JPS5944346A - Preparation of serine - Google Patents

Abstract

PURPOSE:To prepare serine in high yield, without precipitation of metallic copper, by carrying out the reaction of glycine copper complex with formaldehyde using a basic catalyst in the presence of oxygen. CONSTITUTION:The preparation of serine by the reaction of glycine copper complex with formaldehyde in the presence of a basic catalyst (e.g. NaOH) is carried out in the presence of oxygen. A large amount of metallic copper is produced in the reaction of glycine copper complex with formaldehyde by the reduction of glycine copper complex with formaldehyde, causing the lowering of the yield of serine. The precipitation of metallic copper can be prevented by the supply of oxygen to the system. The presence of dissolved oxygen in the reaction liquid is effective for the purpose, and it can be achieved by bubbling oxygen into the reaction liquid or supplying oxygen under pressure. The reaction is carried out at 30-150 deg.C for 0.5-5hr using preferably 2-10pts. of formaldehyde based on 1pt. of glycine copper complex.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing serine from glycine and formaldehyde. More specifically, the present invention relates to a method for producing serine, which is characterized in that when producing serine by reacting glycine steel and pormaldehyde, oxygen is supplied to the reaction solution and the reaction is carried out in the presence of oxygen.

Serine is a type of amino acid, and many methods have been known for synthesizing serine, among which a method in which glycine steel and formaldehyde are reacted in a basic aqueous solution is known (Japanese Patent Publication No. 34-2964). However, the method using glycine steel causes precipitation of metallic copper during the reaction, resulting in a poor yield of serine, and has not yet been put to practical use.

Regarding this reaction, the present inventors aimed to eliminate the precipitation of metallic copper and improve the yield of serine.
As a result of various studies, we found that if the reaction is carried out in the presence of oxygen, such as by supplying oxygen to the reaction solution during the reaction, the precipitation of metallic copper can be eliminated and the yield of serine can be improved. I found it. That is, conventionally, when glycine steel and formaldehyde were reacted, the formaldehyde reduced the glycine steel and produced metallic copper, which was a major cause of a decrease in the yield of serine. However, when the reaction between glycine steel and formaldehyde is carried out by supplying oxygen to the reaction solution, the precipitation of metallic copper is eliminated and the yield of serine, which is the target product, can be increased by 1]. can.

In the method of the invention, the reaction is carried out in the presence of oxygen.

The presence of oxygen means that dissolved oxygen exists in the reaction solution during the reaction. Oxygen can be supplied by blowing oxygen into the reaction solution in the form of bubbles under normal pressure, or oxygen can be supplied under pressure. Since the effect increases as the amount of dissolved oxygen increases, it is preferable to dissolve oxygen in the reaction solution, for example, by sealing high-pressure oxygen in the reaction vessel and stirring the reaction solution. The oxygen pressure in this case is not particularly limited, but is preferably 1.00 kg or less. Further, as the oxygen source, in addition to oxygen, an oxygen-containing gas such as air, a mixed gas with another gas, etc. can be used.

The reaction conditions in the method of the present invention are similar to the conventional reaction conditions for copper glycine and formaldehyde, except that oxygen is supplied to the reaction solution. For example, the catalyst used in this reaction may be inorganic bases such as caustic alkali or alkali carbonate, or organic bases such as pyridine.

Further, it is preferable to use formaldehyde in excess of glycine copper. That is, formaldehyde is 1 to 20 times the theoretical amount, preferably 2 to 1
Can be used 0 times. In addition, when preparing the reaction solution, it is possible to use glycine copper prepared in advance from glycine/copper salt. Copper salts may be added separately.

Moreover, this reaction proceeds in a solvent such as water or methanol. (core temperature is 30-150℃, reaction time is 0.5
~5 hours.

After the reaction, the copper ions in the reaction solution are removed using hydrogen sulfide or ion exchange resin as per the usual force method.2, the copper ion removal solution is concentrated, and monoalcohol etc. are added to the concentrated solution to crystallize serine. It can be separated as The present invention will be explained as follows based on examples.

Example 1 2.3 g of glycine copper, sodium hydroxide O, /I in a Hastelloy C autoclave with contents 5Qm/! 7
．． After adding 14.0 m of formalin and 15 m7 of water and sealing in 5 CJ kg A♂ of oxygen, the temperature was heated to 95°C.
The mixture was stirred for 2 hours. After cooling, the oxygen pressure decreased to 37 kg/i. Moreover, no precipitation of metallic copper was observed. Next, after adding concentrated hydrochloric acid to this reaction solution to make it acidic,
Sodium sulfide was added to precipitate copper ions as copper sulfide, which was separated from P. As a result of measuring the r liquid by liquid chromatography, the production of 1.44 serine was observed. The yield of serine was 63.2 times the theoretical value.

Example 2 Contents 10071/! 2 copper glycine in a three-bottle flask
．． 39, sodium hydroxide 0.4 g, 35 thiformin 14.0- and water 25? d was added, and the reaction solution was stirred at 70° C. for 2 hours while blowing air into the reaction solution. During the reaction, almost no precipitation of metallic copper was observed. After removing copper ions from this reaction solution in the same manner as in Example 1, production of 0.52 g of serine was observed by liquid chromatography measurement.

The yield of serine was 22.8% of theory.

Reference Example 1 In the method carried out in Example 1, nitrogen 1 was used instead of oxygen.
After confining 0 kg/d in an autoclave, 95°
The mixture was stirred at C for 2 hours. After the reaction, a large amount of metallic copper was observed to be deposited in the autoclave. After filtering this reaction solution, copper ions were removed in the same manner as in Example 1, and the production of 0.65';l of serine was confirmed by liquid chromatography measurement. The serine yield was 28.6% of theory.

Reference Example 2 In the method carried out in Example 2, the reaction solution was stirred at 70'C for 2 hours without blowing air into it.

A large amount of metallic copper was deposited during the reaction, and the metallic copper adhered to the inner wall of the flask. Reaction solution: After passing this reaction solution once,
Copper ions were removed in the same manner as in Example 1, and the production of 0.239 Kirin was confirmed by liquid chromatography measurement. The yield of serine was 10.3 times the theoretical value.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1) A method for producing serine, which is characterized in that when producing serine by reacting glycine steel with formaldehyde in the presence of a basic catalyst, the reaction is carried out in the presence of oxygen.