CN104326865A - Method for preparing vinyl chloride through catalyzing acetylene and dichloroethane - Google Patents

Abstract

The invention discloses a method for preparing vinyl chloride by catalyzing the reaction of acetylene dichloroethane. The method is as follows: acetylene and dichloroethane vapor are mixed in a molar ratio of 1:1 to 1:4, and then passed into a fixed-bed reactor equipped with a nitrogen-modified catalyst for reaction, and the reaction temperature is 180-300°C , the space velocity is 20-120h ^-1 ; the nitrogen-modified catalyst uses activated carbon as a carrier to support metal salt compounds and nitrogen-containing compounds; based on the total mass of the catalyst, the mass percentage of the metal salt compound is 0.01-10%, The mass percentage of the nitrogen-containing compound is 0.01-10%. The preparation of vinyl chloride by the method of the invention has the characteristics of high acetylene conversion rate and high vinyl chloride selectivity; the preparation process of the nitrogen-modified catalyst adopted in the process method is simple and low in cost.

Description

A kind of method that catalyzes acetylene dichloroethane to prepare vinyl chloride

technical field

The invention belongs to the technical field of vinyl chloride preparation technology, and in particular relates to a method for preparing vinyl chloride by catalyzing acetylene dichloroethane.

Background technique

Vinyl chloride is a very important chemical raw material, mainly used in the production of polyvinyl chloride resin. Polyvinyl chloride is one of the top five engineering plastics in the world and is widely used in various industries. At present, the industrial synthesis methods of vinyl chloride monomer mainly include acetylene hydrochlorination and ethylene oxychlorination. The ethylene oxychlorination method uses ethylene, hydrogen chloride and oxygen for oxychlorination reaction or chlorination of ethylene to generate dichloroethane, and thermal cracking of dichloroethane to generate vinyl chloride, while producing hydrogen chloride as a by-product. Acetylene hydrochlorination is a method in which acetylene and hydrogen chloride are catalyzed to directly generate vinyl chloride.

my country is short of petroleum resources, but relatively abundant coal resources can provide sufficient acetylene raw materials, so the current domestic production of vinyl chloride monomer is mainly acetylene hydrochlorination. However, the current domestic acetylene process generally uses mercuric chloride loaded on activated carbon as a catalyst. The catalyst is volatile and lost, and mercury is highly toxic, causing serious harm to the environment. Eliminating mercury catalyst pollution, developing catalysts in the direction of low-mercury and mercury-free catalysts, controlling and gradually eliminating mercury pollution, and finding clean catalysts and process routes for the synthesis of vinyl chloride are currently urgent problems in the chlor-alkali industry.

Contents of the invention

The object of the present invention is to provide a process for preparing vinyl chloride by catalyzing the reaction of acetylene and ethylene dichloride, so as to solve the technical problem in the prior art that the acetylene process generally uses a loaded mercury chloride catalyst and causes serious environmental pollution.

The technical scheme that the present invention adopts for solving the problems of the technologies described above is as follows:

A method for preparing vinyl chloride by catalyzing acetylene dichloroethane. The specific process of the method is: mixing acetylene and dichloroethane vapor in a molar ratio of 1:1 to 1:4, and then passing it into a nitrogen-modified The catalyst is reacted in a fixed-bed reactor, the reaction temperature is 180-300°C, and the space velocity is 20-120h ^-1 ; the nitrogen-modified catalyst uses activated carbon as a carrier to support metal salt compounds and nitrogen-containing compounds, and the total mass of the catalyst is In other words, the mass percentage of the metal salt compound is 0.01-10%, and the mass percentage of the nitrogen-containing compound is 0.01-10%. The reaction effluent of the acetylene and ethylene dichloride vapor in the fixed-bed reactor is cooled to room temperature, unreacted ethylene dichloride is condensed, and the remaining gas is frozen and compressed to obtain liquid vinyl chloride.

Further, the metal salt compound supported by the nitrogen modification catalyst is strontium salt or barium salt or a mixture of strontium salt and barium salt, and the nitrogen-containing compound supported is selected from guanidine hydrochloride, acetamidine hydrochloride salt, acrylamide, urea, formazan At least one of sulfonamide and cyanoacetamide.

The nitrogen-modified catalyst that catalyzes the reaction of acetylene dichloroethane, its preparation method comprises the steps:

Step 1, pickling the activated carbon, the pickling time is 5-10 hours, the pickling solution is a mixed solution of one or more of hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid, and the acid concentration is 0.1-5.0 mol/L, after pickling, place the activated carbon at 60-120°C to dry for 6-24 hours, and use the treated activated carbon as a carrier for later use; the activated carbon is selected from coal-based activated carbon, fruit shell activated carbon or coconut shell activated carbon at least one of

Step 2, dissolving the metal salt compound and the nitrogen-containing compound in deionized water to prepare an immersion solution; the concentration of the metal salt compound in the immersion solution is 0.01-20%, and the concentration of the nitrogen-containing compound is 0.01-20% The metal salt compound is a mixture of strontium salt or barium salt or strontium salt and barium salt, and the nitrogen-containing compound is selected from guanidine hydrochloride, acetamidine hydrochloride, acrylamide, urea, methylsulfonamide, cyanoacetamide at least one of

Step 3, immerse the above-mentioned treated activated carbon carrier in the above-mentioned prepared impregnation solution for 0.1-24 hours, and then activate it at 200-800°C under the protection of nitrogen, and the activation time is 3-12 hours to obtain the nitrogen-modified sex catalyst.

Compared with the prior art, the present invention has the following beneficial effects: the catalyst used in the process provided by the present invention has the characteristics of high acetylene conversion rate, high vinyl chloride selectivity, low loss, low cost, and simple preparation process. Compared with the existing domestic method for preparing vinyl chloride by the acetylene method, the invention solves the problem of mercury pollution, and also reduces the synthesis and refining process of hydrogen chloride. Compared with the traditional ethylene method, it solves the high-temperature energy consumption problem of the thermal decomposition of dichloroethane, and avoids the complicated equipment of the oxychlorination operation unit.

Detailed ways

The technical solutions of the present invention are described in detail below through specific examples. The raw materials and reagents used in the present invention are all commercially available.

Hydrochloric acid treatment of activated carbon: Soak coal-based activated carbon in 2mol/L hydrochloric acid solution for 8 hours, wash it, and then dry it at 110°C for 10 hours. The activated carbon can also use fruit shell activated carbon or coconut shell activated carbon, and the pickling solution can also use sulfuric acid, nitric acid or phosphoric acid or a mixture of several acids.

Example 1

Dissolve 5g of strontium chloride and 7.5g of cyanoacetamide in 200ml of deionized water to prepare an impregnation solution. Add 100g of coal-based activated carbon treated with hydrochloric acid, mix evenly, impregnate for 4 hours, and activate with nitrogen at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 80%, and the selectivity of vinyl chloride is over 90%.

Example 2

Dissolve 5g of strontium chloride and 7.5g of cyanoacetamide in 200ml of deionized water to prepare an impregnation solution. Add 100 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate for 6 hours, and activate with nitrogen at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 240°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 60%, and the selectivity of vinyl chloride is over 90%.

Example 3

Dissolve 2g of strontium chloride and 5g of acrylamide in 100ml of deionized water to prepare an impregnation solution. Add 50 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 12 hours, and activate with nitrogen at 600°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.1, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 80%, and the selectivity of vinyl chloride is over 90%.

Example 4

Dissolve 5g of strontium chloride and 10g of acrylamide in 250ml of deionized water to prepare an impregnation solution. Add 150 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 2 hours, and activate with nitrogen gas at 700°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.1, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 82h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 55%, and the selectivity of vinyl chloride is over 90%.

Example 5

Dissolve 7.5g of strontium chloride and 10g of urea in 200ml of deionized water to prepare an impregnation solution. Add 100 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 2 hours, and activate with nitrogen gas at 650°C for 8 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.5, and pass it into a fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 55h ^-1 , and the reaction temperature is controlled at 240°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 60%, and the selectivity of vinyl chloride is over 90%.

Example 6

Dissolve 10g of strontium chloride and 10g of methylsulfonamide in 200ml of deionized water to prepare an impregnation solution. Add 100 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 4 hours, and activate with nitrogen at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 70%, and the selectivity of vinyl chloride is over 90%.

Example 7

Dissolve 10g of strontium chloride and 10g of acetamidine hydrochloride in 200ml of deionized water to prepare an impregnation solution. Add 100 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 2 hours, and activate with nitrogen at 650°C for 6 hours to prepare the catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 70%, and the selectivity of vinyl chloride is over 90%.

Example 8

Dissolve 6g of strontium chloride and 10g of guanidine hydrochloride in 200ml of deionized water to prepare an impregnation solution. Add 100 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 6 hours, and activate with nitrogen at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.1, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 63h ^-1 , and the reaction temperature is controlled at 250°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 60%, and the selectivity of vinyl chloride is over 90%.

Example 9

Dissolve 4g of strontium chloride, 2g of barium chloride and 10g of acrylamide in 200ml of deionized water to prepare an impregnation solution. Add 120 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 4 hours, and activate with nitrogen at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 200°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 18%, and the selectivity of vinyl chloride is over 90%.

Example 10

Dissolve 8g of strontium chloride, 2g of barium chloride and 10g of acrylamide in 200ml of deionized water to prepare an impregnation solution. Add 120 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 2 hours, and activate with nitrogen gas at 650°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 55h ^-1 , and the reaction temperature is controlled at 240°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 55%, and the selectivity of vinyl chloride is over 90%.

Example 11

Dissolve 4g of strontium chloride, 2g of barium chloride and 8g of cyanoacetamide in 200ml of deionized water to prepare an impregnation solution. Add 120 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 4 hours, and activate with nitrogen gas at 700°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 42h ^-1 , and the reaction temperature is controlled at 220°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 30%, and the selectivity of vinyl chloride is over 90%.

Example 12

Dissolve 4g of strontium chloride, 2g of barium chloride and 8g of cyanoacetamide in 200ml of deionized water to prepare an impregnation solution. Add 120 g of coal-based activated carbon treated with hydrochloric acid, mix well, impregnate at room temperature for 6 hours, and activate with nitrogen at 700°C for 6 hours to prepare a nitrogen-modified catalyst. Mix acetylene and ethylene dichloride vapor at a ratio of 1:1.2, and pass it into the fixed-bed reactor equipped with the prepared nitrogen-modified catalyst for reaction. The reaction space velocity is 55h ^-1 , and the reaction temperature is controlled at 260°C. After the reaction gas is cooled to room temperature, the liquid unreacted dichloroethane is separated first, and then the remaining gas is frozen and compressed to obtain liquid vinyl chloride. Calculated by acetylene, the primary conversion rate is over 65%, and the selectivity of vinyl chloride is over 90%.

The above are only some preferred embodiments of the present invention, and the present invention is not limited to the content of the embodiments. For those skilled in the art, various changes and modifications can be made within the concept scope of the technical solutions of the present invention, and any changes and modifications made are within the protection scope of the present invention.

Claims (3)

1. a catalyzing acetylene ethylene dichloride prepares the method for vinylchlorid, it is characterized in that, the method is: the ratio of acetylene and ethylene dichloride steam 1:1 ~ 1:4 in molar ratio mixed, then pass in the fixed-bed reactor that nitrogen modified catalyst is housed and react, temperature of reaction is 180 ~ 300 DEG C, and air speed is 20 ~ 120h-1; Described nitrogen modified catalyst take gac as carrier, loaded metal salt compound and nitrogenous compound, and in catalyzer total mass, the mass percent of described metal salt compound is 0.01 ~ 10%, and the mass percent of described nitrogenous compound is 0.01 ~ 10%.

2. catalyzing acetylene ethylene dichloride as claimed in claim 1 prepares the method for vinylchlorid, it is characterized in that: the metal salt compound of described nitrogen modified catalyst load is the mixture of strontium salt or barium salt or strontium salt and barium salt, the nitrogenous compound of load is selected from least one in Guanidinium hydrochloride, acetamidine hydrochloride salt, acrylamide, urea, methylsulfonamides, Malonamide nitrile.

3. catalyzing acetylene ethylene dichloride as claimed in claim 1 prepares the method for vinylchlorid, it is characterized in that described method also comprises: described acetylene and the ethylene dichloride steam reaction effluent cool to room temperature in fixed-bed reactor, after condensation goes out unreacted ethylene dichloride, by freezing for residual gas compression, namely obtain Liquid vinyl chloride.