# Patent

## Title
Process for hydrogenation of olefinic or acetylenic bonds

## Abstract

The present invention relates to a process for hydrogenation of olefinic or acetylenic bonds. Further, the present invention relates to a process for selective hydrogenation of olefinic or acetylenic bonds and/including triglycerides using modified metal supported on solid acidic metal oxide catalyst and the process for the preparation thereof. The present invention provides a process for hydrogenation of olefinic or acetylenic bonds using metal supported on solid acid metal oxide based catalyst, at moderate conditions. The present invention also relates to the preparation of metal supported on solid acid metal oxide based catalyst for hydrogenation reactions under mild conditions.

## Background
PRIORITY CLAIM TO RELATED APPLICATIONS
This application is a U.S. national stage application filed under 35 U.S.C. §371 from International Application Serial No. PCT/IB2013/000076, which was filed Jan. 24, 2013, and published as WO 2013/110995 on Aug. 1, 2013, and which claims priority to India Application No. 218/DEL/2012, filed Jan. 25, 2012, and to India Application No. 1361/DEL/2012, filed May 4, 2012, which applications and publication are incorporated by reference as if reproduced herein and made a part hereof in their entirety, and the benefit of priority of each of which is claimed herein.
TECHNICAL FIELD OF INVENTION
The present invention relates to a process for hydrogenation of olefinic or acetylenic bonds. Particularly, the present invention relates to a process for the selective hydrogenation of olefinic or acetylenic bonds using supported acidic metal oxide catalyst and the process for the preparation thereof. More particularly, the present invention provides a process for hydrogenation of olefinic or acetylenic bonds using metal supported on acidic metal oxide/modified acidic metal oxides at moderate conditions. The present invention also relates to the preparation of metal oxide based catalyst for hydrogenation reactions under mild conditions.
BACKGROUND AND PRIOR ART
Several catalysts have been tried for hydrogenation reactions. These catalysts are usually based on metals such as palladium, platinum and nickel supported on different oxides like silica, different carbon supports like carbon nanotubes, and charcoal as well as several polymers. Out of all these catalysts, palladium on charcoal is the most frequently used catalyst in industries and academia.
Though Pd/C is frequently used by the industry, it has some drawbacks such as pyrophoric nature when in contact with dry methanol. Normally hydrogenation reactions are carried out at melting temperature and high hydrogen pressure. Conventionally triglycerides and unsaturated fatty acids are hydrogenated using noble metal based catalysts or copper chromite or copper cadmium catalysts at melting temperature in the range of 150 to 250° C. and high hydrogen pressure. Specifically oils like castor oils are hydrogenated using nickel based catalysts at melting temperature (150-250° C.) and high pressure (up to 20 bar). Under these severe conditions, highly dispersed palladium or platinum particles sinter leading to loss of catalytic activity. Many times the noble metal loading in industrial catalyst varies from 1% to 10% of the support and higher loading leads to increase in the catalyst cost.
To overcome the severe reaction conditions and to evolve a cheaper catalyst for hydrogenation reactions is the need of the time.
OBJECT OF INVENTION
The main object of the present invention is to provide a process for hydrogenation of olefinic or acetylenic bonds.
Another object of the present invention is to provide a process for hydrogenation of olefinic or acetylenic bonds using modified acidic metal oxide catalyst and the process for the preparation thereof.
Another object of the present invention is to provide a simple, economical, efficient process for hydrogenation of olefinic or acetylenic bonds using metal oxide based catalyst or modified acidic metal oxide catalyst under mild conditions.
Another object of the invention is to provide a process for the preparation of metal oxide based supported catalyst for hydrogenation of olefinic and acetylenic bonds under mild conditions.
SUMMARY OF INVENTION
Accordingly, the present invention provides a process for hydrogenation of olefinic or acetylenic bonds, said process comprising:

    
    
        a. activating a catalyst in a flow of hydrogen gas in a solvent 10 times volume of the substrate at room temperature ranging between 20-30° C.,
        b. reacting the catalyst of step (a) with reactant in the range of 1-10 wt % with respect of substrate by stirring for 0.5-15 hours at atmospheric pressure and room temperature (20-30° C.),
        c. obtaining the desired product from step (b),
    
    


In an embodiment of the present invention the catalyst used in step (a) is solid acidic support comprising a metal oxide, mixed metal oxides or modified metal oxides.
In one embodiment of the present invention metals selected from group II A, IIIA, IVA, IB, IVB, VIB, and VIIIB.
In another embodiment of the present invention at least one elemental metal dispersed on said support wherein the elemental metal is selected from group VIB, IB or VIIIB metals in an amount up to 0.1-1.0 weight percent based upon the total weight of metal and support.
In yet another embodiment of the present invention yield and selectivity of desired product is up to 100%.
In yet another embodiment of the present invention the solvent is selected from toluene, methanol, and carbon tetra chloride.
In still another embodiment of the present invention a process for preparation of a catalyst for hydrogenation comprising:

    
    
        a. preparing a slurry of solid acidic metal oxide, mixed metal oxides or modified metal oxides in water,
        b. adding aqueous solution of elemental metal salt to solution of step (a) allowing water to evaporate to obtain the catalyst.
    
    


In still another embodiment of the present invention the acidity of the catalyst with modified magnesium oxide support ranges from 0.1-3.0 mmol/g of NH3.
In still another embodiment of the present invention the specific surface area of the metal oxide based solid acid catalyst supports is in the range between 50 to 500 m2/gm.
In still another embodiment of the present invention the specific acidity of the metal oxide based solid acid catalyst supports is in the range of 0.1 to 3.0 mmol/g of NH3.



BRIEF DESCRIPTION OF FIGURE
FIG. 1: XRD patterns of palladium based magnesium fluorooxides.

    
    
        a) PMF (full form) 10: 1% palladium on magnesium oxide
        b) PMF11: 1% palladium on fluorinated magnesium oxide with Magnesium:Fluorine is 1:1
        c) PMF12: 1% palladium on fluorinated magnesium oxide with Magnesium:Fluorine is 1:2
    
    





DETAILED DESCRIPTION OF INVENTION
In the present invention a simple process for hydrogenation of olefinic and acetylene bonds using metal oxide based supported catalysts is disclosed.
In the invention selective hydrogenation of olefinic, acetylenic including edible and non edible triglycerides is carried out at room temperature (20-30° C.) and atmospheric pressure by bubbling hydrogen gas through the oil, using palladium based catalysts with up to 1% Pd loading on the acidic metal oxide support.
The catalyst of the invention comprises a metal selected from noble metals and metals from group VIIIB, IB and VIB. In a preferred embodiment of the invention the metals are selected from Ni, Cu, Cr, Pd, Pt, Rh, and Au. The metals of the invention have been uniformly dispersed on metal oxide based solid acid supports. The acidity of the catalyst ranges from 0.1-3.0 mmol/g of NH3. Table 1 lists the different metal oxide based solid acid catalyst supports with specific surface area and specific acidity.
In the process of hydrogenation of olefinic and acetylenic bonds of the invention comprises:

    
    
        a. Activating the catalyst in a flow of hydrogen gas in a suitable solvent at room temperature, solvents preferably toluene, methanol, carbon tetra chloride;
        b. Reacting catalyst with reactant by stirring for 0.5-15 hours at atmospheric pressure and room temperature ranging from 20-35 deg C. and
        c. Obtaining the product of the process.
    
    


List of active metals supported on solid acidic support: Pd, Pt, Cu, Ni, Rh, Au, Cr







TABLE 1







Different metal oxide based solid acid catalyst supports with


specific surface area and specific acidity.














Range of
Range of





Specific
Specific





Surface
acidity


Sr.

Representative
area
(mmol/g


No.
Type of catalyst
example
(m2/g)
NH3)





1
Acidic Metal
Acidic alumina
100-500
0.1-0.5



Oxides
Sulfted zirconia
100-500
0.1-0.6




(ZrO2—SO4)


2
Mixed metal
MoO3—SiO2
 50-400
0.3-0.9



oxides
SiO2/Al2O3
300-700
0.2-0.4




TiO2—SiO2
100-500
0.1-0.3


3
Supported metal
Heteropoly acids
 50-200
0.5 to 3.0



oxides
supported




(HPW) on SiO2




HPW = Silicotungstic




acid,




silicomolybdic acid,




phosphomolybdic acid,




phosphotungstic acid




Sn/MCM-41
 200-1000
0.1-0.3




ZrO2—B2O6
 50-180
0.2-0.5


4
Acidic Zeolites
ZSM-5
400-450
0.3-2.5




Y- type
 500-1000
0.3-2.5


5
Clays
K-10
220-270
0.1-1.0




Montmorillonite
20-40
0.1-1.0




KSF


6
Acidic Resins
Amberlite IRS-120
 1-20
~1


7
Modified nietal
MxOy modified with
 50-200
0.1-1.0



oxides
aqueous HF;




M = Mg, Ca, Sr, Ba,




Al; X = 1, y = 1 or




x = 2, y = 3









The process of hydrogenation of olefinic and acetylenic bonds is catalyzed by a novel modified magnesium oxide catalyst prepared by a process comprising:

    
    
        a. Preparing a slurry of magnesia in water;
        b. Adding aqueous solution of hydrogen fluoride to slurry of step (a) and stirred at room temperature for about an hour;
        c. Adding aqueous solution of a metal salt to suspension of step (b) with stirring and continued stirring for about 12 hours;
        d. Allowing water to evaporate to obtain modified acidic magnesium oxide catalyst
    
    


The ratio of magnesium to fluoride varies from 1:0.1 to 1:2.
The modified magnesium oxide catalyst of the invention can be prepared replacing magnesium with calcium, strontium, barium or aluminium. The modified magnesium catalyst of the invention comprises a metal selected from noble metals and metals from group VIIIB, IB and VIB.
In the invention the metals are selected from Ni, Cu, Cr, Pd, Pt, Rh and Au.
In another aspect of the invention, the modified magnesium catalyst of the invention is characterized by XRD studies.
In the process of the invention, no leaching of palladium is observed and catalyst of the invention is recyclable.
The modified magnesium catalyst is used for catalysis for the process of hydrogenation of olefinic and acetylenic bonds as given in the following examples.
The metal oxide based catalyst may be further used for selective hydrogenation of olefinic double bonds under very mild conditions for various industrially important molecules including pharmaceuticals.
The invention can be better understood by the following non-limiting examples. The examples given are mere an illustration of the instant invention and should not be construed as limiting the scope of the present invention in any manner.
EXAMPLES
Example 1
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the toluene (10 mL) with constant stirring at room temperature 27° C. To this solution 0.0.5 g styrene was added. The reaction was continued for 3 h. The samples were collected after specified time interval and analyzed by GC. The reaction was monitored by GC analysis. The products were confirmed by GC and GCMS analysis. In this reaction only product obtained was ethyl benzene with 100% conversion and >99.5% selectivity.
Example 2
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the toluene (10 mL) with constant stirring at room temperature 27° C. To this solution 0.0.5 g Cinnamaldehyde was added. The reaction was continued for 3 h. The samples were collected after specified time interval and analyzed by GC. The reaction was monitored by GC analysis. The products were confirmed by GC and GCMS analysis. In this reaction only product obtained is 3-phenylpropanol with >99% selectivity and 95% conversion.
Example 3
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.5 g palm oil was added. The reaction was continued for 1.5 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is palm wax (or hydrogenated palm oil) having Iodine value less than 12 and acid value up to 2 (same as that of the initial palm oil).
Example 4
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.5 g castor oil was added. The reaction was continued for 1.5 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which castor wax (or hydrogenated castor oil) is having Iodine value around 14 and acid value up to 2 (same as that of the initial castor oil
Example 5
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution was added 0.5 g oleic acid. The reaction was continued for 1 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is stearic acid having Iodine value <1. The product was also confirmed by FTIR analysis which shows absence of double bond frequency.
Example 6
The 50 mg 1% Pd—Al2O3 (acidic) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.5 g castor oil was added. The reaction was continued for 6 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is castor wax having Iodine value  ̃12 and acid value up to 2.
Example 7
The 50 mg 1% Pd-20% MoO3/SiO2 (impregnated) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.0.5 g castor oil was added. The reaction was continued for 3 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is castor wax having Iodine value  ̃12 and acid value up to 2.
Example 8
The 50 mg 1% Pd-20% MoO3/SiO2 (sol gel) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room, temperature 27° C. To this solution 0.5 g castor oil was added. The reaction was continued for 8 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is castor wax having Iodine value  ̃30 and acid value up to 2.
Example 9
The 50 mg 1% Pd-resin (Amberlite IRS-120) was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 ml/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.0.5 g castor oil was added. The reaction was continued for 3 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is castor wax having Iodine value  ̃15 and acid value up to 2.
Example 10
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.103 g, 1 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 11
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.052 g, 0.5 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 12
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.0102 g, 0.1 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 13
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.206 g, 2 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 14
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.515 g, 5 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 15
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.0206 g, 0.2 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 16
In 100 mL beaker, 4.0 g commercial magnesium oxide was added to 40 mL distilled water to form suspension at room temperature. This suspension was reacted with 10.0 mL aqueous hydrofluoric acid (commercial, 40%) with stirring at up to 1400 RPM. After the complete addition of hydrofluoric acid the reaction mixture was allowed to stir for 3 h. To this solution 5.0 mL acidic solution (1N HCl) of palladium chloride (0.031 g, 0.3 wt %) was added drop wise. The reaction mixture was kept under stirring for 16 h. The water was allowed to evaporate from the reaction by simply drying at 100° C. using hot plate with magnetic stirrer followed by heating at 150° C. in oven for 3 h. Catalyst yield was about 100%. Catalyst was characterized by PXRD.
Example 17
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the toluene (10 mL) with constant stirring at room temperature 27° C. To this solution 0.0.5 g styrene was added. The reaction was continued for 3 h. The samples were collected after specified time interval and analyzed by GC. The reaction was monitored by GC analysis. The products were confirmed by GC and GCMS analysis. In this reaction only product obtained was ethyl benzene with 100% conversion and >99.5% selectivity.
Example 18
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the methanol (10 ml) with constant stirring at temperature 27° C. To this solution 500 mg styrene was added. The reaction was continued for 3 h. The samples were collected after specified time interval and analyzed by GC. The reaction was monitored by GC analysis. The products were confirmed by GC and GCMS analysis. In this reaction only product obtained was ethyl benzene with 100% conversion and >99.5% selectivity.
Example 19
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the toluene (10 mL) with constant stirring at room temperature 27° C. To this solution 0.5 g Cinnamldehyde was added. The reaction was continued for 3 h. The samples were collected after specified time interval and analyzed by GC. The reaction was monitored by GC analysis. The products were confirmed by GC and GCMS analysis. In this reaction only product obtained is 3-phenylpropanol with >99% selectivity and 95% conversion.
Example 20
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution was added 0.5 g palm oil. The reaction was continued for 1.5 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is palm wax (or hydrogenated palm oil) having Iodine value <12 and acid value  ̃2 (same as that of the initial palm oil).
Example 21
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the methanol (10 mL) with constant stirring at temperature 27° C. To this solution 0.5 g castor oil was added. The reaction was continued for 1.5 h. The samples were collected after specified time and analyzed by titration method for determination of iodine value. At the end of reaction white castor wax (or hydrogenated castor oil) with iodine value around 14 and acid value up to 2 (same as that of the initial castor oil) was obtained.
Example 22
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 2 mL/min in the methanol (10 mL) with constant stirring at room temperature 27° C. To this solution 0.5 g oleic acid was added. The reaction was continued for 1 h. The samples were collected after specified time and analyzed by titration method by determination its Iodine value. At the end of reaction white solid was obtained which is stearic acid having Iodine value <1. The product was also confirmed by FTIR analysis which shows absence of double bond frequency.
Example 23-Example 38
Typical Procedure for Example 23 to Example 38
The 50 mg 1% Pd—MgO modified with HF as prepared in Example 10 was activated for the period up to 0.5 h under the constant flow of hydrogen of 10 mL/min in the methanol (10 mL) with constant stirring at mentioned temperature. To this solution was added 0.5 g of various substrates as given in table 2. The reaction was continued for specified time. The samples were collected intermittently and analyzed by GC and GCMS. The product was also confirmed by FTIR analysis which shows absence of olefinic C═C bond frequency. The reaction conditions and results are given in table 2.













TABLE 2








Time
Temperature
Conversion
Selectivity


Example
Substrate
Products
(h)
(° C.)
(%)
(%)





















23
cyclohexene
cyclohexane
12
RT
~100
100


24
Indene
Dihydroindene
6
RT
~100
100


25
Hexene
Hexane
10
RT
~100
100


26
Cyclooctene
Cyclooctane
8
RT
~100
100


27
α-Methylstyrene
Cumene
12
RT
~100
100


28
crotonaldehyde
Butanal
9
RT
~100
99


29
Cinnamyl alcohol
3-phenyl propanol
12
RT
~100
99


30
Methyl acrylate
Methyl propanoate
6
RT
~100
99


31
Acrylic acid
Propionic acid
5
RT
100
99


32
Benzalaceto-phenone
1,3-diphenyl-propanone
6
RT
64.6
99


33
But-2-yne-1,4-diol
1,4-butandiol
6
RT
~100
98


34
cis-Stilbene
1,2-diphenyl-ethane
6
80
88.9
99


35
trans-Stilbene
1,2-diphenyl-ethane
6
80
65.8
99


36
4-vinylanisole
4-Ethylanisole
6
80
95.0
99


37
2-Vinyl pyridine
Ethyl pyridine
12
80
78.3
99


38
Phenyl acetylene
Ethylbenzene
6
RT
100
89









Example 39 to Example 52
General Procedure for Castor Oil Hydrogenation without Solvent at Melting Temperature and High Pressure
A 50 mL high pressure autoclave was charged with 20.0 g of castor oil and required amount of catalyst from example 10 and hydrogen gas pressure 10 bar. The reaction mixture was stirred with 1800 RPM speed at required temperature. During the reaction the hydrogen gas pressure slowly decreased which was maintained using external gas pressure reservoir. The reaction was allowed to continue for the specific time. Once the reaction completed the product was separated from the catalyst and subjected for analysis. The white castor wax was analyzed using iodine value and melting point. The results are tabulated in table 3.







TABLE 3







Results of castor oil hydrogenation at


high pressure and melting temprearure














Catalyst




Melting



from
Catalyst
Time
Temperature
Iodine
point


Example
Example
(wt %)
(h)
(° C.)
Value
(° C.)
















39
10
10
3
60
10.8
71.8


40
10
5
3
60
12.7
80.2


41
10
3
3
60
29.2
80.2


42
10
4
5.30
90
9.5
81.9


43
10
5
2
100
30
72.9


44
10
3
2.40
100
29
76.9


45
14
3
1.30
100
4
82.0


46
15
5
8.30
100
32.27
68.4


47
14
5
2.25
100
15.6
69.4


48
16
5
3
100
45.04
73.1


49
14
3
2.5
100
31
66.4


50
10
5
3.15
100
22
80.5


51
14
3
4.30
100
66.6
59.0


52
14
3
1.50
100
33.29
79.1


53
16
5
6.0
80
17.16
78.1


 54#
10
10
3
RT
6.54
—


   55@
10
10
4
RT
—
56.6





#with solvent methanol (1:10 oil:solvent),


@with solvent methanol (3:1 oil:solvent)






Example 56
Sunflower Oil Hydrogenation without Solvent at Room Temperature and High Pressure
A 50 mL high pressure reactor charged with 20 g sunflower oil, 1 g catalyst from example 10 as prepared in example 10 and hydrogen gas pressure 10 bar. The reaction mixture was stirred with 1800 RPM speed at room temperature for 3 h. During the reaction the hydrogen gas pressure slowly decreased which was maintained using external gas pressure reservoir. Once the reaction was complete the product was separated from the catalyst and subjected for analysis. The iodine value of the white sunflower wax was found to be 56.
Example 57
Sunflower Oil Hydrogenation without Solvent at STP
A 50 mL high pressure autoclave was charged with 20 g sunflower oil 1 g catalyst from example 10 as prepared in example 10. Hydrogen gas was bubbled with 10 mL per min with constant stirring (1800 RPM speed) at room temperature for 7 h. The flow rate of hydrogen gas was kept constant by using external reservoir. Once the reaction was completed the product was separated from the catalyst and subjected for analysis. The iodine value of the white sunflower wax was found to be 64
Example 58
Rape Seed Oil Hydrogenation without Solvent at Melting Temperature and High Pressure
A 50 mL high pressure autoclave was charged with 20 g rape seed oil, 1 g catalyst from example 10 and hydrogen gas pressure 10 bar. The reaction mixture was stirred with 1800 RPM speed at 100° C. for 3 h. During the reaction the hydrogen gas pressure slowly decreased which was maintained using external gas pressure reservoir. The reaction was allowed to continue for 6 h. Once the reaction was complete the product was separated from the catalyst and subjected for analysis. The iodine value and melting point of the whitish yellow rape seed wax was found to be 32 and 59° C. respectively.
Example 59
Rape Seed Fatty Acid Hydrogenation without Solvent at Melting Temperature and High Pressure
A 50 mL high pressure autoclave was charged with 20 g rape seed fatty acid, 1 g catalyst from example 16, and hydrogen gas pressure 10 bar. The reaction mixture was stirred with 1800 RPM speed at 90° C. for 5 h. During the reaction the hydrogen gas pressure decreased slowly which was maintained using external gas pressure reservoir. The reaction was continued for 6 h. Once the reaction was complete the product was separated from the catalyst and subjected to analysis. The iodine value of the whitish saturated rape seed fatty acid was found to be 39. Also the partial reduction of olefinic double bond was confirmed by FTIR spectroscopy.
The advantages of the invention are:


    
    
        1. Low metal loading—up to 0.1 wt %, hence lower cost of catalyst.
        2. Room temperature hydrogenation at atmospheric pressure
        3. Ease of operation.
        4. No metal leaching.
        5. Easily recyclable catalyst.
        6. Environmentally benign process.
        7. No pressure vessels are required hence low capital investment.
        8. The hydrogenation using the present metal oxide based catalyst will be cheaper and safer compared to the conventional hydrogenation.

## Claims

1. A process for hydrogenation of olefinic or acetylenic bonds, said process comprising:
a. activating a catalyst in a flow of hydrogen gas in a solvent 10 times volume of a reactant at room temperature ranging between 20-30° C.,
b. reacting the catalyst of step (a) with the reactant of step (a) in the range of 1-10 wt % with respect to said reactant by stirring for 0.5-15 hours at atmospheric pressure and room temperature (20-30° C.) and
c. obtaining the desired product from step (b), wherein said catalyst used in step (a) comprises an elemental metal or a metal salt supported on a solid acidic support comprising a metal oxide, mixed metal oxides or modified metal oxides, prepared by a process comprising:
i. preparing a slurry of solid acidic metal oxide, mixed metal oxides or modified metal oxides in water,
ii. adding an aqueous, acidic solution of elemental metal salt to solution of step (i), allowing water to evaporate to obtain the catalyst, and
iii. heating the catalyst obtained in step (ii) at 150° C. for 3 h.

2. The process according to claim 1, wherein the metal in the metal oxide, mixed metal oxides or modified metal oxides are selected from group II A, IIIA, IVA, IB, IVB, VIB, and VIIIB.

3. The process according to claim 1, wherein at least one elemental metal is dispersed on said support, wherein the elemental metal is selected from group VIB, IB or VIIIB metals in an amount ranging from 0.1-1.0 weight percent based upon the total weight of metal and support.

4. The process according to claim 1, wherein yield and selectivity of desired product is up to 100%.

5. The process according to claim 1, wherein the solvent is selected from toluene, methanol, carbon tetra chloride.

6. The process according to claim 1, wherein the catalyst has a specific acidity and the specific acidity of a catalyst with a modified magnesium oxide support as the elemental metal or a metal salt supported on a solid acidic support comprising a metal oxide, mixed metal oxides or modified metal oxides ranges from 0.1-1.0 mmol/g of NH3.

7. The process according to claim 1, wherein the metal oxide based solid acid catalyst support has a specific surface area in the range between 50 to 500 m2/gm.

8. The process according to claim 1, wherein the catalyst has a specific acidity and the specific acidity of a metal oxide based solid acid catalyst support as the elemental metal or a metal salt supported on a solid acidic support comprising a metal oxide, mixed metal oxides or modified metal oxides is in the range of 0.1 to 3.0 mmol/g of NH3.

9. The process according to claim 1, wherein the acidic solution of elemental metal salt comprises an acidic solution of palladium chloride.

10. The process according to claim 1, wherein the acidic solution is added dropwise.