Process for preparing high-purity diketene

A technology for the preparation of diketene, which is applied in the field of preparation of high-purity diketene, can solve the problems of high content of acetic acid in the residual liquid, low product purity, and many side reactions, and achieve the effects of low operating cost, high purity, and long stability time

Active Publication Date: 2010-06-23
NINGBO WANGLONG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The relevant traditional technology contains many side reactions and low product purity in the preparation and purification of ketene; the absorption polymerization of ketene and the refining of crude diketene have low product purity and poor safety; the contained dilute acetic acid is concentrated and recovered. The process is complicated, the cost is high, and the content of acetic acid in the residual liquid is high
[0004] The high-purity diketene production process technology is based on the mature process of acetic acid cracking to produce ketene, a set of new process routes with low consumption and high yield developed by ourselves, so as to solve the problems of low purity and poor safety of the products produced in the existing process , to meet the growing domestic demand for this important organic intermediate

Method used

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  • Process for preparing high-purity diketene
  • Process for preparing high-purity diketene
  • Process for preparing high-purity diketene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Such as Figure 1 to Figure 3 As shown, the preparation process of high-purity diketene includes acetic acid cracking process, diketene synthesis process, dilute acetic acid concentration process.

[0057] The acetic acid cracking process includes:

[0058] The > 80% acetic acid and 99% glacial acetic acid obtained from dilute acetic acid enrichment process are prepared into 92% acetic acid solution; the acetic acid solution is vaporized into acetic acid vapor and the prepared triethyl phosphate solution catalyst is acetic acid per unit time 0.3% of the feeding amount enters the cracking tube at 740°C at the same time and undergoes high-temperature cracking under the negative pressure of 12kPa. The acetic acid is thermally cracked into a mixed cracking gas containing ketene, water and side reaction products; in order to prevent the reverse reaction and polymerization of ketene, mix 0.3% liquid ammonia according to the feeding amount of acetic acid is fed into the crack...

Embodiment 2

[0065] Acetic acid cracking and freezing impurity removal process operate according to the following process, and all the other are with embodiment 1:

[0066] (1) The high-temperature catalyst used in the cracking reaction of acetic acid is triethyl phosphate. The> 80% acetic acid obtained from the dilute acetic acid enrichment process, the concentrated> 80% acetic acid and 99% glacial acetic acid are prepared into a 91% acetic acid solution, and the 91% acetic acid solution is vaporized, and the acetic acid vapor and mass Triethyl phosphate with a percentage of about 8% enters the cracking tube at 730°C and 10kPa negative pressure at the same time at a ratio of 100:2 for high-temperature cracking, and acetic acid is thermally cracked into mixed cracking gas containing ketene, water and by-products ;

[0067] (2) In order to prevent the reverse reaction and polymerization of ketene in the mixed cracking gas, the mixed cracking gas and the 0.3% liquid ammonia added according ...

Embodiment 3

[0070] Acetic acid cracking and freezing impurity removal process operate according to the following process, and all the other are with embodiment 1:

[0071] (1) acetic acid cracking reaction adopts high-temperature catalyst to be ammonium dihydrogen phosphate, will come from the> 80% acetic acid that dilute acetic acid enrichment operation obtains, will concentrate> 80% acetic acid and 99% glacial acetic acid to be mixed with 95% acetic acid solution, The 95% acetic acid solution is gasified, and the acetic acid vapor and the ammonium dihydrogen phosphate with a mass percentage of about 12% are simultaneously entered into the cracking tube at 750°C and 15kPa negative pressure in a ratio of 100:4 for high-temperature cracking, and the acetic acid is Thermal cracking into mixed cracked gas containing ketene, water and side reaction products;

[0072] (2) The mixed cracked gas is rapidly cooled to below -20°C through the cooler group before the pump, and the water in the mixed...

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Abstract

The invention relates to a process for preparing high-purity diketene, which overcomes the defects of low purity of ketene, low purity and poor safety of diketene products formed by absorbing and polymerizing ketene, as well as complex process, high cost and high acetic acid content of raffinate in the concentration recovery of dilute acetic acid. The process for preparing high-purity diketene is suitable for absorbing and polymerizing ketene dimer at low temperature on the basis of adopting stable acetic acid cracking conditions and deep refrigeration to remove impurities from cracking gas and generate pure ketene gas, adopting a film evaporator to further purify diketene products at low temperature under low pressure, and adding stabilizers after introducing polymerization inhibitor and diketene for refining during the absorption and polymerization of ketene in order to improve synthesis safety and the stability of products in storage tanks. Meanwhile, the dilute acetic acid produced in the process reasonably matches the temperature of each point of a stripping section through a sensitive plate technique, improves the water-carrying capability of butyl acetate, and greatly reduces the concentration of acetic acid in concentrated raffinate.

Description

technical field [0001] The invention relates to a process for preparing ketene, in particular to a process for preparing high-purity diketene. Background technique [0002] The molecular structure of diketene contains two double bonds, which makes it highly unsaturated, and its chemical properties are extremely active. It can react with alcohols, amines, halogens, ketones, acids, etc. in addition, decomposition, nitration, polymerization, etc. An important organic intermediate that can be derived from a variety of products. It has a wide range of applications in medicine, pesticides, dyes, food and feed additives, organic synthesis, etc. [0003] There is no disclosed high-purity diketene production technology in the prior art, and it is in a state of technical secrecy. The relevant traditional technology contains many side reactions and low product purity in the preparation and purification of ketene; the absorption polymerization of ketene and the refining of crude diket...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D305/12
Inventor 王国军
Owner NINGBO WANGLONG TECH
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