CA1276144C - Method for oxidation - Google Patents
Method for oxidationInfo
- Publication number
- CA1276144C CA1276144C CA000495857A CA495857A CA1276144C CA 1276144 C CA1276144 C CA 1276144C CA 000495857 A CA000495857 A CA 000495857A CA 495857 A CA495857 A CA 495857A CA 1276144 C CA1276144 C CA 1276144C
- Authority
- CA
- Canada
- Prior art keywords
- organic compound
- diacetone
- alkali
- keto
- electrolysis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H9/00—Compounds containing a hetero ring sharing at least two hetero atoms with a saccharide radical
- C07H9/02—Compounds containing a hetero ring sharing at least two hetero atoms with a saccharide radical the hetero ring containing only oxygen as ring hetero atoms
- C07H9/04—Cyclic acetals
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
- C07C45/30—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with halogen containing compounds, e.g. hypohalogenation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C46/00—Preparation of quinones
- C07C46/02—Preparation of quinones by oxidation giving rise to quinoid structures
- C07C46/04—Preparation of quinones by oxidation giving rise to quinoid structures of unsubstituted ring carbon atoms in six-membered aromatic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/29—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with halogen-containing compounds which may be formed in situ
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Biotechnology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Genetics & Genomics (AREA)
- Molecular Biology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
ABSTRACT
This invention provides an industrially advantageous process of oxidation reaction of an oxidizable organic compound, which comprises a reaction using an alkali hypohalite as an oxidizing agent, wherein an alkali halogenide by-produced is reused and recycled without being discharged. Because the alkali halogenide by-product is recycled, the process has less environmental problems than known process.
This invention provides an industrially advantageous process of oxidation reaction of an oxidizable organic compound, which comprises a reaction using an alkali hypohalite as an oxidizing agent, wherein an alkali halogenide by-produced is reused and recycled without being discharged. Because the alkali halogenide by-product is recycled, the process has less environmental problems than known process.
Description
2~;205-6~8 Oxidation reaction This invention relates to an industrially advan-tageous process of oxidation reaction of an oxidizable organic compound, which comprises a reaction using an alkali hypohalite as an oxidizing agent, wherein an 5 alkali halogenide by-produced is reused and recycled without being discharged.
Alkali hypohalites, such as sodium hypochlorite, are fre~uently used as a reagent for oxidizing an oxidizable organic compound, and examples of such alkali hypohalite oxidation reactions include a reaction involving oxidation of diacetone-L-sorbose to form diacetone-2~keto-L-gulonic acid which is useful as a starting material for the production of vitamin C [Kogyo ~ Zasshi (Gazette of Chemical Society of Japan), 64 (10), 1729 tl961)].
The alkali hypohalites, after oxidation reaction, yield the corresponding alkali halogenide as by-product, and such by-products have been discharged as being contained in the waste fluid left after the objective product of the alkali hypohalite oxidation reaction is separatedj polluting the environment.
: As describèd in the above, the conventional art allows the alkali hal~ogenide by-produced through the oxidation reaction to be~discharged as being contained in the waste fluid, but according to the present invention r~ ~
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.
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alkali halogenide by~produced is reused and recycled without being discharged~
The waste fluid in the conventional method contains additionally high concentration of organic by-products originated from the starting organic compound to be oxidized. From the standpoint of environmental hygiene, it is necessary to reduce the chemical oxygen demand (C~D) component in the waste fluid as far as possible. Also in the alkali hypohalite oxidation reaction, it is necessary to realize the reduction o~ the amount of the above-mentioned organic by-products in order to keep the environment clean because such organic by-products are the main con-stituent of COD component. According to the present invention, the waste fluid is subjected to electrolysis as detailedly mentioned below, whereby COD value is remarkably lowered. The present inventors, in view of the industrial problems involved in the known method using an alkali hypohalite as an oxidiæing agent, carried out extensive investigation for solving such problems of the hitherto known method, and as a result, they have found that the problems involved in the known method are solved by the present invention.
Thus, this invention is concerned with a metllod for oxidation of an oxidizable organic compound, which comprises (1) oxidizing the oxidizable organic compound with alkali hypohalite in an aqueous medium, (2) separat-ing the oxidized organic compound from waste fluid containing alkali halogenide, (3) subjecting the waste fluid to electrolysis to produce alkali hydroxide and halogen, (4) reacting the alkali hydroxide with halogen to produce alkali hypohalite, and (S) recycling the alkali hypohalite as the oxidizing agent.
In the process o~ this invention, the ~irst step is the oxidation reaction of an oxidizable organic .
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-3 24205-6~8 compound with an alkali hypohalite to produce an oxidized organic compound.
The organic compound oxidizable wi~h alkali hypohalite includes a sugar having 3 ko 8 carbon atoms, whereby the sugar having -CHO group ls oxidized to the aorresponding carboxylic acidr the sugar having -CH2OH group is oxidized to the corresponding aldehyde and the sugar having -C~l(OH)CONH2, -CH(NH2)CHO group or -CH(OH)COOH group is oxidized ~o an aldehyde with less carbon atom by one. When resulting aldehyde is further 1~ reacted with alkali hypohalite, the compound is further oxidized into the corresponding carboxylic acid. This is already known before the present invention. Therefore, any one of the aldehyde and the carboxylic acid can be produced according to the reaction condition of the known prior technique.
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Alkali hypohalites, such as sodium hypochlorite, are fre~uently used as a reagent for oxidizing an oxidizable organic compound, and examples of such alkali hypohalite oxidation reactions include a reaction involving oxidation of diacetone-L-sorbose to form diacetone-2~keto-L-gulonic acid which is useful as a starting material for the production of vitamin C [Kogyo ~ Zasshi (Gazette of Chemical Society of Japan), 64 (10), 1729 tl961)].
The alkali hypohalites, after oxidation reaction, yield the corresponding alkali halogenide as by-product, and such by-products have been discharged as being contained in the waste fluid left after the objective product of the alkali hypohalite oxidation reaction is separatedj polluting the environment.
: As describèd in the above, the conventional art allows the alkali hal~ogenide by-produced through the oxidation reaction to be~discharged as being contained in the waste fluid, but according to the present invention r~ ~
:: :
.
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alkali halogenide by~produced is reused and recycled without being discharged~
The waste fluid in the conventional method contains additionally high concentration of organic by-products originated from the starting organic compound to be oxidized. From the standpoint of environmental hygiene, it is necessary to reduce the chemical oxygen demand (C~D) component in the waste fluid as far as possible. Also in the alkali hypohalite oxidation reaction, it is necessary to realize the reduction o~ the amount of the above-mentioned organic by-products in order to keep the environment clean because such organic by-products are the main con-stituent of COD component. According to the present invention, the waste fluid is subjected to electrolysis as detailedly mentioned below, whereby COD value is remarkably lowered. The present inventors, in view of the industrial problems involved in the known method using an alkali hypohalite as an oxidiæing agent, carried out extensive investigation for solving such problems of the hitherto known method, and as a result, they have found that the problems involved in the known method are solved by the present invention.
Thus, this invention is concerned with a metllod for oxidation of an oxidizable organic compound, which comprises (1) oxidizing the oxidizable organic compound with alkali hypohalite in an aqueous medium, (2) separat-ing the oxidized organic compound from waste fluid containing alkali halogenide, (3) subjecting the waste fluid to electrolysis to produce alkali hydroxide and halogen, (4) reacting the alkali hydroxide with halogen to produce alkali hypohalite, and (S) recycling the alkali hypohalite as the oxidizing agent.
In the process o~ this invention, the ~irst step is the oxidation reaction of an oxidizable organic .
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.
.
. : -: - . . , ~ ' - . ..
. .
, , ; .
.... . ~ ' ' .
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-3 24205-6~8 compound with an alkali hypohalite to produce an oxidized organic compound.
The organic compound oxidizable wi~h alkali hypohalite includes a sugar having 3 ko 8 carbon atoms, whereby the sugar having -CHO group ls oxidized to the aorresponding carboxylic acidr the sugar having -CH2OH group is oxidized to the corresponding aldehyde and the sugar having -C~l(OH)CONH2, -CH(NH2)CHO group or -CH(OH)COOH group is oxidized ~o an aldehyde with less carbon atom by one. When resulting aldehyde is further 1~ reacted with alkali hypohalite, the compound is further oxidized into the corresponding carboxylic acid. This is already known before the present invention. Therefore, any one of the aldehyde and the carboxylic acid can be produced according to the reaction condition of the known prior technique.
.
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The alkali hypohalite oxidation of a sugar having 3 to 8 carbon atoms to the oxidized compound is concretely exemplified by oxidation of adonitol to ribose, glyceraldehyde to glyceric acid, glucosamine to arabinose, ~ ~7~
gluconamide to arabinose, arabinose to arabonic acid, ribose to ribonic acid, glucose to gluconic acid, threonic acid 3,4-acetonide to glyceraldehyde acetonide, etc.
The oxidation reaction of the present invention is most preferable for oxidizing the above-mentioned sugar having 3 to 8 carbon atoms to produce a carboxylic acid h~ving 3 to 8 carbon atoms, representatively exemplified by the above-mentioned oxidation of diacetone-L-sorbose to diacetone-2-keto-L-yulonic acid or a salt thereof which is useful as an intermediate for synthesis of vitamin C.
The alakli hypohalite as referred to in the process of this invention is not specifically limited, only if it can be normally used as an oxidizing agent, and is represented by the formula MOX ~wherein M is an alkali metal and X is a halogen atom]. Preferable is sodium or potassium for M and also preferable is chlorine or bromine for X. Therefore, the alkali hypo-halite MOX is exemplified by sodium hypochlorite,potassium hypochlorite, sodium hypobromite, potassium hypobromite, etc. Among others, sodium hypochlorite is the frequently used oxidizing agent and can therefore be applied most favorably to the method of this inven-~5 tion.
An alkali hypohalite MOX, through ~he oxidation reaction by the following equation, is changed into an alkali halogenide MX.
MOX ) MX + [O~
Alkali hypohalite is used in the oxidation reac~
tion usually in an amount of 1.1 to 3.0 times the theorotial amount. The initial concentration o~ MOX in the reaction mixture is preferably S to 13 ~(w/w).
This alkali hypohalite oxidation is advantageously conducted in an aqueous medium, e.g. in water, aqueous ` ,, " . ' '; ; ` ' ' : ~ '' ' ' ,: .' ;: ' '. ' ~
- : . :
:
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methanol, aqueous ethanol, aqueous tetrahydrofuran, aqueous diethyl ether, etc., and is carried out in the presence or absence of a catalyst usually at a temper-ature of about 20 to 100C for 5 minutes to 48 hours.
The catalyst usable in this step is usually metal halide, exemplified by magnesium chloride, magnesium bromide, zinc chloride, ferric chloride, nickel chloride, etc, The amount of the catalyst is usually 10 mg to 1 g per l ~ of ~he reaction mixture.
For example, the oxidation reaction of diacetone-L-sorbose with sodium hypochlorite is carried out in an aqueous medium, preferably in water, using as a catalyst 50 mg to 500 mg of nickel chloride per 1 Q of ~he reaction mixture, at a reaction temperature of about 20 15 to 100C, preferably about 50 to 80C for 10 minutes to 5 hours. The reaction is conducted with or without addition of sodium hydroxide and advantageously carried out with addition of sodium hydroxide in order to avoid decomposition of the hypochlorite, maintaining the reaction mixture alkaline, e,g. pH 10 to 13.
The second step is separation of the oxidized organic compound from waste fluid containing alkali halogenide. Separation is carried out by the conven-tional method. Separation of the oxidized organic compound is usually conducted after neutralization or acidification of the reaction mixture using an acid, preferably aqueous hydrogen halogenide (e.g. HCl, HBr).
After neutralization or acidification, the pH of the mixture is preferably 1 to 4.5, most preferably 1 to 3.
The present invention is advantageously applicable to the case in which the oxidized organic compound is an acid compound, because such an acid compound is easily obtained after neutralization or acidification of the reaction mixture with such an acid as HCl or HBr and the alkali halogenide produced in this neutralization or ~ : . ~ . , .
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acidification step is also usable in the following electrolysis step.
~ eparation or recovery of the objective organic compound is conducted using usual method (e.g. solvent extraction, precipitation, filtration, centrifugation, crystallization, recrystallization, chromatography, etc.). In case the product is diacetone-2-keto-L-gulonic acid, the reaction mixture is neutralized or acidified with hydrochloric acid whereby the objective compound is precipitated, and the resulting diacetone-2-keto-~-gulonic acid is separated by centrifugation or filtration, whereby there is formed a waste fluid containing sodium chloride.
Diacetone-2-keto-L-gulonic acid may be obtained as a salt. Such salts include an inorganic salt (e.g.
sodium salt, potassium salt, calcium salt, etc.) and an organic salt. These salts can be produced through reacting diacetone-2-keto-L-gulonic acid with the corresponding base (e.g. sodium hydroxide, potassium hydroxide, calcium hydroxide,etc.) according to the conventional method. It is preferable to remove nickel chloride used, in advance of separation of the objective product as crystals, so that it can be reused. The removal of nickel chloride is advantageous in terms of protection of electrodes during the below-mentioned electrolysis, and is usually and advantageously conducted by filtra-tion or centrifugation.
The third step is electrolysis of the waste fluid containing alkali halogenide to produce alkali hydroxide and and halogen, whicn is represented by the following equatlon.
MX ~ MOH + X2 :`
. . .
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,, : : . .
. .
The conventional method of electrolysis can be applied to the present electrolysis. As the example of electrolysis, electrolysis of the waste fluid containing sodium chloride is mentioned below.
As is well known, electrolysis of sodium chloride produces chlorine on the side of anode and sodium hydroxide and hydrogen on the side of cathode. With reference to the mèthod of electrolysis, the per se known non-diaphragm and diaphragm electrolytic processes can be adopted,but it is preferable to adopt the diaphragm process.
The electrolysis, in which the anode is a titanium or carbon based electrode and the cathode is a stainless steel or iron based electrode, is carried out for example by passing an electric current through the waste fluid containing sodium chloride formed by the above-described oxidation reaction to thereby produce readily chlorine as well assodium hydroxide and hydrogen. The electrolysis produces the products in such amounts as may be proportionate to the quantity of electricity passed, irrespective of the presence of diaphragm. The reaction temperature does not constitute any great problem in electrolysis, but in view of the fact that this electroly-sis is an exothermic reaction or for the purpose of improving the unit consumption of electric power through increased current efficiency, the reaction temperature of about 75 to 85C is desirable.
The concentration of sodium chloride is a factor involved in the current efficiency, and it is desirable to prepare an aqueous solution of sodium chloride to about 15 to 25% tw/w) of the final concentratlon to subject to electrolysis.
In the present invention, ion exchang0 membrane is advantageously used as a diaphragm. The type of the ion exchange membranes is selected, depending upon the kinds . . . . . . . ..
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of alkali halogenide and alkali hydroxide, the nature and concentration of impurities, etc., and their general-ly suitable examples include NafionO membrane (produced by Du Pont de ~emours), Flemion~ (produced by Asahi Glass Co. of Japan), Aciplex (produced by Asahi Chemical Industry Co. of Japan), etc.
These ion exchange membranes can be used effi-ciently and continuously without being polluted by the CQD component normally contained in not less than about 900 ld ppm in the raw electrolytic solution.
This is because a nascent halogen and a small amount of oxygen generated from the surface of the anode and a hypohalous acid produced in the neighborhood of the electrode oxidize the COD component partially or lS wholly, resulting in releasing out of the system for example as a carbon dioxide gas; the so-called self-cleansing or self-purifying action of them can permit electrolysis to persist, while preventing the progress of pollution of the diaphragm, which is one of the effects provided by this invention. The electrolysis can reduce the COD component in the solution to not more than about 500 ppm.
As the diaphragm in the electrolysis, there can also be used, in addition to the ion exchange membranes, ~5 synthetic or natural conventional type of materials such as asbesto~s memrbanès.s Electrolysis of other alkali halogenides other than sodium chloride can also be conducted in the same way.
The fourth step is reaction of alkali hydroxide with halogen to produce alkali hypohalite. The procedure of producing alkali hypohalite from alkali hydroxide and halogen can be carried out in accordance with the known process, advantageously using counter-current contact process in a tower and batch absorption -. .
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process in a reaction vessel.
In this reaction the alkali hydroxide produced in the above electrolysis is charged in advance into a reaction vessel, and the halogen generated in the electrolytic system is allowed to react with it to thereby produce readily an alkali hypohalite quantita-tively. This reaction is an exothermic reaction, and it is therefore desirable to maintain the reaction system at not higher than about 30C by cooling with cold water, etc. In order to prevent the decomposition the alkali hypohalite thus produced, it is preferable to allow the alkali hydroxide to remain throughout the reaction at a level of more than 0.2% (w/w). For the purpose of this, the reaction solution is normally checked for the concentration of the alkali hydroxide continuously by means of the oxidation-reduction potential measurement method, alkali measurement method, etc. The concentration of the alkali hypohalite and alkali hydroxide is adjusted to the calculated levels to 20 be used recyclingly as an oxidizing agent in the first step.
In the process of this invention, the alkali hypohalite as produced b~ the above fourth step is recycled as an oxidizing agent,which is to be used in ~5 the above-mentioned first step. A specific example of the steps of the above-mentioned process of this inven~
tion is shown in Fig. 1.
Thus, (1) diacetone-L-surbose (DAS) is oxidized with sodium hypochlorite in the presence of sodium hydroxide in an aqueous medium under the catalysis of nickel chloride, (2) nickel chloride is separated, (3) the reaction mixture is neutralized with hydro-chloric acid to produce diacetone-2-keto-L-gulonic acid (DAGA) as crystals, (4~ DAGA is isolated, (5) sodium chloride concentration in mother liquor is adjusted at a . . `. '~. ',. ' : '', .' ' . ~`.' ,' ' . :
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concentration from 15 to 25% (w/v), (6) the sodium chloride solution is electrolyzed to produce hydrogen, chlorine and sodium hydroxide, (7) reacting chlorine and sodium hydroxide to produce sodium hypochlorite,and (8) sodium hypochloride is reused recyclingly. This invention provides an industrially advantageous process for the oxidation reaction using an alkali hypchalite as an oxidizing agent. Thus~ this invention offers the characteristic feature that an alkali halogenide by-produced in the oxidation reaction is subjected toelectrolysis to convert into an alkali hypohalite, which is recycled. This permits the effective utilization of alkali halogenide, such as sodium chloride, which have been so far discarded in the waste reaction fluid, and is advantageous from the standpoint of saving natural resources. At the same time, this, through electroly-sis, can reduce the COD component in the waste reaction 1uid, and is considered advantageous in the aspect of prevention of environmental pollution, as well. Further-more, although the alkali hypohalites are unstablecompounds and must be subjected to an oxidation reaction before their oxidation capacity is deteriorated, this invention, permitting the production of alkali hypo-halites in the continuous process involving the oxida~
tion reaction, is outstandingly advantageous in that the objective reaction can be always carried out with use of the alkali hypohalite in the state o~ its enhanced oxidation capability.
Example Example 1 1) An aqueous sodium-chloride waste fluid containing the COD component as produced in preparing diacetone-2-keto-L-gulonic acid from diacetone-L-sorbose with sodium hypochlorite used as an oxidizing agent was electrolyzed in an electrolytic bath (containing the anode made of .. .. . : .. , , ~ , - ~ ' ~ ' ' ' ' , , , , ~ 12 -titanium and the cathode made of stainless steel) with an electrode surface area of 0.38 m2 being partitioned by the ion exchange membrane (Nafion~ membrane, produced by Du Pont de Nemours Co.) to allow chlorine, and sodium hydroxide and hydrogen, to be formed at the anode and cathode, respectively, followed by synthesis of sodium hypochlorite.
Conditions:
a) Supplied amount of the raw solution (the aqueous sodium chloride waste fluid having average sodium chloride concentration of 293 g/); 6.0 Q/hour b) COD in the raw solution (by the manganese method in accordance with JIS K-0102); 920 ppm c) Reaction temperature; 70 to 80C
d) Current density; 12 A/dm e) Supply of pure water to the cathode . side; 0.6 Q/hour Results:
a) Produced amount of sodium hydroxide; 1.4 ~/hour (average concentration of 417 g/Q) b) Amount of carbon dioxide gas in chlorine; 6% (w/w) c) Sodium chloride concentration of the waste fluid after electrolysis; 216 g/~
(average) d) COD in the waste fluid after electrolysis (by the manganese method in accordance with JIS K-0102); 420 ppm e) Bath voltage 3.2 V
2) To 100 kg of about 30~ (w/w) aqueous solution of diacetone-L-sorbose was added the aqueous sodium hypo-chlorite solution (89 kg as sodium hypochlorite) as obtained previously under 1) in an amount 1.55 times the theoretical amount (about 89 kg as hypochlorous acid), and the oxidation reaction was allowed to proceed in the ::
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':
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' ~' ~ ' '' , presence of nickel chloride (0.24 g/~) used as a catalyst at 60C for 2 hours. This reaction solution showed initially an alkalinity as high as a pH of not less than 13, but a pH of 10 to 11 at the conclusion of the reaction. The reaction solution, when treated with hydrochloric acid, crystallized out the product, and the resulting crystals were separated to give 105 kg (yield of 93.5%) of white diacetone-2-keto-L-gulonic acidO
Example 2 The sodium hypochlorite solution (82 kg as sodium hypochlorite) as obtained by the procedure described under the item 1) of Example 1 was added continuously to 100 kg of about 40% (w/w) aqueous solution of diacetone-L-sorbose over the period of about 2 hours, and a bath reaction was carried out at 60 to 70C. By the addition of hydrochloric acid, diacetone-2-keto-L-gulonic acid was allowed to crystallize out of the resulting reaction solution and separated by filtration to give 104 kg (yield of 92.6%) of white diacetone-2-keto-L-gulonic ~0 acid.
Example 3 The sodium hypochlorite solution (74.5 kg as sodium hypochlorite) as obtained by the procedure described under the item 1) of Example 1 was added to 100 kg of about 40% (w/w) aqueous solution of diacetone-L-sorbose, and nickel chloride (0.36 g/~) was added to the mixture as a catalyst, followed by reaction at 60 to 70C for 2 hours. From the resulting reaction solution, diacetone-2-keto-L-gulonic acid was allowed to crystallize out and separated by filtration.
The separated mother liquor containing sodium chloride was used as a raw solution for electrolysis in the production of the sodium hypochlorite solution in accordance with Example 1. While the resulting sodium hypochlorite solution was used and recycled as an - ' ' . ' .- ' ' . . '' . ,: ' . : ' .' . ,. ~: ' ' ' '~ ' ~ , ~ . , .
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oxidizing agent, the above reaction was continued. This reaction was repeated continuously ten times, and there were obtained the results as shown in the ~ollowing table.
5 ~ time 2 4 6 8 10 _ Yield (%~ of diacetone- 94 1 95 1 93 994 2 94 2 2-keto gulonic acid CUrrent efficiency (~) 92 5 91 6 94 892.9 94.2 in electrolysis Change in voltage of electrolytic bath 1.1 1.0 1.0 1.0 1.0 (initial value = 1.0) :
~ :
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gluconamide to arabinose, arabinose to arabonic acid, ribose to ribonic acid, glucose to gluconic acid, threonic acid 3,4-acetonide to glyceraldehyde acetonide, etc.
The oxidation reaction of the present invention is most preferable for oxidizing the above-mentioned sugar having 3 to 8 carbon atoms to produce a carboxylic acid h~ving 3 to 8 carbon atoms, representatively exemplified by the above-mentioned oxidation of diacetone-L-sorbose to diacetone-2-keto-L-yulonic acid or a salt thereof which is useful as an intermediate for synthesis of vitamin C.
The alakli hypohalite as referred to in the process of this invention is not specifically limited, only if it can be normally used as an oxidizing agent, and is represented by the formula MOX ~wherein M is an alkali metal and X is a halogen atom]. Preferable is sodium or potassium for M and also preferable is chlorine or bromine for X. Therefore, the alkali hypo-halite MOX is exemplified by sodium hypochlorite,potassium hypochlorite, sodium hypobromite, potassium hypobromite, etc. Among others, sodium hypochlorite is the frequently used oxidizing agent and can therefore be applied most favorably to the method of this inven-~5 tion.
An alkali hypohalite MOX, through ~he oxidation reaction by the following equation, is changed into an alkali halogenide MX.
MOX ) MX + [O~
Alkali hypohalite is used in the oxidation reac~
tion usually in an amount of 1.1 to 3.0 times the theorotial amount. The initial concentration o~ MOX in the reaction mixture is preferably S to 13 ~(w/w).
This alkali hypohalite oxidation is advantageously conducted in an aqueous medium, e.g. in water, aqueous ` ,, " . ' '; ; ` ' ' : ~ '' ' ' ,: .' ;: ' '. ' ~
- : . :
:
.
~ ~t7~
methanol, aqueous ethanol, aqueous tetrahydrofuran, aqueous diethyl ether, etc., and is carried out in the presence or absence of a catalyst usually at a temper-ature of about 20 to 100C for 5 minutes to 48 hours.
The catalyst usable in this step is usually metal halide, exemplified by magnesium chloride, magnesium bromide, zinc chloride, ferric chloride, nickel chloride, etc, The amount of the catalyst is usually 10 mg to 1 g per l ~ of ~he reaction mixture.
For example, the oxidation reaction of diacetone-L-sorbose with sodium hypochlorite is carried out in an aqueous medium, preferably in water, using as a catalyst 50 mg to 500 mg of nickel chloride per 1 Q of ~he reaction mixture, at a reaction temperature of about 20 15 to 100C, preferably about 50 to 80C for 10 minutes to 5 hours. The reaction is conducted with or without addition of sodium hydroxide and advantageously carried out with addition of sodium hydroxide in order to avoid decomposition of the hypochlorite, maintaining the reaction mixture alkaline, e,g. pH 10 to 13.
The second step is separation of the oxidized organic compound from waste fluid containing alkali halogenide. Separation is carried out by the conven-tional method. Separation of the oxidized organic compound is usually conducted after neutralization or acidification of the reaction mixture using an acid, preferably aqueous hydrogen halogenide (e.g. HCl, HBr).
After neutralization or acidification, the pH of the mixture is preferably 1 to 4.5, most preferably 1 to 3.
The present invention is advantageously applicable to the case in which the oxidized organic compound is an acid compound, because such an acid compound is easily obtained after neutralization or acidification of the reaction mixture with such an acid as HCl or HBr and the alkali halogenide produced in this neutralization or ~ : . ~ . , .
. ' ' - ` : :. . . :. : :
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~.2~
acidification step is also usable in the following electrolysis step.
~ eparation or recovery of the objective organic compound is conducted using usual method (e.g. solvent extraction, precipitation, filtration, centrifugation, crystallization, recrystallization, chromatography, etc.). In case the product is diacetone-2-keto-L-gulonic acid, the reaction mixture is neutralized or acidified with hydrochloric acid whereby the objective compound is precipitated, and the resulting diacetone-2-keto-~-gulonic acid is separated by centrifugation or filtration, whereby there is formed a waste fluid containing sodium chloride.
Diacetone-2-keto-L-gulonic acid may be obtained as a salt. Such salts include an inorganic salt (e.g.
sodium salt, potassium salt, calcium salt, etc.) and an organic salt. These salts can be produced through reacting diacetone-2-keto-L-gulonic acid with the corresponding base (e.g. sodium hydroxide, potassium hydroxide, calcium hydroxide,etc.) according to the conventional method. It is preferable to remove nickel chloride used, in advance of separation of the objective product as crystals, so that it can be reused. The removal of nickel chloride is advantageous in terms of protection of electrodes during the below-mentioned electrolysis, and is usually and advantageously conducted by filtra-tion or centrifugation.
The third step is electrolysis of the waste fluid containing alkali halogenide to produce alkali hydroxide and and halogen, whicn is represented by the following equatlon.
MX ~ MOH + X2 :`
. . .
: . ~. : .: . . .
- . ~ ' :. : ~ ' : .' ` .. :
,, : : . .
. .
The conventional method of electrolysis can be applied to the present electrolysis. As the example of electrolysis, electrolysis of the waste fluid containing sodium chloride is mentioned below.
As is well known, electrolysis of sodium chloride produces chlorine on the side of anode and sodium hydroxide and hydrogen on the side of cathode. With reference to the mèthod of electrolysis, the per se known non-diaphragm and diaphragm electrolytic processes can be adopted,but it is preferable to adopt the diaphragm process.
The electrolysis, in which the anode is a titanium or carbon based electrode and the cathode is a stainless steel or iron based electrode, is carried out for example by passing an electric current through the waste fluid containing sodium chloride formed by the above-described oxidation reaction to thereby produce readily chlorine as well assodium hydroxide and hydrogen. The electrolysis produces the products in such amounts as may be proportionate to the quantity of electricity passed, irrespective of the presence of diaphragm. The reaction temperature does not constitute any great problem in electrolysis, but in view of the fact that this electroly-sis is an exothermic reaction or for the purpose of improving the unit consumption of electric power through increased current efficiency, the reaction temperature of about 75 to 85C is desirable.
The concentration of sodium chloride is a factor involved in the current efficiency, and it is desirable to prepare an aqueous solution of sodium chloride to about 15 to 25% tw/w) of the final concentratlon to subject to electrolysis.
In the present invention, ion exchang0 membrane is advantageously used as a diaphragm. The type of the ion exchange membranes is selected, depending upon the kinds . . . . . . . ..
. . ' . ~ , . . .
.
.
:- .. : ~',. ...
., . ~ -,, ~ . . `
~ ;Z'7~
of alkali halogenide and alkali hydroxide, the nature and concentration of impurities, etc., and their general-ly suitable examples include NafionO membrane (produced by Du Pont de ~emours), Flemion~ (produced by Asahi Glass Co. of Japan), Aciplex (produced by Asahi Chemical Industry Co. of Japan), etc.
These ion exchange membranes can be used effi-ciently and continuously without being polluted by the CQD component normally contained in not less than about 900 ld ppm in the raw electrolytic solution.
This is because a nascent halogen and a small amount of oxygen generated from the surface of the anode and a hypohalous acid produced in the neighborhood of the electrode oxidize the COD component partially or lS wholly, resulting in releasing out of the system for example as a carbon dioxide gas; the so-called self-cleansing or self-purifying action of them can permit electrolysis to persist, while preventing the progress of pollution of the diaphragm, which is one of the effects provided by this invention. The electrolysis can reduce the COD component in the solution to not more than about 500 ppm.
As the diaphragm in the electrolysis, there can also be used, in addition to the ion exchange membranes, ~5 synthetic or natural conventional type of materials such as asbesto~s memrbanès.s Electrolysis of other alkali halogenides other than sodium chloride can also be conducted in the same way.
The fourth step is reaction of alkali hydroxide with halogen to produce alkali hypohalite. The procedure of producing alkali hypohalite from alkali hydroxide and halogen can be carried out in accordance with the known process, advantageously using counter-current contact process in a tower and batch absorption -. .
. ~ . . .
- . . ~ :
- . ' , :
, - . , ,. :.
. ` ~ '- ' ` ' ' . .
process in a reaction vessel.
In this reaction the alkali hydroxide produced in the above electrolysis is charged in advance into a reaction vessel, and the halogen generated in the electrolytic system is allowed to react with it to thereby produce readily an alkali hypohalite quantita-tively. This reaction is an exothermic reaction, and it is therefore desirable to maintain the reaction system at not higher than about 30C by cooling with cold water, etc. In order to prevent the decomposition the alkali hypohalite thus produced, it is preferable to allow the alkali hydroxide to remain throughout the reaction at a level of more than 0.2% (w/w). For the purpose of this, the reaction solution is normally checked for the concentration of the alkali hydroxide continuously by means of the oxidation-reduction potential measurement method, alkali measurement method, etc. The concentration of the alkali hypohalite and alkali hydroxide is adjusted to the calculated levels to 20 be used recyclingly as an oxidizing agent in the first step.
In the process of this invention, the alkali hypohalite as produced b~ the above fourth step is recycled as an oxidizing agent,which is to be used in ~5 the above-mentioned first step. A specific example of the steps of the above-mentioned process of this inven~
tion is shown in Fig. 1.
Thus, (1) diacetone-L-surbose (DAS) is oxidized with sodium hypochlorite in the presence of sodium hydroxide in an aqueous medium under the catalysis of nickel chloride, (2) nickel chloride is separated, (3) the reaction mixture is neutralized with hydro-chloric acid to produce diacetone-2-keto-L-gulonic acid (DAGA) as crystals, (4~ DAGA is isolated, (5) sodium chloride concentration in mother liquor is adjusted at a . . `. '~. ',. ' : '', .' ' . ~`.' ,' ' . :
-:
~ ~7~
concentration from 15 to 25% (w/v), (6) the sodium chloride solution is electrolyzed to produce hydrogen, chlorine and sodium hydroxide, (7) reacting chlorine and sodium hydroxide to produce sodium hypochlorite,and (8) sodium hypochloride is reused recyclingly. This invention provides an industrially advantageous process for the oxidation reaction using an alkali hypchalite as an oxidizing agent. Thus~ this invention offers the characteristic feature that an alkali halogenide by-produced in the oxidation reaction is subjected toelectrolysis to convert into an alkali hypohalite, which is recycled. This permits the effective utilization of alkali halogenide, such as sodium chloride, which have been so far discarded in the waste reaction fluid, and is advantageous from the standpoint of saving natural resources. At the same time, this, through electroly-sis, can reduce the COD component in the waste reaction 1uid, and is considered advantageous in the aspect of prevention of environmental pollution, as well. Further-more, although the alkali hypohalites are unstablecompounds and must be subjected to an oxidation reaction before their oxidation capacity is deteriorated, this invention, permitting the production of alkali hypo-halites in the continuous process involving the oxida~
tion reaction, is outstandingly advantageous in that the objective reaction can be always carried out with use of the alkali hypohalite in the state o~ its enhanced oxidation capability.
Example Example 1 1) An aqueous sodium-chloride waste fluid containing the COD component as produced in preparing diacetone-2-keto-L-gulonic acid from diacetone-L-sorbose with sodium hypochlorite used as an oxidizing agent was electrolyzed in an electrolytic bath (containing the anode made of .. .. . : .. , , ~ , - ~ ' ~ ' ' ' ' , , , , ~ 12 -titanium and the cathode made of stainless steel) with an electrode surface area of 0.38 m2 being partitioned by the ion exchange membrane (Nafion~ membrane, produced by Du Pont de Nemours Co.) to allow chlorine, and sodium hydroxide and hydrogen, to be formed at the anode and cathode, respectively, followed by synthesis of sodium hypochlorite.
Conditions:
a) Supplied amount of the raw solution (the aqueous sodium chloride waste fluid having average sodium chloride concentration of 293 g/); 6.0 Q/hour b) COD in the raw solution (by the manganese method in accordance with JIS K-0102); 920 ppm c) Reaction temperature; 70 to 80C
d) Current density; 12 A/dm e) Supply of pure water to the cathode . side; 0.6 Q/hour Results:
a) Produced amount of sodium hydroxide; 1.4 ~/hour (average concentration of 417 g/Q) b) Amount of carbon dioxide gas in chlorine; 6% (w/w) c) Sodium chloride concentration of the waste fluid after electrolysis; 216 g/~
(average) d) COD in the waste fluid after electrolysis (by the manganese method in accordance with JIS K-0102); 420 ppm e) Bath voltage 3.2 V
2) To 100 kg of about 30~ (w/w) aqueous solution of diacetone-L-sorbose was added the aqueous sodium hypo-chlorite solution (89 kg as sodium hypochlorite) as obtained previously under 1) in an amount 1.55 times the theoretical amount (about 89 kg as hypochlorous acid), and the oxidation reaction was allowed to proceed in the ::
- . ,. ~ .
,: ' .
':
- ' ' ' ' .
- . :: :
' ~' ~ ' '' , presence of nickel chloride (0.24 g/~) used as a catalyst at 60C for 2 hours. This reaction solution showed initially an alkalinity as high as a pH of not less than 13, but a pH of 10 to 11 at the conclusion of the reaction. The reaction solution, when treated with hydrochloric acid, crystallized out the product, and the resulting crystals were separated to give 105 kg (yield of 93.5%) of white diacetone-2-keto-L-gulonic acidO
Example 2 The sodium hypochlorite solution (82 kg as sodium hypochlorite) as obtained by the procedure described under the item 1) of Example 1 was added continuously to 100 kg of about 40% (w/w) aqueous solution of diacetone-L-sorbose over the period of about 2 hours, and a bath reaction was carried out at 60 to 70C. By the addition of hydrochloric acid, diacetone-2-keto-L-gulonic acid was allowed to crystallize out of the resulting reaction solution and separated by filtration to give 104 kg (yield of 92.6%) of white diacetone-2-keto-L-gulonic ~0 acid.
Example 3 The sodium hypochlorite solution (74.5 kg as sodium hypochlorite) as obtained by the procedure described under the item 1) of Example 1 was added to 100 kg of about 40% (w/w) aqueous solution of diacetone-L-sorbose, and nickel chloride (0.36 g/~) was added to the mixture as a catalyst, followed by reaction at 60 to 70C for 2 hours. From the resulting reaction solution, diacetone-2-keto-L-gulonic acid was allowed to crystallize out and separated by filtration.
The separated mother liquor containing sodium chloride was used as a raw solution for electrolysis in the production of the sodium hypochlorite solution in accordance with Example 1. While the resulting sodium hypochlorite solution was used and recycled as an - ' ' . ' .- ' ' . . '' . ,: ' . : ' .' . ,. ~: ' ' ' '~ ' ~ , ~ . , .
- . .
~ ~t7~
oxidizing agent, the above reaction was continued. This reaction was repeated continuously ten times, and there were obtained the results as shown in the ~ollowing table.
5 ~ time 2 4 6 8 10 _ Yield (%~ of diacetone- 94 1 95 1 93 994 2 94 2 2-keto gulonic acid CUrrent efficiency (~) 92 5 91 6 94 892.9 94.2 in electrolysis Change in voltage of electrolytic bath 1.1 1.0 1.0 1.0 1.0 (initial value = 1.0) :
~ :
.
. ~ :
... . - . .. .
: .. . . . . . .
.. ~ - - . : - . . . . :
. . ,,:.,, ;:; ~` . ' :
' - . ' ~
: - : . .
.
. .
Claims (10)
1. A method for oxidation of an oxidizable organic compound which comprises (1) oxidizing the oxidizable organic compound with alkali hypohalite in an aqueous medium, (2) separating the oxidized organic compound from waste fluid containing alkali halogenide, (3) subjecting the waste fluid to electrolysis to produce alkali hydroxide and halogen, (4) reacting the alkali hydroxide with halogen to produce alkali hypohalite, and (5) recycling the alkali hypohalite as the oxidizing agent; wherein the oxidizable organic compound is a sugar having 3 to 8 carbon atoms and a -CHO group and the oxidized organic compound is a corresponding carboxylic acid; the oxidizable organic compound is a sugar having 3 to 8 carbon atoms and a -CH2OH group and the oxidized organic compound is a corresponding aldehyde; or the oxidizable organic compound is a sugar having 3 to 8 atoms and a CH(OH)CONH2, -CH(NH2)CHO or -CH(OH)COOH group and the oxidized organic compound is an aldehyde with one less carbon atom than the starting compound.
2. A method according to Claim 1, wherein the oxidizable organic compound is a sugar having 3 to 8 carbon atoms and the oxidized compound is a corresponding carboxylic acid having 3 to 8 carbon atoms.
3. A method according to Claim 1, wherein the oxidizable organic compound is diacetone-L-sorbose and the oxidized organic compound is diacetone-2-keto-L-gulonic acid or a salt thereof.
4. A method according to Claim 1, wherein the oxidizable organic compound is diacetone-L-sorbose, alkali hypohalite is sodium hypochlorite and the oxidized organic compound is diacetone-2-keto-L-gulonic acid or a salt thereof.
5. A method according to Claim 4, wherein electrolysis is conducted at the temperature from 75 to 85°C.
6. A method according to Claim 4, wherein electrolysis is conducted at the sodium chloride concentration from 15 to 25%
(w/v).
(w/v).
7. A proaess for the production of diacetone-2-keto-L-gulonic acid or a salt thereof, which process comprises:
(1) oxidizing diacetone L-sorbose with sodium hypochlorite in an aqueous medium to produce sodium salt of diacetone-2-keto-L-gulonic acid in the aqueous medium, (2) acidifying the reaction mixture with hydrochloric acid to precipitate diacetone-2-keto-L-gulonic acid and separating the precipitated acid from the reaction mixture, thereby forming a waste fluid containing sodium chloride, (3) subjecting the waste fluid to eleatrolysls to produae sodium hydroxide and chlorine, (4) reacting sodium hydroxide and chlorine produced in step (3) to produce sodium hypochlorite, (5) recycling sodium hypochlorite produced in step (5) into step (1), and (6) if required, converting diacetone-2-keto-L-gulonic acid produced in step (2) into its salt.
(1) oxidizing diacetone L-sorbose with sodium hypochlorite in an aqueous medium to produce sodium salt of diacetone-2-keto-L-gulonic acid in the aqueous medium, (2) acidifying the reaction mixture with hydrochloric acid to precipitate diacetone-2-keto-L-gulonic acid and separating the precipitated acid from the reaction mixture, thereby forming a waste fluid containing sodium chloride, (3) subjecting the waste fluid to eleatrolysls to produae sodium hydroxide and chlorine, (4) reacting sodium hydroxide and chlorine produced in step (3) to produce sodium hypochlorite, (5) recycling sodium hypochlorite produced in step (5) into step (1), and (6) if required, converting diacetone-2-keto-L-gulonic acid produced in step (2) into its salt.
8. A process according to Claim 7, wherein the oxidation of step (1) is carried out in the presence of nickel chloride catalyst and the nickel chloride catalyst is separated from the reaction mixture before the reaction mixture is acidified to precipitate diacetone-2-keto-L-gulonic acid.
9. A process according to Claim 8, wherein electrolysis is conducted at the temperature from 75 to 85°C.
10. A process according to Claim 7, 8 or 9, wherein electrolysis is conducted at the sodium chloride concentration from 15 to 25% (w/v).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP247193/1984 | 1984-11-22 | ||
| JP24719384A JPS61132502A (en) | 1984-11-22 | 1984-11-22 | Oxidation reaction process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1276144C true CA1276144C (en) | 1990-11-13 |
Family
ID=17159825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000495857A Expired - Lifetime CA1276144C (en) | 1984-11-22 | 1985-11-21 | Method for oxidation |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS61132502A (en) |
| CN (1) | CN1005973B (en) |
| CA (1) | CA1276144C (en) |
| DE (1) | DE3540747A1 (en) |
| DK (1) | DK528485A (en) |
| GB (1) | GB2167416B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK324586A (en) * | 1985-07-15 | 1987-01-16 | Takeda Chemical Industries Ltd | PROCEDURE FOR IMPLEMENTING OXIDATION REACTIONS |
| EP0838435A1 (en) * | 1996-10-25 | 1998-04-29 | Kvaerner Process Technology Limited | Process and plant for treating an aqueous waste stream containing alkali metal carboxylates |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1295535B (en) * | 1966-10-14 | 1969-05-22 | Bayer Ag | Process for the electrochemical production of olefin oxides from olefins |
| US4008133A (en) * | 1974-09-20 | 1977-02-15 | The Lummus Company | Production of epoxy compounds from olefinic compounds |
| US4076762A (en) * | 1977-04-29 | 1978-02-28 | Engelhard Minerals & Chemicals Corporation | Continuous process for the removal of other hydrocarbons from saturated aliphatic hydrocarbons |
| US4154771A (en) * | 1977-05-26 | 1979-05-15 | General Electric Company | Process of forming phosphorus containing block polymers of polyphenylene oxide |
-
1984
- 1984-11-22 JP JP24719384A patent/JPS61132502A/en active Pending
-
1985
- 1985-11-15 DK DK528485A patent/DK528485A/en not_active Application Discontinuation
- 1985-11-16 DE DE19853540747 patent/DE3540747A1/en not_active Withdrawn
- 1985-11-18 CN CN85108493.1A patent/CN1005973B/en not_active Expired
- 1985-11-21 CA CA000495857A patent/CA1276144C/en not_active Expired - Lifetime
- 1985-11-21 GB GB08528629A patent/GB2167416B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85108493A (en) | 1986-05-10 |
| GB8528629D0 (en) | 1985-12-24 |
| JPS61132502A (en) | 1986-06-20 |
| DK528485D0 (en) | 1985-11-15 |
| DE3540747A1 (en) | 1986-05-28 |
| DK528485A (en) | 1986-05-23 |
| GB2167416B (en) | 1988-01-27 |
| GB2167416A (en) | 1986-05-29 |
| CN1005973B (en) | 1989-12-06 |
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