JPS599184A - Manufacture of l-cysteine - Google Patents

Abstract

PURPOSE:To manufacture L-cysteine contg. no impurities in a high yield when L-cysteine is manufactured by the electrolytic reduction of L-cystine, by using an electrolytic cell provided with a cation exchange membrane. CONSTITUTION:An electrolytic cell is divided into an anode chamber and a cathode chamber with a cation exchange membrane made of a polymer of tetrafluoroethylene or the like. The anode chamber is filled with 1-30% aqueous soln. of a mineral acid such as hydrochloric acid, sulfuric acid or phosphoric acid, and a noble metal such as platinum or its oxide is placed in the chamber. The cathode chamber is filled with an aqueous soln. contg. a mineral acid salt of L-cystine and a mineral acid such as hydrochloric acid added by about 0.1-2mol per 1mol salt, and a platelike or netlike cathode of lead, silver, carbon or the like is placed in the chamber. Electrolysis is carried out at 10-60 deg.C, 2.5-6V and 0.1-30A/dm<2> current density to manufacture high purity L-cysteine in a high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing L-7 stain, and in particular to a method for converting L-cysteine to L-cysteine by the 11-i Wf ring formation method using a cation exchange membrane. .

L-cysteine is used in pharmaceutical products, food additives, chemical residue products, and the like. Conventionally, as a resultant force method for L-cysteine, for example, using δ゛1 septa゛ of prime 43 + ξ, ■
- A method of electrolyzing -7 suden is known. (Refer to Special Publication No. 37-2022) According to this method,
Adding additives to the anolyte or surrounding solution [7, also 'P
11. We are also trying to improve conversion and purity by implementing highly specific methods.

However, if a divine additive is added to the anolyte or other liquid, the pressure will generally rise or some of the additive will precipitate near the poles. There is a risk that some of the additives may be mixed in as impurities in the L-cysteine obtained, and an operation to remove them may be necessary. It was something.

In view of this, the present inventor has conducted various studies with the aim of producing highly pure L-7 stain in high yield by the electric angle method using a relatively simple system. As a result, the conventionally used cumulative moon °, 1,
It has been found that the above object can be achieved by using an ion exchange force instead of the ion exchange force.

Thus, the present invention +d uses an electrolytic cell that separates the anode chamber and the inryu chamber separated by a cation exchange membrane, and makes it possible to use the electrolytic cell to separate the anode chamber and the inryu chamber.
Mineral acid is introduced into the cathode chamber, b-cystine is introduced into the cathode chamber, and acid l (k) is introduced into the cathode chamber to dissolve the cloth.
To provide a method for producing a stain.

Hydrochloric acid, acid, and phosphoric acid are introduced into either the yin or yang frame chambers used in the present invention, and these can be used alone or in combination. Furthermore, the mineral acid used in the anode chamber and the acid used in the cathode chamber need not be of the same class.

The concentration of mineral acid introduced into the Yang Akira chamber is generally 1+? In the range from a to 7th, it is difficult to flow the ionization density 'Fli, arc' with a positive ionization density (!')
7.1 Higashitan r liquid 7M soaked in water or water (11μ chamber) in (1).
It is difficult to keep the value constant, so it is difficult to keep it constant.
- Not good.

Also, [X, is introduced into the slow room 70 ry-u of J,-cystine ore, generally L-cystine ore j-d i,
i/mol to 9・]V, gate・201~2 mol
As long as the culm is cooled, the ion-exchange membrane's l'l;
Ichiden Sujin's -7 <, Bkai'';'I・No・月1 i, '1]] Note!, I) 0, (1
・-When Sistine became a middle-aged man, he turned into bamboo shavings.
cormorant. ) il:'i I Ikamae h1 shi from the bag enclosure II, in case of O', L-insti/'s t valley) su' Since the value will be low, there will be no 7 in II.

Illustration for Ki-ni “!J”K ft Ruyo 1ij< )11”
/J, shape VC;l;i l! +('r: without r, 14
11 If there is 4・Iyong-1'l+ Yang 4 years can be platinum snow-covered metal flex or t1 kintoki IP monster yaj o) (7ki 1 unit, thread 1'44Je body, expandanteso)・Any suitable shape and shape can be adopted, such as a metal body plated or coated with cope ink.

Further, as the cathode, since the theoretical value of the redox potential at which L-cystine is converted to L-cystine is -0.27V, for example, lead, silver, or carbon can be used.

It is appropriate to use mercury or the like, and for these shapes, all the same aspects as for the II pole can be adopted.

Next, the ceramic carbonaceous membrane used in the present invention contains, for example, a mixture of cation exchange groups such as sulfonic acid groups, sulfonic acid groups and carboxyl groups, phosphoric acid groups, and phenolic hydroxyl groups. The vehicle body is made of, for example, a vinyl monomer such as tetrafluoroethylene or chlorotrifluoroethylene and an ion exchange group such as a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, or an ion exchange group converted to an ion exchange group. Copolymers with perfluorinated vinyl monomers having Ni groups are preferred.Also, membrane polymers of trifluoroethylene with ion exchange groups such as sulfonic acid groups, and styrene /Sulfone in vinylbenzene? I also use things made by other people.4
do.

In addition, when using a hydrocarbon-based cation exchange membrane, it is necessary to use a porous membrane of a fluorine-containing resin such as polytetrafluoroethylene or tetrafluoroethylene-hexafluoropropylene (combination) and the ion exchange membrane. By combining the entire cation exchange membrane with the membrane, the entire cation exchange membrane can be protected from high temperature and strongly acidic atmospheres.

Further, the above-mentioned fluorine-containing resin cation exchange membrane having a sulfonic acid group is particularly preferred since it has high heat resistance and acid resistance and can be used as is in the present invention.

Furthermore, in the present invention, a liquid- and gas-permeable anode is directly attached to these ion-exchange membranes, or a liquid- and gas-permeable anode that has no electrode function is inserted through a porous thin layer of, for example, a metal oxide. There is a technology that can completely reduce the electrolysis voltage and achieve the purpose of energy saving by using an anode and a cation exchange membrane in combination.

Thus, when carrying out the entire method of the present invention, the liquid temperature was between 10 and 6.
A temperature of about 0°C is used in the lp test.

If the liquid temperature is lower than the above range, the voltage will be high and it will be difficult to perform pile-up operation, whereas if it is high, the reduced cysteine will be decomposed and consumed, leading to a decrease in yield. I don't like either of them.

In addition, the current density is O]~30 A/d,,,z
It is appropriate to adopt all of them. If the current density is less than the above-mentioned range, the coating area will be too large when considering an industrial device, which is not economical. On the other hand, if it exceeds the range described in 1), the current efficiency decreases and the temperature rises, which is not desirable.

Moreover, it is appropriate to employ 25 to 6 Vi- for the electrolytic chamber H-. If the electrolytic voltage is less than the above range, the reduction rate will be extremely reduced, and if it exceeds the above range, this will lead to a decrease in current efficiency and an increase in temperature, which is not trivial.

When the method of the present invention is adopted, the liquid system introduced into both the anode and anode chambers only needs to contain the substances necessary for the actual Ti reaction, and no other additives are required, resulting in high-purity products! This method has the advantage of being able to produce the target product in high yield and with easy operations without unnecessary electrodeposition of substances.

Next, an example J in which the non-invention is continued with an example: between a platinum-made Yoshun with an effective electrode area of 6 dm'' and a lead-made cathode with the same area, an average pore diameter of 01μ, a porosity of 10 to 40, and a thickness of A cation exchange membrane (Celemion CMV manufactured by Asahi Glass Co., Ltd.) made of styrene 7-hinylbenzene with all sulfonic acid groups introduced was put together between two porous membranes of 100 μm of polytetrafluoroethylene. A tank was constructed. Hydrochloric acid with a concentration of 15% was introduced into the anode chamber of the tank at a rate of 0.661.7 hours, and L was introduced into the cathode chamber of the tank.
-/Methine 0.85 mol, f concentration 085
A hydrochloric acid solution of N was introduced at a rate of 0.6617 h, a current density of 10 A/6 m2, and a sliding voltage of 4. When electromagnetization was carried out in the OV, product was removed from the cathode chamber at a rate of 0.6 Gl/h. Analysis of the product revealed that the L-instein concentration f/i] was 61m+) and the conversion rate was 95%. Also, no 4t, R impurities were detected, which would be a problem.

Example 2 The same anode and cathode as in Example 1 were used.

An electrolytic cell was assembled with a fluorine-containing resin membrane containing sulfonic acid groups as cation exchange groups with an anode spacing of 35 mrn, and 30% sulfuric acid 2 (1,6617
At the same time, the cathode chamber contains L-/stin sulfate 0.85
A sulfuric acid solution with a concentration of 1,1 containing mol is 0.6
6 l Introduced at a rate of 7 o'clock, current Wr I'll 1
When electrolysis was carried out at 0 A/d+t+2 and % pressure of 35 V, a product was taken out from the cathode chamber at a rate of 0.661/hour. L-nostein was analyzed as a product of darkening.
, 58 mol/l, and the conversion rate was 93%.

Claims (1)

[Claims] ■ An electrolytic cell having an anode chamber and a cathode Y separated by a cation exchange membrane is used, and the anode chamber contains d, mineral acid,
In the examination room: T. - Did you pour some acid solution into each tray of Nustin? +1, T who enjoys understanding, +-
ii Stin's force θ,. 2 Cation exchange membrane is hydrocarbon photocation exchange +1j
= 4, hydrocarbon photocation father J elevation J conversion and fluorine-containing porous! 1 sword 1: compound j exchange with i, fluorine-containing cation exchange membrane method of axis rotation (1) of viscometry. 3 Mine 1! Method of freezing range (1), which is 11M, 1 sip, and 1 tank. 4. Method (1) in which the concentration of mineral acid added to the anode chamber is in the range of 1 to 30. 5, Th, the solution is a current whistle o1~30 A/am
' Method of calculation and calculation range (1) carried out in '.