Method for preparing caprolactam

A technology of caprolactam and cyclohexyl formic acid, applied in the field of preparation of caprolactam, can solve problems such as insufficient economy and environmental friendliness, and achieve the effects of convenient acquisition, high conversion rate and selectivity, and improved selectivity

Active Publication Date: 2008-04-30
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology

On the other hand, reducing SO 3 Although the concentration can inhibit the formation of sulfonated by-products to a certain extent, but at a certain SO 3 Under the premise of the ratio of nitrosating agent, the use of low concentration of oleum means more ammonium sulfate by-product, which is not an economical and environmentally friendly measure

Method used

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  • Method for preparing caprolactam
  • Method for preparing caprolactam

Examples

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Embodiment 2～7

[0044] Examples 2-7: Raw material ratio, feeding method and reaction time are the same as in Example 1, the difference is that after the mixed acid anhydride is obtained by the pre-mixing reaction, the rearrangement liquid is added first and then the nitrosation reaction is carried out, and the amount of the rearrangement liquid is converted into caprolactam respectively 1.00g, 2.04g, 3.01g, 4.05g, 5.04g and 7.02g, corresponding to 9.73%, 19.84%, 29.27%, 39.39%, 49.02% and 68.27% of the yield of caprolactam in Example 1.

[0045] See Table 1 for the nitrosation conversion rate, yield and selected row results of adding caprolactam in advance.

[0046]

Embodiment 9

[0048] Example 9: Raw material ratio, feeding method and reaction time are the same as those of Comparative Example 8, the difference is that 1.88 g of rearrangement liquid with a caprolactam concentration of 39.86% is added first, and then nitrosation reaction is carried out, and the amount of rearrangement liquid converted into caprolactam is 0.75 g, corresponding to 20.96% of the yield of caprolactam in Example 8. Analysis and calculation showed that the conversion rate of nitrosation reaction was 38.27%, the yield of caprolactam was 37.03%, and the selectivity of caprolactam was 93.78%.

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Abstract

The invention discloses a caprolactam preparation method. In fuming sulfuric acid and hexahydrobenzoic acid or the mixed anhydride substance produced in the derivant reaction, a certain quantity of substance containing caprolactam is added, nitroso sulfuric acid is added in the mixed anhydride containing caprolactam to perform the nitrosation reaction, the product is further hysrolyzed to obtain caprolactam-sulphuric acid solution, and the hexahydrobenzoic acid or the derivant whose reaction is not accomplished is circulated to use. The method can suppress the side reaction of the sulfonationduring the nitrosation process, and realize the selectivity of the main sulfonation reaction under the precondition that the total acid consumption and the by-product are not increased.

Description

technical field [0001] The invention relates to a preparation method of caprolactam. Background technique [0002] Caprolactam is an important petrochemical product, most of which are used to produce nylon 6 fiber and nylon 6 resin. Among them, nylon 6 fiber is widely used in wool spinning, knitting, weaving, cord fabric and carpet and other industries. Nylon 6 resin is developing towards high performance and wide range due to its excellent thermal stability, processability, mechanical properties and chemical resistance. Direction of development, widely used in automobiles, electronics, packaging films and medical products and other industries. [0003] There are many preparation methods of caprolactam, but there are only a few industrial methods that can meet the requirements of polymerization and are economical and reasonable. Volume 3 of the second edition of "Encyclopedia of Organic Chemical Materials" introduces the production methods and industrial status of caprolac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D201/10C07D223/10
Inventor 罗和安吴剑夏珺
Owner CHINA PETROLEUM & CHEM CORP
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