WO2009041766A1 - Process for preparing chlorohydrin by reaction of polyol with hydrochloric acid - Google Patents
Process for preparing chlorohydrin by reaction of polyol with hydrochloric acid Download PDFInfo
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- WO2009041766A1 WO2009041766A1 PCT/KR2008/005474 KR2008005474W WO2009041766A1 WO 2009041766 A1 WO2009041766 A1 WO 2009041766A1 KR 2008005474 W KR2008005474 W KR 2008005474W WO 2009041766 A1 WO2009041766 A1 WO 2009041766A1
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- C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/62—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by introduction of halogen; by substitution of halogen atoms by other halogen atoms
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
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- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
- C07C31/34—Halogenated alcohols
Definitions
- the present inventors completed this invention by confirming that chlorohydrin can be economically and efficiently produced by regulating polyol to be loaded in the first and the second reactors, flow rate of re-circulated feed circulated into the first reactor, concentration of non- reacted hydrogen chloride remaining in feed supplied to the second reactor and the amount of additional polyol feed to be loaded in the second reactor. It is an object of the present invention to provide a method for preparing chlorohydrin in a large industrial scale from polyol such as glycerin by chlorination using hydrogen chloride.
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Abstract
The present invention relates to a method for preparing chlorohydrin by chlorination of polyol such as glycerin with hydrogen chloride. The method of the present invention is composed of the following processes: reaction mixture feed comprising polyol, hydrogen chloride and organic acid (catalyst for chlorination) is loaded into the first reactor, in which chlorohydrin is generated by chlorination; the first product mixture feed containing the chlorohydrin and non- reacted reaction mixture discharged from the first reactor and the additional polyol feed are supplied to the second reactor, in which chlorohydrin is generated by additional chlorination; the second product mixture feed containing the chlorohydrin discharged from the second reactor is loaded in distillation column and then distillation product containing chlorohydrin is separated through the top of the distillation column; and some re-circulated feed of distillation residual solution containing chlorohydrin, is re-circulated into the first reactor.
Description
[DESCRIPTION]
[invention Title]
PROCESS FOR PREPARING CHLOROHYDRIN BY REACTION OF POLYOL WITH HYDROCHLORIC ACID
[Technical Field]
The present invention relates to a method for preparing chlorohydrin used for the production of epichlorohydrin, a raw material for epoxy resin, by chlorination of polyol such as glycerin with hydrogen chloride.
[Background Art]
One of the most common methods for producing epichlorohydrin (ECH) is comprised of the following steps: preparing allyl chloride (ALC) by chlorination of propylene at high temperature (450~550°C); reacting the prepared allyl chloride with hypochlorous acid solution to give dichlorohydrin (dichloropropanol) solution; and preparing epichlorohydrin by dehydrochlorination of the dichlorohydrin using alkali solution such as milk of lime or sodium hydroxide solution.
However, the above method has a disadvantage in the aspect of raw material efficiency, precisely 2 moles of chlorine and 2 equivalents of alkali are required for the
production of 1 tnol epichlorohydrin, suggesting that only 25% of chlorine can be used for the synthesis of epichlorohydrin, theoretically, and the rest of chlorine is converted into hydrogen chloride or salt waste by neutralization. In the aspect of reaction efficiency, the above method also accompanies diverse sub-reactions with generating dichloropropene, trichloropropane, chloropropene, dichloropropane, and isopropyl chloride during the preparation of allyl chloride, resulting in the decrease of yield of the target allyl chloride and the increase of production costs. The method above generates 2, 3-dichlorohydrin as an intermediate, double the amount of 1, 3-dichlorohydrin. The conversion rate of 1, 3-dichlorohydrin into epichlorohydrin is faster than that of 2, 3-dichlorohydrin, suggesting that the method is limited in reaction efficiency. Besides, a huge amount of processing water is required for the production of hypochlorous acid, resulting in the generation of dichlorohydrin solution at a low concentration of approximately 1-10% and at last a large amount of waste water containing salt is generated from the production of epichlorohydrin .
Another commercialized method is composed of the steps of preparing allyl acetate by oxidation/acetoxylation of propylene and acetic acid in the presence of palladium
catalyst; preparing allyl alcohol by hydrolyzing the prepared allyl acetate; preparing 2, 3-dichlorohydrin by addition reaction of the allyl alcohol and chlorine in the presence of liquid hydrogen chloride (hydrochloric acid) catalyst; and preparing epichlorohydrin by dehydrochlorination of dichlorohydrin using alkali solution.
Theoretically, according to the above method, 1 mol of chlorine is needed to produce 1 mol of epichlorohydrin and the process of preparing allyl chloride is omitted, so that the byproduct, hydrogen chloride, is not generated. And 1 equivalent of alkali is consumed to produce 1 mol of epichlorohydrin, theoretically, without hypochlorous acid solution and the amount of waste water is reduced.
There are other methods to prepare epichlorohydrin, which have not been commercialized. For example, a method for preparing epichlorohydrin composed of the steps of preparing allyl chloride by chlorination of propylene at high temperature; and preparing epichlorohydrin by direct epoxidation of the allyl chloride with hydrogen peroxide in the presence of titanium silicalite catalyst, a method for preparing 2 , 3-dichlorohydrin composed of the steps of preparing acrolein by oxidation of propylene; preparing 2,3- dichloropropanal by chlorine addition reaction; and preparing 2 , 3 -dichlorohydrin by hydrogenation of the 2,3-
dichloropropanal, and a method for preparing 1,3- dichlorohydrin composed of the steps of preparing acetone by oxidation of propylene; preparing dichloroacetone by chlorine addition reaction; and preparing 1, 3-dichlorohydrin by hydrogenation of the dichloroacetone have been reported.
The methods mentioned above all use propylene and chlorine as raw materials. However, the costs of propylene, etc is continuously increasing world widely with increasing the production costs . Based on the world wide concern on environmental problems and efforts to develop an alternative for limited petroleum resources, bio-diesel industry has been rapidly growing to substitute the conventional fuel for transportation. Bio- diesel is extracted from plants such as rape, so it is not only pro-environmental but also of great use as a regenerable energy source. During methanolysis to prepare bio-diesel, glycerin is generated. As a new C-3 source that can take the place of propylene, glycerin also draws our attention.
Glycerin is produced not only as a byproduct from the production of bio-diesel but also as a byproduct from hydrolysis to produce fatty acid using animal/vegetable oil or lipid such as oil or fat or from saponification to produce soaps .
With recent increase of glycerin supply, owing to the
active bio-diesel production, the price of glycerin has been reduced enough to replace propylene as a C-3 source. Therefore, reversely from the conventional method for preparing synthetic glycerin, it is more advantageous economically in the aspects of production costs and usability of glycerin to prepare epichlorohydrin (from glycerin) . Preparing epichlorohydrin from glycerin is advantageous because the reaction herein uses anhydrous hydrogen chloride or hydrochloric acid, generated as a byproduct in various industrial fields, as a raw material instead of chlorine.
German Patent Publication No. 197308 (1908) describes a method converting glycerin to chlorohydrin by catalytic hydrochlorination, which is characterized by equilibrium reaction composed of the reaction of glycerin with anhydrous hydrogen chloride in the presence of carboxylic acid catalyst to give monochlorohydrin (monochloropropandiol, MCH) and dichlorohydrin (dichloropropanol, DCH) and generation of water as a byproduct.
The above method was already reported 100 years ago, but has not been commercialized because of the price of glycerin. Just recently since 21st century, with increase of glycerin supply and decrease of the cost of glycerin thereby, attempts have been made to commercialize the method.
Unlike the method for preparing chlorohydrin by the
reaction of propylene and chlorine, the preparing method using glycerin and hydrogen chloride significantly reduces organic chlorides generated from sub-reactions, because this method does not require allyl chloride reaction and reduces the amount of waste water by direct production of dichlorohydrin without using hypochlorous acid solution. Dichlorohydrin generated by this method can be converted into epichlorohydrin by dehydrochlorination using alkali solution such as milk of lime or sodium hydroxide solution according to the conventional commercialized method.
German Patent Publication No. 197308 (1908) describes batch- type equilibrium reaction performed at approximately 100°C (95-120°C). This reaction is a kind of liquid phase reaction induced after anhydrous hydrogen chloride provided is dissolved. But, in this reaction, the serial elimination of reaction water used to move equilibrium to the direction of chlorohydrin generation was not performed. The above patent describes that pressure for the reaction can be atmospheric pressure or can be increased to accelerate the reaction with increasing the solubility of anhydrous hydrogen chloride. And acetic acid, propionic acid, formic acid, cinnamic acid, azelaic acid, succinic acid or phenylacetic acid can be used as a carboxylic acid catalyst. The above patent also proposes that the preferable amount of a catalyst is approximately 1-2
weight% by the weight of glycerin provided because increase of catalyst content can induce sub-reactions with reducing yield.
In German Patent Publication No. 197309 (1908) , hydrochloric acid (for example, 37 weight% Hydrochloric acid solution) was used instead of anhydrous hydrogen chloride, and the amount of acetic acid catalyst was increased to 2 - 30 weight% by the weight of glycerin provided, which was larger amount than that of anhydrous hydrogen chloride .
German Patent Publication No. 238341 (1911) describes the production of monochlorohydrin and dichlorohydrin by the reaction of anhydrous hydrogen chloride and glycerin.
The above patents all relate to batch-type reaction induced under atmospheric pressure or increased pressure. Therefore, it takes long time for complete conversion (24-48 hours) because of the accumulation of reaction water making equilibrium. 10-20 hour reaction cannot give high conversion rate and can only give a very low yield of dichlorohydrin, which is a useful, necessary substance. So, attempts have been made to increase yield by applying semi-batch type reaction which provides excessive amount of anhydrous hydrogen chloride continuously to move equilibrium to the direction of dichlorohydrin generation.
Conant et al reported in their papers Organic Syntheses, Coll. Vol.l, p.292(1941) and Organic Syntheses, Coll. Vol.2,
p.29 (1942) that serai-batch type reaction is induced using 90% glycerin and anhydrous hydrogen chloride with acetic acid catalyst. At this time, the amount of acetic acid catalyst is 2 weight% by the weight of 90% glycerin and the reaction is preferably induced at 100-110°C under atmospheric pressure. According to the method of Conant, the dissolution of anhydrous hydrogen chloride continuously provided is very fast in the early stage, but as reaction time goes on, the speed decreases. In addition, the total weight of the reactor keeps changing in the early stage but it settles down at a certain weight, which suggests termination of the reaction. More precisely, according to the method of Conant, non-dissolved anhydrous hydrogen chloride is collected from all anhydrous hydrogen chloride provided continuously as a gas phase. To minimize the loss of anhydrous hydrogen chloride, the supply of anhydrous hydrogen chloride is regulated according to the changes of total reactor weight. Theoretically, the amount of anhydrous hydrogen chloride (except the amount of loss) dissolved until termination of the reaction is 125%, indicating 25% is over-supplied for the reaction. Upon completion of the reaction, reaction solution is cooled down. Hydrogen chloride (or Hydrochloric acid) and acetic acid dissolved in the reaction solution as non-reacted are treated with soda ash for neutralization. At this time, to accelerate
the neutralization and to prevent the eduction of generated salts, water is additionally added. The method of Conant further describes that liquid phase layer is separated from the neutralized reaction solution by defractionation to obtain the final target compound, and the remaining organic layer (unpurified dichlorohydrin solution) proceeds to vacuum distillation at 14 mmHg to lower the concentration of water. So, a large amount of water is obtained at the temperature up to 680C and the obtained water is distilled again to eliminate water to give highly concentrated dichlorohydrin solution. The solution is mixed with the distilled solution prepared earlier at 68 -75 "C to give highly concentrated dichlorohydrin solution (theoretically 70% concentration) . To increase the concentration, the dichlorohydrin solution is vacuum distilled again at 14 mmHg. At last, 55-57% dichlorohydrin solution is prepared at 70-73°C, theoretically.
The method of Conant et al has disadvantages of great loss of anhydrous hydrogen chloride, accumulation of reaction water, loss of dichlorohydrin during the neutralization (with non-reacted hydrogen chloride (hydrochloric acid) and acetic acid) and during separation of water and dichlorohydrin, and difficulty in recovering dichlorohydrin even after all the complicated separation processes.
Such methods based on semi-batch type distillation which
eliminates reaction water continuously as reaction goes approximately at least 120 °C by distillation and moves equilibrium to generate dichlorohydrin to increase yield have been publicized long since. According to these methods, dehydrochlorination reaction is induced at increased temperature, so non-recyclable chlorohydrin, glyceride, resin polymer and other sub-reaction remnants having high boiling point are generated. Distillation is also performed at increased temperature. Therefore, distilled solution eliminated from the reactant is a sort of corrosive liquid acidic mixture containing a significant amount of dichlorohydrin (having high boiling point but eliminated with water because it forms azeotrope together with water) , hydrochloric acid and acetic acid. It is very difficult to recover dichlorohydrin therefrom. US Patent No. 2,198,600
(1940) describes a method for preparing anhydrous dichlorohydrin, in which reaction residual liquid is vacuum distillated to eliminate a significant amount of water upon completion of the reaction, to give dichlorohydrin; and a proper organic solvent is added to the separated and distilled solution to extract dichlorohydrin therefrom; and the extract is fractional-distillated to give additional anhydrous dichlorohydrin .
US Patent No. 2,144,612 (1939) describes that along with
semi-batch type distillation using a catalyst selected from the group consisting of anhydrous hydrogen chloride, hydrochloric acid, acetic acid and aliphatic carboxylic acid such as formic acid under atmospheric pressure or reduced or increased pressure, a reaction is induced at a low temperature to inhibit the generation of non-recyclable sub-reaction remnants having high boiling point and a proper organic solvent is selected to distill water alone by inhibiting azeotropic distillation of dichlorohydrin and water. At this time, the organic solvent must not have reactivity but have to be able to dissolve dichlorohydrin and is not mixed with water. Reaction temperature depends on the organic solvent. In general, reaction is induced at steam distillation temperature (up to 100 °C or around, which is the temperature of gas phase mixture left off the reaction area) of reaction mixture
(including a solvent) . The acidic solution eliminated and distilled from the reactant is composed of water, hydrochloric acid, a small amount of acetic acid, solvent, and dichlorohydrin. This distilled solution is discarded upon completion of the reactive distillation or proceeds to hydrochloric acid degradation reaction using additional glycerin at 80-95°C to increase usability of hydrochloric acid, which can be further utilized in the next reaction batch, or if necessary, a solvent is added together with the additional
glycerin for hydrochloric acid degradation reaction to eliminate water. In the meantime, it takes at least 35 hours to complete the reaction with the above method, in which the completion of the reaction means stop of distilled acidic solution generation. Upon completion of the reaction, remaining reaction mixture is cooled down, followed by fractional distillation to separate water, dichlorohydrin, organic solvent and monochlorohydrin and other remnants having high boiling point and composed of non-reacted glycerin, respectively. Separated water is discarded. The recovered organic solvent is recycled. The remnants having high boiling point are used again in the next reaction batch.
US Patent No. 2,144,612 (1939) describes a continuous reactive distillation process in which anhydrous hydrogen chloride, glycerin and acetic acid catalyst are continuously provided into a reactor; some of the reaction mixture which has already been through the reaction to some degree is taken to eliminate water by fractional distillation; only dichlorohydrin product is separated; recovered solvent and non-reacted glycerin, monochlorohydrin and acetic acid catalyst are re-circulated into the reactor; organic solvent layer from distilled acidic solution separated as a gas phase by distillation returns to the reactor; liquid phase layer is discarded; glycerin is continuously supplied by the amount
corresponding produced dichlorohydrin; and acetic acid catalyst is continuously provided as much as lost with the liquid phase layer discarded.
The said 20th century methods are represented as follows in brief; batch type reaction, semi-batch type reaction (HCl supplied continuously) , semi-batch type reactive distillation (HCl supplied continuously and water eliminated continuously as a gas phase), and continuous reactive distillation (HCl, glycerin, acid catalyst supplied continuously, water eliminated continuously as a gas phase (reactive distillation) and liquid phase) . All of these methods use carboxylic acid, particularly acetic acid, as a catalyst. The technical characteristics of the previous methods described in prior arts are as follows. - Glycerin is not limited to pure glycerin, and HCl can be anhydrous hydrogen chloride or hydrochloric acid.
- When anhydrous hydrogen chloride is used as a catalyst, the amount of the catalyst is 1-5 weight% by the weight of glycerin, and when hydrochloric acid is used as a catalyst, the amount is 2-30 weight% by the weight of glycerin because this catalyst contains a large amount of water making reaction slow.
- If it is batch type reaction or semi-batch reaction, the reaction is induced at the temperature of up to 120°C, and
if it is semi-batch type reactive distillation or continuous reactive distillation, the reactive distillation is performed at the temperature of at least 120 °C . The temperature for reactive distillation can be lowered by using a proper solvent or by reducing pressure.
- If it is batch type reaction or semi-batch reaction, the reaction is induced under atmospheric pressure or increased pressure (to increase solubility when anhydrous hydrogen chloride is used as a catalyst) , and if it is semi- batch type reactive distillation or continuous reactive distillation, the reactive distillation is performed under atmospheric pressure or increased or reduced pressure.
- It takes 24-48 hours for the completion of the reaction in every said method. Water is eliminated from the reaction remnants and the reactant is fractional-distillated under reduced pressure to isolate dichlorohydrin alone.
The said methods above could not be commercialized because of high price of glycerin, long reaction time and difficulty in separation process, etc. However, since 21st century, the price of glycerin has been lowered, while the price of propylene and chlorine has been going up, and epoxy resin is in increasing demand. So, dichlorohydrin, as an intermediate generated during the production of
epichlorohydrin, draws our attention. Since then, applications for a patent in relation to a method for preparing epichlorohydrin and dichlorohydrin using glycerin as a raw material have been filed up. WO05/021476, recently applied by Spolek, describes a consecutive production technique characterized by continuous supply of anhydrous hydrogen chloride, glycerin and acetic acid catalyst. The method of Spolek is operated under atmospheric pressure or under increased pressure to increase solubility of anhydrous hydrogen chloride, similarly to the conventional batch/semi-batch type reaction processes introduced in early 20th century, and the preferable temperature for the reaction is 100-110°C. The consecutive processes in the above method are similar to the continuous reactive distillation described in US Patent No. 2,144,612 (1939), but slightly modified therefrom, for example water elimination is performed only as a liquid phase. The details of the method are described hereinafter.
In the first embodiment, reaction solution is continuously circulated through reactor and distillation column. Particularly, reaction solution is continuously discharged from the reactor and then proceeds to vacuum distillation column to obtain reaction products (reaction water and dichlorohydrin) . After collecting dichlorohydrin and
reaction water, the distilled remnants are sent back to the reactor for further circulation. At this time, some of the distilled remnants proceed to the secondary vacuum distillation column not to the reactor. Dichlorohydrin and monochlorohydrin are recovered from the top of the column, which are sent back to the reactor again and the distilled remnants obtained from the bottom of the column are treated as waste having high boiling point.
- In the second embodiment, 1 - 3 reactors are connected by cascade for circulation stepwise. Anhydrous hydrogen chloride, glycerin and acetic acid catalyst are consecutively loaded into the first reactor, supplements of the consumed anhydrous hydrogen chloride and catalyst are consecutively loaded in the second and third reactors. Reaction solution is continuously discharged from the first reactor, which proceeds to the primary distillation column to obtain dichlorohydrin and reaction water as reaction products. The distilled remnants proceed to the second reactor. Reaction solution is also continuously discharged from the second reactor, which proceeds to the secondary distillation column to obtain dichlorohydrin and reaction water, and the distilled remnants are sent to the third reactor. After a series of these processes, dichlorohydrin and reaction water are collected from the distillation column of the last reactor and the
distilled remnants therefrom proceed to vacuum distillation column for collection. Dichlorohydrin and monochlorohydrin are recovered from the top of the column, which are sent back to the first reactor and the distilled remnants obtained from the bottom of the column are treated as waste having high boiling point.
WO06/020234, applied by Dow Co., also describes a continuous process, similar to the above method of Spolek. This patent applied by Dow Co. emphasizes "no elimination of a significant amount of water", unlike the method of Spolek. However, if reaction water generated during a series of reaction to produce dichlorohydrin is not eliminated, water will be accumulated in the reaction system continuously, so that it will make the reactor to be over-sized. Thus, the consecutive processes are hardly accomplished. Therefore, "no elimination of a significant amount of water" can be achieved in batch type or semi-batch type reaction but not in the said consecutive processes. Thus the said patent only illustrates semi-batch type reaction in all the embodiments. According to the patent of Dow, partial pressure of anhydrous hydrogen chloride supplied under increased pressure is specifically indicated, similarly to the pressure conditions informed by the previous methods publicized in 20th century, which is also
increased pressure condition to increase solubility of anhydrous hydrogen chloride. So, this method is not much different from the conventional semi-batch type reaction performed under increased pressure and only attempted to induce reaction under the increased pressure as high as acceptable .
WO05/054167, applied by Solvay Co., describes a method for preparing chlorohydrin by continuous supply of liquid Hydrochloric acid and glycerin. The consecutive process of Solvay is similar to the continuous reactive distillation described in US Patent No. 2,144,612 (1939), in which additional distillation column is used to prevent loss of dichlorohydrin during the elimination of water as a gas phase by reactive distillation. But, the additional distillation column is ordinarily accepted to prevent the loss of dichlorohydrin in conventional methods, so the said method is not different from the process informed by US Patent No. 2,144,612 (1939) at the root. The details of the method are described hereinafter.
- This system is composed of a reactor operable under reactive distillation condition, a distillation column linked to vapor phase of the reactor, and a distillation column linked to liquid phase of the reactor. Water is eliminated
through the top of the column linked to vapor phase and dichlorohydrin is collected from the top of the column linked to liquid phase, and the bottom liquid phases of the two columns are re-circulated into the reactor. - Only the distillation column linked to vapor phase can be operated at random without the distillation column linked to liquid phase of the reactor. At this time, distilled solution gathered on the top of the distillation column is separated and dichlorohydrin is recovered from the organic layer thereof.
The recent preparing methods seem to be simpler than those processes proposed in 20th century, which is only because a complicated procedure for separating pure dichlorohydrin is omitted. Dichlorohydrin used as a starting material for preparing epichlorohydrin is not necessarily pure anhydrous dichlorohydrin. There is no problem in the preparing process even if the reaction mixture contains water, suggesting that there is no need to separate dichlorohydrin from water completely. So, constructional characteristic of the recent methods is not much different from that of the conventional method proposed in 20th century which produces chlorohydrin from glycerin.
[Disclosure]
[Technical Problem]
The present inventors completed this invention by confirming that chlorohydrin can be economically and efficiently produced by regulating polyol to be loaded in the first and the second reactors, flow rate of re-circulated feed circulated into the first reactor, concentration of non- reacted hydrogen chloride remaining in feed supplied to the second reactor and the amount of additional polyol feed to be loaded in the second reactor. It is an object of the present invention to provide a method for preparing chlorohydrin in a large industrial scale from polyol such as glycerin by chlorination using hydrogen chloride.
[Technical Solution]
To achieve the above object, the present invention provides a method for preparing chlorohydrin comprising the following processes: reaction mixture feed comprising polyol, hydrogen chloride and organic acid (catalyst for chlorination) is loaded in the first reactor, in which chlorohydrin is generated by chlorination; the first product mixture feed containing the chlorohydrin and non-reacted reaction mixture discharged from the first reactor and the additional polyol feed are supplied to the second reactor, in which chlorohydrin
is generated by additional chlorination; the second product mixture feed containing the chlorohydrin discharged from the second reactor is loaded in distillation column and then distillation product containing chlorohydrin is separated through the top of the distillation column; and some re- circulated feed of distillation residual solution containing chlorohydrin is re-circulated into the first reactor.
In the method of the present invention, the non-reacted reaction mixture of the first product mixture feed discharged from the first reactor contains polyol, hydrogen chloride, organic acid catalyst and water. The re-circulated feed circulated again into the first reactor contains chlorohydrin and non-reacted polyol. The distillation product separated from the top of the distillation column contains chlorohydrin, organic acid catalyst and water. The content of chlorohydrin in the distillation product is preferably 50-90 weight% considering efficiency of the processes. The distillation product is preferably separated by vacuum distillation.
Reaction temperature of the first reactor is preferably 70 -1400C. The said reaction temperature of the first reactor can be maintained by using heat of re-circulated feed and heat of dissolution of anhydrous hydrogen chloride as a heat source.
The method of the present invention is also characterized
by that the ratio of polyol flow rate to be loaded in the first and the second reactors to re-circulated feed flow rate satisfies the following formula (1) .
R+GZk1V1
(D In formula (1), Vi is effective volume [I) of the first reactor, G is total flow rate (kg/hr) of polyol supplied into the first and the second reactors, R is flow rate (kg/hr) of re-circulated feed which is circulated from distillation column to the first reactor, and ki is flow rate optimization constant, which is preferably 0.3-5 kg/(£-hr) and more preferably 0.5-1.5 kg/(«-hr).
The method for preparing chlorohydrin of the present invention is also characterized by that the concentration of non-reacted hydrogen chloride (Hydrochloric acid) in the feed supplied to the second reactor satisfies the following formula (2) .
In formula (2) , Ci is concentration (wt%) of non-reacted hydrogen chloride (Hydrochloric acid) in the first product mixture feed, Vi is effective volume [I) of the first reactor, R is flow rate (kg/hr) of re-circulated feed which is
circulated from distillation column to the first reactor, and k2 is flow rate optimization constant, which is preferably 3-5. The method of the present invention is further characterized by that the flow rates of additional polyol feed supplied into the second reactor and re-circulated feed and the concentration of non-reacted hydrogen chloride (Hydrochloric acid) in the first product mixture satisfy the following formula (3) .
The method for preparing chlorohydrin of the present invention is described in detail hereinafter.
Polyol used as a raw material in this invention can be any diol and triol . Particularly, the polyol can be selected from the group consisting of 1, 2-ethanediol (ethyleneglycol ) and its ester, 1 , 2-propanediol and its ester, 1, 3-propanediol and its ester, 3-chloro-l, 2-propanediol ( 3-monochlorohydrin) and its ester, 2-chloro-l, 3-propanediol (2-monochlorohydrin) and its ester, 1 , 2, 3-propanediol (glycerin, glycerol) and its ester, and a mixture thereof. Preferably, the polyol is selected from the group consisting of 3-chloro-l, 2- propanediol (3-monochlorohydrin) and its ester, 2-chloro-l , 3- propanediol (2-monochlorohydrin) and its ester, 1,2,3- propanetriol (glycerin, glycerol) and its ester, and a mixture thereof.
The polyol of the present invention is most preferably 1, 2, 3-propanetriol (glycerin, glycerol). In this method of the present invention, 3-chloro-l , 2-propanediol (3- monochlorohydrin) and its ester, 2-chloro-l , 3-propanediol (2- monochlorohydrin) and its ester, and 1 , 2, 3-propanetriol
(glycerin, glycerol) and its ester are generated by reaction with hydrogen chloride in the presence of carboxylic acid catalyst to prepare reaction mixtures having different compositions. These reaction mixtures are used as an intermediate material to produce a target product.
Glycerin used in this invention includes glycerin
generated as a byproduct during the production of bio-diesel from plant material or glycerin generated as a byproduct during the production of fatty acid or soaps from raw materials such as animal/vegetable oil, lipid or fat. Preferably, the glycerin is the one generated during the production of bio-diesel or fatty acid. The purity of glycerin used in this invention is preferably at least 50%, more preferably 70-100%, and most preferably 80-100%. These conditions have long been informed to those in the art. The source of hydrogen chloride in this invention is anhydrous hydrogen chloride or hydrochloric acid, more preferably those hydrogen chloride generated as a byproduct from the diverse processes for the production of vinyl chloride (VCM), isocyanate (MDI, TDI) or allyl chloride. Hydrogen chloride generated as a byproduct from the above processes is preferably in the form of the anhydrous hydrogen chloride is preferably supplied continuously to induce reaction under increased pressure.
The catalyst of the present invention can be a carboxylic acid based catalyst. Particularly, when a carboxylic acid catalyst having low boiling point is used, a significant amount of the catalyst is consumed as dichlorohydrin is produced. Therefore, costs for the catalyst consumption have
to be considered to calculate the production costs. Preferably, the catalyst is acetic acid. Acetic acid is the least expensive compound among various carboxylic acids. It is economically appropriate for this invention and the preferable content of acetic acid is 1-5 weight% by the weight of glycerin considering costs for catalyst consumption. To select a proper catalyst, various factors such as efficiency, yield, boiling point, solubility, mixing degree and viscosity, etc, have to be considered together. If carboxylic acid having high boiling point is selected, the loss of catalyst resulted from the elimination with heavy by-product has to be considered along with the recovery of a catalyst.
Chlorohydrin compounds produced by the method of the present invention using glycerin as a starting material are 3- monochlorohydrin ( 3-chloro-l, 2-propanediol , 3-MCH) , 2- monochlorohydrin (2-chloro-l , 3-propanediol, 2-MCH) , 1,3- dichlorohydrin ( 1, 3-dichloropropanol, 1,3-DCH) and 2,3- dichlorohydrin (2, 3-dichloropropanol, 2,3-DCH). Particularly, unlike the conventional methods, the method of the present invention gives more 1,3-DCH selectively than 2,3-DCH, which favors the production of epichlorohydrin (ECH) . The selectivity of 1,3-DCH to 2,3-DCH in this invention is 90-99%. The concentration of dichlorohydrin mixture prepared from the separation process above is higher than that obtained from the
conventional methods, which is approximately 50-90 weight%, and more preferably 60-80 weight%. The obtained high concentrated dichlorohydrin mixed solution is converted into epichlorohydrin (ECH) by dehydrochlorination using alkali solution such as milk of lime and sodium hydroxide solution according to the conventional, commercialized method.
The method of the present invention is same at the root with the conventional method for preparing chlorohydrin proposed in 20th century. Its main reaction pathway is composed of substitution reaction of glycerin with hydrogen chloride to give monochlorohydrin and water and another substitution reaction of the obtained monochlorohydrin with hydrogen chloride to give dichlorohydrin and water. More precisely, this method includes carboxylic acid catalytic reaction. For example, when acetic acid is used as a catalyst, esterification of glycerin and acetic acid is induced to give glycerin acetate and water. Then, monochlorohydrin is generated by substitution reaction of this glycerin acetate with hydrogen chloride and accordingly acetic acid is recovered. Likewise, monochlorohydrin acetate and water are generated from esterification of monochlorohydrin and acetic acid, and then dichlorohydrin is produced by substitution reaction of monochlorohydrin acetate with hydrogen chloride, and acetic acid is recovered thereafter. Monochlorohydrin can
be fast generated by direct substitution reaction of glycerin with hydrogen chloride in the absence of a catalyst. But, to produce dichlorohydrin, the direct substitution reaction becomes very slow without a catalyst. Therefore, for efficient reaction, a catalyst is needed.
The method for preparing chlorohydrin of the present invention meets reaction speed asked for commercialization and the required yield level and is also composed of efficient reaction and separation processes favoring minimization of the waste of raw material, catalyst and product. For example, when a raw material is anhydrous hydrogen chloride or acetic acid catalyst, a significant loss or waste is expected in reaction and separation processes because these compounds have lower boiling point than glycerin or chlorohydrin compound. Particularly in reactive distillation processes, the amount of such raw materials having low boiling point wasted during the processes is significant. Thus, a method has to be designed to have reaction and distillation processes operated separately.
According to the method of the present invention, reaction and distillation proceed separately in different sections, unlike the conventional reactive distillation process in which reaction and distillation proceed together in a reactor. It is more preferred to use a sealed pressure reactor to prevent the loss of a raw material having low
boiling point in order for the material to participate in the reaction. Precisely, a sealed pressure reactor is used to prevent evaporation of a material at reaction temperature or not to over- supply the raw material to the reaction mixture which might result in dissolution and thereby in wasting material. That is, to secure enough pressure for re-dissolving the reaction mixture and for enhancing reaction participation, a sealed pressure reaction vessel is used. It is also preferred to use a pressure reaction vessel equipped with a stirrer or outward circulator for efficient mixing of the reactant and even temperature distribution.
In the method of the present invention, separation does not require any complicated processes including the addition of organic solvent nor delicate equipment. It only needs the most fundamental material, which is distillation column. So, the method of the present invention favors efficient separation of dichlorohydrin solution from the reaction mixture. The reaction mixture herein is composed of non- reacted glycerin and its ester, monochlorohydrin and its ester, dichlorohydrin, catalyst, water, and non-reacted hydrogen chloride (hydrochloric acid) . To separate dichlorohydrin, the reaction mixture is vacuum-distillated. When dichlorohydrin is separated by distillation under atmospheric pressure, unwanted remnants having high boiling point are generated by sub-
reactions such as thermal decomposition and polymerization induced on the bottom of the column at high temperature. So, the sub-reactions are inhibited by lowering the temperature of the bottom of the column with reducing pressure to give dichlorohydrin.
Dichlorohydrin solution usable for the production of epichlorohydrin proceeds to dehydrochlorination and neutralization by using alkali solution such as milk of lime or sodium hydroxide solution, suggesting that it really does not matter whether or not dichlorohydrin mixture contains water or hydrogen chloride (hydrochloric acid) or other acidic components such as carboxylic acid catalyst. The said dichlorohydrin solution can be used directly for the production of epichlorohydrin without any additional separation process to increase purity. So, as mentioned, complicated or difficult processes and equipment are not necessary to separate pure dichlorohydrin alone. Only a process designed to minimize the loss of hydrogen chloride
(hydrochloric acid) and carboxylic acid catalyst is necessary. The method of the present invention is preferably composed of the following processes: Glycerin, acetic acid and anhydrous hydrogen chloride are continuously supplied into the gas-tight pressure to induce reaction under increased pressure. A certain amount of the reaction mixture is continuously
supplied into vacuum distillation column linked to prepare dichlorohydrin mixed solution. And the distilled residual solution is circulated into the reactor consecutively. The distilled residual solution contains monochlorohydrin, dichlorohydrin, non-reacted glycerin and acetate, etc. According to the method of the present invention continuously operated, the composition of dichlorohydrin of the consecutively circulated distilled residual solution is maintained regularly and dichlorohydrin is generated by the additional reaction by feeds, which are also continuously supplied, from the top of the vacuum distillation column.
The preferable processes of the present invention are achieved, as shown in Figure 1, by two air-tight pressure reactors and a vacuum distillation column. Precisely, glycerin is supplied through line (11) linked to the first reactor (23) and carboxylic acid catalyst is loaded through line (12) and hydrogen chloride is provided through line (13) . The liquid reaction mixture of the first reactor (23) is supplied into the second reactor (24) through line (14), which is then reacted with glycerin additionally supplemented therein through line (15) . The liquid reaction mixture of the second rector (24) is transferred onto the vacuum distillation column (25) through line (16), and vapor of distilled product generated in the vacuum distillation column (25) is loaded in
condenser (26) through line (17) . Distilled residual solution is circulated into the first reactor (23) through line (22) . During the above processes, some of reaction mixture can be purged through line (21) to regulate the concentration of remnants having high boiling point and high viscosity. Some of dichlorohydrin solution obtained through line (18) from condenser (26) is moved to vacuum distillation column (25) through line (19) by reflux and then the reaction product dichlorohydrin solution is obtained through line (20) . In the processes shown in Figure 1, main reaction is induced in the first reactor, indicating that dichlorohydrin is largely generated in the first reactor. To promote dichlorohydrin generation by moving equilibrium continuously, a certain amount of liquid reaction mixture is necessarily moved out of the first reactor to the second reactor continuously. This is to eliminate dichlorohydrin and water continuously from the reactor. For more efficient equilibrium movement, anhydrous hydrogen chloride is preferably over- supplied and at the same time it has to be prevented from being wasted with increasing solubility, for which air-tight pressure reactor is needed.
In this invention, the second reactor is operated to treat non-reacted hydrogen chloride (hydrochloric acid) produced from anhydrous hydrogen chloride over-supplied and
dissolved in the first reactor under increased pressure. The liquid reaction mixture supplied from the first reactor to the second reactor contains a significant amount of hydrogen chloride (hydrochloric acid) which does not participated in the reaction in the first reactor, which will be wasted during the collection of dichlorohydrin mixed solution from vacuum distillation column. So, the second reactor is designed to minimize the loss of hydrogen chloride (hydrochloric acid) and to increase the efficiency of hydrogen chloride (hydrochloric acid) reaction. Such non-reacted hydrogen chloride (hydrochloric acid) is reacted with glycerin additionally supplied in the second reactor to be converted into chlorohydrin compound.
The pressure level of the first reactor is regulated in the range favoring solubility of anhydrous hydrogen chloride and reaction speed of glycerin. The entire pressure of the reactor is maintained properly by regulating supply pressure of anhydrous hydrogen chloride, the reactant . Reaction temperature of the first reactor is 70-140°C and preferably 90- 120°C. The present invention is characterized by no need of additional heating to maintain the reaction temperature of the first reactor. Heat to maintain temperature of the first reactor is obtained from the temperature of distilled residual solution circulated from vacuum distillation column and heat
of dissolution of anhydrous hydrogen chloride supplied.
Operation temperature of the second reactor is determined by the temperature of liquid reaction mixture provided from the first reactor. And operation pressure of the second reactor is determined by the pressure of the first reactor and the amount of glycerin supplied into the second reactor. The pressure of the second reactor is formed by anhydrous hydrogen chloride remaining non-reacted in the first reactor, suggesting that the pressure decreases when glycerin is added. The optimized flow rate of the production process according to this invention has a critical effect on the pressure and temperature conditions in reactor and on the reaction speed and yield. When a device for consecutive production process is developed for commercialization, if the balance between input and output is broken, the reactant will be continuously accumulated in the device, and as a result the amount of purge through line (21) will increase. Therefore, without efficient operation of additional recovery equipment, there must be a great loss of reactant, resulting in the decrease of yield, which is a disadvantage for commercialization. The unbalance between input and output is largely attributed to two reasons. First is that reaction speed is too slow to apply the device to consecutive processes, suggesting that conversion of input into output is not very
successful. In that case, in order to increase fundamental reactivity, a new catalyst is required or a specially designed structure is needed for the reactor or batch type process is tried. Second is that although reaction speed is fast enough for operation in such device for consecutive processes, the size of reactor or retention time is not enough for the full conversion of input. If that is the case, input amount, circulation flow rate and the size of reactor have to be optimized. The optimum flow rate of the method of the present invention is determined by the following three technical factors .
First, balance between the sum of flow rate of each glycerin, acetic acid catalyst, and anhydrous hydrogen chloride taken in the regular size reactor (lines (11), (12), (13) and (15)) and the flow rate of dichlorohydrin produced (line (20)) means there is a correlation between the sum of flow rate of each glycerin, acetic acid catalyst, and anhydrous hydrogen chloride and flow rate re-circulated into the first reactor (23) through line (22) from vacuum distillation column (25) , more precisely there is a correlation between flow rate of added glycerin and flow rate of re-circulated glycerin. In the continuous production facility developed in this invention for commercialization,
optimum conditions for correlation are as follows, in which effective volume of the first reactor is indicated as Vi (O, total flow rate of glycerin (sum of line (11) and line (15) ) is indicated as G (kg/hr), and re-circulated flow rate is indicated as R (kg/hr) .
Ri-G=Ic1V1
(1) In formula (1) , ki is optimized flow rate constant, which is preferably 0.3-5 kg/(t-hr) and more preferably 0.5-1.5 kg/U-hr) to give optimum glycerin conversion rate (95-100%) and highest dichlorohydrin production yield (90-95%) .
The second condition for optimizing flow rate determined by the present invention is that there is correlation between flow rate R (kg/hr) re-circulated into the first reactor through line (22) and the concentration of non-reacted hydrogen chloride (hydrochloric acid) Ci (wt%) remaining in the liquid reaction mixture supplied into the second reactor (24) through line (14) from the first reactor (23) .
In formula (2) , an efficient method to reduce concentration of non-reacted hydrogen chloride (hydrochloric acid) is proposed. That is, concentration of non-reacted
hydrogen chloride (hydrochloric acid) can be reduced by increasing re-circulated flow rate R (kg/hr) . However, if re- circulated flow rate R (kg/hr) is increased to reduce the level of non-reacted hydrogen chloride (hydrochloric acid) , flow rate of glycerin supplied by formula (1) will be reduced. Therefore, re-circulated flow rate R (kg/hr) has to be determined by considering the productivity with the facilities and acceptable amount of non-reactive hydrogen chloride (hydrochloric acid) . In formula (2) , when k2 is 3-5, according to the process of the present invention, optimum glycerin conversion rate and dichlorohydrin yield can be expected.
In the meantime, concentration of water W (wt%) in liquid reaction mixture supplied into the second reactor (24) through line (14) from the first reactor (23) can also be presented by formula (2) , which suggests that water concentration is in proportion to solubility of hydrogen chloride (hydrochloric acid) . In this invention, according to formula (2) , the contents of hydrogen chloride (hydrochloric acid) and water in the reactor can be controlled by regulating re-circulated flow rate R and thereby reaction speed can also be regulated by moving reaction equilibrium.
The third condition for optimizing flow rate is that non- reacted hydrogen chloride (hydrochloric acid) remaining in the liquid reaction mixture provided into the second reactor (24)
through line (14) from the first reactor (23) is reacted with glycerin additionally supplied into the second reactor (24) through line (15) . Then, the level of non-reacted hydrogen chloride (hydrochloric acid) is reduced and as a result hydrogen chloride (hydrochloric acid) loss is prevented in vacuum distillation column. The required flow rate of glycerin added at this time (line (15)) is indicated as G2 (kg/hr) in the following formula.
[Advantage] The present invention provides an economical and highly efficient method for preparing chlorohydrin in a large industrial scale from polyol such as glycerin by chlorination using hydrogen chloride.
[Description of Drawings]
The above and other objects, features and advantages of the present invention will become apparent from the following
description of preferred embodiments given in conjunction with the accompanying drawings, in which:
Fig. 1 is a flow diagram illustrating the method of the present invention.
descriptions of Marks in Figures>
11 : glycerin supply line
12 : carboxylic acid catalyst supply line 13 : hydrogen chloride supply line
14 : liquid reaction mixture feed line
15 : additional glycerin supply line 17 : distilled product vapor line
22 : distillation residual solution circulation line 23 : first reactor
24 : second reactor
25 : vacuum distillation column
26 : condenser
[Best Mode]
Practical and presently preferred embodiments of the present invention are illustrative as shown in the following Examples .
However, it will be appreciated that those skilled in
the art, on consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention.
[Examples] [Example 1]
As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 I respectively, and the first reactor was operated at 110 °C at 5 Kgf/cnfc Glycerin (75.42 g/hr) and acetic acid (3.55 g/hr) were continuously supplied into the first reactor. Glycerin (29.83 g/hr) was continuously supplied into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was maintained as 633.28 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and constants presented in formulas (1) - (3) , conversion rate of total glycerin and dichlorohydrin yield were obtained and shown in Table 1.
[Table 1]
[Example 2]
As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 I respectively, and the first reactor was operated at 110°C at 5 Kgf/cm'G. Glycerin (192.35 g/hr) and acetic acid (9.06 g/hr) were continuously supplied into the first reactor. Glycerin (19.33 g/hr) was continuously supplied into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was maintained as 597.83 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and
constants presented in formulas (1) - (3) , conversion rate of total glycerin and dichlorohydrin yield were obtained and shown in Table 2. [Table 2]
[Example 3]
As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 I respectively, and the first reactor was operated at 1100C at 5 Kgf/CiD2G. Glycerin (180.95 g/hr) and acetic acid (8.53 g/hr) were continuously supplied into the first reactor. Glycerin (16.51 g/hr) was continuously supplied into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was
maintained as 990.2 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and constants presented in formulas (1) - (3), conversion rate of total glycerin and dichlorohydrin yield were obtained and shown in Table 3. [Table 3]
[Example 4] As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 i respectively, and the first reactor was operated at 120°C at 5 Kgf/cirfG. Glycerin (181.4 g/hr) and acetic acid (8.55 g/hr) were continuously supplied into the first reactor. Glycerin (18.5 g/hr) was continuously supplied
into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was maintained as 961.4 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and constants presented in formulas (1) - (3) , conversion rate of total glycerin and dichlorohydrin yield were obtained and shown in Table 4. [Table 4]
[Example 5]
As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 I respectively, and the first reactor was
operated at 120°C at 5 Kgf/cnfc Glycerin (189.96 g/hr) and acetic acid (3.88 g/hr) were continuously supplied into the first reactor. Glycerin (19.5 g/hr) was continuously supplied into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was maintained as 956.74 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and constants presented in formulas (1) - (3) , conversion rate of total glycerin and dichlorohydrin yield were obtained and shown in Table 5.
[Table 5]
[Comparative Example]
As shown in Fig. 1, dichlorohydrin was prepared by a series of reactions with continuous supplement of glycerin, acetic acid, and anhydrous hydrogen chloride in the
experimental apparatus composed of two reactors and one vacuum distillation column. The effective reaction volumes of the two reactors were 1 i respectively, and the first reactor was operated at 110 "C at 5 Kgf/cnfG. Glycerin (90 g/hr) and acetic f) acid (5.25 g/hr) were continuously supplied into the first reactor. Glycerin (110.25 g/hr) was continuously supplied into the second reactor. Liquid levels of the two reactors were maintained at a certain level. Flow rate re-circulating from the vacuum distillation column to the first reactor was
10 maintained as 946.8 g/hr. From the continuous operation under the said conditions, concentrations of non-reacted hydrogen chloride (hydrochloric acid) remaining in the reactors and constants presented in formulas (1) - (3) , conversion rate of total glycerin and dichlorohydrin yield were obtained and
In shown in Table 6. [Table 6]
From the results of examples 1 - 5 and comparative
example, it was confirmed that the optimum conditions for the production of chlorohydrin by chlorination of polyol using hydrogen chloride in a large industrial scale were as follows: flow rate optimization constant ki determining the ratio of polyol flow rate to re-circulated feed flow rate is 0.3-5 kg/ (t-hr) ; flow rate optimization constant k2 determining correlation of non-reacted hydrogen chloride (hydrochloric acid) content (wt %) in the first product mixture feed, effective volume of the first reactor {() and/or flow rate of re-circulated feed (wt %) circulated into the first reactor is 3-5 kg/(*-hr); and flow rate optimization constant k3 determining flow rates of polyol feed supplied into the second reactor and re-circulated feed and concentration of non- reacted hydrogen chloride (hydrochloric acid) in the first product mixture is 0.7-2.5.
Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims.
Claims
[CLAIMS]
[Claim l]
A method for preparing chlorohydrin by a series of reactions comprising the following processes: Reaction mixture feed comprising polyol, hydrogen chloride and organic acid (catalyst for chlorination) is loaded into the first reactor, in which chlorohydrin is generated by chlorination;
The first product mixture feed containing the chlorohydrin and non-reacted reaction mixture discharged from the first reactor and the additional polyol are supplied to the second reactor, in which chlorohydrin is generated by additional chlorination;
The second product mixture feed containing the chlorohydrin discharged from the second reactor is loaded into distillation column and then distillation product containing chlorohydrin is separated through the top of the distillation column; and
Some re-circulated feed of distillation residual solution containing chlorohydrin is re-circulated into the first reactor.
[Claim 2]
The method for preparing chlorohydrin by a series of
reactions according to claim 1, wherein the ratio of polyol flow rate supplied into the first and the second reactors to re-circulated feed flow rate satisfies the following formula (D .
R+G≡ψλ (D
[In formula (1), Vx is effective volume (O of the first reactor, G is total flow rate (kg/hr) of polyol supplied into the first and the second reactors, R is flow rate (kg/hr) of re-circulated feed which is circulated from distillation column to the first reactor, and kx is flow rate optimization constant, which is preferably 0.3-5 kq/{t-hr).]
[Claim 3]
The method for preparing chlorohydrin by a series of reactions according to claim 2, wherein the ki is 0.5 - 1.5 kg/U-hr) .
[Claim 4]
The method for preparing chlorohydrin by a series of reactions according to claim 1, wherein the concentration of non-reacted hydrogen chloride (hydrochloric acid) remaining in the first product mixture feed supplied into the second reactor satisfies the following formula (2) .
[In formula (2), Ci is concentration (wt%) of non-reacted hydrogen chloride (hydrochloric acid) in the first product mixture feed, Vi is effective volume (t) of the first reactor, R is flow rate (kg/hr) of re-circulated feed which is circulated from distillation column to the first reactor, and k2 is flow rate optimization constant, which is preferably 3- 5.]
[Claim 5]
The method for preparing chlorohydrin by a series of reactions according to claim 1, wherein the flow rate of polyol feed additionally supplied into the second reactor, the flow rate of re-circulated feed, and the concentration of non- reacted hydrogen chloride (hydrochloric acid) remaining in the first product mixture satisfy the following formula (3) .
[In formula (3) , G2 is flow rate (kg/hr) of polyol supplied into the second reactor, Gi is flow rate (kg/hr) of polyol included in the reaction mixture feed of the first
reactor, G is total flow rate (kg/hr) of polyol supplied into the first and the second reactors, R is flow rate (kg/hr) of re-circulated feed which is circulated from distillation column to the first reactor, Ci is concentration (wt%) of non- reacted hydrogen chloride (Hydrochloric acid) in the first product mixture feed, and k3 is optimized flow rate constant, which is preferably 0.7-2.5.]
[Claim β] The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein the non-reacted reaction mixture remaining in the first product mixture discharged from the first reactor contains polyol, hydrogen chloride, organic acid catalyst and water.
[Claim 7]
The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein the re-circulated feed circulated into the first reactor contains chlorohydrin and non-reacted polyol.
[Claim 8]
The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein
the polyol is selected from the group consisting of 1,2- ethanediol, 1, 2-propanediol, 1, 3-propanediol, 3-chloro-l, 2- propanediol, 2-chloro-l, 3-propanediol and glycerin, and their ester compounds and a mixture thereof.
[Claim 9]
The method for preparing chlorohydrin by a series of reactions according to claim 8, wherein the polyol is glycerin.
[Claim 10]
The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein the organic acid is selected form the group consisting of monocarboxylic acid or dicarboxylic acid, its anhydride, salt and ester compounds.
[Claim 11]
The method for preparing chlorohydrin by a series of reactions according to claim 10, wherein the organic acid is acetic acid.
[Claim 12]
The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein
the hydrogen chloride is an anhydride.
[Claim 13]
The method for preparing chlorohydrin by a series of reactions according to claim 12, wherein the reaction temperature of the first reactor is 70 - 140°C.
[Claim 14]
The method for preparing chlorohydrin by a series of reactions according to claim 12, wherein the reaction temperature of the first reactor is maintained by the temperature of re-circulated feed and heat of dissolution of anhydrous hydrogen chloride .
[Claim 15]
The method for preparing chlorohydrin by a series of reactions according to claim 14, wherein the anhydrous hydrogen chloride is continuously supplied to induce reaction under increased pressure.
[Claim 16]
The method for preparing chlorohydrin by a series of reactions according to any one of claim 1 - claim 5, wherein the distilled product separated from the top of the
distillation column contains chlorohydrin, organic acid catalyst and water.
[Claim 17] The method for preparing chlorohydrin by a series of reactions according to claim 16, wherein the content of chlorohydrin in the distilled product is 50 - 90 weight%.
[Claim 18] The method for preparing chlorohydrin by a series of reactions according to claim 16, wherein the distilled product is separated by vacuum distillation.
[Claim 19] A method for preparing epichlorohydrin from chlorohydrin generated by the method of claim 9.
[Claim 20]
A method for preparing epichlorohydrin from the distilled product containing chlorohydrin prepared according to the method of claim 16, without any separation process.
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| CN103038201A (en) * | 2010-06-30 | 2013-04-10 | 三星精密化学株式会社 | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US20130096327A1 (en) * | 2010-06-30 | 2013-04-18 | Won Seob Song | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US20130102800A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102799A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102801A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102798A1 (en) * | 2010-06-30 | 2013-04-25 | Samsung Fine Chemicals Co. Ltd | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
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| WO2006020234A1 (en) * | 2004-07-21 | 2006-02-23 | Dow Global Technologies Inc. | Conversion of a multihydroxylated-aliphatic hydrocarbon or ester thereof to a chlorohydrin |
| WO2006106154A1 (en) * | 2005-05-20 | 2006-10-12 | Solvay (Société Anonyme) | Continuous method for making chlorhydrines |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60258171A (en) * | 1984-06-04 | 1985-12-20 | Showa Denko Kk | Preparation of epichlorohydrin |
-
2007
- 2007-09-28 KR KR1020070097675A patent/KR101410019B1/en active IP Right Grant
-
2008
- 2008-09-17 CN CN2008801143217A patent/CN101842339B/en not_active Expired - Fee Related
- 2008-09-17 WO PCT/KR2008/005474 patent/WO2009041766A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4665240A (en) * | 1986-05-27 | 1987-05-12 | Shell Oil Company | Process for the production of dichlorohydrin |
| WO2006020234A1 (en) * | 2004-07-21 | 2006-02-23 | Dow Global Technologies Inc. | Conversion of a multihydroxylated-aliphatic hydrocarbon or ester thereof to a chlorohydrin |
| WO2006106154A1 (en) * | 2005-05-20 | 2006-10-12 | Solvay (Société Anonyme) | Continuous method for making chlorhydrines |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103038201A (en) * | 2010-06-30 | 2013-04-10 | 三星精密化学株式会社 | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US20130096327A1 (en) * | 2010-06-30 | 2013-04-18 | Won Seob Song | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US20130102800A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102799A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102801A1 (en) * | 2010-06-30 | 2013-04-25 | Won Seob Song | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US20130102798A1 (en) * | 2010-06-30 | 2013-04-25 | Samsung Fine Chemicals Co. Ltd | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US8916732B2 (en) * | 2010-06-30 | 2014-12-23 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US8969630B2 (en) * | 2010-06-30 | 2015-03-03 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US8969601B2 (en) * | 2010-06-30 | 2015-03-03 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US8969631B2 (en) * | 2010-06-30 | 2015-03-03 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| US8975449B2 (en) | 2010-06-30 | 2015-03-10 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins and method for preparing epichlorohydrin using chlorohydrins prepared thereby |
| US9035108B2 (en) * | 2010-06-30 | 2015-05-19 | Samsung Fine Chemicals Co., Ltd. | Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby |
| CN110922299A (en) * | 2019-11-07 | 2020-03-27 | 无锡市银杏塑业科技有限公司 | Continuous preparation method of high-content 2-chloroethanol |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20090032429A (en) | 2009-04-01 |
| KR101410019B1 (en) | 2014-06-26 |
| CN101842339B (en) | 2013-08-28 |
| CN101842339A (en) | 2010-09-22 |
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