N, N'- dicyclohexyl thiourea microwave synthesis method

A technology of dicyclohexylthiourea and microwave synthesis, applied in the N field, can solve the problems of expensive reagents, hidden dangers, long reaction time, etc., and achieve the effects of simple feeding and post-processing, mild reaction conditions, and short reaction time.

Inactive Publication Date: 2007-05-16
ZHEJIANG UNIV
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Problems solved by technology

In addition, the application of this method will also produce a by-product - highly toxic gas hydrogen sulfide, which is very dangerous in the laboratory or in industry, and is prone to poisonous gas leakage, resulting in great safety hazards
Moreover, in the preparation methods that have been reported, many experimental processes involve various problems such as strong acid or strong alkali conditions, expensive reagents, low yield, complicated post-treatment and long reaction time.

Method used

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  • N, N'- dicyclohexyl thiourea microwave synthesis method
  • N, N'- dicyclohexyl thiourea microwave synthesis method
  • N, N'- dicyclohexyl thiourea microwave synthesis method

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preparation example Construction

[0014] The specific reaction steps of the microwave synthesis method of N, N '-dicyclohexylthiourea are as follows:

[0015] With water as the reaction solvent and PEG-400 as the catalyst, thiourea and cyclohexylamine are heated and reacted in microwave for 0.5 to 2 minutes. After filtration and washing, high yield and high purity N,N'-dicyclohexylsulfide can be obtained by separation. Urea; reaction solvent and catalyst can be recycled. The molar equivalent ratio of thiourea and cyclohexylamine is 0.4-0.6:1; the dosage of catalyst PEG-400 is 1-5% molar equivalent of thiourea; the microwave frequency is 2450MHz; the microwave power is 400-800W. It is recommended that the molar equivalent ratio of thiourea and cyclohexylamine be 0.45-0.55:1, and the most preferred ratio is 0.5:1; the recommended dosage of catalyst PEG-400 is 1-4% molar equivalent of thiourea, and the most preferred is 3% molar equivalent. The recommended microwave power is 500-700W, with 600W being the most p...

Embodiment 1

[0018] Mix 10 mmoles of thiourea, 20 mmoles of cyclohexylamine and 0.3 mmoles of PEG-400 in 15 milliliters of water, set the microwave power to 600W, heat the reaction for 1 minute, end the reaction, cool down, precipitate the product, filter (the filtrate is recovered ), washed with water, and dried to obtain 2.2 grams of N, N'-dicyclohexylthiourea, with a yield of 92% and a melting point of 180-182°C.

Embodiment 2

[0020] Mix 8 millimoles of thiourea and 20 millimoles of cyclohexylamine in the filtrate recovered in Example 1, set the microwave power to 650W, heat the reaction for 1 minute, end the reaction, cool, separate out the product, filter (recover the filtrate) , washed with water, and dried to obtain N,N'-dicyclohexylthiourea with a yield of 76% and a melting point of 179-182°C.

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Abstract

The invention discloses a synthesizing method of N, N'-dicyclohexyl thiourea, which comprises the following steps: adopting water as reacting solvent and 1-5% PEG-400 as catalyst; reacting thiourea and diisopropylamine with molar rate at 0.4-0.6: 1 heat by microwave with frequency at 2450MHz and powder at 400-800W for 0.4-3min; filtering; washing; separating to obtain the product.

Description

technical field [0001] The invention relates to a synthesis method of thiourea, in particular to a microwave synthesis method of N, N'-dicyclohexylthiourea. Background technique [0002] N,N'-dicyclohexylthiourea is an important intermediate for the preparation of N,N'-dicyclohexylcarbodiimide (DCC). N,N'-Dicyclohexylcarbodiimide (DCC) is a condensation dehydrating agent with wide application, mainly used in amikacin and glutathione dehydrating agent, and also used in acid anhydride, aldehyde, ketone, isocyanate Synthesis; as a dehydration condensation agent, the reaction can be completed in a short period of time at room temperature; industrially, it is generally obtained by oxidizing N, N'-dicyclohexylthiourea with aqueous sodium hypochlorite solution. Therefore, how to synthesize N,N'-dicyclohexylthiourea more efficiently and greenly has attracted great attention. [0003] Many methods have been reported for the preparation of N,N'-dicyclohexylthiourea. Among them, a m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C335/14
Inventor 沈阳林旭锋
Owner ZHEJIANG UNIV
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