JPH061755A - Production of 2,2-dibromo-2-nitroethanol - Google Patents

Abstract

PURPOSE:To obtain 2,2-dibromo-2-nitroethanol in high yield and purity by using 2-hydroxymethyl-2-nitro-1,3-propandiol and nitromethane which are inexpensive and readily available compounds at a relatively low cost as raw materials. CONSTITUTION:A reactional raw material containing 2-hydroxymethyl-2-nitro-1,3- propandiol and nitromethane in a molar amount of >0.6 based thereon is made to react with a caustic alkali in an aqueous solution and the obtained reactional product is then allowed to react with bromine to produce the objective 2,2- dibromo-2-nitroethanol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to 2-hydroxymethyl-
The present invention relates to a method for industrially producing high-purity 2,2-dibromo-2-nitroethanol using 2-nitro-1,3-propanediol and nitromethane as starting materials.

[0002]

2. Description of the Prior Art 2,2-Dibromo-2-nitroethanol is effective as an industrial bactericidal agent and a sulfide removing agent, and is disclosed in, for example, JP-A-2-2134302 and JP-A-2-135138. Have been described. As a method for producing 2,2-dibromo-2-nitroethanol, a method of reacting 2-bromo-2-nitro-1,3-propanediol with potassium hypobromite (Chemische Be
richte 57B, 2127-2128 (1924)), 2-bromo-2-nitro-1,3-propanediol was reacted with alcoholate in alcohol solution, and the product was taken out and suspended in dry ether to give bromine. Method of brominating a chloroform solution of (Chemische Berichte
56B, 611-620 (1923)), a method of condensing with 1.5 mol or more of formaldehyde to 1 mol of nitromethane, and then brominating with bromine (JP-A-61-289063), bromine is added to nitromethane. A method of reacting with formaldehyde after reacting in the presence of alkali (JP-A-1-1-1
No. 32549), etc. are known.

[0003]

However, these conventional manufacturing methods have the following drawbacks, and are not always satisfactory as industrial methods.
First, the method of reacting 2-bromo-2-nitro-1,3-propanediol with potassium hypobromite is
The yield is extremely low at 10.7% (literature value), which is not suitable for industrial production. The method using 2-bromo-2-nitro-1,3-propanediol as the starting material is not only complicated in operation, but also the yield is 21% (reference value), which is remarkably low, and is not suitable for industrial production. Not suitable. For the method of condensing formaldehyde to nitromethane and brominating with bromine, the method of Example 1 of JP-A-61-289063 was supplemented, and the separated oily substance 2,2-dibromo-2 was obtained. -Nitroethanol content 57.3 to 62.2
%, And the yield based on nitromethane is 36.6-3.
It is 7.2%, which is not sufficient for industrial production in terms of quality and yield. Further, a method for reacting formaldehyde with nitromethane bromide is disclosed in JP-A-1-132549.
When a supplementary test was conducted based on Example 1 of No. 2, 2,2-dibromo-2-nitroethanol was scarcely produced despite the description of the publication. Also these ~
Formaldehyde is involved as a raw material and a by-product in the above method, and when this remains 2,2-
Dibromo-2-nitroethanol quality, waste disposal,
Problems arise with environmental measures.

[0004]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems of industrialization, and as a result, 2-
By using hydroxylmethyl-2-nitro-1,3-propanediol and nitromethane as starting materials, alkali decomposition in an aqueous solution, bromination, and then adjusting the pH, the problem of formaldehyde as a by-product is solved and high purity is achieved. It was found that 2,2-dibromo-2-nitroethanol can be obtained, and the present invention was completed based on this finding.

That is, according to the present invention, a mixture containing 2-hydroxymethyl-2-nitro-1,3-propanediol and nitromethane in an amount exceeding 0.6 times the molar amount of the mixture is reacted with caustic in an aqueous solution. Then, the present invention provides a method for producing 2,2-dibromo-2-nitroethanol, which comprises reacting this reaction product with bromine. The reaction of the method of the present invention is considered to follow the following equation.

Formula 1 (HOCH ₂ ) ₃ CNO ₂ + 2Br ₂ + 3NaOH + HCl → HOCH ₂ C (Br) ₂ NO ₂ + 2HCHO + 2NaBr + NaCl + 3H ₂ O Formula 2 CH ₃ NO ₂ + 2HCHO + Br ₂ + NaOH → (HOCH ₂ ) ₂ C (Br) NO ₂ + NaBr + H ₂ O Formula 3 (HOCH ₂ ) ₃ CNO ₂ + CH ₃ NO ₂ + 3Br ₂ + 4 NaOH + HCl → HOCH ₂ C (Br) ₂ NO ₂ + (HOCH ₂ ) ₂ C (Br) NO ₂ + 3NaBr + NaCl +
4H ₂ O

The reaction of the present invention can be represented by equations 1 and 2. First, as shown in Formula 1, 2,2-dibromo-2-nitroethanol is produced by brominating 2-hydroxylmethyl-2-nitro-1,3-propanediol with bromine in the presence of caustic alkali. However, at this time, 2 mol of formaldehyde is by-produced. As shown in Formula 2, this formaldehyde is converted to 2-bromo-2-nitro-1,3-propanediol by reacting with nitromethane and further brominating in the presence of caustic. Thus, the present invention is also characterized in that formaldehyde, which is a by-product, is reacted with nitromethane and further brominated to convert it into a useful compound. Formula 3 is a combination of Formulas 1 and 2 and represents all reactions in the method of the present invention.

Further, in the reaction in the formula 2, the product can be changed by changing the proportions of formaldehyde, nitromethane, caustic and bromine. For example, 2 mol of 2,2-dibromo-2-nitroethanol salt can be produced by using 2 mol of formaldehyde, 2 mol of nitromethane, 4 mol of bromine and 6 mol of caustic. However, it is difficult to strictly control this reaction, and 2,2-dibromo-
Further brominated compounds are produced as impurities for the purpose of 2-nitroethanol. Therefore, in order to obtain highly pure 2,2-dibromo-2-nitroethanol, it is more advantageous to leave 2-bromo-2-nitro-1,3-propanediol. Therefore, theoretically, the amount of nitromethane used is not more than 2 times the molar amount of 2-hydroxylmethyl-2-nitro-1,3-propanediol, and usually more than 0.6 times the molar amount, preferably 0.
It is used in the range of 8 to 1.1 times mol. Corresponding amounts of bromine and caustic are also used. The 2-bromo-2-nitro-1,3-propanediol obtained here is also useful as an industrial drug, and many patents have been filed.

In the present invention, 2-hydroxylmethyl-2-nitro-1,3-propanediol and nitromethane are reacted with caustic in an aqueous solution. This first step reaction is 2-hydroxylmethyl-2-nitro-
It is a salt formation reaction of 1,3-propanediol and nitromethane with a caustic alkali. Examples of the alkali include caustic alkalis such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide. From the viewpoint of reactivity, sodium hydroxide, potassium hydroxide, etc. Caustic alkali is preferred. The reaction temperature of the alkali treatment is -10 to 40 ° C, preferably -5 to 5 ° C, and the alkali amount is preferably 2 with respect to the sum of 2-hydroxylmethyl-2-nitro-1,3-propanediol and nitromethane. It is used in an amount of 0.0 to 3.0 times. Caustic is formed 2,2-dibromo-2-
Nitroethanol acts as a salt. If the alkali is insufficient, the reaction may not proceed sufficiently. Therefore, neutralization with a mineral acid such as hydrochloric acid is required as a post-treatment. As the reaction solvent, water alone or a water / alcohol mixed system can be used, but water alone is preferred from the viewpoint of solubility of the metal bromide salt produced as a by-product. In addition, since there is a risk of explosion and the like, a water-only system is preferable from the viewpoint of safety.

Next, bromination is carried out as the second stage reaction.
Without separating the product from the first stage reaction,
As it is, bromine can be added dropwise. This brominating agent is 2-hydroxylmethyl-2-nitro-1,3-
For the number of moles of the sum of propanediol and nitromethane,
It is preferably used in an amount of 1.5 to 2.0 times. In this case, if the brominating agent and caustic alkali are used in excess, the yield of 2,2-dibromo-2-nitroethanol increases, or the reaction proceeds further and the amount of impurities tends to increase. The reaction temperature for bromination is -10 to 15 ° C, preferably 0.
Perform at ℃ or below. The pH of the reaction solution after bromination is adjusted with an acid to pH 7 or less, preferably pH 3 or less, and the reaction is completed.
When the reaction solution is left alkaline, the generated 2,2
-Dibromo-2-nitroethanol and 2-bromo-2
Alkaline decomposition of -nitro-1,3-propanediol may occur, which may cause a decrease in yield. The acid used for neutralization is not particularly limited, but inorganic acids such as hydrochloric acid and sulfuric acid are preferable.

The thus obtained 2,2-dibromo-2 is obtained.
Extract the nitroethanol oil and the aqueous layer with a solvent such as toluene. As the solvent in this case, it is preferable to preferentially extract 2,2-dibromo-2-nitroethanol without extracting 2-bromo-2-nitro-1,3-propanediol in the aqueous layer. If the toluene layer is washed and purified with water, highly pure 2,2-dibromo-2-nitroethanol can be easily obtained in a high yield. Furthermore, 2-bromo-2-nitro-1,3-propanediol can be obtained by extracting the aqueous layer with a solvent such as acetic acid ester or methyl isobutyl ketone. On the contrary, first, both compounds are extracted with a solvent, concentrated, and then 2,2-dibromo-2-nitroethanol and 2-bromo-2-nitro-1,3-propanediol are used with a solvent such as water and toluene. And can be separated.

[0012]

According to the method of the present invention, 2,2-hydroxymethyl-2-nitro-1,3-propanediol and nitromethane, which are relatively inexpensive and easily available compounds, are used as raw materials for 2,2 -Dibromo-2-nitroethanol can be obtained in high yield and high purity.
Furthermore, since the reaction solvent is aqueous, the safety of the process is high, and there are few problematic by-products such as formaldehyde. Therefore, the method of the present invention is extremely suitable as a method to be carried out industrially.

[0013]

EXAMPLES Next, the present invention will be described in more detail based on examples. Example 1 151 g (0.5 mol) of a 50% aqueous solution of 2-hydroxylmethyl-2-nitro-1,3-propanediol and 24.4 g (0.4 mol) of nitromethane were charged into 360 g of water, and the mixture was cooled to 0 with a cryogen. It was cooled to below ℃. 48% in this solution
167 g (2.0 mol) of sodium hydroxide at 0 to -2 ° C
It was dripped at. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and then 264 g (1.65 mol) of bromine was added at -2 to -6 ° C.
It was dripped at. Then, the pH was adjusted to 3 with 35% hydrochloric acid. After stirring at room temperature for 1 hour, the target product was extracted with 200 g of toluene three times from the reaction solution. The toluene layer was washed with water and evaporated under reduced pressure to give 2,2-dibromo-2-nitroethanol. Furthermore, the aqueous layer was extracted 3 times with 150 g of methyl isobutyl ketone each. Methyl isobutyl ketone was distilled off from this extract under reduced pressure to obtain 2-bromo-2-nitro-1,3-propanediol. The results are shown in Table 1. The formaldehyde contents of the toluene solution before washing with water, the methyl isobutyl ketone extract and the aqueous layer were measured and found to be 0.2 g, 0.2 g and 5.4 g, respectively. This was less than 20% of the theoretical amount of formaldehyde generated.

Example 2 The amount of nitromethane used in Example 1 was 27.6 g (0.4
The same procedure as in Example 1 was repeated except that the amount was changed to 5 mol). The results are shown in Table 1. Example 3 Into 320 g of water were charged 151 g (0.5 mol) of a 50% aqueous solution of 2-hydroxylmethyl-2-nitro-1,3-propanediol and 24.4 g (0.4 mol) of nitromethane, and the mixture was cooled to 0 with a cryogen. Cooled to ° C. To this solution, 225 g (2.7 mol) of 48% sodium hydroxide was added dropwise at 0 to 5 ° C. After completion of the dropping, the mixture was stirred at the same temperature for 30 minutes, and then 288 g (1.8 mol) of bromine was added dropwise at 0 to 2 ° C.
Then, the pH was adjusted to 2 with 35% hydrochloric acid. 3 at room temperature
Stir for 0 minutes and add 400 g of the target product from the reaction solution to toluene.
It was extracted 3 times with. After washing the toluene layer with water, the solvent was distilled off under reduced pressure to obtain 2,2-dibromo-2-nitroethanol. Furthermore, the aqueous layer was extracted 4 times with 300 g of isopropyl acetate each. The solvent was distilled off under reduced pressure to obtain 2-bromo-2-nitro-1,3-propanediol. The results are shown in Table 1.

Comparative Example 1 151 g (0.5 mol) of a 50% aqueous solution of 2-hydroxylmethyl-2-nitro-1,3-propanediol was charged in 150 g of water and cooled to 0 ° C. with a freezing agent. To this solution, 137.5 g (1.65 mol) of 48% sodium hydroxide was added dropwise at 0 to -2 ° C. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and then 176.0 g (1.1 mol) of bromine was added dropwise at -2 to -6 ° C. Example 1 after completion of dropping
The same process was carried out. The results are shown in Table 1.

[0016]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Horii 328 Shionoden Hamano, Fukuda-cho, Iwata-gun, Shizuoka Kai Kasei Co., Ltd.

Claims (2)

[Claims] 1. 2-Hydroxymethyl-2-nitro-
A mixture containing 1,3-propanediol and nitromethane in an amount over 0.6 times the molar amount of the mixture, reacted with caustic in an aqueous solution, and then reacted with bromine. -Method for producing dibromo-2-nitroethanol. 2. The method for producing 2,2-dibromo-2-nitroethanol according to claim 1, wherein 2-bromo-2-nitro-1,3-propanediol is also produced.