CA1277681C - Process for the production of 2,3-dichloro-1-propanol - Google Patents
Process for the production of 2,3-dichloro-1-propanolInfo
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- CA1277681C CA1277681C CA000544005A CA544005A CA1277681C CA 1277681 C CA1277681 C CA 1277681C CA 000544005 A CA000544005 A CA 000544005A CA 544005 A CA544005 A CA 544005A CA 1277681 C CA1277681 C CA 1277681C
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- allyl alcohol
- hydrochloric acid
- reaction
- dichloro
- propanol
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Abstract
Abstract:
The present invention is directed to an improved process for the production of 2,3-dichloro-1-propanol in high yield by chlorinating allyl alcohol with chlorine, wherein the chlorination reaction proceeds by simul-taneously introducing allyl alcohol and chlorine gas and optionally hydrogen chloride gas into the reaction system containing aqueous hydrochloric acid without the necessity of extreme cooling and/or pressure.
The present invention is directed to an improved process for the production of 2,3-dichloro-1-propanol in high yield by chlorinating allyl alcohol with chlorine, wherein the chlorination reaction proceeds by simul-taneously introducing allyl alcohol and chlorine gas and optionally hydrogen chloride gas into the reaction system containing aqueous hydrochloric acid without the necessity of extreme cooling and/or pressure.
Description
'776a~
Process for the ~roauction of 2,3-dichloro~ ropanol __ ____________ ____________________________ __ __ This invention relates to an improved process for the production of 2,3-dichloro-1-propanol, more particularly, to an industrial process for the production of 2,3-dichloro-l-propanol by chlorinating allyl alcohol with S chlorine, wherein allyl alcohol and chlorine gas and optionally hydrogen chloride gas are simultaneously added to the reaction system containing aqueous conc. hydro-chloric acid in a batch system or in a continuous system.
It is well known that 2,3-dichloro l-propanol is very useful as a material for the production of glycerin and glycidol, or as an intermediate for the production of epichlorohydrin which is useful as a material for the production of epoxy resins, synthetic rubbers, etc.
Various processes have hitherto ~een known for the lS production of 2,3-dichloro-1-propanol. For example, it has been produced by chlorinating allyl alcohol with chlorine gas in carbon disulfide or without using any solvent, but these processes give the desired product in very low yield for example, about 20 to 40 ~.
It has recently been found that the low yield of the product in the above processes is largely due to some side reactions, e.g. oxidation of allyl alcohol to acrolein by chlorine, and further that these side reactions can be suppressed by the presence of hydrogen chloride. For example, it is known that the compound can be prepared in high yield by dissolving allyl alcohol in an organic solvent, saturating the solution with hydrogen chloride ~,~`t~
768~
and then introducing chlorine gas thereto [cf. Japanese Patent First Publication (Kokai) No. 1361~1971 (= U.S.
Patent 3,823,193), and Japanese Patent Second Publication (Kokoku) No. 18207/1973]. However, these processes have some problems, ~or example, loss of the product and the solvent during the separation of the product from the solvent and hydrogen chloride and purification of the product by distillation.
There are also known processes, which do not use any organic solvent, but simply introduce chlorine gas into aqueous conc. hydrochloric acid thereby dissolving the allyl alcohol [cf. Japanese Patent Second Publication - (Kokoku) No. 17206/1962, and Japanese Patent Second Publication (Kokoku) No. 60054/1986~ In the process disclosed in Japanese Patent Second Publication No.
17206/1962, a commercially available conc. hydrochloric acid can be used, which is advantageous from the indus-trial viewpoint, but this process is still unfavorable because of the low yield of the product (i.e. 50 to 70 yield~. Besides, in the process disclosed in Japanese Patent Second Publication No. 60054/1986, the hydrochloric acid solution should be in a concentration as high as 50 to 75 ~ by weight, and for such a purpose, the hydrogen chloride gas must be introduced into the aqueous allyl alcohol solution prior to the chlorination, which requires disadvantageously an additional step. Moreover, in this process, the reaction should be carried out at a lower temperature and/or under pressure in order to keep the high concentration of hydrochloric acid, which requires disadvantageously a specific expensive apparatus. Thus, this process is not necessarily preferable for the produc-tion of the compound on an industrial scale.
It is also disclosed in Japanese Patent First Publica-tion (Kokai) No. 258171/1985 (= U.S. Patent No. 4,634,784) that 2,3-dichloro-1-propanol is prepared by reacting allyl alcohol with chlorine in aqueous hydrochloric acid having . . . ~
7~8 a concentration of 45 to 70 ~ by weight at a lower tempera-ture and/or under pressure, and the 2,3-dichloro-1-propanol thus prepared is converted into epichlorohydrin in several steps. This process also requires a high concentration of hydrochloric acid and should be carried out at a lower temperature and/or under pressure, and hence, includes the same problems as mentioned above.
The present inventors have researched intensively to improve these known processes in order to produce the desired 2,3-dichloro-1 propanol in higher yields without the problems of the known processes, and have now found that this object can be achieved by simultaneously supply-ing the starting materials (allyl alcohol, chlorine gas and preferably further hydrogen chloride gas) into a reaction system containing aqueous hydrochloric acid, where it is not necessary to use a very high concentration of hydro-chloric acid nor to carry out the reaction at a very low temperature and/or under pressure, and hence, this process is very advantageous for the production of the desired compound on an industrial scale.
An object of the invention is to provide an improved process for the production of 2,3-dichloro-1-propanol in high yield by a simple procedure using commercially avail-able hydrochloric acid. Another object of the invention is to provide a process for the production of 2,3-dichloro-l-propanol without using any specific pressure vessel.
These and other objects and advantages of the invention will be apparent to those skilled in the art from the following description.
The process for the production of 2,3-dichloro-1-propanol of this invention comprises simultaneously introducing allyl alcohol and chlorine gas and preferably further hydrogen chloride gas into the solvent (aqueous hydrochloric acid having a concentration of 25 to 40 ~
by weight), whereby the allyl alcohol is subjected to a chlorination reaction.
76~3~
In the chlorination of allyl alcohol in aqueous hydrochloric acid, there is generally the possibility of the following side reactions:
(1) production of allyl chloride by reaction of allyl alcohol with hydrochloric acid, (2) production of condensation products of allyl alcohol with chloronium ion which is an intermediate of the chlorination reaction, and (3) production of condensation products of the above chloronium ion with the 2,3-dichloro-1-propanol produced.
In order to increase the yield of the desired product, 2,3-dichloro-1-propanol, it is important to suppress the above side reactions. From this viewpoint, the present inventors have researched the conditions suitable fo~
suppressing the side reactions and have found that it is necessary, (i) to keep the concentration of allyl alcohol in the reaction mixture as small as possible and thereby to make the con~act time of allyl alcohol with hydrochloric acid as short as possible in order to suppress the side reaction (1), and tii) to lower the nucleophilicity of allyl alcohol or 2,3-dichloro-1-propanol to the chloronium ion in the reaction mixture in order to suppress the side reactions (2) and ~3).
Based upon the above findings, i~ has recently been found that, by simultaneously introducing allyl alcohol and chlorine gas into the reaction system containing aqueous hydrochloric acid through separate inlets and preferably by also simultaneously supplying hydrogen chloride gas in order to keep the desired concentration of hydrochloric acid in the reaction system, the undesirable side reactions * are effectively suppressed and hence the reaction results in an extremely high yield of the desired product. Accord-ing to this process, the allyl alcohol is immediately chlorinated with the chlorine introduced s.imultaneously because the reaction of allyl alcohol with chlorine proceeds very rapidly in aqueous hydrochloric acid, and ~... . ...
; ~ ~776~
hence, the contact time of allyl alcohol with hydrochloric acid and chloronium ion becomes negligibly small, by which the side reactions (1) and (2) as mentioned above can be minimized. In fact, according to the process of this invention, the by-products, e.g., allyl chloride or deriv-atives thereof, are less than 1 % or preferably less than 0.5 ~. Moreover, in the feature of simultaneously supply-ing the hydrogen chloride gas, even though the aqueous hydrochloric acid is diluted with the 2,3-dichloro-1-propanol produced, the desired concentration of hydro-chloric acid (i.e. in saturated state) can be kept by supplying hydrogen chloride gas, and thereby, the nucleo-philicity of 2,3-dichloro-1-propanol to the chloronium ion is reduced, and hence the above-mentioned side reaction (3) can be significantly s~ppressed even in the presence of a comparatively high concentration of 2,3-dichloro-1-propanol in the reaction system~
As the solvent, commercially available conc. hydro-chloric acid can be used. The aqueous hydrochloric acid used as the solvent in this invention usually has a concen-tration of 25 to 40 ~ by weight, preferably 30 to 40 % by weight, more preferably 35 to 40 % by weight. When the concentration of hydrochloric acid is lower than 25 % by weight, the undesirable oxidation of allyl alcohol to acro-lein is observed. Besides, as is mentioned hereinbefore,with progress of the reaction, the solvent is diluted with the 2,3-dichloro-1-propanol produced, and hence, the concentration of hydrochloric acid in the reaction system is further decreased. In order to prevent such dilution during the reaction, it is preferable to supply hydrogen chloride gas. However, when hydrogen chloride gas is added, the temperature of the reaction mixture rises owing to the heat from dissolution of the hydrogen chloride as well as from the exothermic reaction of the chlorination of allyl alcohol. Accordingly, when too large an amount of hydrogen chloride gas is added, it is difficult to ~ ;~t776~
control the temperature of the reaction mixture, and extra energy is required ~or cooling the reaction mixture. More-over, when the concentration of hydrochloric acid in the solvent is lower at the initiation of the reaction, it results in a low product yield. From these viewpoints, it is preferable to use, as a solvent, aqueous hydrochloric acid having a concentration of not less than 25 ~ by weight. On the other hand, when the solvent has a concen-tration of hydrochloric acid of more than 40 % by ~eight, it is disadvantageously necessary to employ means for increasing the concentration, e.g., a specific cooling device, a pressure vessel, etc.
The solvent, aqueous hydrochloric acid, is used in an amount of not less than two times by weight, preferably 2 to 8 times by weight, more preferably 3 to 5 times by weight, the total amount of allyl alcohol to be introduced thereto. When the amount of the solvent is less than two times by weight, the side reaction (3) as mentioned herein-before increases remarkably.
The allyl alcohol and chlorine gas are introduced in about equimolar amount, usuaLly 1 : 1 to 1 : 1.01 by mole.
These are preferably introduced through separate introduc-tion ducts. ~hen a large excess amount of allyl alcohol and/or chlorine gas is introduced, it induces undesirable side reactions. The allyl alcohol and chlorine gas are introduced at a rate of 0.01 to 50 mole/L.hr (L = liter of initial solvent), preferably 0.1 to 20 mole/L.hr, in a batch system or in a continuous system. In the case of supplying further hydrogen chloride gas, it is supplied in an amount of 0.5 to 3 times by mole, preferably 1 to 1.5 times by mole, the amount of allyl alcohol. The reaction mixture is prevented from being saturated with hydrochloric acid, even though hydrogen chloride gas is continuously supplied to the reaction system, because the concentration of hydrochloric acid in the reaction system does not go over that of conc. hydrochloric acid ~e.g. about 45 ~ by ?`;
,' - i,~
776~3~
weight at OC) as a result of the poor solubility o hydrogen chloride in the 2,3-dichloro-1-propanol produced.
It is also apparent that supply of a large excess of hydrogen chloride gas is fruitless, because the reaction S mixture is saturated with it. The hydrogen chloride gas may be introduced into the reaction system through an independent introduction duct, but is preferably introduced through the same duct as the chlorine gas as a mixture of hydrogen chloride gas and chlorine gas.
The reaction of this invention is preferably carried out with agitation. It is preferable to maintain the reac-tion temperature as low as possible in order to increase the ~ield of the product, but from an industrial viewpoint, in order to keep the viscosity of the reaction mixture low or to save energy for cooling, it is preferable to carry out the reaction at a temperature of from -5 to 10C
under atmospheric pressure. The reaction may be done under light, but is preferably carried out with protection from light in order to increase the yield of the product.
The product, 2,3-dichloro-1-propanol, can be isolate from the reaction mixture by any conventional method, for example, by neutralizing the reaction mixture with a basic compound (e.g. sodium hydroxide, calcium hydroxide, etc.) or purging at least a portion of the hydrogen chloride gas with an inert gas (e.g. nitrogen gas), and then subjecting the mixture to distillation. When the product is used as an intermediate for the preparation of other products, e.g. epichlorohydrin, the reaction mixture containing 2,3-dichloro-l-propanol may be subjected to the subse~uent reactions ater partially removing the hydrochloric acid thererom, without isolation of the product.
The process of this invention can be carried out using commercially available aqueous hydrochloric acid as the solvent in a simple procedure without the necessity of speciic apparatus. Moreover, the reaction proceeds with-out undesirably lowering the concentration of hydrochloric .~ ~
~776~3~
acid in the solvent when hydrogen chloride gas is simul-taneously supplied together with the starting materials, and hence, undesirable side reactions can be effectively prevented and the desired product can be obtained in a very high yield.
The present invention is illustrated by the following Examples and Reference Examples, but should not be construed to be limited thereto.
Exam~le 1 A reaction vessel provided with an agitator was charged with 40 wt. % aqueous hydrochloric acid (110 g, 1.2 mole as ~Cl), and thereto were added with agitation allyl alcohol (23.4 g, 0.4 mole) and chlorine gas ~28.8 g, 0.4 mole) through separate introduction ducts at a rate of an equi-molar amount over a period of time of 45 minutes at -5C
under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was directly analyzed by gas chromatography (hereinafter, abbreviated as GC method) with a column packed with OV*-225 (5 %)/Chromosolve* W AW-DMCS using biphenyl as an internal standard. The yield of 2,3-dichloro-1-propanol was 95.0 %.
Exam~le 2 ___ __ .
The reaction was carried out in the same manner ~s described in Example 1 except that 35 wt. ~ aqueous hydro-chloric acid (115 g, 1.1 mole as HCl) was used, the reac-tion temperature was maintained at 0C, and the reaction mixture was likewise analyzed by the GC method. The desired 2,3-dichloro-1-propanol was produced in a yield o~ 90.2 %.
Exam~le _ The reaction was carried out in the same manner as des-cribed in Example 1 except that 30 wt. ~ aqueous hydro-chloric acid (89 g, 0.73 mole as ~ICl) was used and the reaction temperature was maintained at 10C. The desired 2,3-dichloro-1-propanol was produced in a yield of 85.6 * Trade mark ~, ~7'7~i81 Reference Example 1 ____ __ ___ _ The same reaction vessel as used in Example 1 was charged with 20 wt. % aqueous hydrochloric acid (54.5 g, 0.3 mole as E~Cl), and thereto were added with agitation allyl alcohol (5.9 g, 0.1 mole) and chlorine gas (7.0 g, 0.1 mole) through separate introduction ducts at a rate o~
an equimolar amount over a period of time o~ 45 minutes at OC under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was likewise directly analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 58.6 %.
Reference Exam~ 2 _________ _ The same reaction vessel as used in Example 1 was charged with 35 wt. % aqueous hydrochloric acid (30 g, 0.29 mole as HCl) and allyl alcohol (11.6 g, 0.2 mole), and thereto was added with agitation chlorine gas (14.2 g, 0.2 mole) over a period of time o 45 minutes at OC under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was directly analyzed by the GC method. The yield of 2,3-dichloro-l-propanol was 72.0 ~.
Exam~le 4 ___ ___ A reaction vessel provided with an agitator was charged with 37 wt. ~ aqueous hydrochloric acid (110 g, 1.1 mole as HCl), and thereto were added with agitation allyl alcohol (23.2 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (22 g, 0~6 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol and chlori~e gas over a period of time of 45 minutes at OC under atmos-pheric pressure and under protection from light.
After the reaction was completed, excessive hydrogen chloride gas was purged by blowing nitrogen gas therein, and then the reaction mixture was directly analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 98.1 %.
".; .
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~ ~ ~'7768~
Exam~le 5 ____ ___ The same reaction vessel as used in Example 4 was charged with 30 wt. % aqueous hydrochloric acid (150 9, 1.2 mole as ~Cl), and thereto were added with agitation allyl alcohol (23.5 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (43~8 g, 1.2 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol ancl chlorine gas over a period of time of 45 minutes at 0C under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was treated in the same manner as in Example 4 and was analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 95.1 %O
~ le The same reaction vessel as used in Example 4 was charged with 40 wt. ~ aqueous hydrochloric acid (50 g, 0.54 mole as HCl), and thereto were added with agitation allyl alcohol (23.4 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (7.3 g, 0.2 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol and chlorine gas over a period of time of 45 minutes at -5C under atmospheric pressure and under protection from lig,ht.
After the reaction was completed, the reaction mixture was treated in the same manner as in ~xample 4 and was analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 98.3 ~.
Process for the ~roauction of 2,3-dichloro~ ropanol __ ____________ ____________________________ __ __ This invention relates to an improved process for the production of 2,3-dichloro-1-propanol, more particularly, to an industrial process for the production of 2,3-dichloro-l-propanol by chlorinating allyl alcohol with S chlorine, wherein allyl alcohol and chlorine gas and optionally hydrogen chloride gas are simultaneously added to the reaction system containing aqueous conc. hydro-chloric acid in a batch system or in a continuous system.
It is well known that 2,3-dichloro l-propanol is very useful as a material for the production of glycerin and glycidol, or as an intermediate for the production of epichlorohydrin which is useful as a material for the production of epoxy resins, synthetic rubbers, etc.
Various processes have hitherto ~een known for the lS production of 2,3-dichloro-1-propanol. For example, it has been produced by chlorinating allyl alcohol with chlorine gas in carbon disulfide or without using any solvent, but these processes give the desired product in very low yield for example, about 20 to 40 ~.
It has recently been found that the low yield of the product in the above processes is largely due to some side reactions, e.g. oxidation of allyl alcohol to acrolein by chlorine, and further that these side reactions can be suppressed by the presence of hydrogen chloride. For example, it is known that the compound can be prepared in high yield by dissolving allyl alcohol in an organic solvent, saturating the solution with hydrogen chloride ~,~`t~
768~
and then introducing chlorine gas thereto [cf. Japanese Patent First Publication (Kokai) No. 1361~1971 (= U.S.
Patent 3,823,193), and Japanese Patent Second Publication (Kokoku) No. 18207/1973]. However, these processes have some problems, ~or example, loss of the product and the solvent during the separation of the product from the solvent and hydrogen chloride and purification of the product by distillation.
There are also known processes, which do not use any organic solvent, but simply introduce chlorine gas into aqueous conc. hydrochloric acid thereby dissolving the allyl alcohol [cf. Japanese Patent Second Publication - (Kokoku) No. 17206/1962, and Japanese Patent Second Publication (Kokoku) No. 60054/1986~ In the process disclosed in Japanese Patent Second Publication No.
17206/1962, a commercially available conc. hydrochloric acid can be used, which is advantageous from the indus-trial viewpoint, but this process is still unfavorable because of the low yield of the product (i.e. 50 to 70 yield~. Besides, in the process disclosed in Japanese Patent Second Publication No. 60054/1986, the hydrochloric acid solution should be in a concentration as high as 50 to 75 ~ by weight, and for such a purpose, the hydrogen chloride gas must be introduced into the aqueous allyl alcohol solution prior to the chlorination, which requires disadvantageously an additional step. Moreover, in this process, the reaction should be carried out at a lower temperature and/or under pressure in order to keep the high concentration of hydrochloric acid, which requires disadvantageously a specific expensive apparatus. Thus, this process is not necessarily preferable for the produc-tion of the compound on an industrial scale.
It is also disclosed in Japanese Patent First Publica-tion (Kokai) No. 258171/1985 (= U.S. Patent No. 4,634,784) that 2,3-dichloro-1-propanol is prepared by reacting allyl alcohol with chlorine in aqueous hydrochloric acid having . . . ~
7~8 a concentration of 45 to 70 ~ by weight at a lower tempera-ture and/or under pressure, and the 2,3-dichloro-1-propanol thus prepared is converted into epichlorohydrin in several steps. This process also requires a high concentration of hydrochloric acid and should be carried out at a lower temperature and/or under pressure, and hence, includes the same problems as mentioned above.
The present inventors have researched intensively to improve these known processes in order to produce the desired 2,3-dichloro-1 propanol in higher yields without the problems of the known processes, and have now found that this object can be achieved by simultaneously supply-ing the starting materials (allyl alcohol, chlorine gas and preferably further hydrogen chloride gas) into a reaction system containing aqueous hydrochloric acid, where it is not necessary to use a very high concentration of hydro-chloric acid nor to carry out the reaction at a very low temperature and/or under pressure, and hence, this process is very advantageous for the production of the desired compound on an industrial scale.
An object of the invention is to provide an improved process for the production of 2,3-dichloro-1-propanol in high yield by a simple procedure using commercially avail-able hydrochloric acid. Another object of the invention is to provide a process for the production of 2,3-dichloro-l-propanol without using any specific pressure vessel.
These and other objects and advantages of the invention will be apparent to those skilled in the art from the following description.
The process for the production of 2,3-dichloro-1-propanol of this invention comprises simultaneously introducing allyl alcohol and chlorine gas and preferably further hydrogen chloride gas into the solvent (aqueous hydrochloric acid having a concentration of 25 to 40 ~
by weight), whereby the allyl alcohol is subjected to a chlorination reaction.
76~3~
In the chlorination of allyl alcohol in aqueous hydrochloric acid, there is generally the possibility of the following side reactions:
(1) production of allyl chloride by reaction of allyl alcohol with hydrochloric acid, (2) production of condensation products of allyl alcohol with chloronium ion which is an intermediate of the chlorination reaction, and (3) production of condensation products of the above chloronium ion with the 2,3-dichloro-1-propanol produced.
In order to increase the yield of the desired product, 2,3-dichloro-1-propanol, it is important to suppress the above side reactions. From this viewpoint, the present inventors have researched the conditions suitable fo~
suppressing the side reactions and have found that it is necessary, (i) to keep the concentration of allyl alcohol in the reaction mixture as small as possible and thereby to make the con~act time of allyl alcohol with hydrochloric acid as short as possible in order to suppress the side reaction (1), and tii) to lower the nucleophilicity of allyl alcohol or 2,3-dichloro-1-propanol to the chloronium ion in the reaction mixture in order to suppress the side reactions (2) and ~3).
Based upon the above findings, i~ has recently been found that, by simultaneously introducing allyl alcohol and chlorine gas into the reaction system containing aqueous hydrochloric acid through separate inlets and preferably by also simultaneously supplying hydrogen chloride gas in order to keep the desired concentration of hydrochloric acid in the reaction system, the undesirable side reactions * are effectively suppressed and hence the reaction results in an extremely high yield of the desired product. Accord-ing to this process, the allyl alcohol is immediately chlorinated with the chlorine introduced s.imultaneously because the reaction of allyl alcohol with chlorine proceeds very rapidly in aqueous hydrochloric acid, and ~... . ...
; ~ ~776~
hence, the contact time of allyl alcohol with hydrochloric acid and chloronium ion becomes negligibly small, by which the side reactions (1) and (2) as mentioned above can be minimized. In fact, according to the process of this invention, the by-products, e.g., allyl chloride or deriv-atives thereof, are less than 1 % or preferably less than 0.5 ~. Moreover, in the feature of simultaneously supply-ing the hydrogen chloride gas, even though the aqueous hydrochloric acid is diluted with the 2,3-dichloro-1-propanol produced, the desired concentration of hydro-chloric acid (i.e. in saturated state) can be kept by supplying hydrogen chloride gas, and thereby, the nucleo-philicity of 2,3-dichloro-1-propanol to the chloronium ion is reduced, and hence the above-mentioned side reaction (3) can be significantly s~ppressed even in the presence of a comparatively high concentration of 2,3-dichloro-1-propanol in the reaction system~
As the solvent, commercially available conc. hydro-chloric acid can be used. The aqueous hydrochloric acid used as the solvent in this invention usually has a concen-tration of 25 to 40 ~ by weight, preferably 30 to 40 % by weight, more preferably 35 to 40 % by weight. When the concentration of hydrochloric acid is lower than 25 % by weight, the undesirable oxidation of allyl alcohol to acro-lein is observed. Besides, as is mentioned hereinbefore,with progress of the reaction, the solvent is diluted with the 2,3-dichloro-1-propanol produced, and hence, the concentration of hydrochloric acid in the reaction system is further decreased. In order to prevent such dilution during the reaction, it is preferable to supply hydrogen chloride gas. However, when hydrogen chloride gas is added, the temperature of the reaction mixture rises owing to the heat from dissolution of the hydrogen chloride as well as from the exothermic reaction of the chlorination of allyl alcohol. Accordingly, when too large an amount of hydrogen chloride gas is added, it is difficult to ~ ;~t776~
control the temperature of the reaction mixture, and extra energy is required ~or cooling the reaction mixture. More-over, when the concentration of hydrochloric acid in the solvent is lower at the initiation of the reaction, it results in a low product yield. From these viewpoints, it is preferable to use, as a solvent, aqueous hydrochloric acid having a concentration of not less than 25 ~ by weight. On the other hand, when the solvent has a concen-tration of hydrochloric acid of more than 40 % by ~eight, it is disadvantageously necessary to employ means for increasing the concentration, e.g., a specific cooling device, a pressure vessel, etc.
The solvent, aqueous hydrochloric acid, is used in an amount of not less than two times by weight, preferably 2 to 8 times by weight, more preferably 3 to 5 times by weight, the total amount of allyl alcohol to be introduced thereto. When the amount of the solvent is less than two times by weight, the side reaction (3) as mentioned herein-before increases remarkably.
The allyl alcohol and chlorine gas are introduced in about equimolar amount, usuaLly 1 : 1 to 1 : 1.01 by mole.
These are preferably introduced through separate introduc-tion ducts. ~hen a large excess amount of allyl alcohol and/or chlorine gas is introduced, it induces undesirable side reactions. The allyl alcohol and chlorine gas are introduced at a rate of 0.01 to 50 mole/L.hr (L = liter of initial solvent), preferably 0.1 to 20 mole/L.hr, in a batch system or in a continuous system. In the case of supplying further hydrogen chloride gas, it is supplied in an amount of 0.5 to 3 times by mole, preferably 1 to 1.5 times by mole, the amount of allyl alcohol. The reaction mixture is prevented from being saturated with hydrochloric acid, even though hydrogen chloride gas is continuously supplied to the reaction system, because the concentration of hydrochloric acid in the reaction system does not go over that of conc. hydrochloric acid ~e.g. about 45 ~ by ?`;
,' - i,~
776~3~
weight at OC) as a result of the poor solubility o hydrogen chloride in the 2,3-dichloro-1-propanol produced.
It is also apparent that supply of a large excess of hydrogen chloride gas is fruitless, because the reaction S mixture is saturated with it. The hydrogen chloride gas may be introduced into the reaction system through an independent introduction duct, but is preferably introduced through the same duct as the chlorine gas as a mixture of hydrogen chloride gas and chlorine gas.
The reaction of this invention is preferably carried out with agitation. It is preferable to maintain the reac-tion temperature as low as possible in order to increase the ~ield of the product, but from an industrial viewpoint, in order to keep the viscosity of the reaction mixture low or to save energy for cooling, it is preferable to carry out the reaction at a temperature of from -5 to 10C
under atmospheric pressure. The reaction may be done under light, but is preferably carried out with protection from light in order to increase the yield of the product.
The product, 2,3-dichloro-1-propanol, can be isolate from the reaction mixture by any conventional method, for example, by neutralizing the reaction mixture with a basic compound (e.g. sodium hydroxide, calcium hydroxide, etc.) or purging at least a portion of the hydrogen chloride gas with an inert gas (e.g. nitrogen gas), and then subjecting the mixture to distillation. When the product is used as an intermediate for the preparation of other products, e.g. epichlorohydrin, the reaction mixture containing 2,3-dichloro-l-propanol may be subjected to the subse~uent reactions ater partially removing the hydrochloric acid thererom, without isolation of the product.
The process of this invention can be carried out using commercially available aqueous hydrochloric acid as the solvent in a simple procedure without the necessity of speciic apparatus. Moreover, the reaction proceeds with-out undesirably lowering the concentration of hydrochloric .~ ~
~776~3~
acid in the solvent when hydrogen chloride gas is simul-taneously supplied together with the starting materials, and hence, undesirable side reactions can be effectively prevented and the desired product can be obtained in a very high yield.
The present invention is illustrated by the following Examples and Reference Examples, but should not be construed to be limited thereto.
Exam~le 1 A reaction vessel provided with an agitator was charged with 40 wt. % aqueous hydrochloric acid (110 g, 1.2 mole as ~Cl), and thereto were added with agitation allyl alcohol (23.4 g, 0.4 mole) and chlorine gas ~28.8 g, 0.4 mole) through separate introduction ducts at a rate of an equi-molar amount over a period of time of 45 minutes at -5C
under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was directly analyzed by gas chromatography (hereinafter, abbreviated as GC method) with a column packed with OV*-225 (5 %)/Chromosolve* W AW-DMCS using biphenyl as an internal standard. The yield of 2,3-dichloro-1-propanol was 95.0 %.
Exam~le 2 ___ __ .
The reaction was carried out in the same manner ~s described in Example 1 except that 35 wt. ~ aqueous hydro-chloric acid (115 g, 1.1 mole as HCl) was used, the reac-tion temperature was maintained at 0C, and the reaction mixture was likewise analyzed by the GC method. The desired 2,3-dichloro-1-propanol was produced in a yield o~ 90.2 %.
Exam~le _ The reaction was carried out in the same manner as des-cribed in Example 1 except that 30 wt. ~ aqueous hydro-chloric acid (89 g, 0.73 mole as ~ICl) was used and the reaction temperature was maintained at 10C. The desired 2,3-dichloro-1-propanol was produced in a yield of 85.6 * Trade mark ~, ~7'7~i81 Reference Example 1 ____ __ ___ _ The same reaction vessel as used in Example 1 was charged with 20 wt. % aqueous hydrochloric acid (54.5 g, 0.3 mole as E~Cl), and thereto were added with agitation allyl alcohol (5.9 g, 0.1 mole) and chlorine gas (7.0 g, 0.1 mole) through separate introduction ducts at a rate o~
an equimolar amount over a period of time o~ 45 minutes at OC under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was likewise directly analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 58.6 %.
Reference Exam~ 2 _________ _ The same reaction vessel as used in Example 1 was charged with 35 wt. % aqueous hydrochloric acid (30 g, 0.29 mole as HCl) and allyl alcohol (11.6 g, 0.2 mole), and thereto was added with agitation chlorine gas (14.2 g, 0.2 mole) over a period of time o 45 minutes at OC under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was directly analyzed by the GC method. The yield of 2,3-dichloro-l-propanol was 72.0 ~.
Exam~le 4 ___ ___ A reaction vessel provided with an agitator was charged with 37 wt. ~ aqueous hydrochloric acid (110 g, 1.1 mole as HCl), and thereto were added with agitation allyl alcohol (23.2 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (22 g, 0~6 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol and chlori~e gas over a period of time of 45 minutes at OC under atmos-pheric pressure and under protection from light.
After the reaction was completed, excessive hydrogen chloride gas was purged by blowing nitrogen gas therein, and then the reaction mixture was directly analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 98.1 %.
".; .
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~ ~ ~'7768~
Exam~le 5 ____ ___ The same reaction vessel as used in Example 4 was charged with 30 wt. % aqueous hydrochloric acid (150 9, 1.2 mole as ~Cl), and thereto were added with agitation allyl alcohol (23.5 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (43~8 g, 1.2 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol ancl chlorine gas over a period of time of 45 minutes at 0C under atmospheric pressure and under protection from light.
After the reaction was completed, the reaction mixture was treated in the same manner as in Example 4 and was analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 95.1 %O
~ le The same reaction vessel as used in Example 4 was charged with 40 wt. ~ aqueous hydrochloric acid (50 g, 0.54 mole as HCl), and thereto were added with agitation allyl alcohol (23.4 g, 0.4 mole) and a mixture of chlorine gas (28.8 g, 0.4 mole) and hydrogen chloride gas (7.3 g, 0.2 mole) through separate introduction ducts at a rate of an equimolar amount of the allyl alcohol and chlorine gas over a period of time of 45 minutes at -5C under atmospheric pressure and under protection from lig,ht.
After the reaction was completed, the reaction mixture was treated in the same manner as in ~xample 4 and was analyzed by the GC method. The yield of 2,3-dichloro-1-propanol was 98.3 ~.
Claims (6)
1. A process for the production of 2,3-dichloro-1-propanol comprising reacting allyl alcohol and chlorine gas in aqueous hydrochloric acid, wherein an aqueous solution of hydrochloric acid having a concentration of 25 to 40 %
by weight is used and the reaction of allyl alcohol and chlorine gas is carried out by simultaneously supplying allyl alcohol and chlorine gas to the reaction system.
by weight is used and the reaction of allyl alcohol and chlorine gas is carried out by simultaneously supplying allyl alcohol and chlorine gas to the reaction system.
2. The process according to claim 1, wherein hydrogen chloride gas is also simultaneously supplied thereto.
3. The process according to claim 1, wherein the allyl alcohol and chlorine gas are introduced in a ratio of 1 : 1 to 1 : 1.01 by mole.
4. The process according to claim 1, wherein the allyl alcohol and chlorine gas are introduced at a rate of 0.01 to 50 mole/L.hr, respectively.
5. The process according to claim 1, wherein the aqueous solution of hydrochloric acid has a concentration of 30 to 40 % by weight.
6. The process according to claim 2, wherein the hydrogen chloride gas is supplied to in an amount of 0.5 to 3 times by mole the amount of allyl alcohol.
//
//
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000544005A CA1277681C (en) | 1987-08-07 | 1987-08-07 | Process for the production of 2,3-dichloro-1-propanol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000544005A CA1277681C (en) | 1987-08-07 | 1987-08-07 | Process for the production of 2,3-dichloro-1-propanol |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1277681C true CA1277681C (en) | 1990-12-11 |
Family
ID=4136225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000544005A Expired - Fee Related CA1277681C (en) | 1987-08-07 | 1987-08-07 | Process for the production of 2,3-dichloro-1-propanol |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1277681C (en) |
-
1987
- 1987-08-07 CA CA000544005A patent/CA1277681C/en not_active Expired - Fee Related
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