JPH0129791B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an oxirane compound by dehydrohalogenating a vicinal haloalcohol in the presence of a hydrohalide salt of an imidazole compound. ethylene oxide, propylene oxide,
Oxirane compounds such as butylene oxide are useful as intermediates in the production of diols and polyols. These diols and polyols are widely used as antifreeze coolants and as raw materials for polyethers, polyesters, polyurethanes, and the like. Known methods for producing oxirane compounds include a method in which the corresponding olefin is reacted with oxygen in the gas phase, and a method in which the olefin is oxidized in the liquid phase with hydroperoxide or percarboxylic acid. Industrially, the method of reacting with oxygen in the gas phase is limited to the production of ethylene oxide from ethylene, and furthermore, the loss of complete combustion of ethylene is large. In addition, the method of oxidizing with hydroperoxide or percarboxylic acid has a large risk due to the use of hydroperoxide or percarboxylic acid. In addition, in this method, large amounts of alcohol, olefin, acid, etc. are co-produced;
It is difficult to secure customers for acid. Another method for producing oxirane compounds is to produce vicinal haloalcohol from olefin and hypohalous acid, and then react it with an aqueous solution of a strong alkali such as sodium hydroxide or calcium hydroxide. This method is widely used because it has a wide range of applications and can be used to produce oxirane compounds from various olefins. However, in this method, strong alkalis such as sodium hydroxide are consumed stoichiometrically, and halogen elements are converted into inexpensive compounds such as sodium chloride. The present inventors investigated a method for recovering halogen as hydrogen halide, which has a wide range of uses and has high utility value, when producing oxirane compounds from vicinal haloalcohols, and arrived at the present invention. That is, the present invention

【formula】 or

[Formula] (However, R ₅ , R ₆ , R ₇ , R ₈ , and R ₉ are hydrogen, methyl, ethyl, or phenyl groups.)

[Formula] (However, R ₁ , R ₂ , R ₃ , and R ₄ represent hydrogen, an alkyl, alkenyl, or aryl group having up to 16 carbon atoms, and X represents a halogen such as chlorine or bromine.) By dehydrohalogenating cinalhaloalcohol,

[Formula] (However, R ₁ , R ₂ , R ₃ , and R ₄ represent hydrogen, an alkyl, alkenyl, or aryl group having up to 16 carbon atoms.) This is a method for producing oxirane compounds. According to the present invention, an oxirane compound and a hydrogen halide can be produced from a vicinal haloalcohol in the presence of a hydrogen halide salt of an imidazole compound according to the following formula. In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent hydrogen, alkyl, alkenyl or aryl groups having up to 16 carbon atoms.
Alkyl, alkenyl, aryl groups may be substituted with one or more electron withdrawing groups such as halo, cyano, etc.
The aryl group may be substituted with one or more alkyl groups having 1 to 4 carbon atoms. The aforementioned R ₁ , R ₂ ,
Preferably, at least two of the R ₃ and R ₄ groups are hydrogen, and the remaining one is methyl, ethyl, butyl, hexyl, phenyl, chloromethyl, hydroxymethyl, or the like. Also, R ₁ and
R ₄ may be bonded to form a cycloalkyl ring such as cyclohexyl. In the formula, X represents a halogen element, preferably chlorine or bromine. In the present invention, vicinal haloalcohols include ethylene chlorohydrin, ethylene bromohydrin, propylene chlorohydrin, propylene bromohydrin, butylene chlorohydrin, butylene bromohydrin, hexene chlorohydrin,
Hexene bromohydrin, octenc chlorohydrin, octene bromohydrin, styrene chlorohydrin, styrene bromohydrin, methylstyrene chlorohydrin, methylstyrene bromohydrin, cyclohexene chlorohydrin, cyclohexene bromohydrin, allyl alcohol These include chlorohydrin, allyl alcohol bromohydrin, and allyl chlorohydrin chloride. The oxirane compounds in the present invention include ethylene oxide, propylene oxide, butylene oxide, hexane oxide, octene oxide, styrene oxide, methylstyrene oxide, cyclohexene oxide, glycidol, epichlorohydrin, and the like. What is the imidazole compound in the present invention?

[Formula] or

It is an imidazole compound with the structure: [Formula] Here, R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are hydrogen, methyl, ethyl or phenyl groups. Preferred examples of the imidazole compound include imidazole, methylimidazole, phenylimidazole, and methyl-ethylimidazole. The hydrogen halide salt of an imidazole compound in the present invention is a hydrogen chloride salt or a hydrogen bromide salt of an imidazole compound. Preferably, the invention is practiced in the gas phase. The temperature at which the present invention is carried out is 150 to 400°C.
is preferable, 180°C to 350°C is more preferable, and 230°C to 320°C is also preferable. The present invention may be carried out under increased pressure, atmospheric pressure, or reduced pressure; however, it is preferably carried out at or near atmospheric pressure, or under reduced pressure. When carrying out the present invention, an inert gas such as nitrogen may coexist. In the present invention, it is preferable to support a hydrogen halide salt of an imidazole compound on a carrier. As the carrier, silica such as silica gel and silica glass is preferable. Although various commonly known methods can be used for supporting the imidazole compound, a method in which a chemical bond is formed between the imidazole compound and the carrier is preferable. In this case, it is desirable to use a coupling agent, such as a silane coupling agent. As the coupling agent, a silane coupling agent having a functional group with a halogen at the end such as a haloalkyl group, a halomethylphenethyl group, or a halophenyl group is desirable. Here, halogen is chlorine or bromine. Examples of desirable coupling agents include γ-
These include chloropropyltrialkoxysilane, chloromethylphenethyltrialkoxysilane, chlorophenyltrialkoxysilane, and the like. The vicinal haloalcohol used in the present invention can be produced by various known methods. For example, it can be produced by adding hypochlorous acid or hypobromous acid to olefins. To illustrate the method of the present invention, vapor of a vicinal haloalcohol is heated at 150°C to 400°C, preferably 180°C to 350°C, in the presence of a hydrohalide salt of an imidazole compound supported on silica using a silane coupling agent. , most preferably 230℃
This is a method for producing oxirane compounds by dehydrohalogenation at temperatures ranging from 320°C to 320°C. Example 1 2-methylimidazole 2g and 3-chloropropyltrimethoxysilane in 100ml meta-xylene
To this was added 10 g of silica gel previously dried at 150° C., and the mixture was relaxed for 8 hours to remove meta-xylene and washed with benzene and acetone. Example 2 3 g of silica gel-supported methylimidazole hydrochloride prepared in Example 1 was filled into a glass reaction tube,
Keep ethylene chlorohydrin vapor at 250℃
A mixed gas of 40NTPml/Hr and nitrogen 2NTP/Hr was introduced. Ethylene oxide was obtained at a rate of 27% based on the amount of ethylene chlorohydrin fed, with a selectivity of 83%. Example 3 Silica gel-supported methylimidazole hydrochloride was prepared in the same manner as in Example 1 except that 4.8 g of 3-chloropropyltrimethoxysilane was replaced with 6.7 g of chloromethylphenethyltrimethoxysilane. Example 4 3 g of silica gel-supported methylimidazole hydrochloride prepared in Example 3 was filled into a glass reaction tube,
Ethylene chlorohydrin vapor kept at 300℃
A mixed gas of 80NTPml/Hr and nitrogen 1.5NTP/Hr was introduced. Ethylene oxide was obtained in an amount of 9% based on the amount of ethylene chlorohydrin fed, with a selectivity of 87%. Example 5 3 g of silica gel-supported methylimidazole hydrochloride prepared in Example 1 was filled into a glass reaction tube,
Keep at 250℃, propylene chlorohydrin 40NTP
A mixed gas of ml/Hr and nitrogen 2/Hr was introduced.
Propylene oxide was obtained in an amount of 10% based on the amount of propylene chlorohydrin fed. Example 6 3 g of silica gel-supported methylimidazole hydrochloride prepared in Example 3 was filled into a glass reaction tube,
Keep at 270℃, ethylene bromohydrin 100NTP
A mixed gas of ml/Hr and nitrogen 1NTP/Hr was introduced. Ethylene oxide was obtained at a rate of 20% based on the amount of ethylene bromohydrin fed, with a selectivity of 85%. Examples 7-9 In Example 1, 2-methylimidazole 2
Silica gel-supported imidazole hydrochloride, silica gel-supported phenyl imidazole hydrochloride, and silica gel-supported benzimidazole hydrochloride were prepared in the same manner as in Example 1, except that 1.7 g of imidazole, 3.6 g of 2-phenylimidazole, or 2.9 g of benzimidazole was used instead of g. Prepared salt. 3 g of imidazole compound hydrochloride supported on silica gel was kept at the temperature shown in the table below, and heated with 40 NTPml/Hr of ethylene chlorohydrin vapor and nitrogen.
A mixed gas of 2NTP/Hr was introduced. The results are shown in the table below.

[Table] Example 10 A glass reaction tube was filled with 3 g of silica gel-supported methylimidazole hydrochloride prepared in the same manner as in Example 1, kept at 250°C, and 40 NTP/Hr of styrene chlorohydrin vapor and 4 NTP/Hr of nitrogen were added. A mixed gas of Styrene oxide was obtained in a yield of 18% based on the amount of styrene chlorohydrin fed. Example 11 A glass reaction tube was filled with 6 g of silica gel-supported methylimidazole hydrochloride prepared in the same manner as in Example 3, kept at 300°C, and mixed with 40NTP/Hr of allylchlorohydrin chloride vapor and 4NTP/Hr of nitrogen. Gas was delivered. Epichlorohydrin was obtained in a yield of 6% based on allylchlorohydrin chloride fed. Example 12 3 g of silica gel-supported methylimidazole hydrochloride prepared in the same manner as in Example 1 was charged into a glass reaction tube, kept at 250°C, and mixed with butylene chlorohydrin (2-chlorobutanol-1 and 1-chlorobutanol). -2 mixture) 40NTPml/Hr and nitrogen
A mixed gas of 2NTP/Hr was introduced. Butylene oxide was obtained in a yield of 8% based on the butylene chlorohydrin fed.

Claims (1)

[Claims] 1 An imidazole represented by the formula [Formula] or [Formula] (wherein R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are hydrogen, methyl, ethyl or phenyl groups) In the presence of a compound, [Formula] (where R ₁ , R ₂ , R ₃ , and R ₄ are hydrogen, alkyl, alkenyl, or aryl groups having up to 16 carbon atoms, and X represents a halogen such as chlorine or bromine.) _By dehydrohalogenating _a vicinal haloalcohol represented by the formula, [ _{Formula ]} .) A method for producing an oxirane compound, characterized by converting it into an oxirane compound represented by the formula: