WO2009151175A1

WO2009151175A1 - Method of preparing dichloropropanol from glycerol in the presence of heteropolyacid catalyst and/or absorbent under solvent-free conditions

Info

Publication number: WO2009151175A1
Application number: PCT/KR2008/003680
Authority: WO
Inventors: In-Kyu Song; Sang-Hee Lee; Sun-Ho Song; Dong-Ryul Park; Sung-Yul Woo; Won-Seob Song; Myong-Suk Kwon
Original assignee: Samsung Fine Chemicals Co., Ltd.
Priority date: 2008-06-11
Filing date: 2008-06-26
Publication date: 2009-12-17
Also published as: KR20090128886A

Abstract

Provided is a method of preparing dichloropropanol from glycerol. The method includes reacting glycerol with a chlorinating agent, and the reaction is performed in the presence of a heteropolyacid catalyst and/or an absorbent under solvent-free conditions. Thus, according to the method, dichloropropanol can be directly prepared from glycerol. Since a solvent is not used, a process of removing the solvent is not necessary, and thus the volume of a reactor can be reduced. In addition, conventional problems such as recovery of the catalyst and separation of an azeotropic mixture including the catalyst and products can be overcome. In addition, expensive dichloropropanol can be produced at high yield from inexpensive glycerol.

Description

METHOD OF PREPARING DICHLOROPROPANOL FROM

GLYCEROL IN THE PRESENCE OF HETEROPOL YACID

CATALYST AND/OR ABSORBENT UNDER SOLVENT-FREE

CONDITIONS

Technical Field

[1] The present invention relates to a method of preparing dichloropropanol from glycerol, and more particularly, to a method of preparing dichloropropanol from glycerol in the presence of a heteropolyacid catalyst and/or an absorbent under solvent- free conditions. Background Art

[2] Recently, bio-diesels have been competitively developed and produced worldwide, and also domestically manufactured and brought to markets as an additive to petro- diesel.

[3] During the production of bio-diesel, a large amount of glycerol, corresponding to about 10% of the amount of the produced bio-diesel, is generated as a by-product. However, supply of glycerol is greater than demand. Therefore, oversupply of glycerol decreases its value. Thus, it is economically advantageous to convert glycerol into dichloropropanol which is a higher- value product compared to glycerol.

[4] Meanwhile, dichloropropanol is a raw material used to produce epichlorohydrin which is applied to a variety of fields as a raw material for epoxy resins, synthesized glycerol, ion exchange resins, flame retardants, solvents, medicines, dyes, and the like. Most of the dichloropropanol which is currently supplied to markets is manufactured from propylene. More particularly, a method of preparing dichloropropanol includes two stages of preparing allyl chloride through chlorination of propylene at a high temperature and preparing dichloropropanol by reacting the allyl chloride with hydrochloric acid using an excess amount of industrial water (US Patent Nos. 4,479,020, 6,051,742, and 6,333,420). However, the method of preparing dichloropropanol using propylene is disadvantageous because of instability of propylene supply and demand caused by increased price of propylene, generation of a large amount of waste water and other waste, excessive initial investment costs due to the 2 stage manufacturing process and difficulty of newly constructing/modifying the process thereby.

[5] Accordingly, a single stage process of directly preparing dichloropropanol by reacting glycerol with hydrochloric acid is more economical. The single stage process using glycerol is advantageous in that costs of raw materials can be reduced by using inexpensive glycerol as a reactant, the amount of waste water and other waste can be dramatically reduced since industrial water is not required for the process, thereby being environmentally friendly and initial investment costs related to the process and environment can be reduced. In addition, the method of preparing dichloropropanol from glycerol using a single stage process is environmentally friendly since dichloropropanol is directly prepared from glycerol which is a by-product generated in the preparation of bio-diesels, which is different from the conventional method of preparing dichloropropanol through the 2 stage manufacturing process.

[6] In addition, since dichloropropanol is directly prepared by reacting glycerol with hydrochloric acid using a catalyst, manufacturing costs for dichloropropanol and energy consumption can be reduced by developing efficient catalysts. Thus, when an excellent catalyst process by which dichloropropanol can be directly prepared using glycerol is developed, technological competitiveness in the preparation of dichloropropanol can be gained with regard to environmental, economical, and investment cost aspects.

[7] Recently, International Publication Nos. WO2006/020234, WO2005/054167 and

WO2005/021476 disclose techniques of preparing dichloropropanol from glycerol by a continuous process using a carboxylic acid-based homogeneous catalyst and hydrogen chloride gas as a chlorinating agent. In addition, Chinese Patent Publication No. CN 10100775 IA discloses a method of preparing dichloropropanol in which consumption of hydrogen chloride gas is decreased by performing a first reaction in a plug flow reactor using a nitrile-based catalyst and continuously removing water from a second reaction performed using a bubble cap tray.

[8] In addition, a method of preparing dichloropropanol by diluting glycerol in a solvent and passing the diluted glycerol and hydrogen chloride gas through a packed bed packed with glass beads without using a catalyst is reported by Isu Chemical Company, Korea (Korean Patent Publication No. 2008-0038284).

[9] However, apart from the above publications, inventions related to a method of directly preparing dichloropropanol from glycerol have not been disclosed. In particular, inventions related to a method of directly preparing dichloropropanol from glycerol in the presence of a heteropolyacid catalyst and/or an absorbent under solvent- free conditions have not been disclosed. Thus, the present invention has novelty in this regard. Disclosure of Invention Technical Problem

[10] The present invention provides a method of preparing dichloropropanol (DCP) from glycerol at a high yield in the presence of a heteropolyacid catalyst and/or an absorbent under solvent-free conditions.

[11] The present invention also provides a method of preparing dichloropropanol by simplifying manufacturing processes, thereby reducing manufacturing costs.

[12] The present invention also provides a method of preparing dichloropropanol in which a catalyst and a reactant do not form an azeotropic mixture and the catalyst can be easily recovered and reused.

[13] The present invention also provides a method of preparing dichloropropanol for efficiently treating glycerol generated during the preparation of bio-diesels and converting glycerol to a higher value product. Technical Solution

[14] According to an aspect of the present invention, there is provided a method of preparing dichloropropanol by reacting glycerol with a chlorinating agent in the presence of at least one of a heteropolyacid catalyst and an absorbent under solvent- free conditions.

[15] The absorbent may comprise silica gel.

[16] The heteropolyacid catalyst may comprise a Keggin-type heteropolyacid catalyst in which the ratio of the number of central atoms to the number of poly atoms is 1:12.

[17] The Keggin-type heteropolyacid catalyst may comprise at least one heteropolyacid selected from the group consisting of a plurality of 12-molybdotungstophosphoric acids (H₃PMo₁₂-_XWxO₄₀), wherein x is a number in the range of 0 to 12.

[18] All of or some of the hydrogen atoms in 124nolybdotungstophosphoric acids (H ₃

PMo₁₂.χWχO₄₀) may be substituted with metal.

[19] The heteropolyacid catalyst may be recovered after the reaction and reused.

[20] The chlorinating agent may be hydrogen chloride gas or hydrochloric acid.

[21] The reaction may be performed in a batch reactor, a semi-batch reactor, or a constant stirred tank reactor (CSTR).

[22] The reaction may be performed at a stirring rate in the range of 600 rpm or higher.

[23] The reaction may be performed at a temperature in the range of 50 to 300 ⁰C .

[24] The reaction may be performed at a pressure in the range of 0.1 to 30 bar.

[25] The reaction may be performed for 10 minutes to 50 hours.

[26] According to another aspect of the present invention, there is provided a method of preparing epichlorohydrin (ECH) after preparing dichloropropanol by reacting glycerol and a chlorinating agent, the method comprising the method of preparing dichloropropanol, or using dichloropropanol prepared according to the method of preparing dichloropropanol. Description of Drawings

[27] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[28] FD. 1 shows a graph of yields for dichloropropanol (DCP) against stirring rates

(rpm) of a mixture of reactants when dichloropropanol is prepared from glycerol and hydrogen chloride gas in the absence of an absorbent and a catalyst under solvent-free conditions (Experimental Example 1); and

[29] FD. 2 shows a graph of yields for dichloropropanol against the number of tungsten atoms among coordinated atoms in a Keggin-type heteropolyacid catalyst basically including phosphorous (P) as a central atom and tungsten (W) and/or molybdenum (Mo) as poly atoms (Example 1). Best Mode

[30] Hereinafter, a method of preparing dichloropropanol according to an embodiment of the present invention will be described.

[31] The method of preparing dichloropropanol according to the current embodiment of the present invention includes chlorination reaction of glycerol performed in the presence of a heteropolyacid catalyst and/or an absorbent under solvent-free conditions.

[32] A chlorinating agent used in the chlorination reaction may be hydrogen chloride gas or hydrochloric acid, but is not limited thereto.

[33] A solvent is used in order to increase contact area between glycerol and the chlorinating agent by uniformly dispersing glycerol in the solvent, and such a solvent has been commonly used in conventional preparation of dichloropropanol. However, according to the method of preparing dichloropropanol according to the present invention, the contact area between glycerol and the chlorinating agent can be increased even under solvent-free conditions by maintaining a high stirring rate of a mixture of reactants of 600 rpm or higher. If the stirring rate is less than 600 rpm, glycerol and the chlorinating agent are not completely mixed so that the contact area between glycerol and the chlorinating agent is decreased, thereby decreasing reaction activity. [34] Since fast stirring is an essential condition for preparation of dichloropropanol under solvent-free conditions, the reactions may be performed in a batch reactor, a semi- batch reactor, or a constant stirred tank reactor (CSTR). In addition, the reactor may be a reactor formed of a material which is resistant to the chlorinating agent or a reactor including interior elements coated with the material resistant to the chlorinating agent. Examples of the material resistant to the chlorinating agent are Hastelloy C and Teflon.

[35] Here, the chlorination reaction is performed at a temperature in the range of 50 to

300 ⁰C , and preferably in the range of 100 to 200 ⁰C . When the reaction temperature is less than 50 ⁰C , the reaction rate may not be sufficiently high. On the other hand, when the reaction temperature is greater than 300 ⁰C , energy loss may be greater. In addition, generally, the chlorination reaction may be performed at a pressure in the range of 0.1 to 30 bar, and preferably 1 to 15 bar. Even though higher activity can be observed at a higher reaction pressure, when the pressure is higher than a predetermined level (30 bar), the reaction activity is not increased any longer. The reaction pressure is regulated by the pressure of the chlorinating agent. Generally, the reaction may be performed for 10 minutes to 50 hours, and preferably for 1 to 20 hours. When the reaction is performed for less than 10 minutes, the glycerol conversion is too low. On the other hand, when the reaction is performed for longer than 50 hours, the reaction is nearly completed, and thus the conversion or selectivity are not increased any longer. Here, the 'dichloropropanol' indicates a mixture of isomers including l,3-dichloropropane-2-ol and l,2-dichloropropane-3-ol. In the method of preparing dichloropropanol according to the present invention, l,3-dichloropropane-2-ol, which is a suitable reactant for the preparation of epichlorohydrin, is mainly produced.

[36] The chlorination reaction may be performed under solvent-free and catalyst-free conditions, and preferably performed in the presence of a heteropolyacid catalyst under solvent-free conditions. If the chlorination reaction is performed in the presence of the heteropolyacid catalyst, reaction activity is so increased that glycerol conversion, yields for dichloropropanol, and selectivity for dichloropropanol may be increased compared to when the chlorination reaction is performed under catalyst-free conditions.

[37] The heteropolyacid catalyst may be used in a homogeneous or heterogeneous catalytic reaction.

[38] The heteropolyacid catalyst may include a Keggin-type heteropolyacid in which the ratio of the number of central atoms to the number of poly atoms is 1:12.

[39] The Keggin-type heteropolyacid catalyst includes at least one heteropolyacid selected from the group consisting of a plurality of 12-molybdotungstophosphoric acids (H₃PMo₁₂-_XWxO_4O) in which all of or some of the hydrogen atoms may be substituted with metal, wherein x is a number in the range of 0 to 12. The metal may include Cs or Ag.

[40] The heteropolyacid catalyst substituted with a metal such as Cs or Ag is insoluble in water and forms a three-dimensional structure which has a surface area equal to or greater than 40 m²/g. When the insoluble heteropolyacid catalyst forming a three- dimensional structure is used, the reaction can be a heterogeneous catalytic reaction.

[41] In addition, the heteropolyacid catalyst can be recovered after the reaction and reused. That is, solid heteropolyacid can be recovered by evaporating liquid products after the reaction, and the recovered solid heteropolyacid can be added to a reactor and reused. Since the mixture solution including the heteropolyacid catalyst and reaction products does not form an azeotropic mixture after the reaction, the heteropolyacid catalyst can be recovered after the reaction and reused. When a mixture solution forms an azeotropic composition as in the case of using a conventional carboxylic acid-based catalyst, equilibrium is established between liquid and gas phases. Thus, the catalyst cannot be simply separated from the mixture solution since the ratio of components between the liquid and gas phases is constantly maintained and the boiling point of each component is not changed.

[42] The addition of the catalyst can be performed in a continuous or discontinuous way in the batch reactor, the semi-batch reactor, or the CSTR.

[43] The chlorination reaction may be performed in the presence or absence of the absorbent. That is, the chlorination reaction may be performed (i) in the absence of the absorbent and the catalyst under solvent-free conditions (ii) in the absence of the absorbent and in the presence of the heteropolyacid catalyst under solvent-free conditions (iii) in the presence of the absorbent and in the absence of catalyst under solvent-free conditions, and (iv) in the presence of the heteropolyacid catalyst and the absorbent under solvent-free conditions. The chlorination reaction may most preferably be performed under conditions (iv). If the chlorination reaction is performed in the presence of the absorbent, the absorbent absorbs water from the products during the reaction, thereby removing water, and thus the glycerol conversion, yields for di- chloropropanol, and selectivity for dichloropropanol may be increased compared to when the chlorination reaction is performed in the absence of the absorbent. Since water is a by-product of the reaction and prohibits dichloropropanol generation, water preferably needs to be removed. [44] If the chlorination reaction is performed in the presence of the absorbent, the absorbent may include silica gel, particularly silica gel blue. [45] In the preparation of dichloropropanol directly from glycerol under solvent-free conditions, the glycerol conversion, the selectivity for dichloropropanol, and the yield for dichloropropanol are respectively calculated using Equations 1 to 3. [46] Equation 1

[47] Glycerol conversion (%) = (the number of moles of reacted glycerol/the number of moles of supplied glycerol)^χ 100

[48] Equation 2

[49] Selectivity for dichloropropanol (%) = (the number of moles of produced dichloropropanol/the number of moles of reacted glycerol)* 100

[50] The selectivity for dichloropropanol is calculated based on the mixture of isomers of l,3-dichloropropane-2-ol and l,2-dichloropropane-3-ol.

[51] Equation 3

[52] Yield for dichloropropanol (%) = (the number of moles of produced dichloropropanol/the number of moles of supplied glycerol) ^χ 100

[53] Yield for dichloropropanol (%) = (the number of moles of produced dichloropropanol/the number of moles of supplied glycerol) xlOO

[54] Meanwhile, the present invention also provides a method of preparing epi- chlorohydrin (ECH) including the method of preparing dichloropropanol described above, or using dichloropropanol prepared according to the method of preparing dichloropropanol described above. In particular, a method of preparing epichlorohydrin from glycerol using a heteropolyacid catalyst is shown in Reaction Scheme 1 below.

[55] Reaction Scheme 1

propaπe-3-ol

NaOH

Epichlorohydrin Mode for Invention [57] Hereinafter, the present invention will be described in greater detail with reference to the following examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[58] Examples [59] Experimental Example 1 : Reaction activity in the preparation of dichloropropanol according to stirring rate (RPM) of a reactor when dichloropropanol is directly prepared from glycerol and hydrogen chloride gas in the absence of an absorbent and a catalyst under solvent-free conditions

[60] Dichloropropanol was prepared by reacting glycerol with 99.7 vol.% hydrogen chloride gas in the absence of an absorbent and a catalyst under solvent-free conditions. The reaction was performed in a liquid phase in a 200 ml batch reactor from which water was completely removed. The interior elements of the batch reactor were formed of Hastelloy C and Teflon which has resistance to a chlorinating agent. First, 100 g of glycerol was added to the batch reactor. Then, the reaction temperature was fixed at 120 ⁰C, and reaction was performed by continuously supplying 99.7 vol.% hydrogen chloride gas as a chlorinating agent at a constant pressure of 3 bar to the batch reactor for 3 hours while stirring. After the reaction was completed, the batch reactor was cooled to room temperature and products were analyzed using gas chro- matograph. In addition, glycerol conversions, selectivities for dichloropropanol, and yields for dichloropropanol were respectively calculated using Equations 1 to 3, and the results are shown in Table 1 below. 'MCPD' and 'DCP' of Table 1 respectively indicate monochloropropandiol and dichloropropanol.

[61] Table 1

[62] Referring to Table 1, reaction activity was significantly changed according to the stirring rate at a low stirring rate, that is, less than 600 RPM, since the reactants were not sufficiently mixed due to mass transfer resistance at such a low stirring rate. However, yields of dichloropropanol were not significantly changed since sufficient mass transfer occurred at a high stirring rate, that is, greater than 600 RPM. Thus, the reactions were performed at a stirring rate of 900 RPM in order to exclude effects of mass transfer resistance in all subsequent examples.

[63] Experimental Example 2: Reaction activity in the preparation of dichloropropanol according to reaction conditions (temperature, pressure, and time) when dichloro- propanol is directly prepared from glycerol and hydrogen chloride gas in the absence of an absorbent and a catalyst under solvent-free conditions

[64] Dichloropropanol was prepared in the same manner as in Experimental Example 1, except that reactions were performed by varying temperature, pressure, and time, as shown in Table 2 below. After the reaction was completed, products were analyzed using gas chromatograph. In addition, glycerol conversions, selectivities for dichloropropanol, and yields for dichloropropanol were respectively calculated using Equations 1 to 3, and the results are shown in Table 2 below.

[65] Table 2

[66] Referring to Table 2, effects of the reaction temperature can be determined by respectively comparing Experimental Example 2-1 with Experimental Example 2-5, comparing Experimental Example 2-2 with Experimental Example 2-3, and comparing Experimental Example 2-4 with Experimental Example 2-6. Effects of the reaction pressure can be determined by comparing Experimental Example 2-3 with Experimental Example 2-4, and effects of the reaction time can be determined by respectively comparing Experimental Example 2- 1 with Experimental Example 2-2 and comparing Experimental Example 2-6 with Experimental Example 2-7. As a result of the comparisons, it can be seen that the selectivity for dichloropropanol and yield for dichloropropanol are increased as the temperature, pressure, and time of the reaction are increased. As shown in Table 2, dichloropropanol can be prepared with a high yield by adjusting the reaction temperature, reaction pressure, and/or reaction time. For example, if the reaction was performed at a relatively low temperature of 110 ⁰C at 5 bar for 20 hours (Experimental Example 2-8), the yield for dichloropropanol was 96.4%.

[67] Such a high yield can be obtained by decreasing the reaction temperature and reaction pressure and increasing the reaction time. [68] Example 1: Reaction activity in the preparation of dichloropropanol according to types of a catalyst when dichloropropanol is directly prepared from glycerol and hydrogen chloride gas in the presence of 12-molybdotungstophosphoric acid (H₁PMo i2 xW-v O An) catalyst and in the absence of an absorbent under solvent-free conditions

[69] Dichloropropanol was prepared in the same manner as in Experimental Example 1, except that 5 g of each of 5 types of catalyst represented by H₃PMo₁₂ χW_xO₄₀ (X=O, 3, 6, 9, 12) as a heteropolyacid catalyst was respectively added to a batch reactor respectively with 100 g of glycerol, and the reaction temperature was fixed at 110 ⁰C . After the reaction was completed, products were analyzed using gas chromatograph. In addition, glycerol conversions, selectivities for dichloropropanol, and yields for dichloropropanol were respectively calculated using Equations 1 to 3, and the results are shown in Table 3 below. Furthermore, analyzed data of Experimental Example 2-2 was added to Table 3 for comparisons.

[70] Table 3

[71] Referring to Table 3, activities of reactions performed in the presence of the heteropolyacid catalyst was higher than activities of reactions performed under catalyst-free conditions if other conditions are the same. As the amount of tungsten (W) (that is, the number of tungsten atoms), which is the poly atom, was increased, the yield for dichloropropanol was increased. Among the Keggin-type heteropolyacid catalysts used, 12-tungstophosphoric acid (H₃PW₁₂O₄₀) catalyst was the most effective in the reaction. The yield for dichloropropanol prepared in the presence of 12-tungstophosphoric acid catalyst was at least about 34% higher than the yield of dichloropropanol prepared under catalyst-free conditions. This indicates that reactions performed in the presence of a heteropolyacid are more efficient than reactions performed under catalyst-free conditions in preparation of dichloropropanol from glycerol and hydrogen chloride gas under solvent-free conditions.

[72] Example 2: Reaction activity in the preparation of dichloropropanol in the presence

and/or an absorbent (silica gel blue) when dichloropropanol is prepared under solvent- free conditions

[73] Dichloropropanol was prepared in the same manner as in Experimental Example 1, except that 100 g of glycerol and 5 g of silica gel blue (Samchun Pure Chemical Go., Ltd./Silicagel blue, medium glanular, 5-10 mesh) as an absorbent were added to a batch reactor, and the reaction temperature was fixed at 110 ⁰C .

[74] Dichloropropanol was prepared in the same manner as in Experimental Example 1, except that 100 g of glycerol and 5 g of H₃PW₁₂O₄₀ as a heteropolyacid catalyst were added to a batch reactor, and the reaction temperature was fixed at 110 ⁰C .

[75] Dichloropropanol was prepared in the same manner as in Experimental Example 1, except that 100 g of glycerol, 2.5 g of silica gel blue (Samchun Pure Chemical Go., Ltd./Silicagel blue, medium glanular, 5-10 mesh) as an absorbent, and 5 g Of H₃PWi₂O 40 were added to a batch reactor, and the reaction temperature was fixed at 110 ⁰C .

[76] After the reactions were completed, products were analyzed using gas chro- matograph. In addition, glycerol conversions, selectivities for dichloropropanol, and yields for dichloropropanol were respectively calculated using Equations 1 to 3, and the results are shown in Table 4 below. Furthermore, analyzed data of Experimental Example 2-2 was added to Table 4 for comparisons.

[77] Table 4

[78] Referring to Table 4, the yield for dichloropropanol were significantly increased when glycerol and silica gel blue were added to the reaction. This is because water generated during the reaction is absorbed in silica gel blue and removed. The yield for dichloropropanol was significantly increased when glycerol and H₃PW₁₂O₄₀ catalyst were added to the reaction as shown in Example 1. Meanwhile, the yield for dichloropropanol was more significantly increased when glycerol, silica gel blue, and H₃PW₁₂O 40 catalyst were added to the reaction, since effects of silica gel blue on removing water have synergistic effects with effects of the H₃PW₁₂O₄₀ catalyst, than when only silica gel blue or H₃PW₁₂O₄₀ catalyst was added to the reaction.

[79] Evaluation Examples

[80] Evaluation Example 1: Yields for dichloropropanol according to stirring rate (RPM) of a reaction mixture when dichloropropanol is prepared from glycerol and hydrogen chloride gas in the absence of an absorbent and a catalyst under solvent-free conditions (Experimental Example 1)

[81] Yields for dichloropropanol prepared from glycerol in the absence of an absorbent and a catalyst under solvent-free conditions as shown in Experimental Example 1 are shown in FD. 1.

[82] Referring to FD. 1, it can be seen that the yield for dichloropropanol was significantly different at stirring rates above and below 600 RPM. In addition, the stirring rate needs to be equal to or greater than 600 RPM in terms of the yield for dichloropropanol according to Evaluation Example 1.

[83] Evaluation Example 2: Yields for dichloropropanol against the number of tungsten atoms among poly atoms in a Keg gin-type heteropolyacid catalyst basically including phosphorous (P) as a central atom and tungsten (W) and/or molybdenum (Mo) as poly atoms (Example 1)

[84] FD. 2 shows a graph of yields for dichloropropanol when dichloropropanol is prepared from glycerol in the presence of heteropolyacid catalyst and in the absence of an absorbent under solvent-free conditions (Example 1).

[85] Referring to FD. 2, the yield for dichloropropanol was increased as the number of the tungsten (W) atoms is increased in the heteropolyacid catalyst. In addition, 12-tungstophosphoric acid was preferable in terms of the yield for dichloropropanol according to Evaluation Example 2.

[86] According to the method of preparing dichloropropanol according to the present invention, dichloropropanol can be directly prepared from glycerol in the presence of a heteropolyacid catalyst and/or an absorbent under solvent-free conditions. Since a solvent is not used, a process of removing the solvent is not necessary, and thus the volume of a reactor can be reduced. In addition, conventional problems such as recovery of the catalyst and separation of an azeotropic mixture including the catalyst and products can be overcome. In addition, since the catalyst can be easily recovered and reused, the manufacturing process can be simplified and expensive dichloro- propanol can be produced at high yield from inexpensive glycerol. [87] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

[I] L A method of preparing dichloropropanol by reacting glycerol with a chlorinating agent in the presence of at least one of a heteropolyacid catalyst and an absorbent under solvent-free conditions.

[2] 2. The method of claim 1, wherein the absorbent comprises silica gel.

[3] 3. The method of claim 1, wherein the heteropolyacid catalyst comprises a

Keggin-type heteropolyacid catalyst in which the ratio of the number of central atoms to the number of poly atoms is 1:12.

[4] 4. The method of claim 3, wherein the Keggin-type heteropolyacid catalyst comprises at least one heteropolyacid selected from the group consisting of a plurality of 12-molybdotungstophosphoric acids (H ₃PMo₁₂.χWχO₄₀), wherein x is a number in the range of 0 to 12.

[5] 5. The method of claim 4, wherein all of or some of the hydrogen atoms in

124Ωθlybdotungstophosphoric acids (H ₃PMo₁₂.χWχO₄₀) are substituted with metal.

[6] 6. The method of claim 1, wherein the heteropolyacid catalyst is recovered after the reaction and reused.

[7] 7. The method of claim 1, wherein the chlorinating agent is hydrogen chloride gas or hydrochloric acid.

[8] 8. The method of claim 1, wherein the reaction is performed in a batch reactor, a semi-batch reactor, or a constant stirred tank reactor (CSTR).

[9] 9. The method of claim 7, wherein the reaction is performed at a stirring rate in the range of 600 rpm or higher.

[10] 10. The method of claim 7, wherein the reaction is performed at a temperature in the range of 50 to 300 ⁰C .

[I I]

11. The method of claim 7, wherein the reaction is performed at a pressure in the range of 0.1 to 30 bar.

[12] 12. The method of claim 7, wherein the reaction is performed for 10 minutes to

50 hours.

[13] 13. A method of preparing epichlorohydrin (ECH) after preparing dichloropropanol by reacting glycerol and a chlorinating agent, the method comprising preparing dichloropropanol according to any one of claims 1 to 12, or using dichloropropanol prepared according to any one of claims 1 to 12