JPS6041644A - Preparation of glycine salt - Google Patents

Abstract

PURPOSE:To obtain a glycine salt useful as a raw material for a food additive, agricultural chemical, drug, and amino acid in a shortened reaction time in high yield, by reacting monoethanolamine with alkaline (earth)metal hydroxide in the presence of water and a copper-containing catalyst. CONSTITUTION:Monoethanolamine is reacted with an aqueous solution of an alkali metal hydroxide and/or an alkaline earth metal hydroxide (e.g., sodium hydroxide, potassium hydroxide, magnesium hydroxide, etc.) in the presence of a safe copper-containing catalyst under mild conditions at 120-220 deg.C at 0-20 kg/cm<2>G, to give the desired glycine salt. The amounts of the alkali metal or alkaline earth metal hydroxide used is <= the equivalent amount of monoethanolamine, preferably 1.0-2.0 equivalents.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new process for producing glycine salts from monoethanolamine. More specifically, monoethanolamine in the presence of alkali metal and/or alkaline earth hydroxides.

This article relates to characteristic reaction conditions, additives, and catalysts for producing glycine salts.

The production of glycine soda from monoethanolamine proceeds according to the following reaction formula (1), and the production of glycine 7 from glycine soda proceeds according to reaction formula (2).

1I2NcI-12CH201-1+Na01-1 water'
Touch-T-12NCI2COONa+2112 (I)1
12NCII2COONa4-%l]2N for 2S04-
CI-12COOH+%NX]2SO4(2) Glycine salt is usually neutralized to glycine and is widely used as a food additive for meat processing, soft drinks, instant foods, and other processed foods.

It is also used in a wide range of fields, including pharmaceuticals, agricultural chemicals, and amino acid sources.

As an industrial method for producing glycine salts, Strecker i, which uses 1'J' acid and formaldehyde as main raw materials, is generally known. However, since prussic acid is a highly toxic gas, there are major restrictions in terms of manufacturing equipment, handling, and location.
Moreover, most of the hydrocyanic acid is a by-product during the production of acrylonitrile? There was also a big problem in ensuring the stability of Mehara.

On the other hand, a method for producing monoethanolamine by oxidative dehydration in caustic alkali; etc. are disclosed. US Patent No. 2. The method disclosed in ``Example: 344,816 inches'' involves the reaction of monoethanolamine and potassium hydroxide without any catalyst, and the reaction time is approximately 1 (about 1.3 mm). In addition, the presence of water (it is stated that it promotes the attack of d-amine groups by 1%), and potassium hydroxide, which has good solubility in monoethanolamine, is used as a -1 correcting alkali.On the other hand, US Patent No. 2
, 384, 817 - The horn method (d, 4 ÷ hydroxylation power of ethanolamine and flakes 1], um, disclosed in Examples 1 and 2) in the presence of a cadmium oxide catalyst, which is a poisonous substance. The reaction was carried out while raising the temperature at 160-185°Ct, but in this case too, the glycine yield was about 65°C.
In this way, in the conventional technology, the non-catalytic reaction has a low yield, and the reaction using cadmium oxide as a catalyst does not react with cadmium compounds that are toxic. There is a risk of contamination with foods / ζ Food cooperation [l The production of chrysin salt as a durable product requires 7j, and since it has a low yield, it is competitive with the Stresono J-method. The present inventors (Yumi 1) have been earnestly researching the oxidative dehydration method of monoethanolamine as a method for producing vine chrysine salt as an alternative to the Strecker method. r
ib (Death results, toxicity Ih [problematic power 1' high yield even though mium compound is used 5") 5?t
We have discovered a unique method for manufacturing XJ'f, and have completed the present invention.

The present invention combines monoethanolamine with an alkali metal and/or
1) is concerned with a method for producing chrysine salt in high yield by reacting an alkaline earth metal hydroxide in the presence of a catalyst and water.

The V4M feature of the present invention is that in the production of chrysine salt from monoethanolamine, a safe copper-containing catalyst can be used for the hydration of alkali metal iJ/l or alkaline earth metal without using a catalyst. 120-220 in an aqueous solution of
By using it under the very mild conditions of 'C,
Glycine salt yield: (-92 based on monoethanolamine)
It is on the high side at ~97 mol. By implementing the present invention, compared to the conventional method, the yield of chrysin salt is improved, reaction 1
T! Pre-condensation for 1 hour, mild reaction conditions, etc. are possible. As a result, it became possible to reduce the production cost by a large amount of 5glycide/salt, and completed a process for producing 1glycide salt 1 using the oxidative dehydrogenation method of monoethanolamine, which is easy to implement industrially. It is a ζ thing.

In one embodiment of the present invention, the catalyst used in the method of the present invention contains copper as an essential component. The catalyst is 1 or 1qj, 111I alkali 471-4
- It can be used by carrying 4';'+shi in one body. .

The amount of catalyst used is 1 to 70% relative to monoethanolamine.
- a small weight factor, preferably in the range 10-30 weight factor 1
The form of the catalyst is not particularly limited; however, after oxidizing the surface of metallic copper in air, oxygen, or with an appropriate oxidizing agent, it is oxidized in a hydrogen atmosphere. After development [7], it is washed with water, and copper-activated products, such as those made by heating copper formate or other copper salts, are preferably used.

Catalysts usually have low activity and aL during reactions, so they can be used repeatedly or used repeatedly.

In the reaction of the present invention, A( was conventionally thought to promote the decomposition of Amitsuno, (, and (r-);
Under Vll reaction conditions, the decomposition of the amino group is as follows.
Rather, it has the advantage of reacting monoethanolamine with alkali metal and alkaline earth metal hydroxide in a homogeneous system; It is a rare occasion for the purpose of

The amount of water used in the reaction is 1 for monoethanolamine/
0 weight φ or more, preferably in the range of 10 () to 500 weight ratio6. As the alkaline total pressure hydroxide used in the present invention, lithium hydroxide, Contains potassium hydroxide, rubidium hydroxide, cesium hydroxide.Alkaline earth metal hydroxides include potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, etc. In particular, sthorium hydroxide and potassium hydroxide are preferably used.The amount of alkali metal and/or alkaline earth metal hydroxide used is preferably at least the equivalent of monoethanolamine used in the reaction. In the range of 10 to 20 equivalents.Alkali metal and/'
8. The hydroxides of alkaline earth metals are flakes, powders,
Although pellets and their aqueous solutions can be used, aqueous solutions of alkali metals are generally preferred because they are easier to handle.

Monoethanolamine is preferably of high purity in order to avoid contamination of the glycine salt with impurities.

Although there are no particular limitations on the purity, a purity of 96% by weight or more, preferably 99% by weight or more is used.

The reaction temperature is 220°C or less, usually 120 to 2200°C, in order to prevent thermal decomposition and hydrogenolysis of the N1-12 groups of monoethanolamine and the N1-12 groups of glycino salt.
Preferably, the temperature range is from 140 to 190°C. In addition, when the temperature exceeds 220°C, some parts of the surface of the copper catalyst start to shrink, the surface viscosity decreases, and the catalyst 7'Ii properties begin to deteriorate. temperature is more suitable.

Since the reaction pressure is an oxidative dehydrogenation reaction, it is better to lower the reaction pressure as much as possible from the viewpoint of reaction rate. Usually, the minimum pressure of the vessel in which the reaction proceeds in the liquid phase, preferably 0
The range is from 5 to 9 g/cnYa, more preferably from 5 to 9 g/cnYa.

The reaction time can be selected as appropriate, but it is determined by the reaction temperature, amount of catalyst, and reaction pressure. For example, in the case of a reaction temperature of 160'C1 reaction pressure "Okg/cniG" and a catalyst amount of 10 parts by weight relative to monoethanolamine (1': 14 to 6 hours).

Any reaction method (batch, semi-batch, or continuous reaction method can be used).

Hereinafter, embodiments of the present invention will be specifically illustrated and explained with reference to Examples. The present invention is not limited to these examples.

Here, the conversion rate of monoethanolamine, glycine 1] (
The selectivity of is derived from the following formula.

Conversion rate of monoethanolamine (%) Selectivity of Gly7in 2, Example 1 Monoethanolamine 79.3 ? , sodium hydroxide 5 Gf/, water] 35.3 S' and developed Raney copper 807 were charged into a 500 ml autoclave, and after internal displacement with hydrogen gas three times, hydrogen was added at a reaction temperature of 160° C. and a reaction pressure of 9 kg/cnio. The reaction is carried out until the occurrence of ζ is stopped. Time required for reaction r ↓ Rise to 160℃? A7
After the reaction was completed, the reaction solution was taken out and analyzed.The conversion of monoethanolamine was 81 moles, and the selectivity of glycine salt was 972 moles.

Example 2 Monoethanolamine 79.3 g, sodium hydroxide 569, water 135.3 fi and copper formate were heated overnight at 200'G for 3 hours in a stream of hydrogen.
After 50 (i ml) of copper s, o y was charged into a Qy4--1-crepe and internally replaced with hydrogen gas three times, at a reaction temperature of 160"G and a reaction pressure of 9kg/'c11(),
The reaction is carried out until hydrogen is no longer produced. The time required for the reaction was 6 hours after the temperature was raised to 50°C.

After reaction path Y, the reaction solution was taken out and analyzed, and the conversion rate of monoethanolamine was 975 mol, glycine 1)
,,1 had a selectivity of 951 moles.

Example 3 Monoethanolamine 71J, 3 y, /J<
Oxidizing power 1) Ul, 7857, water +353y and expanded Raney t1. lI 8. OV f 500 ml J-
After charging into a l-crepe and internally purging with water and gas 3 times, the reaction temperature was 160'', and the reaction +1 force was 9 kg/c.
The reaction is carried out in such a state that nfa and water L4' are not generated. The time required for the reaction was ylt at 160°O, 1. ．．
1. It was 4 days later. After the reaction is complete, take out the reaction solution and add 11'J of monoethanolamine, 982 moles of chemical compound, and glycine B.
,; ;'s L' cane 1 scale is! It was 165 molti.

Claims (5)

[Claims] (1) Processing monoethanolamine with alkali metals/
Alternatively, a method for producing a glycine salt, which comprises reacting in the coexistence of an alkaline earth metal hydroxide, water, and a copper-containing catalyst. (2) The method according to claim (1), wherein the reaction is carried out at a temperature of 120 to 220°C. (3) The method according to claim (1), wherein the reaction is carried out at a pressure of 0 to 20 kg/cIO. (4) The alkali metal hydroxide is sodium hydroxide9
The method according to claim (1). (5) The method according to claim 11, wherein the alkali metal hydroxide is potassium hydroxide.