JPS6025951A - Production of gamma-chloroacetoacetyl chloride - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as an intermediate of quinacridone (a red pigment) or raw material of pharmaceuticals and other synthetic chemicals, in high yield and quality, with littled production of by-products, by reacting diketene with chlorine using a rotary thin film reactor. CONSTITUTION:gamma-Chloroacetoacetyl chloride is produced by reacting diketene with chlorine in an inert solvent such as dichloromethane, carbon tetrachloride, etc. preferably at -20-0 deg.C, introducing diketene and chlorine from the top of a rotary thin film reactor composed of a tubular reactor and a rotary blade inserted in the tube, wherein the reaction raw material introduced into the reactor forms a thin film on the wall of the tube by the rotary force of the blade, and the reaction of the raw material proceeds in the course of flowing down spirally along the tube wall. Since the gamma-chloroacetoacetyl chloride is unstable, it is preferably converted to a relatively stable ester, amide, anilide, etc. by reacting with alcohol, phenol, amine, aniline, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION T-talolacetoacetic acid chloride is useful as an intermediate for quinacridone, which is a red pigment, or as a raw material for pharmaceuticals and other synthetic raw materials. However, as a method for producing the talolide, a general method is a punch method in which diketene and chlorine are introduced into an organic solvent and the two are reacted.

However, as confirmed by the present inventors, although the chloride production reaction is an exothermic reaction with a high reaction heat, the reaction requires a relatively low temperature. Because of this, trying to keep the refrigeration load within an industrially practical range inevitably tends to lengthen the reaction time. The inevitable formation of by-products such as α-taloacetoacetic acid chloride and higher chlorinated products became a problem. As a countermeasure against this, it has been proposed to carry out the reaction using a barrier tower type reactor or a flow tube type reactor, but the yield of the target product in MfJ is at most about 8996, and it is difficult to carry out the reaction on an industrial scale. In the case of the latter, it is necessary to further improve the yield, and in the case of the latter, the reaction apparatus is complicated, so that industrial implementation has the disadvantage that practical troubles are expected.

However, in order to solve this problem, the present inventors
As a result of extensive research, we have found that when diketene and chlorine are reacted in a rotary membrane reactor, T-talolacetoacetic acid of excellent quality is produced with very few by-products such as α-talolacetoacetic acid chloride and higher chlorinated products. The present inventors discovered novel facts such as the fact that chloride can be obtained in a high yield of 95% or more, and that heat removal during the reaction is easy, and that the reaction is therefore easy to manage, leading to the completion of the present invention. .

The rotary thin film reactor used in the present invention is a tubular reactor in which rotating blades are inserted, and the reaction raw materials introduced into the vessel form a thin film on the tube wall due to the rotational force of the blade. A reactor in which the reaction proceeds while rotating and flowing downward can be used in any shape or style. Usually, diketene and chlorine may be introduced from the upper part of a tubular reactor and reacted. It is possible to use not only one reactor but also multiple reactors in parallel.

The diketene and chlorine to be supplied are usually dissolved in a solvent inert to diketene and chlorine, such as dichloromethane, dichloroethane, dichloropropane, carbon tetrachloride, chloroform, liquid sulfur dioxide, and the like. If dissolved, chlorine,
The lower the concentration of diketene, the less by-products will be produced, but in terms of solvent recovery after the reaction, the concentration should be 1 to 25% by weight.
The content is preferably 10 to 20% by weight. The supply amount of the above raw materials has a chlorine/diketene ratio of 0.95 to +
, I O (molar ratio).

The reaction temperature is selected from a wide range of temperatures from -50°C to +20°C, but a suitable temperature range is from -20°C to +20°C.

Further, although the rotation vi of the rotary blade cannot be unconditionally defined depending on its shape, it usually needs to be at least AOOrpm. Furthermore, the residence time of raw materials in the vessel is 0.1 to 60 minutes, and the time is 1 to 60 minutes.
Select from a range of about 15 minutes.

When the reaction is carried out in this manner, the desired T-chloroacetoacetic acid chloride is obtained from the bottom of the reactor, but since this product is extremely unstable, it is desirable to collect it under cooling below 0°C. You also need to be careful about storage. Therefore, it is advantageous to react T-chloroacetoacetate chloride with alcohol, phenol, amine, aniline, etc. to convert it into relatively stable T-chloroacetoacetate, T-chloroacetoacetamide, T-chloroacetoacetanilide, etc. as soon as possible. It is. Thereafter, distillation is performed under normal pressure or reduced pressure to recover the solvent.

Next, the method of the present invention will be explained in more detail with reference to examples.

Example 1 The jacket of a rotating thin film reactor with an inner diameter of 80 M and a height of 120 mm was cooled to below -15.0°C with a refrigerant, and the rotating blades were
About 70d while rotating at a rate of D 00 rpm.
of dichloroethane was dropped to form a rotating thin film on the tube wall. Next, it was cooled to -20'C, and a 1t 10% chlorine-containing dichloroethane solution and a 1196 dictene-containing dichloroethane solution were added at 44Wd each! It was fed continuously at a rate of 1/min. At this time, the internal temperature was 9°C.

The T-chloroacetoacetic acid chloride flowing out from the bottom is
It was collected under cooling at 10 to -20°C.

- Methyl alcohol was added dropwise to the thus obtained T-thalolanatoacetic acid chloro24 reaction solution at a temperature of -5 to θ°C to obtain a γ-methyl thalolanatoacetate reaction solution. Next, hydrochloric acid was expelled from the liquid under reduced pressure at room temperature, and dichloroethane was distilled off under reduced pressure while heating to 50°C. Gas chromatography analysis of crude methyl T-talolacetoacetate revealed that T-
The yield of methyl chloroacetoacetate was 95%.

Example 2 T-chloroacetoacetic acid chloride and its methyl ester were synthesized according to Example 1 with the temperature of the refrigerant set to 0°C. As a result, the yield was 9,596.

Claims (1)

[Claims] A method for producing T-talolacetoacetic acid chloride, which comprises reacting diguten and chlorine in a rotating thin film reactor.