JPS5993073A - Preparation of propane sultone - Google Patents

Abstract

PURPOSE:To prepare the titled compound, in high yield, with simple operation, by converting the alkali metal salt of hydroxypropane sulfonic acid (abbreviated as HPS) to acid form using an ion exchange resin, and carrying out the dehydrative cyclization of the acid. CONSTITUTION:Pure sodium carbonate and sodium bicarbonate are charged together with water into a reaction vessel, and made to react with equimolar amount of sulfur dioxide gas blown into the vessel to obtain fresh sodium bisulfite. A reaction initiator is added to the product, and allyl alcohol is added dropwise thereto to obtain an aqueous solution of HPS sulfonic acid sodium salt almost free from inorganic salts. The solution is passed through a strongly acidic cation exchange resin such as Amberlite IR-12OB to obtain an aqueous solution of HPS. The objective propane sultone can be obtained by concentrating the solution with heat in a vacuum of <=40mm.Hg in a flow-down thin film evaporator made of glass, and subjecting the product to the dehydrative cyclization at 130- 150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing propane sultone with high yield.

Propane sultone is usually made as follows. An alkali metal salt of hydroxypropanesulfonic acid (hereinafter referred to as HPS alkali metal salt) is treated with hydrochloric acid in methanol to convert it into a free acid to obtain hydroxypropanesulfonic acid (hereinafter referred to as HPS). Alkali metal hydrochloride and other inorganic salts contained in the raw materials or produced by hydrochloric acid treatment precipitate in the methanol 178 solution, and are therefore removed by filtration. Inorganic salts are HP
This is because if it is contained in S, the yield of propane sultone will decrease. Another method for obtaining HPS is to convert it into the free acid by adding hydrochloric acid or other mineral acid (inorganic acid) to an aqueous solution of HPS alkali metal salt. In this case, the obtained HPS aqueous solution is concentrated at low temperature or a solvent such as methanol or ethanol in which inorganic salts are difficult to dissolve is added to the HPS aqueous solution to precipitate as much inorganic salts as possible, and then this is filtered. Remove. The obtained HPS is heated in vacuum to cause dehydration and ring closure, and propane sultone (PS
).

The reaction formula is shown below. However, X is an alkali metal such as Na or the like.

HOCH2CH2CH2303X-4-HCIHOCI
-12CH2CH2SO3H For a detailed document on the manufacturing method of HPS, see BP7561
There is 05.

As the inventor continued his research in an attempt to increase the yield of propane sultone, he discovered that reducing the amount of alkali metal contained as an impurity in the intermediate HPS (and increasing the purity of 11PS would increase the yield). However, in the conventional method described above, in which inorganic salts are precipitated and filtered, it is difficult to reduce the amount of alkali metals present as impurities in HPS. Therefore, the inventor developed an HPS system using simple operations.
Further research was carried out in an attempt to almost completely remove the alkali metals inside and increase the yield of propane sultone. As a result, they discovered that if the HPS alkali metal salt is converted to an acid using an ion exchange resin, the alkali metal can be removed at the same time as the conversion, and the present invention has now been completed.

This invention is based on the dehydration and ring closure of hydroxypropanesulfonic acid obtained by converting an alkali metal salt of hydroxypropanesulfonic acid into a free acid.
The gist of the present invention is a method for producing propane sultone, which is characterized in that the alkali metal salt of hydroxypropane sulfonic acid is converted into an acid using an ion exchange resin. The present invention will be explained in detail below.

The HPS alkali metal salt used in this invention is produced, for example, as follows. Although the case where the alkali metal is thorium will be explained below, the same applies to the case where the alkali metal is potassium equivalent.

Allyl alcohol and sodium bisulfite (sodium hydrogen sulfite) are reacted in an aqueous medium in the presence of sodium sulfite using oxygen or an oxygen-containing gas (eg, air) as a reaction initiator. The reaction formula is shown below.

CH2=CHCH20H+Na H3O3 (allyl alcohol) Na035CH2CH2CH20H Sodium bisulfite is as pure as possible, and
It is preferable to use a fresh product produced immediately before this reaction or as the reaction progresses.

HP obtained using fresh sodium bisulfite
This is because the use of S sodium salt results in a higher yield of propane sultone. For example, a predetermined amount of sodium sulfite is placed in a reactor, and then sulfuric acid and allyl alcohol are simultaneously dropped into the reactor. In the reactor, sodium sulfite and sulfuric acid react to form fresh sodium bisulfite. This sulfur-lium bisulfite immediately reacts with allyl alcohol, and the allyl alcohol is sulfonated to form UPS sodium sulfonate. Further, this reaction is preferably carried out at a pH of about 7 to 8 throughout. This is because the use of HPS sodium salt obtained in this pH range also increases the yield of propane sultone.

The reaction mother liquor obtained by this reaction contains sulfite ions, and if sulfuric acid is used as described above, sulfate ions are also contained. It may also contain sulfur dioxide. Each sulfur oxide, sulfite ion, sulfate ion, and sulfur dioxide, is subjected to the 11PS dehydration ring closure reaction,
It is necessary to remove as much as possible together with inorganic salts.

This is because if a dehydration ring closure reaction is performed using HPS containing these sulfur oxides, polymerization of HPS will occur and the yield will be low.

Sulfur oxides and inorganic salts are removed, for example, as follows. Hydrogen peroxide is added as an oxidizing agent to the reaction mother liquor to oxidize sulfite ions and sulfur dioxide into sulfate ions. Alternatively, sulfur dioxide is converted to sulfite ions.

Sulfur dioxide gas is generated when sulfuric acid or the like is used as an oxidizing agent, whereas sulfur dioxide gas is not generated when hydrogen peroxide is used, so sulfur dioxide pollution can be avoided. Next, the reaction mother liquor is concentrated until it becomes a 35-65% solution of HPS sodium sulfonate, and methanol is further added to make a 40-70% methanol solution. Then, most of the sulfate ions or sulfite ions in the methanol solution are precipitated as sodium sulfate or sodium sulfite, and other inorganic salts are also precipitated. The precipitated inorganic salts are removed by filtration.

After this, methanol from the methanol solution is removed by distillation. By adding an aqueous solution of barium chloride, chloride, etc. to the distillation residue, trace amounts of sulfate ions or sulfite ions contained therein are precipitated as barium sulfate, calcium sulfate, barium sulfite, or calcium sulfite. If this precipitate is filtered, HPS sodium salt containing almost no sulfur oxides and inorganic salts can be obtained.

Inorganic salts and sulfur oxides may be removed as follows without using methanol.

After concentrating the reaction mother liquor to precipitate as much sodium sulfate and other inorganic salts as possible, the precipitated inorganic salts are removed by filtration. Next, remaining sulfate ions or sulfite ions are removed by adding barium chloride or the like.

In addition, when reacting pure and fresh sodium bisulfite and allyl alcohol, the following may be used. Pure sodium carbonate (Na2CO3) and/or
Alternatively, sodium hydrogen carbonate (Na2HC○3) is added into a reaction vessel together with water, and then an equimolar amount of sulfur dioxide (S02) gas is blown into the reactor while stirring to cause a reaction, thereby producing fresh sodium bisulfite. While blowing in sulfur dioxide gas, or immediately after blowing in a predetermined amount of sulfur dioxide gas, a reaction initiator is added to the reactor and allyl alcohol is added dropwise.
Allyl alcohol can be reacted with pure and fresh sodium bisulfite. In such a reaction, allyl alcohol is added in an amount that is slightly in excess of equimolar to the sodium bisulfite produced, so that at the end of the reaction, almost no sodium bisulfite is present, and only a very small amount of sodium bisulfite is present. In the presence of excess allyl alcohol, a HPS sodium sulfonate brine solution is obtained that is almost free of inorganic salts.

The HPS sodium salt thus obtained is converted to HPS using an ion exchange resin. This is different from the conventional method. Examples of ion exchange resins include:
Strongly acidic cation exchange resins such as Amberlite I R-120B, Diaion SKI or Doiiex 50W are commonly used.

After converting the ion exchange resin as described above into H type, this is brought into contact with an aqueous solution of HPS sodium salt. For example, after filling a column with ion exchange resin to form H-type, an aqueous solution of I(PS sodium salt) is continuously passed through the column. Contact may be made in a hatch type without using a column. HPS The concentration of an aqueous solution of sodium salt is 3-5
It is better to set it as %. In this way, hydrogen ions in the ion exchange resin and sodium ions in the aqueous solution are exchanged.

Then, the HPS sodium salt is converted to HPS and sodium is removed from the aqueous solution to obtain an aqueous solution of HPS. Sodium ions are adsorbed on the ion exchange resin,
Almost completely removed from aqueous solutions. Next, HPS can be obtained by concentrating the HPS aqueous solution. This HPS contains almost no sulfur oxides, inorganic salts or sodium ions.

For concentration, for example, a glass falling-type thin-film evaporator is used, and only the evaporator is heated with steam, and the 40m111
It is recommended that the process be carried out under a vacuum of less than g. Also, water C
The distillation rate is preferably 8 to 12 p/hour, and the concentration is preferably completed in about 30 to 40 minutes.

Propane sultone can be obtained by subjecting the thus obtained HPS to dehydration and ring closure in the same manner as in the conventional method. For example, heating HPS to 130-150'C yields propane sultone. a If necessary, this propane sultone is purified by vacuum distillation or the like.

In the method of this invention, the dehydration ring closure is carried out using HPS, which hardly contains sodium ions, so the yield of propane sultone is extremely high.

The method for producing propane sultone according to the present invention is configured as described above, and since the alkali metal salt of hydroxypropanesulfonic acid is converted to an acid using an ion exchange resin, At the same time, the desorbed alkali metal can be almost completely removed from the HPS solution. Therefore, when propane sultone is extracted using this HPS solution, the yield is extremely high.

Examples and comparative examples will be explained below.

The HPS J-thorium salt used in the Examples and Comparative Examples was prepared as follows.

Add 101g of sulfuric acid to 100mA of water to make a sulfuric acid aqueous solution, and add 10100O of water! Sodium sulfite 40
0g was added to make a sodium sulfite aqueous solution, and the rainwater solution was mixed and stirred well. By this mixing operation, sulfuric acid and sodium sulfite react in this mixed solution, resulting in 2 mo
1 of sodium bisulfite is produced, so this and excess sodium sulfite will eventually make 1 liter of sodium sulfite.
This means that a /8 solution containing 2 mol of sodium bisulfite and 2 mol of sodium bisulfite has been created. On the other hand, 120 g (2 mol) of allyl alcohol was mixed with 50 g of water to prepare 200 ml of a 70% aqueous solution of allyl alcohol. 1500 ml of water was placed in a reactor.

1 Sodium sulfite to 4 grams of Zolium and 4 grams of 30% hydrogen peroxide
g and mixed. The solution in the reactor has a pH of 9.75
Met. While stirring the solution in the reactor and blowing air into the solution at a rate of 2 p/min, the solution was added dropwise to the mixture and allyl alcohol 7 to cause the allyl alcohol and sodium bisulfite to react. Dripping of the mixed liquid and the allyl alcohol aqueous solution was started at the same time, and the dropping was completed at the same time. Further, the solution was added dropwise over a period of 1.5 hours.

The reaction temperature was 45-55°C. During the reaction, the pH of the reaction solution
was 7-8. After dripping, 20 mj of water! sulfuric acid 2
An aqueous sulfuric acid solution prepared by adding g was added to the reaction solution, and stirring was continued for 30 minutes at the same temperature to eliminate the allyl alcohol odor.

At this time, the pH of the reaction solution was 9.7. next,
5 hours of 30% hydrogen peroxide solution was added to the reaction solution and stirred for about 1 hour to oxidize the sulfite ions in the reaction solution to sulfate ions. At this time, the pH became 7.5. After that, the reaction solution was concentrated and the water was distilled off to aNm degree LL' below 109°C and Lf. 2450m7! OJ) After water was distilled off, 100 ml of methanol was added to the concentrate, and the mixture was cooled to 50°C. The precipitated sodium sulfate was removed by filtration. The weight of sodium sulfate was 280 g. The washing liquid obtained by washing this sodium sulfate with 70% methanol was added to the filtrate, and then the methanol was distilled off at 80 to 100"C. 12 g of calcium chloride was added to the concentrated liquid and stirred for about 1 hour. Then, 2 g of activated carbon was added and filtered to remove the precipitated calcium sulfate.The calcium sulfate was thoroughly washed with water, and the resulting washing liquid and filtrate were combined to obtain an aqueous solution of HPS sodium salt.

[Example 1] Water was added to the HPS aqueous solution obtained as described above.
~5% (7)HPS to 4500 rn
Pass this through a column filled with H-type cation exchange resin,
HPS sodium salt was converted to HPS. Diaion SKI was used as the ion exchange resin.

Next, water was distilled off by vacuum distillation, and the column-passing liquid was concentrated. Heat the concentrate to 130-150°C and
Crude propane sultone was produced by dehydration and ring closure of S. Purified propane sultone was obtained by vacuum distillation of 1 ml (g) of crude propane sultone.

[Fruit can (-12)] Amberlite IR-1 as an ion exchange resin
Purified propane sultone was produced in the same manner as in Example 1, except that 20B was used.

[Comparative example]

After distilling off the water in the HP S sodium salt aqueous solution, 1000 cc of methanol was added, and then 250 g of 35% hydrochloric acid was added.
was added to convert the HPS sodium salt to the free acid. Next, the precipitated sodium chloride was removed by filtration, and HPS
A methanol solution of was obtained. After distilling off methanol from the methanol solution, HPS was subjected to dehydration ring closure to obtain crude propane sultone.

Crude propane sultone was vacuum distilled at 1 Tsuru Hg to obtain purified propane sultone.

In Examples 1 and 2 and Comparative Example, the amount of chlorium contained in the HPS obtained as an intermediate and the yield of purified propane sultone obtained in each were measured. The measurement results are shown in Table 1.

Table 1 According to Table 1, Example 1.2 contained 1 less sodium in HPS and had a higher yield of propane sultone than Comparative Patch 11.

Agent: Patent Attorney Takehiko Matsumoto

Claims (2)

[Claims] (1) In obtaining propane sultone by dehydration and ring closure of hydroxypropanesulfonic acid obtained by converting an alkali metal salt of hydroxypropanesulfonic acid into a free acid, converting the alkali metal salt of hydroxypropanesulfonic acid into an acid. A method for producing propane sultone, characterized by carrying out using an ion exchange resin. (2) The method for producing propane sultone according to claim 1, in which sulfur oxide, an impurity contained in hydroxypropanesulfonic acid, is removed before performing the dehydration ring closure.