Production process for refining dichlorohydrin by glycerol reaction distillation

Abstract

The invention provides a production process for preparing dichloropropanol by reactive distillation of glycerol. The production process comprises the following steps: the raw material glycerol containing a homogeneous catalyst is sent to a reactive rectification tower from the top after heat exchange, hydrogen chloride gas enters from the lower part of a rectification section of the tubular reactive rectification tower, and the raw material glycerol and countercurrent flow of the hydrogen chloride gas are subject to absorption and chlorination reaction by a packing layer at the temperature of 90-120 DEG C and the temperature of 0.001-0.1MPa (absolute pressure) and are rectified; omonochloropropylene glycol at the bottom of the tubular reactive rectification tower, glycerol and glycerol oligomer are sent to a heavy constituent separation tower for decompressing and recovering the monochloropropylene glycol and the glycerol is returned to the raw material glycerol; and product gas on the top of tubular reactive rectification tower is cooled by a heat exchanger to obtain the dichloropropanol which is sent to a cyclization working procedure, and tail gas is further washed with lye, and is discharged from by a vacuum pump.

Description

1. Technical Field

[0001] The invention provides a production process for preparing dichloropropanol by reactive distillation of glycerin, which belongs to the field of fine chemicals. 2. Background technology

[0002] At present, epichlorohydrin and its precursor dichloropropanol mainly have two production processes: propylene high temperature chlorination method, allyl alcohol method and glycerin chlorination method. The high-temperature chlorination of propylene has been the world’s main production method for epichlorohydrin and its precursor dichloropropanol. The production process is flexible, the process is mature, and the operation is stable, but there are high conversion rates, many by-products, and high energy consumption. Severe equipment corrosion, more waste water and slag, and higher and higher prices of propylene raw materials. The allyl alcohol method has mild reaction conditions, high yield, less by-products, and less sewage, but has many reaction steps, short cat...

Examples

Embodiment 1

[0015] Example 1: After the heat exchange, the raw material glycerin containing the homogeneous catalyst enters from the top of the tubular reaction rectification tower 1, and hydrogen chloride gas enters from the lower part of the packing 2 section of the tubular reaction rectification tower 1 through the gas distributor 10. The raw material glycerin and hydrogen chloride gas coming down from the liquid distributor 3 countercurrently pass through the 2 layers of packing and undergo absorption chlorination reaction rectification at 90~120℃ and 0.001~0.1MPa (absolute pressure); the heat of reaction passes through the cooling water between the tubes 4 Remove and maintain the reaction temperature; the monochloropropanediol, glycerol and glycerol oligomers at the bottom of the tubular reaction rectification tower 1 are sent to the heavy component separation tower 7 to recover the monochloropropanediol and glycerol under reduced pressure and return to the raw glycerin; The product gas ...

Embodiment 2

[0016] Example 2: After heat exchange, the raw material glycerin containing homogeneous catalyst enters from the top of the first-stage tubular reaction rectification tower 1, and hydrogen chloride gas passes through the gas distributor 10 from the lower part of the packing 2 of the tubular reaction rectification tower 1 Enter, the raw material glycerin and hydrogen chloride gas coming down from the liquid distributor 3 countercurrently pass through the 2 layers of packing, and undergo absorption chlorination reaction rectification at 90~120℃ and 0.001~0.1MPa (absolute pressure); the heat of reaction passes through the tube 4 The cooling water is removed and the reaction temperature is maintained; the liquid at the bottom of the first-stage tubular reactive distillation tower 1 is sent to the top of the second-stage tubular reactive distillation tower 1 as feed; The liquid is sent to the top of the three-stage tubular reactive distillation tower 1 as feed; the monochloropropanedio...

1. Technical Field

[0001] The invention provides a production process for preparing dichloropropanol by reactive distillation of glycerin, which belongs to the field of fine chemicals. 2. Background technology

[0002] At present, epichlorohydrin and its precursor dichloropropanol mainly have two production processes: propylene high temperature chlorination method, allyl alcohol method and glycerin chlorination method. The high-temperature chlorination of propylene has been the world’s main production method for epichlorohydrin and its precursor dichloropropanol. The production process is flexible, the process is mature, and the operation is stable, but there are high conversion rates, many by-products, and high energy consumption. Severe equipment corrosion, more waste water and slag, and higher and higher prices of propylene raw materials. The allyl alcohol method has mild reaction conditions, high yield, less by-products, and less sewage, but has many reaction steps, short cat...

Examples

Embodiment 1

[0015] Example 1: After the heat exchange, the raw material glycerin containing the homogeneous catalyst enters from the top of the tubular reaction rectification tower 1, and hydrogen chloride gas enters from the lower part of the packing 2 section of the tubular reaction rectification tower 1 through the gas distributor 10. The raw material glycerin and hydrogen chloride gas coming down from the liquid distributor 3 countercurrently pass through the 2 layers of packing and undergo absorption chlorination reaction rectification at 90~120℃ and 0.001~0.1MPa (absolute pressure); the heat of reaction passes through the cooling water between the tubes 4 Remove and maintain the reaction temperature; the monochloropropanediol, glycerol and glycerol oligomers at the bottom of the tubular reaction rectification tower 1 are sent to the heavy component separation tower 7 to recover the monochloropropanediol and glycerol under reduced pressure and return to the raw glycerin; The product gas ...

Embodiment 2

[0016] Example 2: After heat exchange, the raw material glycerin containing homogeneous catalyst enters from the top of the first-stage tubular reaction rectification tower 1, and hydrogen chloride gas passes through the gas distributor 10 from the lower part of the packing 2 of the tubular reaction rectification tower 1 Enter, the raw material glycerin and hydrogen chloride gas coming down from the liquid distributor 3 countercurrently pass through the 2 layers of packing, and undergo absorption chlorination reaction rectification at 90~120℃ and 0.001~0.1MPa (absolute pressure); the heat of reaction passes through the tube 4 The cooling water is removed and the reaction temperature is maintained; the liquid at the bottom of the first-stage tubular reactive distillation tower 1 is sent to the top of the second-stage tubular reactive distillation tower 1 as feed; The liquid is sent to the top of the three-stage tubular reactive distillation tower 1 as feed; the monochloropropanedio...

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