JP2009167112A - Method for producing laurolactam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing laurolactam solving a problem of a large amount of sulfonic acid loss or a large energy loss by producing the laurolactam with the Beckmann rearrangement of cyclododecanone oxime by using a catalytic amount of methane sulfonic acid. <P>SOLUTION: This method for producing the laurolactam by the Beckmann rearrangement of the cyclododecanone oxime is characterized by using the methane sulfonic acid in acetonitrile. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a process for producing laurolactam useful as a raw material for 12-nylon. In particular, the present invention relates to a method for producing laurolactam by Beckmann rearrangement of cyclododecanone oxime.

As a technique related to the production method of the present invention, Patent Documents 1 and 2 disclose a process for producing a lactam having 12 carbon atoms from cycloalkanone oxime using methanesulfonic acid. However, this method uses a large excess of methanesulfonic acid relative to the cycloalkanone oxime. Since sulfonic acid forms a salt with laurolactam, in order to obtain the desired free laurolactam, an operation of dissolving sulfonic acid in water by adding water is usually performed. Recovery of sulfonic acid from water is not easy, and when a large amount of sulfonic acid is used, a large amount of sulfonic acid is lost or a great amount of energy is lost.
Japanese Patent No. 3352654 Japanese Patent No. 3584324 Japanese Patent Publication No. 51-46109

  To provide a method for producing laurolactam that can solve the above-mentioned problem of loss of a large amount of sulfonic acid or loss of energy by producing Bolocmann rearrangement of cyclododecanone oxime with a catalytic amount of methanesulfonic acid to produce laurolactam. It is.

The inventors of the present invention have found that by carrying out a reaction in an acetonitrile solvent, a catalytic amount of methanesulfonic acid can be used to produce laurolactam by Beckmann rearrangement of cyclododecanone oxime, and a large amount of sulfonic acid is lost. It was found that the above problem of loss can be solved.
That is, the present invention provides a method for producing laurolactam by Beckmann rearrangement of cyclododecanone oxime, using a catalytic amount of methanesulfonic acid in an acetonitrile solvent.

  INDUSTRIAL APPLICABILITY According to the present invention, an industrially suitable process for producing laurolactam that can produce laurolactam by Beckmann rearrangement of cyclododecanone oxime without causing loss of a large amount of sulfonic acid or loss of energy. Is provided.

  This reaction can be carried out by heating and stirring cyclododecanone oxime and a catalytic amount of methanesulfonic acid in an acetonitrile solvent.

  Cyclododecane oxime can be obtained by reacting cyclododecanone and hydroxylamine sulfate as described in Patent Document 3, for example.

Although the usage-amount of acetonitrile is not specifically limited, Usually, 0.3 to 100 weight times with respect to cyclododecanone oxime, Preferably it is 1 to 50 weight times.
Methanesulfonic acid is used in a catalytic amount, that is, 10 mol% or less, preferably 5 mol% or less, based on cyclododecanone oxime.

The reaction temperature is not particularly limited but is preferably 50 to 120 ° C.
The reaction pressure is not particularly limited, and can be performed under normal pressure or pressurized conditions.
Although reaction time changes with reaction conditions, such as the said density | concentration and temperature, it can carry out normally in 0.01 to 24 hours. Preferably, it is 0.05 to 6 hours.

As a treatment after the reaction, for example, after removing acetonitrile as a solvent by distillation and adding water, laurolactam free to methanesulfonic acid can be obtained.
The reaction apparatus is not particularly limited and can be carried out in a reactor equipped with a normal stirring apparatus.

  Laurolactam obtained in the present invention can be separated and purified by distillation, crystallization or the like.

  Next, an Example is given and this invention is demonstrated concretely.

[Example 1]
1.0 g (5.1 mmol) of cyclododecanone oxime and 5 mol% (0.025 g) of methanesulfonic acid with respect to cyclododecanone oxime were added to 5 g of acetonitrile, and the mixture was heated and stirred at 82 ° C. for 1 hour. When quantified by an internal standard method of gas chromatography, the yield of laurolactam was 66%.

[Examples 2 to 6]
It implemented like the Example below and the result was put together in the table | surface.

１）シクロドデカノンオキシムに対するモル％
２）実施例３〜６は、封管中反応を行った。

1) mol% relative to cyclododecanone oxime
2) In Examples 3 to 6, reactions were performed in a sealed tube.

[Comparative Example 1]
Add 0.6 g (3 mmol) of cyclododecanone oxime and 5 mol% of methanesulfonic acid (added in 0.23 g of acetonitrile) to cyclododecanone oxime to 2.8 g of toluene, and heat at 82 ° C. for 1 hour. Stir. When quantified by an internal standard method of gas chromatography, the yield of laurolactam was 4%.

[Comparative Example 2]
1 g (5 mmol) of cyclododecanone oxime and 5 mol% of p-toluenesulfonic acid with respect to cyclododecanone oxime were added to 5 g of acetonitrile, and the mixture was heated and stirred at 82 ° C. for 1 hour. When quantified by an internal standard method of gas chromatography, the yield of laurolactam was 11%.

Claims (2)

  A method for producing laurolactam, which comprises using a catalytic amount of methanesulfonic acid in acetonitrile in a method for producing laurolactam by Beckmann rearrangement of cyclododecanone oxime.   The method for producing laurolactam according to claim 1, wherein the amount of methanesulfonic acid is 10 mol% or less of cyclododecanone oxime.