JPS60260421A - Separation of boric acid - Google Patents

Abstract

PURPOSE:To separate and recover boric acid from a mixture contg. boric acid, carboxylic acids and oxycarboxylic acids by distilling the mixture in the presence of an aliphatic lower alcohol to take out the boric acid as boric triester. CONSTITUTION:The mixture of 1-10wt% boric acid with aliphatic carboxylic acids and oxycarboxylic acids such as adipic acid, oxycaproic acid, butyric acid, valeric acid and caproic acid is fed to a distilling column, and at the same time, an aliphatic lower alcohol such as methanol is fed to the column by >=6mol per 1mol boric acid. When the mixture is distilled in the distilling column, the boric acid is converted into boric triester by esterification with the methanol. At this time, the carboxylic acids and oxycarboxylic acids are not esterified, so the boric triester can be separated and recovered as a distillate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of application for industry] The present invention provides IllI! 'It relates to a method for separating and recovering iTh.

[Prior art]

For example, oxidizing cyclohexane in the presence of a boric acid catalyst,
In the process of producing cyclohexanol by obtaining IIIll[ester of cyclohexanol and then hydrolyzing the -9 ester, a considerable amount of organic substances such as cyclohexane and acid are contained in the mixture after hydrolysis. .

So, as a way to utilize these shoulders @Qallm,
It is conceivable to recover organic IPi21 containing all of adibic acid and oxycarboxylic acid by recovering the liquid in this aqueous phase by crystallization, and then dehydrating the discharged crystallization mother liquor.

[Problem that the invention seeks to solve]

However, the organic matter recovered here contained a considerable amount of phosphoric acid, so it was not possible to utilize this organic matter as expected. For example, when this F pickle is used as a fuel, the equipment is severely corroded due to the presence of chloride, making it unsuitable for use in industrial equipment for scrubbing. Therefore, without losing the value of this organic matter,
It has been desired that a method for easily separating boric acid be developed.

[Means for solving the problem between 111' and 111'] In view of the above-mentioned circumstances, the present inventors have proposed
Or, as a result of various studies on methods for efficiently separating boric acid from a mixture containing oxycarboxylic acids, it was found that distilling the mixture in the presence of an aliphatic alcohol,
- It is possible to separate the 0131 acid and the carboxylic acid and/or oxycarboxylic acid, which are the targets of the present invention, from the viewpoint of non-invention. In the mixture containing boric acid, the content of violet is traced to g, total *-f! It is 1 to 10% by weight based on the weight of the product. However, in the present invention, there is no problem in containing /f4 mechanized derivatives of KM other than carboxylic acids and oxycarboxylic acids. Specific examples of carboxylic acids and oxycarboxylic acids include adipic acid, oxycaproic acid, l'l
& iν, Hitomi Yakuza, caproic acid and other carvone liquids are given.

In the present invention, even if a mixture having the above-mentioned composition is used, the entire aqueous phase after hydrolysis is used to produce cyclohexanol by IM of clohegisanol and then hydrolyzing this ester. An organic substance obtained by dehydrating the crystallization mother liquor discharged from the step of crystallizing and recovering boric acid crystals is used. This organic substance contains adipine 1
Waves, oxycaproic acid, boric acid, K and other organic compounds, and in some cases, a small amount of water are also present.

In the invention, it is necessary to distill the mixture as described above in the presence of an aliphatic lower alcohol. , inglovir alcohol, n-butanol, and especially,
Methanol is preferred. The amount of the aliphatic lower alcohol to be used (1) Usually, 6 moles or more, preferably io to 20 moles, of the boric acid in the mixture.Also, the method for supplying the aliphatic lower alcohol to the distillation column. For this purpose, either the method of mixing the carboxylic acid and/or oxycarboxylic acid in advance and supplying the mixture to the distillation box, or supplying each separately and simultaneously to the distillation box may be used.This distillation operation may be used. is usually carried out batchwise.

The steam flute is carried out at a high pressure,
The esters added to the mixture undergo an esterification reaction with an aliphatic primary alcohol in a distillation column, and are converted into a triester. 2. No esterification catalyst is required except for distillation. Next, under the conditions in which methanol is used as the lower alcohol of this group, carboxylic acids and/or μ-oxycarboxylic acids are not esterified;

After removing the boric acid from the mixture, the excess aliphatic lower alcohol is removed, and the water produced in the enetherization reaction is successively distilled off, thereby increasing the amount of the boric acid. Shoulder ratio 'm' containing -1 less carboxylic acid and/or oxycalcibone cough r: i: can be obtained 0
On the other hand, the boric acid triester distilled off by distillation is usually
'm=Add 7 to 3 times as much water to the triester and hydrolyze at a temperature of 20 to soC for 10 to 30 minutes. The mixture after hydrolysis is usually distilled again to remove and recover the aliphatic lower alcohol, and the remaining aqueous boric acid solution is condensed or crystallized by cooling.
Crystals of JIA relatives can be collected.

[Effects of the Invention] As described above, according to the present invention, rL is obtained from a mixture of adipic acid and/or oxycaproic acid containing acetic acid discharged from the cyclohexanol production process, for example, from a 1N
't' uN acid)! For example, it has become possible to apply it to various uses such as fuel.Furthermore, by hydrolyzing boric acid triester, boric acid
The present invention has great industrial effects in that aliphatic lower alcohols can be recovered.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

2. In the examples, "parts" and "parts by weight" are used.

Example Cyclohexanol MM A mixture of 100 parts of organic matter discharged from a MM factory (3% of oxycaprone, related to adipic acid Z, other concentrated Smudge%, and boric acid) and 50 parts of methanol. This mixture was distilled 4 times (20 stages).
column), distillation was carried out under normal pressure with a reflux rAL ratio of 5, and 15 parts of the first fraction was distilled out at a column top temperature of S5 to sgc. Next, 31 parts of the middle distillate was distilled off at a column top temperature of 5 g to 65 DEG C., and all of 5 parts of the rear distillate were distilled off at a column negative temperature of 65 g to 65 DEG C.

The compositions of each distillate and residual fraction recovered in this manner were determined and the results are shown in Table 1.

As seen in the results in Table 1, Distillery 8! The M content of 1 excited acid in the tentative residue is only 0.3%, which is practically 1 liter.
All of the llI acid content becomes trimethyl W acid, which is listed as the first distillate in Wang.

Applicant: Mitsubishi Chemical Industries, Ltd. Agent Patent Attorney Hase - 1 other person

Claims (4)

[Claims] (1) A mixture containing all boric acid and carboxylic acid and/or oxycarboxylic acid is distilled in the presence of a m-aliphatic lower alcohol to distill boric acid as a triester. New separation method◎ (2) The method according to claim 1, characterized in that the boric acid content in the raw material mixture is /-70 plates (2. (3)) The amount of trt aliphatic lower alcohol used is 6 moles or more of boric acid. (4) The claimed method, wherein the aliphatic lower alcohol is methanol.