TWI600466B - Preparation of iron oxide-titania-supported nano-gold catalysts and its application on hydrogenation of chloronitrobenzene - Google Patents

Description

Nano gold is supported by an iron oxide-titanium dioxide catalyst and its application in the hydrogenation reaction of chloronitrobenzene. PREPARATION OF IRON OXIDE-TITANIA -SUPPORTED NANO-GOLD CATALYSTS AND ITS APPLICATION ON HYDROGENATION OF CHLORONITROBENZENE

The invention discloses a method for preparing a gold catalyst supported on iron oxide and titanium dioxide, and a method for catalyzing the catalytic loading of nano gold on iron oxide and titanium dioxide in a hydrogen-rich environment for halogen nitroaromatic Such as the liquid phase hydrogenation of p-chloronitrobenzene.

The hydrogenation of aromatic nitrobenzenes (halontiroaromatics) using noble metals to form halamines has been extensively studied. Aromatic halonamines are important intermediates in the chemistry of herbicides, dyes, pharmaceuticals and pesticides. Traditional synthetic pathways and methods can cause harm to the environment. Baltzly pointed out that direct access to haloamine from aromatic halonitro seems to be the best route, but this process is not easy to perform because there is a large amount of dehalogenation in this process [ J. Am. Chem, Vol. 68, p. 261, 1946].

Chloroaniline (CAN) can be obtained by hydrogenation of chloronitrobenzene (p-CNB). The invention can be widely applied to the petrochemical, specialization, perfumery and pharmaceutical industries, and its economic effects are considerable.

A method for the formation of chloroaniline by liquid hydrogenation of chloronitrobenzene, the prior art is based on a precious metal catalyst, which comprises three catalysts of palladium, platinum and rhodium, which are used to hydrogenate p-chloronitrobenzene to p-chloroaniline. Hydrogenation of m-chloronitrobenzene to m-chloroaniline, Coq with noble metals such as platinum and rhodium, to investigate the effect of catalyst grain size on the selective hydrogenation of p-chloronitrobenzene [J. Molecular Catalysis, Vol. 79 , p. 243, 1993]. , Figueras et al. [Applied Catalysis, Vol. 76, pp. 255-266, 1991] reveals the use of base metals as a hydrogenation catalyst for p-chloronitrobenzene; a paper by Liao et al. [J.Chem. Soc., Chem. Comm., pp. 1155-1156, 1995] discloses the use of a palladium-ruthenium bimetallic as a hydrogenation catalyst for p-chloronitrobenzene; a paper by Vitulli et al. [Catalysis Letter, Vol. 44, Pages 205-210, 1997] Reveals the hydrogenation reaction catalyst for platinum/alumina as p-chloronitrobenzene; Lin et al. [J. Molecular Catalysis A: Chemical, Vol. 159, pp. 115-120 , 2000] revealed the addition of surfactant surfactant polyvinyl alcohol (polyvinylpyrrole) on platinum metal, as a hydrogenation reaction catalyst for p-chloronitrobenzene. U.S. Patent No. 4,326,078, discloses precious metals as hydrogenation of nitrobenzene to generate oxygen-azobenzene; U.S. Patent No. 4,140,719 discloses a phase transfer catalyst as in 2,4,5-trichloro-nitrobenzene fluoride generated Method for 2,4-difluoroaniline. U.S. Patent No. 7,381,844 , the use of a nickel-boron catalyst for the hydrogenation of p-chloronitrobenzene, the atomic ratio of boron to nickel is from 0.1 to 0.9; the reaction solvent is a hydrocarbon of less than four carbons, hydrogen pressure It is 5 to 40 atm and the reaction temperature is 40 to 150 °C. Valuable metals such as platinum, palladium or rhodium metal are used as catalysts, which are not only expensive, but also have high by-products due to their high hydrogenation capacity. Nickel metal is often used as a liquid hydrogenation catalyst, but its activity is not High, regarding the method for the nickel alloy catalyst to be used for the hydrogenation reaction of chloronitrobenzene , the domestic patent No. TWI 269786B can be seen.

Early gold was considered to be an inactive passive metal species, until Dr. Haruta of Japan discovered that when nano-scale gold is carried on a metal support, it has high activity and can catalyze the oxidation of carbon monoxide in a low-temperature environment. Gradually valued [Catal.Today, Vol. 72, p. 89, 2000]. Gold catalysts have recently been a hot research topic because of their selectivity and activity advantages, but in the past they have always focused on the study of oxidation reactions. In the literature, Claus pointed out that the gold catalyst has excellent adsorption capacity for hydrogen molecules, and its structurally sensitive properties. The hydrogenation reaction can make the selection rate of main products extremely high. By changing different supports, Catalysts are used in different hydrogenation reactions [Applied Catalysis A: General, Vol. 291, p. 222, 2005]. In the literature, Okumura used Au/Al ₂ O ₃ , Au/SiO ₂ and Au/TiO ₂ for hydrogenation of 1,3-butadiene, and found that all gold catalysts have a 100% selectivity for butene with 65-76. % is then converted to 1-butene [Catalysiss Today, Vol. 74, p. 265, 2002]. U.S. Patent No. 4,243,610 , the addition of gold and cobalt to a ruthenium catalyst as a reaction catalyst for olefinically unsaturated aliphatics, can effectively increase the yield. Moreover, the data shows that the gold-bismuth alloy catalyst without cobalt added has lower performance than the cobalt-ruthenium alloy catalyst or the tantalum catalyst. U.S. Patent No. 6,509,292 , acetylene hydrogenation is used in the ethylene purification procedure, using a gold-palladium bimetallic catalyst as a reaction catalyst, and a gold to palladium weight ratio of 6:1 to 50:1 is prepared by impregnation.

Most of the existing patents related to gold catalysts in China are used for the oxidation of carbon monoxide. Hydrogenation of chloronitrobenzene is not carried out in a hydrogen atmosphere, and iron oxide-titanium oxide mixed oxide is not used as a support. At present, domestic patent applications for gold catalysts such as domestic patent No. 200,410,754 . From the published patent, there is no method for utilizing nanogold supported on iron oxide and titanium dioxide catalyst for hydrogenation reaction of chloronitrobenzene as disclosed in the present invention.

In the case of foreign patents, the catalyst used in the hydrogenation reaction of chloronitrobenzene, in the case of precious metals, mostly platinum, rhodium, ruthenium and these alloys, or nickel metal catalyst, and Compared with these patents, the invention has the advantage that the price of gold is lower than that of platinum, rhodium, ruthenium and the like, and is higher than that of the nickel metal catalyst.

The invention discloses a gold catalyst method for preparing iron oxide and titanium dioxide, and a method for hydrogenating chloronitrobenzene in a hydrogen-rich environment under the catalyst of nano gold supported on iron oxide and titanium dioxide Wherein iron oxide and titanium dioxide are mixed according to different molar ratios, the iron/titanium molar ratio is between 1/9 and 5/5, and the actual weight percentage of gold is between 3.5 and 4, and the diameter of the gold particles carried is Between 2 and 5 nm. The invention uses a gold/iron oxide-titanium dioxide catalyst in a hydrogen-rich environment, using a batch reactor or a fixed bed flow reactor, the reaction solvent is an alcohol of four carbon or less, and the hydrogen pressure is about 5 to 50 atmospheres. The reaction temperature is 50 to 150 °C. The invention can be applied to the oxidation reaction of chloronitrobenzene, which has the characteristics of high activity and high product selectivity.

Embodiment 1

The iron oxide-titanium dioxide composite metal oxide is prepared by incipient wetness impregnation method as a gold-loaded support, wherein iron oxide and titanium dioxide are mixed according to different molar ratios, and an appropriate amount of ferric oxide is dispersed in water, and three The aqueous solution of ferric oxide is slowly dropped into an appropriate amount of titanium dioxide and stirred, and calcined in air at 200 to 400 ° C for 2 to 10 hours to form iron oxide-titania powder, which is taken out and ground.

Example 1

1. An iron oxide-titanium oxide oxide having an iron/titanium ratio of 1/9 was prepared, and 0.909 g of ferric oxide was weighed and dispersed in 3.87 ml of distilled water.

2. 4.91 g of titanium dioxide was weighed, and the aqueous solution of the first step was slowly dropped into it and stirred, and calcined in air at 300 ° C for 4 hours to form iron oxide-titania powder, which was taken out and ground.

Example 2

1. A ferric oxide-titanium oxide oxide having an iron/titanium ratio of 4/6 was prepared, 2.587 g of ferric oxide was weighed, and it was dispersed in 2.71 ml of distilled water.

2. 2.143 g of titanium dioxide was weighed, and the aqueous solution of the first step was slowly dropped into it and stirred, and calcined in air at 300 ° C for 4 hours to form iron oxide-titania powder, which was taken out and ground.

Example 3

1. An iron oxide-titanium oxide oxide having an iron/titanium ratio of 5/5 was prepared, and 3.333 g of ferric oxide was weighed and dispersed in 2.33 ml of distilled water.

2. 1.667 g of titanium dioxide was weighed, and the aqueous solution of the first step was slowly dropped thereinto and stirred, and calcined at 300 ° C for 4 hours in the air to form iron oxide-titania powder, which was taken out and ground.

Example 4

1. An iron oxide-titanium oxide oxide having an iron/titanium ratio of 2/8 was prepared, and 1.666 g of ferric oxide was weighed and dispersed in 3.67 ml of distilled water.

2. 3.34 g of titanium dioxide was weighed, and the aqueous solution of the first step was slowly dropped thereinto and stirred, and calcined at 300 ° C for 4 hours in the air to form iron oxide-titania powder, which was taken out and ground.

Example 5

1. An iron oxide-titanium oxide oxide having an iron/titanium ratio of 3/7 was prepared, 2.307 g of ferric oxide was weighed, and it was dispersed in 3.15 ml of distilled water.

2. Weigh 2.639 g of titanium dioxide, and slowly add the aqueous solution of the first step to the mixture and stir it, and calcined at 300 ° C for 4 hours in the air to form iron oxide-titania powder, which was taken out and ground.

Embodiment 2

Weigh the appropriate proportion of iron oxide-titanium dioxide powder into distilled water, stir it with magnet, and heat it to 50~70 °C, and maintain it; weigh tetrachloroauric acid and dissolve it in distilled water, of which gold accounts for 4wt. %; control the acidity of the solution of step 2 at 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10-20 ml per minute, and simultaneously control the base value at 7± 0.2, the temperature is maintained at 50~70 °C; after the titration is completed, the magnet is stirred and mixed for 1 to 10 hours, the pH value is maintained at 7±0.2, the temperature is 50-70 ° C, and the reaction is completed; the obtained precipitate is filtered and The distilled water of 65-80 ° C is washed several times until the chloride ion is completely removed, and then dried at 60-120 ° C for 6-20 hours; the dried catalyst is burned in the air at 100-180 ° C for 2-10 hours. That is, an Au/Fe ₂ O ₃ —TiO ₂ catalyst is formed; the Au/Fe ₂ O ₃ —TiO ₂ catalyst is placed in a batch reactor to carry out a hydrogenation reaction of p-chloronitrobenzene in a hydrogen-rich environment. The reaction solvent is an alcohol having four or less carbons, a hydrogen pressure of 5 to 50 atm, and a reaction temperature of 50 to 150 °C.

Example 6

1. Weigh 2 g of Fe ₂ O ₃ -TiO ₂ powder (iron/titanium molar ratio of 1/9) into 500 ml of distilled water, stir with a magnet, and heat to 65 ° C, and maintain it.

2. Weigh 0.14 g of tetrachloroauric acid and dissolve it in 40 ml of distilled water, of which gold accounts for 0.08 g.

3. Control the pH value of the solution of step 2 to 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10 ml per minute, and simultaneously control the base value at 7±0.2. The temperature was maintained at 65 °C.

4. After the completion of the titration, the mixture was stirred and stirred for two hours with a magnet to maintain a pH of 7 ± 0.2 and a temperature of 65 ° C to complete the reaction.

5. The obtained precipitate was filtered and washed with distilled water at 65 ° C several times until the chloride ions were completely removed, and then dried at 80 ° C for 16 hours.

6. The dried catalyst was fired in air at 180 ° C for 4 hours to form 4% Au/Fe ₂ O ₃ -TiO ₂ powder with an iron/titanium molar ratio of 1/9.

7. The catalyst is 0.50 g of 4 wt.% Au/Fe ₂ O ₃ -TiO ₂ , a powder having an iron/titanium molar ratio of 1/9, 2.54 g of p-chloronitrobenzene and 80 ml of methanol. In the reactor; first flush the reaction system with hydrogen for 10 minutes to remove the air in the system; first stir at low speed (about 100 rpm), and raise the temperature to 80 ° C, and gradually pressurize to a reaction pressure of 160 psig. When the temperature and pressure reach the reaction conditions, increase the stirring speed to 500 rpm, which is determined as the reaction start time (t=0); sample every 10 minutes, and overflow about 10 drops of sample solution to eliminate the sampling. The error caused by the residual sample liquid in the tube; after the reaction is completed, the hydrogen supply is stopped, and the temperature is lowered and the pressure is reduced in turn; the sample is analyzed by a gas chromatograph analyzer (China Chromatography 8700 F) for the concentration of the reactant and the product.

8. The analytical chromatography column is a 3 cm long, 1/8 inch diameter non-embroidered steel tube with a 5% OV-101/80-100 mesh Chromosorb WAW-DMSC.

The reaction results are as follows:

Example 7

1. Weigh 2 g of Fe ₂ O ₃ -TiO ₂ powder (iron/titanium molar ratio of 4/6) into 500 ml of distilled water, stir with a magnet, and heat to 65 ° C, and maintain it.

2. Weigh 0.14 g of tetrachloroauric acid and dissolve it in 40 ml of distilled water, of which gold accounts for 0.08 g.

3. Control the pH value of the solution of step 2 to 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10 ml per minute, and simultaneously control the base value at 7±0.2. Temperature dimension Hold 65 ° C.

4. After the completion of the titration, the mixture was stirred and stirred for two hours with a magnet to maintain a pH of 7 ± 0.2 and a temperature of 65 ° C to complete the reaction.

5. The obtained precipitate was filtered and washed with distilled water at 65 ° C several times until the chloride ions were completely removed, and then dried at 80 ° C for 16 hours.

6. The dried catalyst was fired in air at 180 ° C for 4 hours to form 4% Au/Fe ₂ O ₃ -TiO ₂ powder with an iron/titanium molar ratio of 4/6.

7. A catalyst of 0.50 g of 4 wt.% Au/Fe ₂ O ₃ -TiO ₂ , a powder having an iron/titanium molar ratio of 4/6, 2.54 g of p-chloronitrobenzene and 80 ml of methanol were placed. In the reactor; first flush the reaction system with hydrogen for 10 minutes to remove the air in the system; first stir at low speed (about 100 rpm), and raise the temperature to 80 ° C, while gradually pressurizing to a reaction pressure of 160 psig, until the temperature When the pressure reaches the reaction condition, increase the stirring speed to 500 rpm, which is set as the reaction start time (t=0); sample every 10 minutes, and overflow about 10 drops of sample solution to eliminate the sampling tube. The error caused by the residual of the sample before and after the reaction; after the reaction is completed, the hydrogen supply is stopped, and the temperature is lowered and the pressure is reduced in turn; the sample is analyzed by the gas chromatography layer analyzer (China Chromatography 8700 F) for the concentration of the reactant and the product.

8. The analytical chromatography column is a 3 cm long, 1/8 inch diameter non-embroidered steel tube with a 5% OV-101/80-100 mesh Chromosorb WAW-DMSC.

The reaction results are as follows:

Example 8

1. Weigh 2 g of Fe ₂ O ₃ -TiO ₂ powder (iron/titanium molar ratio of 2/8) into 500 ml of distilled water, stir with a magnet, and heat to 65 ° C, and maintain it.

2. Weigh 0.14 g of tetrachloroauric acid and dissolve it in 40 ml of distilled water, of which gold accounts for 0.08 g.

3. Control the pH value of the solution of step 2 to 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10 ml per minute, and simultaneously control the base value at 7±0.2. The temperature was maintained at 65 °C.

4. After the completion of the titration, the mixture was stirred and stirred for two hours with a magnet to maintain a pH of 7 ± 0.2 and a temperature of 65 ° C to complete the reaction.

5. The obtained precipitate was filtered and washed with distilled water at 65 ° C several times until the chloride ions were completely removed, and then dried at 80 ° C for 16 hours.

6. The dried catalyst was fired in air at 180 ° C for 4 hours to form 4% Au/Fe ₂ O ₃ -TiO ₂ powder with an iron/titanium molar ratio of 2/8.

7. The catalyst was 0.50 g of 4 wt.% Au/Fe ₂ O ₃ -TiO ₂ , iron/titanium molar ratio of 2/8 powder, 2.54 g of p-chloronitrobenzene and 80 ml of methanol. In the reactor; first flush the reaction system with hydrogen for 10 minutes to remove the air in the system; first stir at low speed (about 100 rpm), and raise the temperature to 80 ° C, and gradually pressurize to a reaction pressure of 160 psig. When the temperature and pressure reach the reaction conditions, increase the stirring speed to 500 rpm, which is determined as the reaction start time (t=0); sample every 10 minutes, and overflow about 10 drops of sample solution to eliminate the sampling. The error caused by the residual sample liquid in the tube; after the reaction is completed, the hydrogen supply is stopped, and the temperature is lowered and the pressure is reduced in turn; the sample is analyzed by a gas chromatograph analyzer (China Chromatography 8700 F) for the concentration of the reactant and the product.

8. The analytical chromatography column is a 3 cm long, 1/8 inch diameter non-embroidered steel tube with a 5% OV-101/80-100 mesh Chromosorb WAW-DMSC.

9. The reaction results are as follows:

Example 9

1. Weigh 2 g of Fe ₂ O ₃ -TiO ₂ powder (iron/titanium molar ratio of 5/5) into 500 ml of distilled water, stir with a magnet, and heat to 65 ° C, and maintain it.

2. Weigh 0.14 g of tetrachloroauric acid and dissolve it in 40 ml of distilled water, of which gold accounts for 0.08 g.

3. Control the pH value of the solution of step 2 to 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10 ml per minute, and simultaneously control the base value at 7±0.2. The temperature was maintained at 65 °C.

4. After the completion of the titration, the mixture was stirred and stirred for two hours with a magnet to maintain a pH of 7 ± 0.2 and a temperature of 65 ° C to complete the reaction.

5. The obtained precipitate was filtered and washed with distilled water at 65 ° C several times until the chloride ions were completely removed, and then dried at 80 ° C for 16 hours.

6. The dried catalyst was fired in air at 180 ° C for 4 hours to form 4% Au/Fe ₂ O ₃ -TiO ₂ powder with an iron/titanium molar ratio of 5/5.

7. The catalyst was 0.50 g of 4 wt.% Au/Fe ₂ O ₃ -TiO ₂ , a powder having an iron/titanium molar ratio of 5/5, 2.54 g of p-chloronitrobenzene and 80 ml of methanol. In the reactor; first flush the reaction system with hydrogen for 10 minutes to remove the air in the system; first stir at low speed (about 100 rpm), and raise the temperature to 80 ° C, and gradually pressurize to a reaction pressure of 160 psig. When the temperature and pressure reach the reaction conditions, increase the stirring speed to 500 rpm, which is determined as the reaction start time (t=0); sample every 10 minutes, and overflow about 10 drops of sample solution to eliminate the sampling. The error caused by the residual sample liquid in the tube; after the reaction is completed, the hydrogen supply is stopped, and the temperature is lowered and the pressure is reduced in turn; the sample is analyzed by a gas chromatograph analyzer (China Chromatography 8700 F) for the concentration of the reactant and the product.

8. The analytical chromatography column is a 3 cm long, 1/8 inch diameter non-embroidered steel tube with a 5% OV-101/80-100 mesh Chromosorb WAW-DMSC.

9. The reaction results are as follows:

Example 10

1. Weigh 2 g of Fe ₂ O ₃ -TiO ₂ powder (iron/titanium molar ratio of 3/7) into 500 ml of distilled water, stir with a magnet, and heat to 65 ° C, and maintain it.

2. Weigh 0.14 g of tetrachloroauric acid and dissolve it in 40 ml of distilled water, of which gold accounts for 0.08 g.

3. Control the pH value of the solution of step 2 to 7±0.2 with 0.1M ammonia water, and then add the tetrachloroauric acid solution to the solution at a rate of 10 ml per minute, and simultaneously control the base value at 7±0.2. The temperature was maintained at 65 °C.

4. After the completion of the titration, the mixture was stirred and stirred for two hours with a magnet to maintain a pH of 7 ± 0.2 and a temperature of 65 ° C to complete the reaction.

5. The obtained precipitate was filtered and washed with distilled water at 65 ° C several times until the chloride ions were completely removed, and then dried at 80 ° C for 16 hours.

6. The dried catalyst was fired in air at 180 ° C for 4 hours to form 4% Au/Fe ₂ O ₃ -TiO ₂ powder with an iron/titanium molar ratio of 3/7.

7. The catalyst was 0.50 g of 4 wt.% Au/Fe ₂ O ₃ -TiO ₂ , iron/titanium molar ratio of 3/7 powder, 2.54 g of p-chloronitrobenzene and 80 ml of methanol. In the reactor; first flush the reaction system with hydrogen for 10 minutes to remove the air in the system; first stir at low speed (about 100 rpm), and raise the temperature to 80 ° C, and gradually pressurize to a reaction pressure of 160 psig. When the temperature and pressure reach the reaction conditions, increase the stirring speed to 500 rpm, which is determined as the reaction start time (t=0); sample every 10 minutes, and overflow about 10 drops of sample solution to eliminate the sampling. The error caused by the residual sample liquid in the tube; after the reaction is completed, the hydrogen supply is stopped, and the temperature is lowered and the pressure is reduced in turn; the sample is analyzed by a gas chromatograph analyzer (China Chromatography 8700 F) for the concentration of the reactant and the product.

8. The analytical chromatography column is a 3 cm long, 1/8 inch diameter non-embroidered steel tube with a 5% OV-101/80-100 mesh Chromosorb WAW-DMSC.

9. The reaction results are as follows:

The results of the above examples are shown in Figure 1.

Figure 1 is a graph showing the relationship between the conversion of p-chloronitrobenzene and the reaction time.

Claims (1)

A method for producing chloroaniline by hydrogenation reaction of chloronitrobenzene, characterized in that: in the presence of a gold catalyst containing iron oxide and titanium dioxide, chloronitrobenzene is hydrogenated to form chloroaniline, which comprises The gold catalyst of iron oxide and titanium dioxide is prepared by mixing iron oxide with titanium dioxide, calcining between 100 ° C and 200 ° C for 2 to 6 hours, and then adding a tetrachlorohydrogen gold aqueous solution and iron oxide by deposition precipitation method. - Titanium dioxide mixed oxide is placed in water, the pH value is controlled between 6 and 8 with ammonia water and the temperature is maintained between 50 ° C and 90 ° C and stirring is continued for 1 to 10 hours, between 50 and 90 ° C Distilled in water, dried at 50 to 80 ° C, calcined between 50 and 120 ° C for 2 to 8 hours, in which iron oxide and titanium dioxide are mixed in different proportions, the iron / titanium molar ratio is between 1 / 9 to 5 / 5 And the weight percentage of gold is between 3 and 4, and the diameter of the gold particles carried is between 2 and 5 nm; the hydrogenation reaction is carried out in a batch reactor or a fixed bed fluid reactor, and the reaction solvent is four carbons. The following alcohols have a hydrogen pressure between 5 and 50 atmospheres and a reaction temperature of 50 to Between 150 ° C.