Preparation method of beta-methylnaphthalene

A technology for crude methylnaphthalene and methylnaphthalene, which is applied in crystallization purification/separation, organic chemistry, distillation purification/separation, etc., can solve problems such as high cost, solution pollution, and large treatment cost, and avoid acid and alkali washing , simple preparation method and low production cost

Inactive Publication Date: 2008-08-27
苏州市锋齐高新技术有限公司
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Problems solved by technology

The biggest problem that this method brings is that the solution pollution after the initial pickling is very big, and the treatment cost is relatively expensive, and the β-methylnaphthalene content produced is not high (the β-methylnaphthalene content is greater than 95%, and the indole content is between 0.2~1%), in order to obtain high content of β-methylnaphthalene, it is necessary to deindole again, with 55~65% concentration of H 2 SO 4 Solution, according to the ratio of oleic acid to 1: 1 ~ 4: 1, carry out pickling; : 1~4: 1, carry out alkali washing, finally obtain the β-methylnaphthalene of the white crystal of indole content through distillation and be less than or equal to 0.02%, although the β-methylnaphthalene purity that this kind of method obtains can reach 98%, But the cost is high, and the pollution increases after pickling and alkali washing, and the use of 55-65% sulfuric acid solution is also an important source of danger for the safety of workers

Method used

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Embodiment Construction

[0012] The specific embodiment of the present invention is described below:

[0013] According to the preparation method of the β-methylnaphthalene of the present embodiment, comprises the steps:

[0014] (1), the petroleum grade mixed methylnaphthalene that contains about 60% of β-methylnaphthalene is obtained crude product β-methylnaphthalene through decompression distillation, and its specific process is as follows:

[0015] First, pump the heating kettle and tower body to 600-640mmHg with a vacuum pump, and maintain this vacuum degree during the whole production process, then feed raw materials into the heating kettle, use heat-conducting oil to heat, and control the outlet temperature of the heat-conducting oil at 220-224°C. The temperature of the heating kettle is controlled at 195-205°C (the best temperature is about 197°C), the reflux ratio is controlled at 35-45 (the best state is 40), and the vacuum degree of the heating kettle is controlled according to the height o...

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Abstract

The invention relates to a preparation method of beta-methylnaphthalene, which uses oil level mixed methylnaphthalene containing 50-70% of beta-methylnaphthalene as raw material, depressurizes and distills to obtain beta-methylnaphthalene product containing at least 80% of beta-methylnaphthalene, freezing and centrigually treating the beta-methylnaphthalene to obtain the beta-methylnaphthalene product. The preparation method can obtain the beta-methylnaphthalene whose purity is higher than 97%, with simple operation, low production cost and little environment pollution.

Description

technical field [0001] The invention relates to a preparation method of methylnaphthalene. Background technique [0002] At present, the method of producing β-methylnaphthalene is to use the crude methylnaphthalene in coal tar as raw material, after pickling to obtain the methylnaphthalene fraction with a content of 50% of β-methylnaphthalene, and then azeotropic distillation to produce β-methylnaphthalene -Methylnaphthalene. The biggest problem that this method brings is that the solution pollution after the initial pickling is very big, and the treatment cost is relatively expensive, and the β-methylnaphthalene content produced is not high (the β-methylnaphthalene content is greater than 95%, and the indole content is between 0.2~1%), in order to obtain high content of β-methylnaphthalene, it is necessary to deindole again, with 55~65% concentration of H 2 SO 4 Solution, according to the ratio of oleic acid to 1: 1 ~ 4: 1, carry out pickling; : 1~4: 1, carry out alkali...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/24C07C7/04C07C7/14
Inventor 庄伟荣钱晓华庄寒锋
Owner 苏州市锋齐高新技术有限公司
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