METHOD FOR CHLORINATION AND DEHYDROGENATION OF ETHANE

Abstract

The present invention relates to a method for chlorination and dehydrogenation of ethane, comprising: mixing and reacting a low-melting-point metal chloride with C.sub.2H.sub.6, such that the low-melting-point metal chloride is reduced to a liquid-state low-melting-point metal, and the C.sub.2H.sub.6 is chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl. In the method, the low-melting-point metal chloride is used as a raw material for chlorination and dehydrogenation, and the low-melting-point metal produced after the reaction is used as an intermediate medium. The method has the characteristics of simple process, low cost and high yield. Moreover, some acetylene and vinyl chloride can be produced as by-products at the same time when the ethylene is produced, by controlling the ratio of ethane to the chloride as desired in production.

Claims

1. A method for chlorination and dehydrogenation of ethane, comprising: mixing and reacting a low-melting-point metal chloride with C.sub.2H.sub.6, such that the low-melting-point metal chloride is reduced to a liquid-state low-melting-point metal, and the C.sub.2H.sub.6 is chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl.

2. The method for chlorination and dehydrogenation of ethane according to claim 1, wherein the low-melting-point metal chloride is in a gaseous state at the reaction temperature, and can be reduced at the reaction temperature by H.sub.2 to give a liquid-state low-melting-point metal and hydrogen chloride.

3. The method for chlorination and dehydrogenation of ethane according to claim 2, wherein the low-melting-point metal chloride is BiCl.sub.3 or SnCl.sub.2.

4. The method for chlorination and dehydrogenation of ethane according to claim 1, wherein the reaction temperature is 500-800 C.

5. The method for chlorination and dehydrogenation of ethane according to claim 1, wherein the molar ratio of the element chlorine in the low-melting-point metal chloride to the C.sub.2H.sub.6 is 1-4:1.

6. The method for chlorination and dehydrogenation of ethane according to claim 1, wherein the reaction time is controlled such that the conversion rate of C.sub.2H.sub.6 is up to 50-99.9%.

7. The method for chlorination and dehydrogenation of ethane according to claim 1, further comprising: reacting a low-melting-point metal to obtain a low-melting-point metal chloride, and feeding back to mix and react the low-melting-point metal chloride with C.sub.2H.sub.6.

8. The method for chlorination and dehydrogenation of ethane according to claim 7, wherein the method for reacting a low-melting-point metal to obtain a low-melting-point metal chloride is selected from one of: Method 1: reacting a low-melting-point metal with chlorine, to obtain a low-melting-point metal chloride; Method 2: reacting a low-melting-point metal with oxygen or the air, to obtain a metal oxide; and absorbing the HCl obtained after the chlorination and dehydrogenation of C.sub.2H.sub.6 by the metal oxide, to obtain a low-melting-point metal chloride; and Method 3: when the low-melting-point metal chloride is SnCl.sub.2, reacting the low-melting-point Sn obtained from the reduction of the SnCl.sub.2 with hydrochloric acid, to obtain a low-melting-point metal chloride, that is, SnCl.sub.2, and H.sub.2.

9. The method for chlorination and dehydrogenation of ethane according to claim 1, wherein the the present method further comprises the utilization of HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl through any one of: Method 1: absorbing the HCl with water to produce a hydrochloric acid product; Method 2: applying HCl in the oxidation and chlorination of C.sub.2H.sub.4 to obtain a dichloroethane product; and Method 3: catalytically oxidizing HCl with oxygen or the air into Cl.sub.2, and feeding back to react with a low-melting-point metal, to obtain a low-melting-point metal chloride.

10. The method for chlorination and dehydrogenation of ethane according to claim 9, wherein the mixed gas from which the HCl is separated is further separated to obtain a C.sub.2H.sub.4, a C.sub.2H.sub.2, and a C.sub.2H.sub.3Cl product.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The technical solutions of the present invention will now be described by way of specific examples. It is to be understood that one or more process steps mentioned in the present invention do not exclude the presence of other process steps before or after the combined steps, or other process steps may be added between these explicitly mentioned steps. It is to be understood that these examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the numbering of each process step is only a convenient means of identifying the process steps, rather than limiting the order of the process steps or limiting the scope of the present invention to be implemented, and the change or adjustment made to the relative relationship therebetween without substantially changing the technical content is contemplated in the scope of the invention to be implemented.

EXAMPLE 1

[0031] (1) The BiCl.sub.3 vapor was mixed with C.sub.2H.sub.6, and the reaction time was controlled, such that the conversion rate of C.sub.2H.sub.6 was 50%. The molar ratio of the element chlorine in BiCl.sub.3 to the C.sub.2H.sub.6 was 1:1, and the reaction temperature was 500 C. The C.sub.2H.sub.6 was chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, and BiCl.sub.3 was reduced to liquid-state Bi.

[0032] (2) Chlorine was bubbled through the metal Bi melt obtained in the step 1), to convert Bi into BiCl.sub.3 for continuous reaction with ethane.

[0033] (3) The HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl obtained in the step 1) was absorbed with water, to obtain a mixed gas containing C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, etc., and a by-product hydrochloric acid. The main ingredients in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane are shown in Table 1.

TABLE-US-00001 TABLE 1 Main ingredients in the gaseous phase in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane in Example 1 Retention Molar time Peak Peak concentration Component (min) area height (%) Methane 0.86 9666 7364 0.023 Ethane 1.04 20614375 14146103 48.38 Ethylene 1.13 21798544 13254713 51.16 Acetylene 1.46 185413 116140 0.44 Chloroethylene 5.01 2260 140 0.0053 In total 42610258 27524460 100.01

EXAMPLE 2

[0034] (1) The BiCl.sub.3 vapor was mixed with C.sub.2H.sub.6, and the reaction time was controlled, such that the conversion rate of C.sub.2H.sub.6 was 74%. The molar ratio of the element chlorine in BiCl.sub.3 to the C.sub.2H.sub.6 was controlled to 2:1, and the reaction temperature was 600 C. The C.sub.2H.sub.6 was chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, and BiCl.sub.3 was reduced to liquid-state Bi.

[0035] (2) Oxygen was bubbled through the metal Bi melt obtained in the step 1), to convert Bi into Bi.sub.2O.sub.3, and the HCl obtained in the step (1) was absorbed by the Bi.sub.2O.sub.3 subsequently to obtain BiCl.sub.3 for continuous reaction with ethane.

[0036] (3) The HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl obtained in the step 1) was absorbed by the Bi.sub.2O.sub.3 layer, to obtain a mixed gas containing C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, etc. The main ingredients in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane are shown in Table 2.

TABLE-US-00002 TABLE 2 Main ingredients in the gaseous phase in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane in Example 2 Retention Molar time Peak Peak concentration Component (min) area height (%) Methane 0.85 184217 134826 0.45 Ethane 1.03 10747164 7560033 26.16 Ethylene 1.12 29432421 16559447 71.40 Acetylene 1.45 424604 261458 1.03 Chloroethylene 5.04 369146 692598 0.92 In total 41157554 24463623 99.96

EXAMPLE 3

[0037] (1) The BiCl.sub.3 vapor was mixed with C.sub.2H.sub.6, and the reaction time was controlled, such that the conversion rate of C.sub.2H.sub.6 was 97%. The molar ratio of the element chlorine in BiCl.sub.3 to the C.sub.2H.sub.6 was 3:1, and the reaction temperature was 650 C. The C.sub.2H.sub.6 was chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, and BiCl.sub.3 was reduced to liquid-state Bi.

[0038] (2) Chlorine was bubbled through the metal Bi melt obtained in the step 1), to convert Bi into BiCl.sub.3 for continuous reaction with ethane.

[0039] (3) The HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl obtained in the step 1) was absorbed with water, to obtain a mixed gas containing C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, etc., and a by-product hydrochloric acid. The main ingredients in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane are shown in Table 3.

TABLE-US-00003 TABLE 3 Main ingredients in the gaseous phase in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane in Example 3 Retention Molar time Peak Peak concentration Component (min) area height (%) Methane 0.86 532721 407419 1.31 Ethane 1.05 1053504 785805 2.61 Ethylene 1.13 34063085 18044507 83.96 Acetylene 1.45 3108821 1846049 7.68 Chloroethylene 4.96 1805211 322805 4.46 In total 40563342 21406585 100.02

EXAMPLE 4

[0040] (1) The BiCl.sub.3 vapor was mixed with C.sub.2H.sub.6, and the reaction time was controlled, such that the conversion rate of C.sub.2H.sub.6 was 98%. The molar ratio of the element chlorine in BiCl.sub.3 to the C.sub.2H.sub.6 was 4:1, and the reaction temperature was 700 C. The C.sub.2H.sub.6 was chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, and BiCl.sub.3 was reduced to liquid-state Bi.

[0041] (2) Oxygen was bubbled through the metal Bi melt obtained in the step 1), to convert Bi into Bi.sub.2O.sub.3, and the HCl obtained in the step (1) was absorbed by the Bi.sub.2O.sub.3 subsequently, to obtain BiCl.sub.3 for continuous reaction with ethane.

[0042] (3) The HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl obtained in the step 1) was absorbed by the Bi.sub.2O.sub.3 layer, to obtain a mixed gas containing C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, etc. The main ingredients in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane are shown in Table 4.

TABLE-US-00004 TABLE 4 Main ingredients in the gaseous phase in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane in Example 4 Retention Molar time Peak Peak concentration Component (min) area height (%) Methane 0.86 532055 412012 1.31 Ethane 1.05 618220 468862 1.53 Ethylene 1.13 30433728 16630354 75.12 Acetylene 1.45 6019903 3423861 14.86 Chloroethylene 4.94 2879373 471988 7.11 In total 40483279 17983216 99.90

EXAMPLE 5

[0043] (1) The SnCl.sub.2 vapor was mixed with C.sub.2H.sub.6, and the reaction time was controlled, such that the conversion rate of C.sub.2H.sub.6 was 77%. The molar ratio of the element chlorine in SnCl.sub.2 to the C.sub.2H.sub.6 was 2:1, and the reaction temperature was 800 C. The C.sub.2H.sub.6 was chlorinated and dehydrogenized to give a mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, and SnCl.sub.2 was reduced to liquid-state Sn.

[0044] (2) The metal Sn obtained in the step 1) was reacted with hydrochloric acid obtained subsequent to the step 1), to obtain SnCl.sub.2 for continuous reaction with ethane.

[0045] (3) The HCl in the mixed gas containing HCl, C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2 and C.sub.2H.sub.3Cl obtained in the step 1) was absorbed with water, to obtain a mixed gas containing C.sub.2H.sub.6, C.sub.2H.sub.4, C.sub.2H.sub.2, and C.sub.2H.sub.3Cl, etc., and a by-product hydrochloric acid. The main ingredients in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane are shown in Table 5.

TABLE-US-00005 TABLE 5 Main ingredients in the gaseous phase in the HCl removed tail gas obtained from chlorination and dehydrogenation of ethane in Example 5. Retention Molar time Peak Peak concentration Component (min) area height (%) Methane 0.86 1681688 1111058 5.99 Ethane 1.05 6545196 4367150 23.24 Ethylene 1.14 19506153 10995253 69.07 Acetylene 1.47 405920 235319 1.46 Chloroethylene 4.94 39475 3749 0.14 In total 28178432 16712529 99.90

[0046] The foregoing descriptions are merely preferred embodiments of the present invention, which are not intended to limit the present invention in any way. It should be noted that modifications and supplements may be made by those of ordinary skill in the art without departing from the spirit of the present invention, which are contemplated in the scope of the present invention. Various changes, modifications and evolved equivalent variations may be made to the disclosure of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, which constitute equivalent embodiments of the present invention. Any equivalent changes, modifications and evolutions made to the embodiments in accordance with the essential technical aspects of the present invention fall within the scope of the present invention.