KR0169196B1 - Method of preparing chloroforum - Google Patents

Abstract

The present invention relates to a method for producing chloroform, and more particularly to porous gamma-alumina (γ-Al ₂ O ₃ ) or silica (SiO ₂ ) K ₂ PtCl ₆ , (NH ₄ ) ₂ PtCl ₆ , Pt (NH ₃ ) ₂ (NO ₂

) ₂ , gas phase hydrogen / carbon tetrachloride in a reactor with a heterogeneous platinum catalyst that is evenly dispersed by supporting Pt (NH ₃ ) ₄ (NO ₃ ) ₂ or Pt (NH ₃ ) ₄ Cl ₃ . The present invention relates to a method for inhibiting catalyst deactivation and introducing chloroform with high conversion and selectivity by introducing at a molar ratio of 20 to gas phase reaction.

Description

Method of Making Claw Form

1 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 1),

2 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 2),

3 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 3),

4 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 4),

5 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 5),

6 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 6),

7 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 7),

8 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 8),

9 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 9),

10 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform according to the preparation method of the present invention (Example 10),

The present invention relates to a method for preparing chloroform, and more particularly to K ₂ Pt / Cl ₆ , (NH ₄ ) ₂ PtCl ₆ , Pt in porous gamma-alumina (γ-Al ₂ O ₃ ) or silica (SiO ₂ ). Gas phase in a reactor in which a heterogeneous platinum catalyst is evenly dispersed by supporting (NH ₃ ) ₂ (NO ₂ ) ₂ , Pt (NH ₃ ) ₄ (NO ₃ ) ₂ or Pt (NH ₃ ) ₄ Cl ₂ The present invention relates to a method for inhibiting catalyst deactivation and introducing chloroform with high conversion and selectivity by introducing hydrogen / carbon tetrachloride in a 4-20 molar ratio and gas phase reaction.

Carbon tetrachloride is a colorless liquid with a unique odor at room temperature and atmospheric pressure, and has been used in detergents and solvents.Because of its toxicity, the use of carbon tetrachloride has been prohibited from use in daily household goods since 1970. It is used as a raw material for chlorofluorocarbon (CFC). However, as CFCs were recognized as ozone depleting substances, their use was banned, and carbon tetrachloride was also classified as an additional regulatory substance at the 1990 London Conference. Therefore, research on converting carbon tetrachloride to a substance having no ozone layer destruction problem has attracted much attention, and a method of decomposing carbon tetrachloride as a method of treating carbon tetrachloride [J. Phys. Chem., Vol 97, pp. 1914 (1993)] and converting them into useful compounds such as chloroform (CHCl ₃ ) or dichloromethane (CH ₂ Cl ₂ ) through the hydrogenation of carbon tetrachloride. In the treatment method of carbon tetrachloride, conversion to useful materials through hydrogenation reaction is considered to be more preferable than decomposition method, and the hydrogenation reaction of carbon tetrachloride can be expressed as follows.

CCl ₄ + H ₂ → CHCl ₃ + HCl

CCl ₄ + 4H ₂ → CH ₄ + 4HCl

As a method of preparing chloroform by hydrogenation of carbon tetrachloride using a catalyst, a homogeneous catalyst using an organometallic catalyst has been reported {J. Organomet. Chem., Vol. C8, pp. 364 (1989)], in this method, precious metals such as Pt, Pd, Ir, Rh, and Ru which are mostly supported are used. International Patent Publication No. 91-0982 reported a method of converting carbon tetrachloride to chloroform as a basic process of gas phase or liquid phase reaction using a catalyst having Pd, Rh, Ru or Pt supported on activated carbon, alumina or silica. In addition, European Patent No. 479,116 of Dow Chemical Co., Ltd. discloses hexachloroethane, perchloroethylene, methane ( nethane), etc., increased selectivity to chloroform and suppressed catalyst deactivation.

Crawloform has been used as an anesthetic for pharmaceuticals, but its use as an anesthetic has been banned because of its toxicity, and is currently used primarily in the solvent, cleaning and rubber industries. These chloroforms have been mainly prepared from chlorination of methane, hydrogenation of carbon tetrachloride or acetone.

Pt / γ- evenly dispersed by supporting a platinum precursor on a porous gamma-alumina (γ-Al ₂ O ₃ ) or silica (SiO ₂ ) carrier to convert it to chloroform, which is useful as a solvent of carbon tetrachloride which is prohibited for future use. It is an object of the present invention to provide a method for selectively preparing chloroform by reacting carbon tetrachloride and hydrogen in a continuous flow reactor using an Al ₂ O ₃ catalyst or a Pt / siO ₂ catalyst.

Hereinafter, the present invention will be described in detail.

The present invention is a method for producing chloroform by hydrogenating carbon tetrachloride in the presence of a platinum (Pt) catalyst, the platinum (Pt) catalyst as a porous gamma-alumina or silica in K ₂ PtCl ₆ , (NH ₄ ) ₂ PtCl ₆ . Chloroform, characterized by using a heterogeneous catalyst which is uniformly dispersed by supporting Pt (NH ₃ ) ₂ ) NO ₂ ) ₂ , Pt (NH ₃ ) ₄ (NO ₃ ) ₂ or Pt (NH ₃ ) ₄ Cl ₂ . The manufacturing method has its characteristics.

Referring to the present invention in more detail as follows.

The present invention relates to a method for converting carbon tetrachloride into an industrially useful chloroform, which is recognized as an environmental pollutant and classified as a regulated substance and prohibited from use. In the conversion process to chloroform, K ₂ PtCl ₆ , (NH ₄ ) ₂ PtCl ₆ , Pt (NH ₃ ) ₂ (NO ₂ ) ₂ in a porous gamma-alumina (γ-Al ₂ O ₃ ) or silica (SiO ₂ ) carrier To prepare a heterogeneous platinum catalyst of Pt / γ-Al ₂ O ₃ in which a platinum precursor of Pt (NH ₃ ) ₄ (NO ₃ ) ₂ or Pt (NH ₃ ) ₄ Cl ₂ was evenly dispersed, and in the presence of a platinum catalyst Gas and hydrogen gas are introduced into the reactor in a 1: 4-20 molar ratio to maximize the conversion of carbon tetrachloride and the selectivity of chloroform.

Briefly describing the manufacturing process of the heterogeneous platinum catalyst used in the present invention, that is, Pt / γ-Al ₂ O ₃ or Pt / SiO ₂ catalyst, first, a platinum precursor containing platinum (Pt) is dissolved in water to 0.1-10. A platinum solution is prepared at the% concentration, which carries the platinum to gamma-alumina (γ-Al ₂ O ₃ ) or silica (SiO ₂ ) carrier by incipient wetness. Then, the mixture was calcined for 3 to 5 hours at 300 to 500 ° C while flowing air, and then reduced to 1.5 to 2.5 hours at 200 to 500 ° C while flowing hydrogen gas, thereby evenly dispersing Pt / r-Al in the carrier. Prepare a ₂ O ₃ Pt / SiO ₂ catalyst.

Gamma-alumina (γ-Al ₂ O ₃ ) used as a carrier in the preparation of the heterogeneous platinum catalyst has a specific surface area of 100 to 300 m ₃ / g and a pore volume of 0.5 to 1.5 ml / g, and is typically silica (SiO). ₂ ) is a conventional one having a specific surface area of 300 to 600 m 3 / g and a pore volume of 1.0 to 2.5 ml / g. However, when the specific surface area or pore volume of these carriers is out of the above range, there is a problem in that the platinum dispersion in the carrier is poor or mass transfer is poor. The amount of platinum (Pt) supported on the carrier is equivalent to 0.1 to 10% by weight relative to the carrier. If the amount of platinum (Pt) is less than 0.1% by weight, the catalytic activity is low and the amount is more than 10% by weight. It is uneconomical to make.

Chloroform is selectively prepared by reacting carbon tetrachloride and hydrogen in a continuous flow reactor using a heterogeneous platinum catalyst prepared by the above manufacturing process, wherein the reaction temperature is preferably 100 to 140 ° C, and hydrogen / tetrachloride. The molar ratio of the toxin is preferably 4 to 20, and the space velocity of the reactant (hydrogen gas and carbon tetrachloride gas) of the gas passing per kilogram of the catalyst is preferably 500 to 50,000 liters / kg / hr.

In the production process of the chloroform, the catalytic activity is low when the reaction temperature is less than 100 ℃, catalyst inactivation is observed above 140 ℃. If the molar ratio of hydrogen / carbon tetrachloride is less than 4, catalyst deactivation is observed, and if it exceeds 20, the yield of chloroform per unit time drops. When the space velocity flowing into the reactor of the gaseous reactant exceeds 500 l / kg / hr, the conversion rate of carbon tetrachloride is reduced.

As described above, in the case of the present invention for preparing chloroform by hydrogenation of carbon tetrachloride under a heterogeneous platinum catalyst of Pt / γ-Al ₂ O ₃ or Pt / SiO ₂ , it is presented as a catalyst or a comparative example prepared in the present invention. It showed more stable activity without any catalyst deactivation than any other catalysts, which greatly improved catalyst life and showed high selectivity for chloroform.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited to the examples.

Preparation Example 1

[Production of Platinum Catalyst]

Platinum aqueous solution in which commercial gamma-alumina (γ-Al ₂ O ₃ , 10 g) with a specific surface area of 100 m 2 / g and a pore value of 0.5 ml / g and K ₂ PtCl ₆ (0.299 g) are dissolved in water (5 ml) (5 ml) was loaded with platinum in an amount corresponding to 1% by weight based on the gamma-alumina carrier by incipient wetness. Then, after firing at 300 ° C. for 4 hours while flowing air, a heterogeneous catalyst of Pt / γ-Al ₂ O ₃ was prepared by reducing hydrogen gas at 300 ° C. for 2 hours.

[Production Examples 2 to 10, Comparative Production Example]

[Production of Platinum Catalyst]

A heterogeneous catalyst was prepared in the same manner as in Preparation Example 1, except that the platinum precursor or carrier was changed as shown in Table 1 below.

Example 1

The Pt / γ-AlO catalyst (0.2 g) was added to the continuous-flow quartz reactor (self-made) in Preparation Example 1 and reduced with hydrogen gas at 300 ° C. for 2 hours. The reaction temperature was 120 ° C., and the molar ratio of hydrogen / carbon tetrachloride in the saturator was 9, and the gaseous reactants were introduced into the reactor at a space velocity of 9000 L / kg / hr to perform atmospheric pressure and gas phase reactions. As a result, 50% of chloroform, 7% of methane, and 43% of a substance having 2 or more carbon atoms were produced, and the conversion rate of the steady state was 20%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 2

Experiment with the catalyst prepared in Preparation Example 2 in the same manner as in Example 1 produced 68% of chloroform, 16% of methane and 16% of a substance having 2 or more carbon atoms, respectively, and the conversion rate of the steady state was 98%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 3

Experiment with the catalyst prepared in Preparation Example 3 in the same manner as in Example 1 resulted in almost no side reactions with 80% of chloroform, 20% of methane. And the conversion rate in the steady state was 99.5%.

The other conditions were the same and the catalyst was not deactivated when the reaction temperature was higher than 140 ° C, but the selectivity of chloroform was reduced to about 50%, the selectivity of methane was 30%, and 20% of carbon atoms or more. . In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 4

Experiment with the catalyst prepared in Preparation Example 4 in the same manner as in Example 1, almost no side reactions were produced by 79% chloroform, 21% methane. And the conversion rate of the steady state was 90%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 5

Experiment with the catalyst prepared in Preparation Example 5 in the same manner as in Example 1 resulted in almost no side reactions with 82% chloroform, 18% methane. And the conversion rate of steady state was 99.5%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 6

Experiment with the catalyst prepared in Preparation Example 6 in the same manner as in Example 1, when the conversion rate of the tetrachloride was 72%, 72% of chloroform, 19% of methane and 9% of a substance having 2 or more carbon atoms were produced. And the deactivation phenomenon of the catalyst was observed.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 7

Experiment with the catalyst prepared in Preparation Example 7 in the same manner as in Example 1 produced 79% of chloroform, 18% of methane and 3% of a substance having 2 or more carbon atoms. The conversion rate at steady state was 86%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 8

Experiment with the catalyst prepared in Preparation Example 8 in the same manner as in Example 1 produced 78% of chloroform, 18% of methane and 4% of a substance having 2 or more carbon atoms. And, the steady state conversion was 99%.

When the other conditions were the same and the reaction temperature was higher than 140 ° C., the catalyst deactivation was not observed, but the selectivity of chloroform decreased to about 75%, the selectivity of methane was 25%, and almost no side reactions were produced. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 9

Experiment with the catalyst prepared in Preparation Example 9 in the same manner as in Example 1, when the conversion rate of carbon tetrachloride was 95%, 66% of chloroform, 30% of methane and 4% of a substance having at least 2 carbon atoms were produced. And the deactivation phenomenon of the catalyst was observed.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Example 10

Experiment with the catalyst prepared in Preparation Example 10 in the same manner as in Example 1, when the conversion glass of the tetrachloride 40%, 37% of chloroform, 19% of methane and 44% of the carbon atoms of 2 or more, respectively. And the deactivation phenomenon of the catalyst was observed.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Comparative Example 1

Experiment with the catalyst prepared in Preparation Example in the same manner as in Example 1, 50% of chloroform, 10% of methane and 40% of a substance having two or more carbon atoms were produced, respectively, the conversion rate of the steady state was 20%.

The other conditions were the same and the catalyst deactivation was observed when the reaction temperature exceeded 140 ° C. In addition, the catalyst deactivation phenomenon was observed when only the molar ratio of hydrogen / carbon tetrachloride was changed to less than 4.

Comparative Example 2

In the same manner as in Example 1, but using a catalyst prepared using MgO as a carrier and HPtCl.xHO as a platinum precursor, when the reaction temperature is 140 ℃ and the molar ratio of hydrogen / carbon tetrachloride is 5 , 76% of chloroform, 17% of methane and 7% of a substance having 2 or more carbon atoms were produced, and the conversion of the steady state was 50%.

When the other conditions were the same and the molar ratio of hydrogen / carbon tetrachloride was changed to 9, 80% of chloroform, 17% of methane, and 3% of substances having 2 or more carbon atoms were produced, respectively, and the conversion of the steady state was 60%.

Figures 1 to 10 are shown by comparing the conversion rate of carbon tetrachloride and the selectivity of chloroform with the reaction time of Examples 1 to 10 and Comparative Example 1, while Comparative Example 1 shows a low conversion rate and selectivity of chloroform Examples 1 to 10 of preparing chloroform using a heterogeneous platinum catalyst carrying a platinum precursor according to the present invention are somewhat different depending on the type of carrier, but generally have high conversion rate of carbon tetrachloride and selection of chloroform without decreasing the activity of the catalyst. Shows the figure.

Therefore, the method for producing chloroform of the present invention is excellent in that the conversion rate of carbon tetrachloride reaches almost 100% even at low temperature without deactivation of the catalyst, and the selectivity of chloroform is 80% or more and almost no carbon atoms or more are generated. It is particularly useful in the field of carbon tetrachloride removal and chloroform manufacturing process using carbon tetrachloride.

Claims (1)

In the method for producing chloroform by hydrogenating carbon tetrachloride in the presence of a platinum (Pt) catalyst, the platinum (Pt) catalyst may be silica or gamma-alumina in K ₂ PtCl ₆ , (NH ₄ ) ₂ PtCl ₆ , Pt (NH ₃ ) Using a heterogeneous catalyst which is uniformly dispersed by supporting a platinum precursor of ₂ (NO ₂ ) ₂ , Pt (NH ₃ ) ₄ (NO ₃ ) _2, or Pt (NH ₃ ) ₄ Cl ₂ , gaseous hydrogen / carbon tetrachloride A method for producing chloroform, which is introduced into a reactor at a 4 to 20 molar ratio, and introduced at a space velocity of 500 to 50,000 l / kg / hr per 1 kg of catalyst and per unit time to be hydrogenated at 100 to 140 ° C.