JPS59210028A - Method for oxidation - Google Patents

Abstract

PURPOSE:To obtain an oxygen-containing compound, e.g. an aldehyde or carboxylic acid, by adding nitric acid successively to an aqueous solution of a nonoxidizing strong acid to form an aqueous oxidizing agent composition of very low nitric acid concentration, and oxidizing an active alkyl compound, compound containing a c=c bond, etc. with the resultant oxidizing agent composition. CONSTITUTION:Nitric acid is successively added to an aqueous solution of a nonoxidizing strong acid, e.g. hydrochloric acid or sulfuric acid, in 1-5mol/kg initial concentration to give an aqueous oxidizing agent composition in <=1% nitric acid concentration, which is used to oxidize an organic substrate, e.g. xylene, durene or tetrahydrophthalic acid anhydride or cyclohexene except glyoxal, to afford the aimed oxygen-containing organic compound, e.g. an aldehyde or carboxylic acid. The reaction temperature is 0-100 deg.C. Nitrogen oxide corresponding to the consumed nitric acid emerges into the vapor phase part of a reactor, but the nitrogen oxide can be recovered as nitric acid by the oxidation with air, and passing the nitrogen oxide through a water absorption column, etc. EFFECT:The aimed aqueous solution of the aimed substance containing almost no remaining nitric acid is obtained.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for oxidizing organic compounds,
It can be used to produce oxygen-containing organic compounds such as aldehydes and carboxylic acids.

(Prior Art) One of the oxidation methods in the field of organic chemistry is the nitric acid oxidation method.

For example, according to Nishi Toiso Patent No. 932369, a highly concentrated glyoxylic acid aqueous solution 7r can be obtained by oxidizing cryoxal with 30 to 50% (wt%) nitric acid.

Nitric acid oxidation is also used to oxidize active alkyl compounds and carbon-carbon compounds.

Examples of active alkyl compounds include alkylcarbonyl compounds (aldehydes and ketones) and aromatic I-chain alkyl compounds. In these compounds, the carbon-hydrogen bond of the alpha carbon atom -1- adjacent to the carbonyl group or aromatic nucleus is cleaved to form a carbon-oxygen bond, resulting in 7 lutehi+" yacarboxylic acid. It is trimelinated from acetaldehydone. An example of nitric acid oxidation of a carbon double bond compound is tetrahydrophthal, where the carbon carbon bond is broken and a carbon oxygen bond is formed to produce butane tetracarboxylic acid.

The nitric acid concentration used in these nitric acid oxidation reactions varies. For example, Yoshibe Ogata, Oxidation and Return of Organic Compounds (Nankodo), p. From the numerous examples shown in 436-452, it can be as low as 5-15%, and as high as 90% for one island. There seems to be no known example of oxidation occurring at a satisfactory rate at an extremely low concentration of nitric acid, such as 1% or less; Nitric acid is used.

Nitric acid is often used by a sequential addition method such as dropwise addition, or it is usually present in the reaction solution at a concentration of around 5% or more. Example (1 Japanese Patent Publication No. 51/1944 2944
1 states that it is 5 to 7%.

If a mixture containing a significant amount of nitric acid is obtained in this way, purification treatment is required, but if it is difficult to apply distillation or crystallization methods, ion exchange resin treatment, electrodialysis, and cost-effective treatment are necessary.
・Special purification methods with high levels of The purification process also resulted in the loss of some of the target product and residual nitric acid.

Sulfuric acid, hydrochloric acid,
A method is known in which the reaction is accelerated by the presence of a compound selected from the group consisting of phosphoric acid and aluminum nitrate (Japanese Unexamined Patent Publication No. 103517/1983).

These substances are chopped into glyoxal and are usually 0.02~
The use of 0.2 mol of unreacted glyoxal reduces unreacted glyoxal and increases the yield of glyoxylic acid. There was no particular difference from conventional nitric acid oxidation in that the concentration was 5% 1] 1 or more during the dropping reaction.

An oxidizing agent composition made by mixing 1 volume of concentrated nitric acid and 3 volumes of concentrated hydrochloric acid has been known for a long time as HNOl-3HC.
1-CQ +NOC, 6+-21-103←
22 Contains nascent chlorine and nitrosyl chloride (has strong oxidation solubility.Also, dilute aqua regia is diluted with aqua regia, and inverted aqua regia with 3 nitric acid and 1 hydrochloric acid. Water is also known, but it also contains minerals such as metals and ores, including ordinary aqua regia.
Its use was limited to as an oxidizing solubilizer in the field of biology.

Thus, the known aqueous oxidizing agent t11 containing nitric acid and hydrochloric acid
All of the products contained a high concentration of nitric acid, and none of them were used in the reaction to produce oxygen-containing organic compounds from active alkyl compounds or double bond compounds. Therefore, using a nitrate acid mixture, a reaction mixture with a very low concentration of residual sulfuric acid can be directly prepared. There is no known oxidation method.

(Objective of the invention) Wood sprouting is reduced to several percent or more than that required by the known nitric acid oxidation method (compared to 1% or less, which is extremely low, for example, Ii'
1,11 at a nitric acid concentration of 0.1% or higher
, 17, the organic group τ1 is oxidized to obtain an oxygen-containing organic compound at a reaction rate of less than 17. This method has the advantage of eliminating the step of removing nitric acid from the reaction mixture and eliminating nitric acid loss.

(Structure of the Invention) The present inventor uses nitric acid as an oxidation source, and instead of directly reacting it with an organic substrate, it is added sequentially to a non-oxidizing strong acid aqueous solution so that the nitric acid concentration is 1% or more. The aqueous oxidant composition υ) formed in the system oxidizes the organic substrate.
It was discovered that an oxidizing agent composition can be obtained at a rate of 1 liter while keeping the concentration of octopus acid in the system at an extremely low concentration of 1 q (non-oxidizing strong acid). A strong oxidizing acid is hydrochloric acid or the typical σ).
Strong acids (pK a
<0) of perchloric acid. J: :) Non-oxidizing acids can be used as usual.3.

Since there are many different types and concentrations of acids,
1.A non-oxidizing strong acid, water,
Oxidizing agent composition III starting with nitric acid produces an oxidizing species more powerful than nitric acid itself (
・It seems that From this point of view, non-acid [H+1
1.The concentration of strong acid is 11 (mol/lz in g) of oxidizing agent composition 11 (g).
There are no numbers. As the water in the nitric acid is successively added, the concentration of the nitric acid decreases, or at the end of the reaction, the concentration of nitric acid decreases.
It is preferable that the ratio is 7 mol/1<g or more, and it is preferably maintained immediately at 0.5 mol/Kg or more even for about 1 hour. This limit concentration can be determined experimentally by checking the nitric acid concentration in the reaction solution.

In the case of sulfuric acid, there is no need to increase the sensitivity to an unnecessarily high level. 3. In the case of hydrochloric acid, which has a different function as shown in FIG.
Q mol/Kg or more, which is also a practical upper limit. After all, the preferred initial concentration is about 1 to 5 mol/g. This value is more than 6 times the concentration of nitric acid (1% or less) that is present in the system after being dropped.

Hydrochloric acid is also a non-oxidizing strong acid, and it is easily obtained as a by-product of the mineralization reaction. 4
] It is most preferable in that it improves the rate and can be removed by evaporation if desired.

Not only weak acids such as acetic acid but also moderately strong acids such as phosphoric acid do not have the effect of the present invention of reducing the nitric acid concentration in the reaction solution.

((Sequential addition of +l'i acid)) Considering the objective 1-1 of the present invention, which is to proceed with the reaction at a low nitric acid concentration, the composition itself containing a high concentration of nitric acid, such as sewage, is used as it is. In order to keep the nitric acid concentration as low as possible and use the concentrations of hydrochloric acid and sulfuric acid effectively, nitric acid is dropped into the aqueous solution containing the substrate and i'sA acid and sulfuric acid.Of course, y+゛i :il·'' may be added sequentially.

As a result, the reaction is carried out with a very small amount of the oxidizing agent composition equivalently to the substrate, and the consumed oxidized paris is separated from the nitric acid successively added and the non-oxidizing strong acid present in large amounts in the system.
Live 1f. The non-oxidizing strong acid present in a relatively large amount immediately converts nitric acid into an oil oxidizer composition and quickly oxidizes the substrate, making it easy to maintain the nitric acid concentration in the system at 1% or less. High concentration similar to conventional technology, e.g. 40-50
Even if 1% nitric acid is added dropwise, the nitric acid concentration in the reaction solution is about 1% higher than 0.019a.

(Presence (many substrates)) The above oxidation method is based on 1, which was discovered regarding the reaction of oxidizing an oxygen-containing organic compound to an oxygen-containing organic compound at a higher oxidation stage. Examples include reactions to obtain carbonyl compounds from carphones, acids, and alcohols.Reactions to obtain carbonyl compounds from cryoxal to cryoxylic acid, from henzin to hibenonyl, etc. It can also be used for the oxidation of active alkyl compounds.When oxidizing alkylcarbonyl compounds such as artechite and ketones, the argyl group is oxidized next to the carbonyl (α
- position). An example is the formation of cryoxal from acetaldehyde. The alkyl group in the aromatic side chain is also oxidized at the viscous α-position, producing aromatic artefacts and aromatic carboxylic acids.

Kingfishers, Huidokumen, Duren, Hiss (3
The methyl group can be oxidized such as 4-dimethylphenyl)ethane. The side chain argyl group of an aromatic nucleus having a 21-group base, such as p-21-rotoluene, is less likely to be oxidized than those listed in IIG.

The oxidation of compounds with carbon-carbon double bonds can also be carried out by the method of the present invention.
/ Kuro ＼ xeno, kinoline, etc.
Examples of white are i-J.

(I1 Portion) Nitric acid is used in the conventional nitric acid oxidation method: Same as J6. J
, Calcium, product'e1, concentration, use of added IJ11 loss, for example, 11 industrial use after 45 zo (ll"i acid 4, anti-1,1", drops in skin irritation). .

(71) Make them respond. The ability of nitric acid to react with acid 1' is transferred to a non-acid 11Z strong acid (dissolved in a water-based oxidation product made with 1111), and the organic parts are quickly oxidized.
, /iii 1% of the nitric oxide (removed 1°): The nitrogen oxide that is consumed comes to the gas phase of the vessel at 111.

The nitrogen oxide in the off-gas is empty/, IC. Oxidation, water absorption tower 4
・Publicly known as pass/f)) It can be recovered as nitric acid using method 7.

(Reaction 15 conditions) The reaction i'iirj degree is the group I, r! J and [] things; koLi
'fi j;Finally, I've made my choice.

From a range of 0 to + 0 0'C, the progress of j-1 and F-2, which are known for the generation of scum and heat, can be confirmed. 6・ζ1
! - Is the description in F about dropping nitric acid while keeping it constant? We also looked at actual data on cryoxylic acid, including cryoxylic acid. Are you at 1?
G゛ also applies to other cases of J and Igo↓. That is, at the end of the dropping, the concentration of nitric acid in the reaction solution does not exceed 5%, or more than 2% or 1%. Nitric acid concentration is i
i: Iij lower end history (after 1 hour, it usually reaches 0005-003%, especially rll, production, etc., without any need for residual pre-11 concentration of cryoxyl of 01% or less) In the case of conventional nitric acid oxidation, in which an acid solution is obtained, glyoxal-
(The rate itself is difficult to move -12, and after the drop is completed, so
``C I・'11 degrees: F?'tll+'+'t L
In the case of the present invention, it is not necessary to ripen at elevated temperature.

In the reaction, a known initiator such as sulfuric acid, chloride, etc. can be used, or alumina, vanosic acid, ammonium chloride, copper powder, etc. can be added to the reaction.

(Actions and Effects of the Invention) When nitric acid is dropped into an aqueous solution containing a large amount of non-oxidizing strong acid, a strong oxidizing agent composition is formed, and the nitric acid concentration is so low that oxidation does not proceed in the conventional nitric acid oxidation method. (1% or more 1'
) was maintained (the oxidation of oxygenated organic compounds progresses. As a result, it contains almost no residual nitric acid [an aqueous solution of the target product can be easily obtained; this removes residual nitric acid, which was previously required) :It has become possible to omit the culm and use it for organic synthesis reaction.If the purpose requires a target product that does not contain a stronger acid, for example, evaporation of hydrochloric acid. It is better to do the processing with

Since nitric acid as an oxidizing agent can be recovered mostly from nitrogen oxide in off-gas, the nitric acid that cannot be recovered in the T industry and results in C loss is the residual nitric acid in the reaction solution. Since the present invention drastically reduces this residual nitric acid, it has a great effect in saving auxiliary materials.Also, since the accumulation of nitric acid that was seen in the conventional method (il!i acid oxidation) does not occur, the reaction may run out of control. Since there is no need to emit a large amount of exhaust gas containing NOx, it is very advantageous from the standpoint of operation management and environmental conservation.

Example 1. 59.3 g of water, 30 g of sulfuric acid (concentration in aqueous solution 34 mol/+<g), 45.6 g of teI-rahydrophthalic anhydride, 0.7 g of copper powder, ammonium vananate \0. : 70 when prepared with 3 g and heated
It becomes 1 j- at ~80℃ l': o63% i + f'i
l'i* was added dropwise and the reaction was continued at 90-100-C.
, dripping amount until reaction completion IL'j 5 Q g +: 11
When water was added, the degree of sulfuric acid div in the aqueous oxidizer #1 composition was 288 mol/<g. The crystals (4, s g) precipitated from the reaction mixture were butanetetracarphonic acid. When the leaked liquid was converted into methyl ester and analyzed, phthanetetracarboxylic acid or ester was also found in the leaked liquid.

Example 2 149 g of 355% hydrochloric acid, 10% rn;, 8 g of nitric acid sorter aqueous solution (HCβ93 mol/1<g) were mixed with 355 g of acetal and 1L + 44% nitric acid deficient;8
8 g was added dropwise at 40-42°C over 15 hours. The concentration of nitric acid in the reaction solution was t.
5.15' was also used for ζ and 10% 111I using hydrochloric acid j 4 9 1:.

Add sodium nitrate aqueous solution (HC & 1.34 mol/K.
g), 355g of ace:・40″0 with aldate
5 g of alumina was added, and 288 g of 44% nitric acid was added dropwise to react (40"C 1.5 hours).
Subtracting the reaction mixture and the remaining acetaldehyde dehyde, the rate of change was approximately 31%, and the glyoxal obtained in the reaction solution was 659 g. It was also analyzed that 1 g of the sample contained 1 g of other acids (30%), acetic acid (4.4%), chloroformic acid, and other acids (111 g).

[ri11 3. 1 8. 2% sulfuric acid 1. 3 9
g, 3% sulfuric acid 10g, 10% + 11 (sodium nitrate tog
(H2SOi.

16 mol/Kg) f A, acetaldehyde 3
5514, lL+: combined with alumina lOg, 4
288 g of 4% nitric acid was added dropwise at 40°C.

The reaction solution (717.2 g) contained acetaldehyde (26.62%) and paraaldehyde (496%).
%) remained, and 7.2 g of glyoxal (9.37%) was obtained as the reaction product. In addition, the acid content of formic acid (227%), acetic acid (4.26%), and cryoxylic acid mef (+2.Ci 4 '(O)) was analyzed.

Example 4. Concentrated hydrochloric acid (i (Cβ97 mol/+<g) 30
40.3 g of Teyulene was added to the solution, and 167 g of 68% nitric acid was added dropwise. At a reaction temperature of 70 to 95° C., progress of the oxidation reaction was observed from the generation of scum and the disappearance of raw materials.

Similar oxidation of active methyl groups was observed when his(34-dimethylphenyl)ethane was used as the raw material.

Example 5. When 45% nitric acid was dropped into a heterogeneous phase mixture of cyclohexene and hydrochloric acid (concentration 153%) at 40°C, the oxidation reaction proceeded and a complex product of enzyme and chlorine was obtained.1, Example 6. 435g of an aqueous solution containing 1996% glyoxal, 049% glyoxylic acid, and 1002% hydrochloric acid.
154 g of 45% nitric acid was added dropwise over 4 hours at a reaction humidity of 40'C to form an oxidizing agent on the spot: [↓Acid (
At the start, glyoxal was oxidized at 40°C using FIC-kun (345 mol/1\g) for 1 hour after the dropwise addition was completed (same?j).
A reaction solution containing 1,658% of cryoxylic acid and only 0,007% of nitric acid was obtained. This reaction solution contained 084% glyoxal and 7.3% IJ'lin'l acid.
4%, oxalic acid 3.31%2, Cryoxylic acid concentration (947%, Cryoxylic acid selection) No I! The concentration of hydrochloric acid in the aqueous oxidizing agent mixture was 84.7% and the yield was 821%. Shown below.

Table 1 Example 7. Instead of hydrochloric acid, an aqueous solution containing sulfuric acid with an initial concentration of 14.16% (144 mol/Kg) was used to conduct the reaction rAii.
Glyoxal was oxidized in the same manner as in Example 2, except that the temperature was changed to 60°C.

One hour after the completion of the dropwise addition (at 60°C), an aqueous solution of cryoxylic acid (1357%) containing nitric acid (0011%) was obtained. The glyoxal conversion rate was 975% and the cryoxylic acid selectivity was 66.8%.

Example 8. (Comparative Example) Example 7 except that an aqueous solution containing phosphoric acid with an initial concentration of 15.05% was used instead of sulfuric acid. Glyoxal was oxidized in the same manner as V. After completion of the dropwise addition], a glyoxylic acid solution of 1174% was obtained between 1 and 1 (60°C), and 3.04% of nitric acid remained. A,,e(NO3)3
9 When using aluminum nitrate with an initial concentration of 27.6% as H20 (reaction temperature 40"C:
The concentration of nitric acid in the glyoxylic acid aqueous solution was 761%. As described above, even if additives other than strong acids are used in large amounts, they do not have the effect of essentially changing conventional nitric acid oxidation.

Claims (1)

[Claims] 1. Organic substrates (excluding cryoxal) are removed by an aqueous oxidant composition formed in the system by sequentially adding nitric acid to an aqueous solution of a non-oxidizing strong acid so as to maintain the nitric acid concentration at 1% or less. Oxidation method 2 characterized in that the organic substrate is oxidized to obtain an oxygen-containing organic compound; Oxidation method 3 according to claim 1, wherein the organic substrate is an active alkyl compound or a carbon-carbon double bond compound; Non-oxidizing strong acid or hydrochloric acid or sulfuric acid, the oxidation method according to claim 1 or 2.