JPH09255599A - Production of dichlorobutene derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and inexpensively obtain dichlorobutene derivative in high yield with industrial advantage by allowing isoprene to react with chlorine in the presence of an onium salt catalyst. SOLUTION: (A) Isoprene is allowed to react with (C) chlorine in the presence of (B) a catalyst, preferably one or more kinds of onium salts selected from among tetrametylammonium bromide, tetrabutylammonium bromide, tetrabutylphosphonium bromide and hexadecyltrimethylammonium chloride. This reaction is preferably carried out in a solvent in an amount of 0.02-1 mole of a solvent per mole of the component A, preferably an aprotic polar solvent such as dimethylformamide, dimethylacetamide or hexamethylphosphoramide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a dichlorobutene derivative using isoprene as a raw material.

[0002]

2. Description of the Related Art The dichlorobutene derivative is a butenediol derivative, 3-methyl-2,5-dihydrofuran,
It can be an important intermediate such as 3-methyltetrahydrofuran, and particularly its 1,4-dichloro compound has a high reactivity and thus has a high industrial value. This dichlorobutene derivative is produced from isoprene as a raw material,
Conventionally, chlorination of isoprene is generally carried out without solvent or in a general-purpose organic solvent, and general-purpose organic solvents include aliphatic hydrocarbons such as hexane and cyclohexane, and aromatic hydrocarbons such as toluene and xylene. Hydrogen or halogenated hydrocarbons such as carbon tetrachloride and chloroform have been mainly used.

However, in that case, by side reaction such as dehydrochlorination or addition of desorbed hydrogen chloride to isoprene,
50% of monochlorobutadiene derivative and polychlorinated form
There was a drawback that it was generated to some extent. As a prescription for compensating for this drawback, JP-A-49-85007 and USP39
The method described in 32543 is currently in use. That is, in JP-A-49-85007,
N-alkylamides such as dimethylformamide (DMF) with isoprene are also disclosed in US Pat.
In No. 3, DMF and dimethylacetamide (D
(MA), hexamethylphosphoramide (HMPA), dimethylsulfoxide (DMSO) and the like in the coexistence of an aprotic polar solvent to suppress the formation of monochlorobutadiene derivatives and polychlorinated compounds, to obtain the desired dichlorobutene derivative. There is.

[0004]

In the conventional method for producing a dichlorobutene derivative using isoprene as a raw material, for example, in the formulation described in USP3932543, if the conversion rate of isoprene is increased, the selectivity for the dichlorobutene derivative is lowered, so that high selectivity is obtained. In order to maintain
However, it is necessary to recover unreacted isoprene from the system in order to improve the yield. However, in the case of the above formulation, nearly 30% of the converted components are occupied by the monochlorobutadiene derivative and the polychlorinated product, and the boiling point of the monochlorobutadiene derivative is relatively close to that of isoprene, so isoprene is separated, Difficult to collect,
Therefore, there arises a problem that the cost is further increased. Further, in the case of the formulation described in JP-A-49-85007, a solvent containing an N-alkylamide is used in order to absorb chlorine necessary for the reaction in advance in the solvent or to enhance the selectivity by increasing the dilution rate of isoprene. Is required in a large excess amount with respect to isoprene, and the volumetric efficiency of the apparatus is industrially very poor, which is also a problem in terms of cost.

In view of such circumstances, the present invention is a simple and inexpensive method for producing a dichlorobutene derivative from isoprene, in which the amount of remaining raw materials is extremely small, and a monochlorobutadiene derivative and a polychlorinated product are little produced, and The highly reactive 1,4-dichloro compound was used as an intermediate for 3,4-
It is an object of the present invention to provide a method for producing a dichlorobutene derivative that is contained in a larger amount than the dichloro form.

[0006]

[Means for Solving the Problem] As a result of intensive studies conducted by the present inventors in order to achieve the above object, as a result, isoprene is reacted with chlorine in the presence of an onium salt catalyst. Of monochlorobutadiene derivative and polychlorinated product at a high rate, and moreover, a simple and inexpensive dichlorobutene derivative containing a large amount of highly reactive 1,4-dichloro compound as an intermediate compared to 3,4-dichloro compound The manufacturing method was found. Further, during the present study, by using a small amount of the aprotic polar solvent of 0.02 to 1 mol per mol of isoprene together with the onium salt catalyst, the dichlorobutene derivative can be obtained in a higher yield, and 1 It was found that a remarkable synergistic effect that a relative production ratio of the 4,4-dichloro compound is increased can be obtained, and the present invention has been completed.

[0007] In the above reaction for adding chlorine to isoprene, the mechanism of action of the onium salt as a catalyst has not been clarified, but chlorine is retained so far in order to accelerate the chlorine addition in the reaction. It is considered that not only does the unnecessary excess amount of solvent that has been used for this purpose be unnecessary, but it also has the inhibitory action on the formation of monochloro derivative. Therefore, it is presumed that the monochloro derivative produced is further dichlorinated to suppress the increase of polychlorinated products mainly of the trichloro derivative produced. As a result, it is considered that the high conversion of isoprene and the production of dichloro derivatives, particularly 1,4-dichloro compounds with high selectivity are compatible with each other. This action also makes it unnecessary to use an excess amount of solvent in order to increase the selectivity to the dichloro compound by diluting isoprene when carrying out the addition reaction, which is a conventionally used method. . Furthermore, the use of an aprotic polar solvent in combination resulted in a synergistic increase in these effects, but as described above, the solvent is not particularly required for chlorine retention or for diluting the raw material, It is thought that the aprotic polar solvent can exert the effect even in a small amount.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Isoprene and a compound represented by the general formula (R1) ₄ M ⁺ X ⁻ (wherein, R 1 is a hydrocarbon group independently selected from four groups, which may be ring-closed to each other. Is a phosphorus or nitrogen atom, X ⁻ represents a counter anion), or the general formula (R2) ₃ S ⁺ X ⁻ (wherein, R 2 is a hydrocarbon group independently selected from each other, and they are ring-closed to each other. X ⁻ represents a counter anion), and chlorine is blown into the mixed solution with an onium salt represented by the formula) while keeping the temperature at preferably −15 to 35 ° C., more preferably 0 to 30 ° C. The chemical reaction is performed. The reaction solution thus obtained is washed with water and, if necessary, dried with a dehydrating agent such as anhydrous magnesium sulfate to obtain the desired dichlorobutene derivative containing a large amount of 1,4-dichloro compound.

In the above general formula of the onium salt, the substituent R1,
R2 may be linear, branched, or cyclic, and may be bonded to each other to form a ring to form, for example, a piperidine ring or a pyridine ring. It may also contain aromatic hydrocarbons such as phenyl, benzyl and naphthyl. X ⁻ is an organic or inorganic anion, for example, F ⁻ , Cl ⁻ , Br ⁻ , NO ₃ ⁻ , HSO ₄ ⁻ , ClO ₄
^- , HCO ₃ ⁻ , CH ₃ COO ⁻ , C ₆ H ₅ COO ^{− and the} like. Onium salts should be industrially selected considering their availability and price. From these aspects, an ammonium salt is preferable, and examples thereof include tetramethylammonium bromide, tetrabutylammonium bromide, or in the compound represented by the above general formula, two or three R1 are methyl groups and the remaining 2 to 1 Examples thereof include ammonium bromide in which each R1 is an alkyl group having about 3 to 18 carbon atoms or a benzyl group, ammonium chloride, and the like. These onium salts may be used alone or in combination of two or more.

With respect to the amount of the onium salt, if the amount is too small, the effect decreases and if the amount is large, it is wasted. Therefore, 0.002 to 1 mol is preferable to 1 mol of isoprene, and particularly 0.05.
.About.0.5 mol is preferred.

The chlorine introduction rate is not particularly limited because it depends on the reaction scale, but if it is too slow, the reaction takes a long time, and if it is too fast, the reaction temperature is controlled and the raw material and chlorine are dissipated. Therefore, it is preferable to blow at a rate at which the temperature can be controlled to 30 ° C. or less. If the amount of chlorine is less than equimolar to isoprene, the amount of remaining raw materials will increase,
Further, if the amount is equal to or more than equimolar, polychlorination is caused, and any of them causes a decrease in yield. Therefore, blowing in equimolar is optimal.

When the above reaction is carried out in an aprotic polar solvent, a remarkable synergistic effect is observed, and a dichlorobutene derivative containing a large amount of 1,4-dichloro compound is obtained in a high yield with less by-products. . Examples of the aprotic polar solvent include DMF, DMA, HMPA, DMSO, acetonitrile and the like. These solvents are usually used alone, but two or more kinds may be mixed and used.

If the amount of the aprotic polar solvent is less than 0.02 mol with respect to 1 mol of isoprene, the effect cannot be exhibited. Therefore, a larger amount is required. There is no particular limitation on the upper limit, but from the viewpoint of cost, etc.,
It is preferably up to 1 mol, and particularly preferably 0.05 to 0.5 mol per 1 mol of isoprene.

[0014]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 48 g of chlorine was introduced into a mixed solution of 50 g of isoprene and 5.0 g of tetrabutylammonium bromide (TBAB) at 2-28 ° C. over 1.3 hours. After the introduction of chlorine, the reaction mixture was washed 3 times with 50 ml of water and then dried over anhydrous magnesium sulfate,
A mixture containing the desired dichlorobutene derivative was obtained.
The yield of the mixture was 97 g. As a result of analysis by gas chromatography (GC) of the mixture containing the dichlorobutene derivative, the weight abundance ratio of main components was as follows. Isoprene 0.4%, monochlorobutadiene derivative 32.3%, dichlorobutene derivative 56.1% (1,
4-form 30.1%, 3,4-form 26.0%), polychlorinated form 9.7%. Yield of dichlorobutene derivative is 54.4%
(Isoprene base).

Example 2 Isoprene 50 g, DMF
9.0 g and tetrabutylammonium bromide (T
BAB) 5.0 g of a mixed solution, chlorine at 2 ~ 28 ℃ 5
3 g were introduced over 2.8 hours. After the introduction of chlorine was completed, the reaction mixture was washed 3 times with 50 ml of water and then dried over anhydrous magnesium sulfate to obtain a desired mixture containing the dichlorobutene derivative. The yield of the mixture was 96g.
As a result of GC analysis of the mixture containing the dichlorobutene derivative, the weight abundance ratios of the main components were as follows.
Isoprene 2.5%, monochlorobutadiene derivative 5.
5%, dichlorobutene derivative 83.6% (1,4-body 5
5.2%, 3,4-body 28.4%), polychlorinated body 8.1
%. The yield of the dichlorobutene derivative was 79.4% (isoprene base).

Example 3 Hexadecyltrimethylammonium chloride 5.6 was added to TBAB 5.0 g.
The same operation as in Example 2 was carried out except that the amount was changed to g to obtain 95 g of a mixture containing a dichlorobutene derivative. The weight abundance ratio of the main components by GC analysis is isoprene 4.9%, monochlorobutadiene derivative 8.8%, dichlorobutene derivative 77.8% (1,4-body 49.5%, 3,4-body 2).
8.3%), polychlorinated form 6.9%. The yield of the dichlorobutene derivative was 72.4%.

Example 4 96 g of a mixture containing a dichlorobutene derivative was obtained in the same manner as in Example 2 except that 5.2 g of tetrabutylphosphonium bromide was used instead of 5.0 g of TBAB. The weight abundance ratios of the main components by GC analysis are as follows: isoprene 2.7%, monochlorobutadiene derivative 8.6%, dichlorobutene derivative 80.3
% (1,4-body 50.8%, 3,4-body 29.5%),
Polychlorinated form 6.9%. Yield of dichlorobutene derivative is 7
6.3%.

A comparative example will be shown below.

Comparative Example 1 50 g of isoprene, 2 to
53 g of chlorine was introduced at 28 ° C. over 1.4 hours. After the introduction of chlorine was completed, the reaction mixture was washed 3 times with 50 ml of water and then dried over anhydrous magnesium sulfate to obtain a desired mixture containing the dichlorobutene derivative. The yield of the mixture was 95 g. As a result of GC analysis of the mixture containing the dichlorobutene derivative, the weight abundance ratios of the main components were as follows. Monochlorobutadiene derivative 47.2
%, Dichlorobutene derivative 41.3% (1,4-body 2
6.9%, 3,4-body 14.4%), polychlorinated body 9.1
%. The yield of the dichlorobutene derivative was 38.4% (isoprene base).

[0021]

EFFECTS OF THE INVENTION In order to suppress the formation of by-products, the conversion rate of isoprene is limited to about 50%, or as compared with the conventional production method which requires a large excess amount of solvent with respect to isoprene, 1) The conversion rate can be improved to nearly 100%, and (2) the raw material recovery step can be omitted,
(3) Since a large excess amount of solvent is not required and the volumetric efficiency of the reaction apparatus is high, a dichlorobutene derivative with a high yield and a small amount of by-products can be simply and inexpensively produced.

Therefore, the present invention is a very industrially advantageous method for producing a dichlorobutene derivative.

Claims (6)

[Claims] 1. A process for producing a dichlorobutene derivative, which comprises reacting isoprene with chlorine in the presence of a catalyst. 2. A catalyst of the general formula (R1) ₄ M ⁺ X ⁻ (wherein R 1 is a hydrocarbon group independently selected from four groups, which may be ring-closed to each other, and M is phosphorus. Or a nitrogen atom, X ⁻ represents a counter anion), or a general formula (R2) ₃ S ⁺ X ⁻ (in the formula, R 2 is a hydrocarbon group independently selected from each other, and they are ring-closed to each other. May be used, and X ⁻ represents a counter anion.) The method for producing a dichlorobutene derivative according to claim 1, characterized in that an onium salt represented by the formula: is used. 3. The onium salt is one or more selected from the group consisting of tetramethylammonium bromide, tetrabutylammonium bromide, tetrabutylphosphonium bromide and hexadecyltrimethylammonium chloride. The method for producing a dichlorobutene derivative according to item 1. 4. The reaction is carried out at a rate of 0.
The method for producing a dichlorobutene derivative according to claim 1, which is carried out in a solvent of 02 to 1 mol. 5. The method for producing a dichlorobutene derivative according to claim 4, wherein the solvent is an aprotic polar solvent. 6. The aprotic polar solvent is one or more selected from dimethylformamide, dimethylacetamide, hexamethylphosphoramide, dimethylsulfoxide, and acetonitrile, and is characterized in that: The method for producing a dichlorobutene derivative according to item 1.