KR0169198B1 - Preparation of solid catalyst for preparing chloroform - Google Patents

Abstract

The present invention relates to a method for producing a solid catalyst for the production of chloroform, and more particularly, to a platinum (Pt) precursor and a tin (Sn) precursor on a gamma-alumina support, followed by drying, to convert carbon tetrachloride to chloroform with high conversion and selectivity The present invention relates to a method for producing a convertible solid catalyst.

Description

Method for preparing solid catalyst for chloroform production

1 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform in the presence of the solid catalyst prepared in Example 1 and Comparative Example of the present invention,

2 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform in the presence of the solid catalyst prepared in Example 2 and Comparative Example of the present invention,

3 is a graph showing the conversion rate of carbon tetrachloride and the selectivity of chloroform in the presence of the solid catalyst prepared in Example 3 and Comparative Example of the present invention.

The present invention relates to a method for producing a solid catalyst for the production of chloroform, and more particularly, to a platinum (Pt) precursor and a tin (Sn) precursor on a gamma-alumina support, followed by drying, to convert carbon tetrachloride to chloroform with high conversion and selectivity The present invention relates to a method for producing a convertible solid catalyst.

Carbon tetrachloride (CCl ₄ ) is a colorless liquid with a characteristic odor at room temperature and atmospheric pressure. It has been used for raw materials, cleaners, and solvents of chlorofluorocarbon (CFC). It is forbidden.

Therefore, there is an urgent need for a technique for converting carbon tetrachloride to a useful material, and various studies for this are being conducted. As known catalysts for the conversion of carbon tetrachloride to chloroform, homogeneous catalysts using organometallic catalysts have been reported [J. Organomet. Chem., Vol. C8, pp. 364 (1989)], this method uses precious metals such as Pt, Pd, Ir, Rh, Ru, which are mostly supported. In International Patent Publication No. 91-0982, a method of converting carbon tetrachloride to chloroform as a basic process of gas phase or liquid phase reaction using a catalyst in which Pd, Rh, Ru or Pt is supported on activated carbon, alumina or silica has been reported. In addition, European Patent No. 479,116 of Dow Chemical Co., Ltd. prepares a catalyst using platinum-based noble metals such as Pt, Pd, Rh, Ru, and Ir as an active ingredient. By reducing the production of hexachloroethane (perchloroethylene), methane (methane), etc., which are produced as, the selectivity to chloroform was increased and the catalyst was deactivated.

Therefore, in the present invention, as a result of research on a method for producing a solid catalyst that can be usefully used in converting carbon tetrachloride, which is prohibited to use in the future into chloroform useful as a solvent, platinum in a porous gamma-alumina (τ-Al ₂ O ₃ ) carrier The present invention was completed by supporting (Pt) precursors and tin (Sn) precursors and dispersing them evenly.

Accordingly, an object of the present invention is to provide a method for preparing a solid catalyst which can produce chloroform with high conversion and selectivity by gas phase hydrogenation of carbon tetrachloride.

Hereinafter, the present invention will be described in detail.

The present invention provides a method for preparing a platinum catalyst for producing chloroform, characterized in that the platinum precursor is supported on a gamma-alumina carrier and dried, and then the tin (Sn) precursor is supported and dried. It is done.

Referring to the present invention in more detail as follows.

The present invention relates to a method for preparing a solid catalyst which can be usefully used in converting carbon tetrachloride, which is recognized as an environmental pollutant and classified as a regulated substance, to be prohibited, to industrially useful chloroform.

The solid catalyst according to the present invention is a Pt-Sn / γ-Al prepared by uniformly dispersing a platinum precursor and a tin precursor by incipient wetness in a porous gamma-alumina (γ-Al ₂ O ₃ ) carrier, followed by drying. _{It is a 2} O ₃ binary metal catalyst.

Gamma-alumina (τ-Al ₂ O ₃ ) used as a carrier in the preparation of the solid catalyst according to the present invention has a specific surface area of 100 to 300 m ² / g and a pore volume of 0.5 to 1.5 ml / g. If the specific surface area or pore volume is out of the above range, there is a problem in that the dispersion of the metal catalyst in the carrier is poor or mass transfer is poor.

As a metal precursor, a platinum precursor is supported and dried, and then a tin (Sn) precursor is supported and dried to produce a binary metal catalyst Pt-Sn / τ-Al ₂ O _3. The platinum precursor and the tin precursor used in the present invention are As long as it is used normally, it can use all. Preferably platinum precursors are H ₂ PtCl ₆ , K ₂ PtCl ₆ , (NH ₄ ) ₂ PtCl ₆ , Pt (NH ₃ ) ₂ (NO ₂ ) ₂ , Pt (NH ₃ ) ₄ ) (NO ₂ ) ₂ and Pt One selected from (NH ₃ ) ₄ Cl ₂ is used, which is dissolved in tertiary distilled water and used as an aqueous solution. Preferably, one selected from tetrabutyltin and tetraphenyltin is used as the tin precursor, and when tetrabutyltin is used as the tin precursor, it is dissolved in a toluene solvent and tetraphenyltin is used as the tin precursor. It is dissolved in tetrahydrofuran solvent.

In the carrying amount of the metal support, platinum (Pt) is supported from 0.1 to 1.0 wt% with respect to the gamma-alumina (τ-Al ₂ O ₃ ) carrier, and if the supported amount of platinum (Pt) is less than 0.1 wt%, catalytic activity It is uneconomical to make this poor and more than 1.0% by weight supported. And tin (Sn) is 0.01 to 1.0% by weight based on the gamma-alumina (τ-Al ₂ O ₃ ) carrier, if the amount of tin (Sn) is less than 0.01% by weight, the catalyst deactivation and selectivity of chloroform It does not have a great effect, and if it exceeds 1.0% by weight, there is a problem in that the activity of the catalyst is reduced.

In the present invention, each of the metal carriers is supported on a gamma-alumina carrier and dried to prepare a binary metal catalyst without firing. Alternatively, the platinum precursor is supported and dried, and then calcined under oxygen gas, or tin precursor is dried. It is then calcined under oxygen gas to prepare a binary metal catalyst, or it is supported by a platinum precursor, dried, calcined under oxygen gas, and then tin precursor, dried and calcined under oxygen gas to prepare a binary metal catalyst of the present invention. You may.

In the production method of the present invention, the drying process is carried out at 50 ~ 200 ℃ and atmospheric or vacuum conditions. In addition, the firing process was performed for 2 to 5 hours while flowing oxygen at 300 to 500 ℃.

The solid catalyst prepared by the production method according to the present invention is activated by reacting with hydrogen gas in a continuous flow reactor, the activation is carried out for 1 to 10 hours at a temperature of 200 ~ 500 ℃.

In addition, hydrogen / carbon tetrachloride is introduced into the activated solid catalyst at a molar ratio of 3 to 9/1, and carbon tetrachloride is converted into chloroform by gas phase hydrogenation. The hydrogenation reaction is performed at 100 to 180 ° C. The space velocity introduced into the reactor is preferably maintained at 500 to 50,000 l / kg / hr per kilogram of catalyst. In the production process of the chloroform, the catalytic activity is low when the reaction temperature is less than 100 ℃, catalyst deactivation is observed when it exceeds 180 ℃. If the molar ratio of hydrogen / carbon tetrachloride is less than 3, catalyst deactivation is observed, and if it exceeds 9, the yield of chloroform per unit time drops. When the space velocity flowing into the reactor of the gaseous reactants is less than 500 l / kg / hr, the yield of chloroform generated per unit time and the weight of the catalyst decreases, and when it exceeds 50,000 l / kg / hr, the conversion rate of carbon tetrachloride decreases. do.

The solid catalyst prepared by the production method of the present invention has an advantage of improving the deactivation of the catalyst and improving the selectivity of chloroform as compared to the catalyst used for converting carbon tetrachloride to chloroform.

In addition, the conversion of carbon tetrachloride to chloroform using the prepared solid catalyst showed stable activity without deactivation of the catalyst, which greatly improved the catalyst life and the selectivity for chloroform was 70% or more.

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

Example 1

Pt (NH ₃ ) ₂ (NO ₂ ) corresponding to 0.1 g of platinum (Pt) in 10 g of commercial gamma-alumina (τ-Al ₂ O ₃ ) with a specific surface area of 100 m ² _/ g and a pore volume of 0.5 ml / g ₂ was dissolved in tertiary distilled water to form a 5 ml aqueous solution of platinum, and then detected by gamma-alumina carrier by incipient wetness. It was then dried in an oven at 100 ° C. for 24 hours to prepare a catalyst containing 1 wt% platinum.

Then, tetrabutyltin corresponding to 0.005 g of tin (Sn) was dissolved in toluene in 10 g of the catalyst containing platinum to prepare 5 ml of tin solution, and then supported by incipient wetness. It was then dried in an oven at 100 ° C. for 100 hours to prepare a solid catalyst containing 1 wt% platinum and 0.05 wt% tin.

Example 2

Pt (NH ₃ ) ₂ (NO ₂ ) ₂ corresponding to 0.1 g of platinum (Pt) in 10 g of commercial gamma-alumina (τ-Al ₂ O ₃ ) with a specific surface area of 100 m ² / g and a pore volume of 0.5 ml / g Was dissolved in tertiary distilled water to form a 5 ml aqueous solution of platinum, and then supported on a gamma-alumina carrier by incipient wetness. Then, dried at 100 ° C. oven for 24 hours and calcined under 300 ° C. oxygen gas to prepare a catalyst containing 1 wt% platinum.

Then, tetrabutyltin corresponding to 0.005 g of tin (Sn) was dissolved in toluene in 10 g of the catalyst containing platinum to prepare 5 ml of tin solution, and then impregnated by incipient wetness, followed by 100 ° C. Drying in an oven for 100 hours yielded a solid catalyst containing 1 wt% platinum and 0.05 wt% tin.

Example 3

Pt (NH ₃ ) ₂ (NO ₂ ) corresponding to 0.1 g of platinum (Pt) in 10 g of commercial gamma-alumina (τ-Al ₂ O ₃ ) with a specific surface area of 100 m ² / g and a pore volume of 0.5 ml / g ₂ was dissolved in tertiary distilled water to form a 5 ml aqueous solution of platinum, and then supported on a gamma-alumina carrier by incipient wetness. Then, dried at 100 ° C. oven for 24 hours to prepare a catalyst containing 1 wt% platinum.

Then, tetrabutyltin corresponding to 0.005 g of tin (Sn) was dissolved in toluene in 10 g of the catalyst containing platinum to prepare 5 ml of tin solution, and then supported by incipient wetness. It was then dried in an oven at 100 ° C. for 100 hours and calcined under 300 ° C. oxygen gas to prepare a solid catalyst containing 1 wt% platinum and 0.05 wt% tin.

[Comparative Example]

Pt (NH ₃ ) ₂ (NO ₂ ) ₂ corresponding to 0.1 g of platinum (Pt) in 10 g of commercial gamma-alumina (τ-Al ₂ O ₃ ) with a specific surface area of 100 m ² / g and pore volume of 0.5 ml / g Was dissolved in tertiary distilled water to form 5 ml of an aqueous platinum solution, and then supported on a gamma-alumina carrier by incipient wetness. Then, dried at 100 ° C. oven for 24 hours and calcined under 300 ° C. oxygen gas to prepare a catalyst containing 1 wt% platinum.

Then, tetrabutyltin corresponding to 0.005 g of tin (Sn) was dissolved in toluene in 10 g of the catalyst containing platinum to prepare 5 ml of tin solution, and then supported by incipient wetness. It was then dried for 100 hours in an oven at 100 ° C. and calcined under 300 ° C. oxygen gas to prepare a solid catalyst containing 1 wt% platinum and 0.05 wt% tin.

Experimental Example

The solid catalyst (0.2 g) prepared in Examples 1 to 3 and Comparative Example was placed in a continuous flow quartz reactor (self-made), and the catalyst was activated by reducing with hydrogen gas at 300 ° C. for 2 hours. The reaction temperature was 140 ° C., the molar ratio of hydrogen / carbon tetrachloride was 5 in a saturator, and the gaseous reactants were injected into the reactor at a space velocity of 9000 l / kg / hr to carry out an atmospheric pressure and gas phase reaction.

As a result, Figures 1 to 3 show the comparison of the conversion rate of carbon tetrachloride and the selectivity of chloroform over the course of the reaction time in the presence of the solid catalyst prepared in Examples 1 to 3 and Comparative Example, the presence of the catalyst prepared in Comparative Example Under low conversion and chloroform selectivity. However, under the solid catalyst prepared by the preparation method of the present invention, although there are some differences depending on the type and loading amount of the platinum precursor and the tin precursor, the conversion rate of carbon tetrachloride and the selectivity of chloroform were generally shown without decreasing the activity of the catalyst.

Therefore, it was found that the catalyst is inactivated in the presence of the solid catalyst prepared by the method for preparing a solid catalyst according to the present invention.

Therefore, the solid catalyst prepared in the preparation method of the present invention is particularly useful in the field of chloroform preparation process using carbon tetrachloride and removal of carbon tetrachloride.

Claims (5)

A method of producing a platinum-tin catalyst, wherein the platinum precursor is supported on a gamma-alumina carrier and dried, and then the tin (Sn) precursor is supported and dried. The method of claim 1, wherein the platinum precursor is supported, dried and calcined under oxygen gas. The method for preparing a solid catalyst for producing chloroform according to claim 1, wherein the tin precursor is supported, dried and calcined under oxygen gas. The method of claim 1, wherein the platinum precursor is 0.1 to 10% by weight based on the gamma-alumina carrier. The method of claim 1, wherein the tin precursor is 0.01 to 1.0% by weight relative to the gamma-alumina carrier.