JP5294144B2 - Method for producing dichlorohydrin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of an alkali required in a subsequent dehydrochlorination process and the amount of water and a salt formed in the dehydrochlorination process by efficiently recovering hydrogen chloride from the resulting reaction mixture in the process of producing dichlorohydrin by way of chlorinating glycerin. <P>SOLUTION: It has been discovered that the above problem can be solved by separating and recovering hydrogen chloride gas by way of heating at least a part of the reaction mixture comprising dichlorohydrin, hydrogen chloride and water obtained by chlorinating glycerin. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing dichlorohydrin used for producing an organic compound such as epichlorohydrin.

  Dichlorohydrin used for the production of epichlorohydrin is generally produced by chlorohydrinating allyl chloride. However, a general production method has a problem that a chlorinated product such as trichloropropane, which is a by-product, is generated, and a problem that a large amount of waste water is generated, and a new production method is desired.

  As another method for producing dichlorohydrin, a method for producing dichlorohydrin by reacting glycerin with hydrogen chloride gas in the presence of a catalyst such as formic acid or acetic acid is known. This method is preferable in that dichlorohydrin can be produced without producing a chlorinated product such as trichloropropane.

  Furthermore, since glycerin as a raw material used in this production method is a low-cost renewable resource produced by reaction using vegetable oil or animal oil or production of biodiesel, it is viewed from an economic or environmental point of view. Is also considered a desirable raw material.

  For the above reasons, in recent years, research has been actively conducted on the search for effective catalysts for the reaction, reaction conditions, and production steps with respect to a method for producing chlorohydrin using glycerin as a raw material (see Patent Documents 1 to 4). Currently, carboxylic acids, carboxylic acid derivatives, and compounds having a carboxylic acid structure are used as catalysts.

By the way, the above-mentioned method for producing dichlorohydrin in which glycerin and hydrogen chloride gas are reacted is generally represented by the following formula (1) in the presence of the carboxylic acid catalyst.

  The above reaction is known to be an equilibrium reaction, and the reaction proceeds by extracting the products monochlorohydrin, dichlorohydrin and water out of the reaction system. The reaction can also proceed by increasing the hydrogen chloride concentration, that is, by continuously supplying hydrogen chloride.

  However, the reaction mixture obtained by continuously supplying hydrogen chloride contains not only the target dichlorohydrin but also water and hydrogen chloride. When this reaction mixture is dehydrochlorinated with a base such as aqueous sodium hydroxide to produce epichlorohydrin, not only an excess base is required to neutralize hydrogen chloride, but also hydrogen chloride and Water and salt are produced by the neutralization reaction. The generated water increases drainage, and salt can cause clogging of equipment in other processes.

WO2005 / 021476 WO2005 / 054167 WO2006 / 020234 WO2006 / 110810

  In the production of dichlorohydrin by chlorinating glycerin, the present invention efficiently recovers hydrogen chloride from the resulting reaction mixture, thereby reducing the amount of base required for the subsequent dehydrochlorination step. The amount of water and salt generated in the hydrogen chloride process is reduced.

  As a result of various studies to solve the above problems, the present inventors heated at least a part of a reaction mixture containing dichlorohydrin obtained by chlorinating glycerin, hydrogen chloride, and water to generate hydrogen chloride gas. It has been found that the above problems can be solved by separating and collecting.

That is, the present invention
(A) The step of reacting glycerin with a chlorinating agent (step (A)), and (B) The reaction mixture obtained in step (A), or the reaction mixture obtained in step (A) is distilled or stripped. And a step of (step (B)) separating and recovering hydrogen chloride by heating at least a part of the mixture containing dichlorohydrin, hydrogen chloride and water obtained in this manner.

  Since dichlorohydrin, hydrogen chloride, water and the reaction mixture after recovering hydrogen chloride have a reduced hydrogen chloride concentration, they can be separated into an oil layer and an aqueous layer. The amount of waste water can be further reduced by using the aqueous layer for the production of dichlorohydrin that chlorohydrinates allyl chloride, for example.

The present invention will be described in detail below.
The present invention
(A) The step of reacting glycerin with a chlorinating agent (step (A)), and (B) The reaction mixture obtained in step (A), or the reaction mixture obtained in step (A) is distilled or stripped. Heating at least a part of the mixture containing dichlorohydrin, hydrogen chloride and water obtained in this manner to separate and recover hydrogen chloride (step (B))
At least two steps.

First, step (A) will be described.
The glycerin that is a starting material may include a glycerin ester such as glycerin monoacetate, water, an organic solvent, a salt, and an organic compound. Examples of such a starting material include crude glycerin containing alkali metal salts such as water, sodium salt and potassium salt, and alkaline earth metal salts such as magnesium salt and calcium salt. Alternatively, crude glycerin may be purified, and purified glycerin may be used. About the purity of glycerol, it is preferable that it is 50-99.9 weight%, and it is more preferable that it is 80-99 weight%.

  The dichlorohydrin produced by the reaction of the starting material glycerin with the chlorinating agent is a mixture of 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, but 1,3-dichloro. -2-propanol is produced as the main product. The molar ratio is 1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 90: 10 to 99: 1. In the present invention, 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, and a mixture thereof are also collectively referred to as “dichlorohydrin”. In the present invention, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, and mixtures thereof are collectively referred to as “monochlorohydrin”.

  As the “chlorinating agent” according to the present invention, hydrogen chloride gas and a gas obtained by mixing hydrogen chloride gas and an inert gas (nitrogen gas, argon, helium, etc.) can be used.

  When reacting glycerin with the “chlorinating agent”, a catalyst can be used as appropriate. The “catalyst” is not particularly limited as long as it is a catalyst capable of producing dichlorohydrin from glycerin. Examples of such a catalyst include carboxylic acids, carboxylic acid derivatives, lactones, lactams, solid catalysts. And combinations thereof.

Examples of “carboxylic acid” include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, stearic acid, succinic acid, phthalic acid, benzoic acid, cinnamic acid And malonic acid, adipic acid and the like.
Examples of the “carboxylic acid derivative” include chlorides, anhydrides and esters of the above carboxylic acids.
Examples of the “lactone” include caprolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, and the like.
Examples of “lactam” include ε-caprolactam and γ-butyrolactam.

Examples of the “solid catalyst” include inorganic oxides, inorganic halides, strongly acidic organic compounds, and combinations thereof.
As the “inorganic oxide”, for example, metal oxide, composite oxide, oxyacid and oxyacid salt are preferable.
Examples of “metal oxide” include SiO ₂ , Al ₂ O ₃ , TiO ₂ , Fe ₂ O ₃ , ZrO ₂ , SnO ₂ , Ga ₂ O ₃ , La ₂ O ₃ , CeO ₂ , MoO _{3 and the} like. Can do.
Examples of the “composite oxide” include SiO ₂ —Al ₂ O ₃ , SiO ₂ —TiO ₂ , TiO ₂ —ZrO ₂ , SiO ₂ —ZrO ₂ , MoO ₃ —ZrO ₃ , zeolite, heteropolyacid (eg, P, Examples thereof include polyacids containing elements such as Mo, V, W, and Si), heteropolyacid salts, and the like.
As “oxyacid” and “oxyacid salt”, for example, BPO ₄ , AlPO ₄ , polyphosphoric acid, acidic phosphate, H ₃ BO ₃ , acidic borate, niobic acid (Nb ₂ O ₅ .nH ₂ O) Etc. can be illustrated.

As the “inorganic halide”, for example, a metal halide is preferable. Examples of the metal halide include transition metals such as group 3A elements of the periodic table such as scandium, yttrium, lanthanoid, and actinoid, group 4A elements of the periodic table such as titanium, zirconium, and hafnium, and group 5A elements of the periodic table such as vanadium, niobium, and tantalum. Periodic group 8 elements such as iron, cobalt, nickel, palladium and platinum, periodic table 2B elements such as zinc), periodic table 3B metals such as aluminum and gallium, periodic table 4B metals such as germanium and tin, etc. Examples thereof include metal fluoride, chloride, bromide or iodide.
As the strongly acidic organic compound, for example, an organic sulfonic acid compound is preferable. Examples of the organic sulfonic acid compound include a strongly acidic ion exchange resin such as a sulfonic acid group-containing ion exchange resin and a sulfonic acid compound (CiHjOkSm) containing a carbon condensed ring.

  The concentration of the catalyst is preferably 0.01 to 90 parts by weight, more preferably 0.1 to 40 parts by weight, based on 100 parts by weight of glycerol as a starting material to be reacted with the chlorinating agent, and 0.3 to More preferably, it is 20 parts by weight. When a solid catalyst is used, a fixed bed flow type reactor in which the catalyst is molded to an appropriate size and filled in a tubular reactor can also be used.

  The starting material glycerin is put into a suitable reactor such as a tank reactor, a tube reactor, etc., and a catalyst is optionally used and a chlorinating agent is introduced and reacted. As the reaction, a batch reaction or a continuous reaction can be selected at any time.

  The reaction temperature in step (A) is preferably 20 ° C. to 300 ° C., more preferably 50 ° C. to 200 ° C., and particularly preferably 90 ° C. to 150 ° C.

  The pressure during the reaction in the step (A) is preferably a pressurizing condition from the viewpoint of efficiently proceeding with the reaction, but there is no problem even if it is a normal pressure or a depressurizing condition. The reaction is preferably performed at 0.01 MPaA to 10 MPaA, more preferably 0.01 MPaA to 2 MPaA, and further preferably 0.1 MPaA to 0.6 MPaA.

Next, step (B) will be described.
The reaction mixture containing dichlorohydrin to be heated, water, and hydrogen chloride was obtained by distilling or stripping the direct reaction mixture obtained in the step (A) or the reaction mixture obtained in the step (A). Both mixtures containing dichlorohydrin, hydrogen chloride and water are conceivable. However, in addition to dichlorohydrin, water and hydrogen chloride, the reaction mixture obtained in step (A) uses a high boiling point product such as monochlorohydrin which is an intermediate product, unreacted glycerin and diglycerin, and a catalyst. In this case, a catalyst such as a carboxylic acid, a carboxylic acid ester and the like are included. These substances can be collected separately and recycled to the reaction system to increase productivity. Therefore, the reaction mixture obtained in the step (A) or a part thereof can be obtained by an operation such as distillation or stripping. A mixture containing dichlorohydrin, water and hydrogen chloride is preferred.

  The heating temperature in the step (B) is preferably 0 ° C. to 200 ° C., more preferably 10 ° C. to 150 ° C., and particularly preferably 20 ° C. to 120 ° C.

  The pressure in the step (B) is preferably 0.01 MPaA to 10 MPaA, more preferably 0.05 MPaA to 1.0 MPaA, and further preferably 0.09 MPaA to 0.11 MPaA.

  Hydrogen chloride recovered by heating is not only circulated to a reaction system (for example, step (A)) that requires continuous supply as hydrogen chloride gas, but also glycerin containing hydrogen chloride by dissolving hydrogen chloride gas in glycerin. Can be recycled to the reaction system.

  In step (B), when a part of hydrogen chloride is recovered from the reaction mixture containing dichlorohydrin, water, and hydrogen chloride, the concentration of dichlorohydrin in the mixture is compared because the concentration of hydrogen chloride in the mixture decreases. Even if the amount is high, for example, 40% by weight or more, when the residual liquid after recovering hydrogen chloride is cooled to 40 ° C. or lower, for example, an oil layer mainly composed of dichlorohydrin, a small amount of dichlorohydrin and hydrogen chloride It becomes easy to isolate | separate into two layers of the water layer which melt | dissolved dichlorohydrin as an oil layer.

  Since the separated aqueous layer contains dichlorohydrin and hydrogen chloride, it is preferably used as a reaction process again for the reaction with glycerin. Moreover, it can use for manufacture of other dichlorohydrins, for example, manufacture of the dichlorohydrin which chlorohydrinates allyl chloride, and can reduce the waste_water | drain amount as a whole further.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to the examples without departing from the gist thereof.

Example 1
A 200 ml glass four-necked flask equipped with a thermometer and a stirrer was charged with 100 g (1.09 mol) of glycerin and 5 g (0.042 mol) of succinic acid, heated and stirred at 120 ° C., and hydrogen chloride gas was passed through a blowing tube. It was introduced at a pressure of 3 MPaG and reacted. Unreacted hydrogen chloride gas passed through a rectification column (20 cm height, inner diameter 18 mm, 5 × 5 mm Raschig ring packing) provided at the top of the reactor, then cooled by a cooler and entrained with hydrogen chloride gas. Water and dichlorohydrin were condensed to obtain a uniform distillate. Hydrogen chloride gas that was not condensed in the cooler was circulated to the reactor by a gas pump. After 6 hours of reaction, the weight of the distillate was 126.6 g. Moreover, the residual liquid in a reactor was 86.7g. The distillate was 67.48 g of dichlorohydrin (1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 98.1: 1.9, 0.523 mol), 22.26 g of hydrogen chloride. Was included. The residual liquid in the reactor was 42.14 g of dichlorohydrin (1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 95.7: 4.3, 0.327 mol), monohydride It contained phosphorus 26.17 (3-chloro-1,2-propanediol: 2-chloro-1,3-propanediol = 72.5: 27.5, 0.237 mol) and 1.99 g of hydrogen chloride. The organic matter was analyzed by gas chromatograph analysis by an internal standard method, and the hydrogen chloride was analyzed by titration analysis.

  The above distillate was placed in a 100 ml glass flask equipped with a reflux condenser, a stirrer, and a thermometer, and heated to reflux with stirring. Hydrogen chloride gas not condensed in the reflux condenser was absorbed into glycerin through a tube made of polytetrafluoroethylene. When the amount of hydrogen chloride in glycerin was analyzed by titration, it was 14.9 g. The residual liquid after collecting the hydrogen chloride gas was separated into two layers. As a result of liquid separation, 41.24 g of an aqueous layer and 70.54 g of an oil layer were obtained. The aqueous layer contains 0.86 g of dichlorohydrin (1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 85.7: 14.3, 0.0067 mol) and 6.1 g of hydrogen chloride. It was out. The oil layer contains 55.59 g of dichlorohydrin (1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 98.1: 1.9, 0.431 mol) and 2.61 g of hydrogen chloride. It was.

  In a 100 ml glass three-necked flask equipped with a thermometer and a stirrer, 56.0 g (0.61 mol) of glycerin and 2.80 g (0.024 mol) of succinic acid were added and heated to 130 ° C. with stirring, and the above hydrogen chloride gas 30.0 g of an aqueous layer of the remaining liquid after being recovered was fed with a metering pump. Water in the feed liquid and water produced by the reaction were distilled. After completion of the feed, the reaction temperature was raised to 160 ° C., and water was further distilled to obtain 27.48 g as a distillate and 60.07 g as a residual liquid. The distillate contained 0.71 g of dichlorohydrin (1,3-dichloro-2-propanol: 2,3-dichloro-1-propanol = 84.6: 15.4, 0.0055 mol). The residual liquid contained 11.71 monochlorohydrin (3-chloro-1,2-propanediol: 2-chloro-1,3-propanediol = 72.5: 27.5, 0.106 mol).

  As Example 1 shows, the hydrogen chloride used in the reaction could be efficiently recovered by heating. In addition, the residual liquid after recovering hydrogen chloride can be separated into an oil layer and an aqueous layer. Since the amount of water and hydrogen chloride is small in the oil layer, dehydrochlorination is performed to remove epichlorohydrin. In the case of production, the amount of base and the amount of water and salt produced in the dehydrochlorination step can be greatly reduced in order to neutralize hydrogen chloride.

As described above, in the method for producing dichlorohydrin in which glycerin and a chlorinating agent are reacted, the recovery of hydrogen chloride of the present invention is very useful. This dichlorohydrin is used for the production of organic compounds such as epichlorohydrin.

Claims (5)

(A) reacting glycerin with a chlorinating agent ,
(B) At least a part of the reaction mixture obtained in step (A), or a mixture containing dichlorohydrin, hydrogen chloride and water obtained by distillation or stripping of the reaction mixture obtained in step (A). Heating and separating and recovering hydrogen chloride , and
A method for producing dichlorohydrin, further comprising a step of separating the residual liquid after recovering hydrogen chloride in step (B) into an aqueous layer and an oil layer, and recovering dichlorohydrin as an oil layer .   The method for producing dichlorohydrin according to claim 1, wherein the heating temperature in the step (B) is 10 to 150 ° C. The method for producing dichlorohydrin according to claim 1 or 2, wherein the hydrogen chloride recovered in step (B) is circulated in the reaction system. The method for producing dichlorohydrin according to claim 3 , wherein the circulation of hydrogen chloride to the reaction system is carried out by dissolving the recovered hydrogen chloride in glycerin to produce glycerin containing hydrogen chloride. A method for producing epichlorohydrin, comprising dehydrochlorinating dichlorohydrin obtained by the production method according to claim 1.