mixture is agitated at the required speed with the help of a variable motor. Reaction completed within 60 min with 100 % conversion of benzyl chloride. These results represent the good acidic strength of ICaT-3.

EXAMPLE 4-7: Oxidation of benzyl alcohol to benzaldehyde by ICaT-3

The liquid phase oxidation of benzyl alcohol to benzaldehyde is taken as model reaction to study the oxidation ability of ICaT-3 catalyst. The standard experiments are carried out with O.Olmol benzyl alcohol, 0.00274 mol cetyltrimethylammonium bromide (CTAB) and the volume was made up to 20 cm³ with 1 ,2-dichloroethane (EDC) as solvent at temperature 60 °C. The catalyst loading is 0.05 g/cm³. Agitation speed is 1000 rpm. 0.04 mol of 30% H₂0₂ is added by means of HPLC pump with the constant flow rate. Samples are withdrawn and analyzed by gas chromatography. As the iron content is increased from 3 to 9 % in the catalyst, there is subsequent increase in catalyst activity. However, 6 and 9% iron loading gives the similar results. The duration of reaction is 60 min.

EXAMPLE 8-11: ICaT-3 reusability study

The reusability of the catalyst is tested by conducting four runs. After completion of the reaction, the catalyst is filtered and washed with methanol. Then it is refluxed with 50 cm³ of methanol for 30 min and dried at 120 C for 2 h. ICaT-3 catalyst has good reusability.

EXAMPLE 12-18: Oxidation of substituted alcohols to respective aldehydes

Various substrates such as substituted benzyl alcohol, styrene, substituted styrene, methyl phenyl sulfide are oxidized by using ICaT-3 catalyst. Substrate (0.01 mol), 30% H₂0₂ (0.04 mol), catalyst (0.05g/cm³), CTAB (0.00274 mol), 1,2-dichloroethane (20 cm³), temperature (60 °C), rpm (1000). H₂0₂ is added by HPLC pump.

Claims

CLAIMS We Claim:

1. A heterogeneous solid acid catalyst (ICaT-3) composition comprising of at least 1 to 30 mass percentages of iron or tungsten and/or mixture thereof supported on chlorosulfonic acid treated anatase nano titanium. ICaT-3 has surface area in the range of 20-200 m²/g.

2. Process for preparation of catalyst composition claimed in claim 1 comprising the steps of:

a. Converting titania precursor (titanium isopropoxide, titanium tetrachloride) into anatase nano titania by controlled hydrolysis.

b. Incorporating iron or tungsten and/or mixture thereof by wet impregnation technique and/or co-precipitation method.

c. Acidifying heterogeneous material by treatment with chlorosulfonic acid. d. Calcining at temperature in the range of 400-850 °C, more preferably 550 °C for a minimum of 3 hr.

3. Heterogeneous solid acid catalyst as claimed in claim 1 wherein chlorosulfonic acid treated anatase nano titania acts as support base.

4. Heterogeneous solid acid catalyst as claimed in claim 1 wherein metal ions are preferably selected from Fe, W, Mo, Ti and/or mixture thereof.

5. Heterogeneous solid acid catalyst as claimed in claim 1 wherein catalyst composition is acidify by treatment with chlrosulfonic acid with 0.1 to 5.0 molar solution.

6. Heterogeneous solid acid catalyst as claimed in claim 1 and 4 wherein composition has titania (Ti) 10-90 wt %, Iron (Fe) 1-30 wt %, tungsten (W) 1-10 wt % and sulfur 2-30 wt %.

7. Heterogeneous solid acid catalyst as claimed in claim 1 and 4 wherein metal ions are in the form of nitrate, chloride, acetate, sulphate, hydroxide salts of metal ions.

8. Heterogeneous solid acid catalyst as claimed in claim 1 wherein the catalyst shows excellent activity for liquid phase alkylation reaction and liquid phase oxidation of benzyl alcohol to bezaldehyde by using phase transfer catalyst.

9. Heterogeneous solid acid catalyst as claimed in claim 1 and 9 wherein the catalyst is used in an amount of 0.5 to 15 % wt wt of the reaction mixture.

10. Heterogeneous solid acid catalyst as claimed in claim 1 and 9 wherein the catalyst is stable and reusable.