Technological Parameters of Dehydrochlorination of 1,3

Jul 22, 2013 - West Pomeranian University of Technology in Szczecin, Institute of Organic Chemical Technology, Pułaski 10 Street, 70-322. Szczecin, P...
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Technological Parameters of Dehydrochlorination of 1,3Dichloropropan-2-ol to Epichlorohydrin Anna M. Krzyzȧ nowska,* Eugeniusz Milchert, and Waldemar M. Paździoch West Pomeranian University of Technology in Szczecin, Institute of Organic Chemical Technology, Pułaski 10 Street, 70-322 Szczecin, Poland S Supporting Information *

ABSTRACT: The results of continuous dehydrochlorination of an 88 wt % aqueous solution of 1,3-dichloropropan-2-ol (13DCP2OL) to epichlorohydrin (EPI) are presented. The dehydrochlorination was carried out in the reaction-stripping column system. The influence of the following parameterslime milk concentration, the molar ratio of Ca(OH)2/13DCP2OL, the rate of steam flow through the column, pressure, changes in loading of reaction-stripping column, reaction time in a prereactor and reactor on the conversion of 13DCP2OL, and the selectivity of transformation to EPIwere studied. In one series of investigations, EPI was collected from the column in the form of distillate, in the second one, from the distillation reboiler under the column. It was evaluated which methods of collection of EPI distillate are more favorable. The technological parameters were provided for the operation of the reaction-stripping system, which allow one to obtain EPI with the selectivity close to 100%, simultaneously giving high conversion (90%) of 13DCP2OL.

1. INTRODUCTION Epichlorohydrin (EPI) is an extremely important chemical intermediate due to its high reactivity. This compound is mostly used for the production of epoxy resins, moreover, its derivatives are utilized in the production of elastomers, plasticizers, softening agents, greases, adhesives, paints, lacquers,1 glycidol ethers formed in the reaction of EPI with phenols or alcohols, applied as the reactive solvents or polymer stabilizers containing chlorine,2 water-resistant resins used in the paper-mill industry, resins for water purification and others,3 as well as the biologically active compounds.4,5 The studies concerning the utilization of epichlorohydrin for the synthesis of sorbents for the purpose of the removal of methylene blue from water,6 for cross-linking of starch,7 and for the synthesis of modern surface-active agents are still ongoing.8 EPI is mainly produced by the chlorine method, which suffers from several disadvantages.9 Nowadays, the glycerol method of production has been introduced, which is more economical and generates lesser amounts of wastewater and waste.10 Kinetic parameters of dichloropropanols dehydrochlorination were studied.11 According to the results, the rate of dehydrochlorination of 1,3-dichloropropan-2-ol (13DCP2OL) is about 20 times higher than that of 2,3-dichloropropan-1-ol (23DCP1OL). The technological parameters of EPI preparation by the chlorine method were presented in the previous paper.12 That paper presented the dehydrochlorination of an aqueous solution of dichloropropanols with a composition of 0.57 wt % 13DCP2OL, 1.73 wt % 23DCP1OL, and 0.045 wt % hydrogen chloride. Such a diluted solution was formed during the chlorohydroxylation of allyl chloride in the industrial chlorine method. In a new glycerol method of EPI production, 13DCP2OL with purity of 98 wt %, which contained no more than 2 wt % of 23DCP1OL, was subjected to dehydrochlorination. This intermediate was obtained during the chlorination of glycerol (GLYC) with dry hydrogen chloride. These two © 2013 American Chemical Society

solutions are completely different, and they require different technological parameters at the stage of dehydrochlorination. The Solvay Company started in 2007 the first installation producing EPI via the glycerol method. The process was realized under the name of Epicerol Technology.13 In this technology, sodium hydroxide was used as a dehydrochlorination agent. Dehydrochlorination by NaOH solution requires a very accurate dosing of this reagent. High alkalinity of NaOH or disturbances in substrate flow at even a very small excess of NaOH intensifies the side reactions, ultimately leading to glycerol and polyglycerols. However, on the other hand, the use of NaOH permits recovery of NaCl from the brine after dehydrochlorination and repeated use of this salt to obtain NaOH and chlorine by membrane electrolysis. For this purpose, it is necessary to concentrate the waste brine and to perform its careful purification. The hitherto applied technological solutions are very expensive and have not been used on an industrial scale. In our research, the dehydrochlorination agent is an aqueous solution of calcium hydroxide. The dehydrochlorination is carried out in the apparatus and according to the method described in a previous paper.14 A byproduct formed in this process, and the influence of prereactor temperature on the conversion of 13DCP2OL and the selectivity of transformation to EPI using different methods of product collection were also presented in the mentioned paper. The present paper shows the influence of the following technological parameters: lime milk concentration, Ca(OH)2/13DCP2OL molar ratio, flow rate of steam, pressure, reaction time, and the flow rate of Received: Revised: Accepted: Published: 10890

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Figure 1. The influence of lime milk concentration on (a) 13DCP2OL conversion (−■−) and the selectivity of transformation to EPI (−▲−) and (b) selectivity of transformation to byproducts: 3-chloropropane-1,2-diol (3Ch12PD) (light gray) and GLYC (dark gray). Epichlorohydrin collected from the reaction-stripping column.

depending on the process parameters and the mode of dehydrochlorination. Up to 88 wt % concentration, the 13DCP2OL solution in water is one phase. After mixing it with an aqueous solution of calcium hydroxide of 4−14 wt % concentration, it transforms into a two-phase one. Because of a lower solubility of EPI formed compared with that of 13DCP2OL and a high rate of dehydrochlorination, upon stirring of the solutions, the organic layer, primarily composed of EPI, is separated. The highest solubility of EPI in water at a temperature of 20 °C is 6.0 wt %, while the solubility of 13DCP2OL is close to 11 wt %. The highest concentration of lime milk solution amounted to 14 wt %. In the case of more concentrated solutions of lime milk, in spite of a vigorous stirring, the sedimentation of Ca(OH)2 particles proceeded in the feeding line, which precluded its flow. The technological parameters of these syntheses were compiled in Table S1 in the Supporting Information. The obtained conversions of 13DCP2OL and the selectivities of transformation to EPI and byproducts were shown in Figure 1. These studies demonstrated that the 13DCP2OL conversion at a level of 93.0−95.3% was obtained irrespective of the concentration of lime milk in the range of 5.0−14.0 wt %, and EPI was collected from the reaction-stripping column in the form of distillate. However, a change of lime milk concentration significantly influences the selectivity of transformation to EPI. The selectivity of transformation to EPI increases from 53.8 to 91.2%, along with increasing the lime milk concentration from 5 to 14 wt %. The largest changes in the selectivity were observed in the concentration range of lime milk from 5 to 8 wt %. Under these technological parameters and using this method of EPI collection, the dehydrochlorination proceeds most advantageously with the use of a 14 wt % lime milk solution. In this case, a high selectivity of transformation to EPI (91.2%) was also achieved, and the smallest amount of byproducts (3chloropropane-1,2-diol-3Ch12PD, 1.8%; glycerol−GLYC, 2.0%) was formed. The 13DCP2OL conversion was reduced by less than 2% in comparison with that obtained for more diluted solutions. 3.2. The Effect of Lime Milk Concentration Collection of Epichlorohydrin Distillate from Reboiler of Reaction-Stripping Column. When this method of dehydrochlorination was used, a temperature of the reaction mixture in the prereactor was varied from 42.2 to 52.7 °C. The reactor temperature was maintained in the range of 62.6−71.6 °C, whereas that of the reboiler was in the range 66.1−75.5 °C.

reactants. The magnitudes characterizing the dehydrochlorination process were the 13DCP2OL conversion and the selectivity of transformation to EPI and byproducts. The selectivity was calculated from the amount of obtained EPI in relation to the amount of 13DCP2OL consumed.

2. EXPERIMENTAL SECTION 2.1. Materials. The following raw materials were used in the studies: 1,3-dichloropropan-2-ol with a purity of 98 wt % purchased from Merck (Darmstadt, Germany). Dehydrochlorination was carried out with a lime milk solution, obtained by the dissolution of pure calcium hydroxide in water (96 wt % Ca(OH)2 and 3 wt % CaCO3), a product of Chempur, Poland. 2.2. Analytical Methods. The organic and water layer of the distillate and wastewater were quantitatively determined using the GC technique based on the internal standard method. A Trace GC 2000 Thermo apparatus was equipped with a flame ionization detector (FID) and a capillary column TRWAX (30 m × 0.25 mm × 0.5 μm). The volume flow rate of carrier gas (helium) amounted to 1.8 mL/min. The column temperature was programmed as follows: 55 °C for 2 min, followed by an increase at a rate 15 °C/min to 160 °C, being held for 3 min, then a ramp of 25 °C/min to 240 °C, and being maintained at 240 °C for 4 min. A sample was introduced to a feeder with a partition (split 1:10) at a temperature of 200 °C. After the calculating of mass balance, the main functions describing the process were determined: the selectivity of transformation to EPI and byproduct in relation to the 13DCP2OL consumed and the conversion of the 13DCP2OL. The concentration of inorganic combined chlorine was determined by the argentometric method. Titrator TitroLine Easy module 3 produced by Schott was used for these determinations. The amount of water in the organic layer of distillate was determined by a modified coulometric method on a KF831 apparatus produced by Metrohm. The GLYC concentration in wastewater from the reboiler of the reactionstripping column was determined via the periodate method. 3. RESULTS 3.1. The Influence of Lime Milk Concentration Collection of Epichlorohydrin Distillate from ReactionStripping Column. In the process studied, the following side products are formed: 3-chloropropane-1,2-diol (3Ch12PD), glycidol (GLD), glycerol (GLYC), di- and polyglycerols, and diglycidyl ether (ET; Figure S1 in the Supporting Information), 10891

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Figure 2. The influence of lime milk concentration on (a) 13DCP2OL conversion (−■−) and the selectivity of transformation to EPI (−▲−) and (b) selectivity of transformation to byproducts: 3Ch12PD (light gray), glycidol (GLD) (dark gray), diglycidyl ether (ET) (black), and GLYC (medium gray). Epichlorohydrin was collected from the reboiler.

Steam at a temperature of 85.5−96.9 °C was flowing in at a rate of 2.0 L/min. The dehydrochlorination was carried out under a pressure of 54.3−58.6 kPa for 120 min. The contact time of reactants in the reaction-stripping column amounted to 52 s. During the experiments, the pH was in the range of 10.9−11.6 in the reboiler of the reaction-stripping column. The obtained conversions of 13DCP2OL and the selectivities of transformation to EPI and byproducts are presented in Figure 2. The collection of epichlorohydrin distillate from the reboiler of the reaction-stripping column allows one to achieve higher conversions (about 99.0%) than those in the case of distillate collection from the column. The selectivity of transformation to EPI increases in a similar manner to that during the collection from the reaction-stripping column. It results from the course of selectivity changes (Figure 2) that the highest concentration of calcium hydroxide is advantageous. However, its concentration should not exceed 14 wt % with regard to the sedimentation of hydroxide particles. Additionally, the byproducts are formed in larger amounts with this method of EPI collection. Such a result of dehydrochlorination is associated with slightly longer reaction times. EPI formed in the upper part of column must pass through the entire length of the column before it leaves the reaction system through the reboiler. In this way of product collection, the wastewater contains GLYC with a concentration of 0.1−0.5 wt % and polyglycerols, as well as 3Ch12PD, at a level 0.2−0.8 wt %. Moreover, the wastewater also contains glycidol (GLD; 0.2−0.5 wt %) when the concentration of lime milk was in the range of 4−10 wt %. The diglycidyl ether (ET) was formed in a significantly smaller amount (0.01−0.02 wt %). However, these compounds (GLYC, polyglycerols, ET) only occur in the wastewater from the reboiler. The distillate from the reboiler is composed of EPI, 13DCP2OL, 23DCP1OL, and water. The largest effect on a decrease of the selectivity of transformation to EPI has the transformation of 13DCP2OL to GLYC and 3Ch12PD. When the influence of lime milk concentration is studied, a very important condition is to maintain a constant molar rate of Ca(OH)2/13DCP2OL. Thus, a decrease in the rate of flow of a more concentrated lime milk solution had to be accompanied by an increase in the rate of flow of 13DCP2OL solution. A similar intensity of the stirring of reagents in a reactionstripping column was achieved by a high flow of steam. The flow rate of steam was about 180 times greater than that of the sum of the reagents. An increase in lime milk concentration increases the selectivity of transformation to EPI as the

hydrolysis of EPI to 3Ch12PD is slower because of a limited solubility of Ca(OH)2. The subsequent reactions leading to glycidol, glycerol, and polyglycerols are also slower. Thanks to a limited solubility of Ca(OH)2 in the reaction environment, a strict control of its concentration and rate of flow is not necessary. With the concentration of Ca(OH)2 increasing from 4 to 14 wt %, the conversion of 13DCP2OL is constant and equal to 99%, while the high selectivity of transformation to EPI (90%) is obtained in the hydroxide concentration range 11−14 wt %. A comparison of two methods of process operation reveals that the collection of distillate from the reaction-stripping column is more beneficial. In this case, the conversion of 13DCP2OL (at a level of 95%) is lower, while the selectivity of transformation to EPI (92%) is slightly higher. Moreover, lesser amounts of the following byproductsGLYC, 3Ch12PD, GLD, ET, and polyglycerolswere generated in the process. 3.3. The Influence of Ca(OH)2/13DCP2OL Molar RatioCollection of Epichlorohydrin Distillate from Reaction-Stripping Column. The molar ratio of Ca(OH)2/ 13DCP2OL was varied in the range from 0.46:1 to 0.71:1 mol/ mol. Hence, the experiments were carried out either with insufficiency of calcium hydroxide or with its excess in relation to the reaction stoichiometry. The values of the remaining parameters and obtained conversions of 13DCP2OL, the selectivities of transformation to EPI and byproducts, and the wastewater composition were compiled in Table S2 in the Supporting Information. The 13DCP2OL conversion increases along with an increase in the molar ratio of Ca(OH)2/13DCP2OL from 0.46:1 to 0.71:1, whereas the selectivity of transformation to EPI decreases significantly from 99.5% to 73.2%. This was caused by an increase of the reaction rate of the side reactions such as: the hydration of EPI to 3Ch12PD, dehydrochlorination of 3Ch12PD to GLD, hydration of GLD to GLYC, and the formation of polyethersmainly polyglycerols. The polyetherification proceeds both as the polycondensation of GLYC and as its polyaddition to GLD and EPI to GLYC. The ET was present in both the distillate and wastewater at the highest molar ratio. In other studies,14 we have shown that it forms in the reaction EPI with DCP. The selectivity of transformation to the polyethers is a supplementation of the selectivity of transformation to the organic compounds (Table S2) to 100%. When the molar ratio of Ca(OH)2/13DCP2OL was equal 0.5:1 and corresponded to the reaction stoichiometry, the selectivity of transformation to EPI amounted to 95.0%, and the 10892

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a more strongly alkaline reaction medium. This causes a decrease of the selectivity of transformation to EPI by 30 to 40% in relation to the collection in the form of distillate from the column, at the most advantageous molar ratio of Ca(OH)2/ 13DCP2OL = 0.45−0.5:1. Moreover, the complete conversion of calcium hydroxide proceeds at this molar ratio, and wastewater contains only the trace amounts of this compound. 3.5. The Influence of the Flow Rate of Steam Collection of Epichlorohydrin Distillate from ReactionStripping Column. The influence of the flow rate of steam was presented in relation to the amount of 13DCP2OL introduced. The flow rate was changed in the range of 0.3−1.0 L/g13DCP2OL. The parameters of performed experiments, obtained conversions of 13DCP2OL, and the selectivities of transformation to the main products are presented in Table S3 in the Supporting Information. A change of the flow rate of steam at a temperature of 104.0−109.0 °C in a given range did not influence the selectivity of transformation to EPI. This selectivity remains at a high level of 98.3−99.5%. However, an increase of the steam flow rate causes a decrease of the 13DCP2OL conversion from 87.7% to 72.3%. Simultaneously, the amount of distillate water layer increases significantly. Moreover, the flow rate of steam significantly influences the composition and quantity of wastewater. The EPI concentration in wastewater amounts to 0.045 wt % at the lowest flow rate of steam, −0.34 L/g 13DCP2OL. When the steam flow rate was enhanced to 0.91 L/g 13DCP2OL, the EPI was not present in wastewater. The 13DCP2OL concentration in wastewater in the boundaries determined by the steam flow rates (0.34−0.91 L/g 13DCP2OL) decreases from 5.120 wt % to 0.020 wt %. The concentration of 3Ch12PD was then decreased from 0.025 wt % to 0.000 wt %. The GLYC concentration is constant and amounts to about 0.028 wt %. The GLYC is only present in wastewater, whereas the GLD, ET, and polyglycerols were not present in wastewater. 3.6. The Effect of the PressureCollection of Epichlorohydrin Distillate from Reaction-Stripping Column. The influence of pressure in a column of the reactionstripping system on the 13DCP2OL conversion and the selectivities of transformation to EPI and byproducts are presented in Table S4 in the Supporting Information. The pressure was varied in the range from 53.0 to 101.3 kPa, with a simultaneous removal of EPI in the form of distillate from the reaction-stripping column. A similar conversion of 13DCP2OL and the selectivity of transformation to EPI was obtained under both atmospheric pressure (101.3 kPa) and the pressure reduced to the range of 53.0−80.0 kPa. The pressure does not influence the 13DCP2OL conversion and the selectivity of transformation to EPI and byproducts. However, a reduction of pressure facilitates the collection of EPI and byproducts in the form of distillate from the reaction-stripping column. 3.7. The Reaction Times in the Prereactor and Reactor. The reaction times in both the prereactor and reactor were treated as the contact times of a 10 wt % solution of calcium hydroxide and 13DCP2OL solution. The studies were carried out at the flow rates presented in Table 1 and after the stabilization of column operation. The temperature in the prereactor amounted to 45−50 °C and in the reactor was 60− 70 °C. The length of the prereactor amounted to 26 cm and constituted about 1/3 of the reactor length at the same internal diameter (36 mm). Thus, the reaction time in the prereactor

13DCP2OL conversion was equal to 87.5%. The conversion of 13DCP2OL decreases to 84.0% at a molar ratio of Ca(OH)2/ 13DCP2OL = 0.45:1. However, the selectivity of transformation to EPI reaches 100%. Therefore, the operation of the process at a ratio below that of stoichiometric is beneficial. Moreover, in this way of process operation, a recycling of unreacted 13DCP2OL contained in the water layer to the reaction-stripping column is advantageous. The distillate from the column after the condensation was then separated into an aqueous and organic layer. The aqueous layer which contained 13DCP2OL (0.5−2.5 wt %), EPI (5.0−6.9 wt %), and 23DCP1OL (0.1−0.3 wt %) was recycled to the reactionstripping column. The organic layer of distillate was then subjected to the purification on a separate rectifying column in order to separate a pure EPI, whereas the tail fraction (mainly 13DCP2OL) was also recycled for the dehydrochlorination. An enhancement of the molar ratio of Ca(OH)2/13DCP2OL increases the content of GLYC, GLD, ET, and polyethers in wastewater (Table S2), which is associated with facilitation of a further conversion of EPI. The concentrations of 13DCP2OL and 23DCP1OL remain at a constant level, which confirms that the steam flow was appropriate. 3.4. The Influence of Ca(OH)2/13DCP2OL Molar RatioCollection of Epichlorohydrin Distillate from Reboiler of Reaction-Stripping Column. The studies on the effect of the molar ratio of Ca(OH)2/13DCP2OL were also carried out by collection of the product from the reboiler. The technological parameters of syntheses were the same as those during the collection of distillate from the reaction-stripping column. The course of changes of 13DCP2OL conversion and the selectivities of transformation to EPI over the studied range of variations of the Ca(OH)2/13DCP2OL molar ratio was shown in Figure 3.

Figure 3. The effect of the molar ratio of Ca(OH)2/13DCP2OL on 13DCP2OL conversion (−■−) and selectivity of transformation to EPI (−▲−). Epichlorohydrin collected from the reboiler.

An increase of the molar ratio of Ca(OH)2/13DCP2OL from 0.45:1 to 0.73:1 mol/mol increases the selectivity of transformation to EPI to a maximum of 90.0%, whereas the 13DCP2OL conversion was maintained at a constant level and amounted to about 99.0%. When the EPI was collected from the reboiler, the selectivity of transformation to EPI attains a lower value at a higher conversion of 13DCP2OL, particularly in the range of lower molar ratios. This indicates the formation of larger quantities of byproducts in the form of GLYC, polyglycerols, 3Ch12PD, and GLD. The collection of distillate from the reboiler of the reaction-stripping column is associated with a longer residence time of 13DCP2OL and EPI formed in 10893

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4. CONCLUSIONS The highest effectiveness of dehydrochlorination of 13DCP2OL to EPI in the reaction-stripping column was achieved during the collection of product in the form of distillate from the column. In this method of process operation, the EPI was removed in the moment of its formation, and the residence time in an alkaline reaction medium was shortened. As a result, the selectivity of transformation was significantly increased and reached 99−100%. The achievement of such a high selectivity of transformation was accompanied by the 13DCP2OL conversion at a level of 90%. It is very important to maintain the molar ratio of Ca(OH)2/13DCP2OL = 0.45− 0.5:1 in order to achieve a high selectivity. A slight decrease of the molar ratio of Ca(OH)2 to 13DCP2OL in relation to the reaction stoichiometry decreased the conversion of 13DCP2OL, but simultaneously the selectivity of transformation to EPI was significantly increased. The EPI with a purity of 97.5−99.6% was obtained after application of this method. Unreacted 13DCP2OL leaves the reaction system with the distillate of epichlorohydrin, water, and light byproducts. After the separation of distillate from the reaction-stripping column into the organic and aqueous layer, the 13DCP2OL can be separated from the organic layer by distillation at a different column and then recirculated on the reaction-stripping column. The aqueous layer can be completely recycled to the reactionstripping column. The wastewater from the column mainly contains water, calcium chloride, and small amounts of calcium hydroxide and GLYC. The achievement of the highest selectivity of transformation to EPI with simultaneously high conversion of 13DCP2OL requires the following process parameters: prereactor temperature, 50−70 °C; reactor temperature, 60−70 °C; column reboiler, 72−80 °C; steam temperature at the inlet to the reboiler, 100−120 °C; flow rate of 88 wt % 13DCP2OL solution of 2−4 mL/min; flow rate of 10−14 wt % lime milk solution of 8−9 mL/min; flow rate of steam 2.5−4.3 L/min (0.34−0.50 L/g13DCP2OL); and pressure in the column, 52.0−80.0 kPa. The dehydrochlorination under these technological conditions caused the maintenance of the pH = 8.5−9.5 in the column reboiler.

Table 1. The Reaction Times in the Reactor and Prereactor reaction time (s) flow rate of 88 wt % 13DCP2OL solution (mL/min)

flow rate of 10 wt % of lime milk solution (mL/min)

flow rate of steam (L/min)

prereactor

reactor

column

3 6 9

10 20 28

2.5 2.5 2.5

20 16 11

32 28 21

52 44 33

was always shorter than that in the reactor. The studies were carried out by a 3-fold increase of the flow rate from 3 mL/min to 9 mL/min of an 88 wt % solution of 13DCP2OL. Simultaneously, the flow rate of a 10 wt % lime milk solution was increased from 10 to 28 mL/min, while the flow rate of steam was constant, 2.5 L/min. The reaction time in the prereactor was shortened by almost a half, whereas that in the reactor was from 32 to 21 s. After increasing the flow rate of steam up to 4.3 L/min and the reactor temperature to 88−92 °C, the reaction times in the column were shortened to 42 s, 33 s, and 25 s, as the flow rate of 13DCP2OL solution and lime milk was gradually elevated, in the order presented in Table 1. Reduction in the reaction time in the column from 52 to 33 s at the total flow of reactants in the range of 12 to 37 mL/min (Table 1), and at a constant steam streamflow 2.5 L/min, while setting other technological parameters unchanged allows a selectivity of transformation to EPI at 99% with a slight reduction of 13DCP2OL conversion from 93 to 89%. Longer reaction times led to hydration of EPI to 3Ch12PD and further reaction of this compound (Figure S1). 3.8. The Effect of the Flow Rate of Reactants. When the flow rate of steam was at a constant level of 4.3 L/min and the column was operated at the following parameters: prereactor temperature, 65.6−70.3 °C; reactor temperature, 71.7−77.1 °C; reboiler, 78.2−82.1 °C; steam temperature, 110−112 °C; pressure in the reactor, 51.2−54.4 kPa; and pH in the reboiler, 8.4−9.4, the flow rate of an 88 wt % solution of 13DCP2OL and 10 wt % lime milk solution was increased in such a way as to maintain a constant molar ratio of Ca(OH)2/13DCP2OL, i.e., about 0.45:1. The total loading of the column by the reagents in the consecutive experiments was increased from 12 mL/min to 70 mL/min. The obtained conversion of 13DCP2OL and the selectivities of transformation to EPI and byproducts, at increasing flow rates of reactants, are presented in Table S5 in the Supporting Information. An increase of the total flow rate of reactants in the range from 12 to 70 mL/min, at a constant flow rate of steam of 4.3 L/min, decreased the 13DCP2OL conversion from about 90% to 80%. The selectivities of transformation to EPI were constant and amounted to about 99%. Under the conditions of increasing flow rates of reactants, the ET was not formed in the process. In the majority of experiments, a small amount of GLD was present in wastewater. Whereas, the GLYC was present in wastewater in each of the syntheses, and the selectivity of transformation to this compound amounted to 0.2−1.3%. The highest selectivity of transformation to EPI99%was achieved at a total flow rate of reactants in the range of 12− 70 mL/min and that of steam equal to 4.3 L/min. The highest conversion of 13DCP2OLabout 90%was observed only at the lowest flow rate of the reactantsequal to 12 mL/min.

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ASSOCIATED CONTENT

* Supporting Information S

The reaction scheme of products of 13DCP2OL dehydrochlorination (Figure S1) and details of technological parameters, the conversions of 13DCP2OL, selectivities of transformation to EPI and byproducts, and the composition of the wastewater (Tables S1−S5). This information is available free of charge via the Internet at http://pubs.acs.org/

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AUTHOR INFORMATION

Corresponding Author

*Tel.: +48 91 449 48 91. Fax: +48 091 449 43 65. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This scientific work received financial support from the Resources for Science in years 2011−2014 as a Ministry of Science and Higher Education research project (No. N N209 089940). 10894

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dx.doi.org/10.1021/ie400924c | Ind. Eng. Chem. Res. 2013, 52, 10890−10895