JPH0415795B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing mesitylphosphonite dichloride. (Prior Art) Conventionally, the method for producing mesitylphosphonite dichloride (2,4,6-trimethylphenyldichlorophosphine in IUPAC nomenclature) is as follows:
As described by WCDavies in J.Chem.Soc., 462-464 (1935), this method used the Friedel-Crafts reaction, in which phosphorus trichloride and mesitylene were reacted using aluminum chloride as a catalyst. However, although this method attempted to synthesize on a large scale, the yield was extremely low at about 8%, and it was also uneconomical. For this reason, it was not industrialized. (Problems to be Solved by the Invention) The object of the present invention is to solve the problems that conventional methods were uneconomical due to low yields, and to industrially mass-produce mesitylphosphonite dichloride. (Means for Solving the Problems) The present invention involves dissolving bromomesitylene in tetrahydrofuran under a stream of inert gas, cooling it, adding a solution of alkyl lithium or metallic lithium to produce lithiomesitylene, and then producing trichloride. A process for producing mesitylphosphonite dichloride, which is characterized by adding phosphorus, slowly raising the solution temperature to approximately room temperature, heating under reflux, separating the phosphorus from the formed precipitate, and distilling off the solvent from the phosphorous solution. This is the manufacturing method. The reaction formula of the production method is shown below. Cooling is preferably about -60 to -100°C. (Function) When considering industrial use, the produced mesitylphosphonite dichloride itself is the most basic substance among organic phosphorus reagents, and therefore can be an important intermediate in organic industrial chemistry. In addition, phenylphosphonite dichloride, which is sold as an analogue of the manufactured mesitylphosphonite dichloride, is extremely easily hydrolyzed by moisture in the air (if the storage bottle is left open, it will emit white smoke). It is rapidly hydrolyzed by moisture in the air) and has a foul odor, so care must be taken when handling it. However, mesitylphosphonite dichloride is difficult to be hydrolyzed (it is hardly hydrolyzed even if the storage bottle is left with the stopper open);
Furthermore, it is a substance that has various advantages because it does not have a bad odor. If purified mesitylphosphonite dichloride is stored tightly sealed under nitrogen gas, it will not decompose at all and can be stored stably for a long period of time. For these reasons, it is a substance that can replace phenylphosphonite dichloride (presumably, it has not been industrialized because the conventional method was too uneconomical and had a low yield). (Examples) Hereinafter, the present invention will be described in more detail with reference to Examples. Example 1 Bromomesitylene (5.0 g) was dissolved in anhydrous tetrahydrofuran (30 ml) under a nitrogen stream and cooled to -78°C. A n-butyllithium hexane solution (17.5 ml of 1.6M solution) was added dropwise to this, and the mixture was stirred for 1 hour. Then, phosphorus trichloride (8 g) was added and stirred at the same temperature for 1 hour. The temperature was then slowly raised to room temperature, and the reaction mixture was then refluxed at 70°C. The lithium chloride precipitate produced at the same time as the target product is filtered out, and the filtrate is distilled under reduced pressure to obtain pure mestylphosphonite dichloride.
3.6 g was obtained at a boiling point of 85-90°C (degree of vacuum: 1 mmHg).
Yield: 65% (The physical constants of mesitylphosphonite dichloride by the conventional production method are as follows.
Boiling point 150-157°C (degree of vacuum 16mmHg, yield 8%). Examples 2 to 5 The yields shown in Table 1 were obtained by carrying out the same procedure as in Example 1 while changing the amounts of raw materials as shown in Table 1 below.

【table】

[Table] *Solvent = Anhydrous tetrahydrofuran (Effects) Thus, the following excellent effects could be obtained by the present invention. (a) Extremely high yield. (b) It is inexpensive and economical. (c) The operating method is extremely simple. (d) The raw materials are all easily available reagents. (e) Large-scale synthesis, that is, industrialization is possible. Although the present invention has been described with reference to specific examples and numerical values, the present invention is not limited to only these examples;
Of course, various changes and modifications may be made without departing from the broader spirit and scope of the invention. For example, sec-butyllithium can be used as the alkyllithium.

Claims (1)

[Claims] 1 Dissolve bromomesitylene in tetrahydrofuran under a stream of inert gas, cool it, add a solution of alkyllithium or metallic lithium to produce lithiomesitylene, then add phosphorus trichloride,
1. A method for producing mesitylphosphonite dichloride, which comprises slowly raising the solution temperature to approximately room temperature, heating under reflux, filtering off the formed precipitate, and distilling off the solvent from the filtrate.