Methyl acetate preparation method

Abstract

The present invention provides a method for producing methyl acetate, and the method comprises a step in which dimethyl ether and a raw gas containing carbon monoxide and hydrogen go through a reactor loaded with a catalyst for carrying out a carbonylation reaction; wherein the catalyst contains an acidic EMT zeolite molecular sieve. The present invention has provided a new method for producing methyl acetate. In the method of the present invention, the carbonylation is carried out in the presence of the catalyst containing the acidic EMT zeolite molecular sieve, and the reaction activity is high, and the stability has been significantly improved, meeting the requirement of industrial production.

Claims

1. A method for producing methyl acetate, which comprises a step in which dimethyl ether and a raw gas containing carbon monoxide go through a reactor loaded with a catalyst for carrying out a carbonylation reaction; wherein the catalyst contains an acidic EMT zeolite molecular sieve.

2. A method for producing methyl acetate according to claim 1, wherein in the acidic EMT zeolite molecular sieve, the molar ratio of silicon atoms to aluminum atoms is in a range from 1.5 to 30.

3. A method for producing methyl acetate according to claim 1, wherein the acidic EMT zeolite molecular sieve contains a catalyst promoter which is one or more metals selected from gallium, iron, copper and silver.

4. A method for producing methyl acetate according to any of claims 1 to 3, wherein the acidic EMT zeolite molecular sieve contains a binder which is one or more compounds selected from alumina, silicon dioxide and magnesium oxide.

5. A method for producing methyl acetate according to claim 1, wherein the carbonylation reaction is carried out at a temperature range from 160 C. to 250 C. and at a pressure range from 0.5 MPa to 20.0 MPa, and the feeding mass space velocity of dimethyl ether is in a range from 0.05 .sup.1 to 3 h.sup.1, and the molar ratio of carbon monoxide to dimethyl ether is in a range from 20:1 to 0.5:1.

6. A method for producing methyl acetate according to claim 1, wherein the carbonylation reaction is carried out at a temperature range from 170 C. to 240 C. and at a pressure range from 1.0 MPa to 15.0 MPa, and the feeding mass space velocity of dimethyl ether is in a range from 0.1h.sup.1 to 2.5h.sup.1, and the molar ratio of carbon monoxide to dimethyl ether is in a range from 15:1 to 1:1.

7. A method for producing methyl acetate according to claim 1, wherein the raw gas containing carbon monoxide contains carbon monoxide, hydrogen and one or more inactive gases selected from nitrogen, helium, argon, carbon dioxide, methane and ethane.

8. A method for producing methyl acetate according to claim 1, wherein the methyl acetate is hydrolyzed to acetic acid.

9. A method for producing methyl acetate according to claim 1, wherein the methyl acetate is hydrogenated to ethyl alcohol.

10. A method for producing methyl acetate according to claim 1, wherein the carbonylation reaction is carried out in a fixed bed reactor, a fluidized bed reactor or a moving bed reactor.

11. A method for producing methyl acetate according to claim 1, wherein in the acidic EMT zeolite molecular sieve, the molar ratio of silicon atoms to aluminum atoms is in a range from 2 to 15.

12. A method for producing methyl acetate according to claim 3, wherein the catalyst promoter is introduced to the acidic EMT zeolite molecular sieve by a method selected from in-situ synthesis, metal ion exchange or impregnation loading.

13. A method for producing methyl acetate according to claim 3, wherein based on the total weight of the catalyst, the weight fraction of the catalyst promoter calculated by weight of metal elementary substance is in a range from 0.01 wt % to 10 wt %.

14. A method for producing methyl acetate according to claim 3, wherein based on the total weight of the catalyst, the weight fraction of the catalyst promoter calculated by weight of metal elementary substance is in a range from 0.05 wt % to 1.0 wt %.

15. A method for producing methyl acetate according to any of claims 4, wherein based on the total weight of the catalyst, the weight fraction of the binder is in a range from 0 wt % to 50 wt %.

16. A method for producing methyl acetate according to claim 7, wherein based on the total volume of the raw gas containing carbon monoxide, the volume fraction of carbon monoxide is in a range from 50% to 100%, and the volume fraction of hydrogen is in a range from 0% to 50%, and the volume fraction of the in-ert gas is in a range from 0% to 50%.

Description

DETAILED DESCRIPTION OF THE EMBODIMENT

(1) The present invention provides a method for synthesizing methyl acetate, which comprises a step carrying out a carbonylation reaction of dimethyl ether and a raw gas containing carbon monoxide and hydrogen on a catalyst containing an acidic EMT zeolite molecular sieve.

(2) Preferably, the carbonylation reaction is carried out at a temperature range from 160 to 250 and at a pressure range from 0.5 MPa to 20.0 MPa, and the feeding mass space velocity of dimethyl ether is in a range from 0.05 h.sup.1 to 3 h.sup.1, and the molar ratio of carbon monoxide to dimethyl ether is in a range from 20:1 to 0.5:1. More preferably, the feeding mass space velocity of dimethyl ether is in a range from 0.1 h.sup.1 to 2.5 h.sup.1, and the molar ratio of carbon monoxide to dimethyl ether is in a range from 15:1 to 1:1, and the reaction temperature is in a range from 170 to 240, and the reaction pressure is in a range from 1.0 MPa to 15.0 MPa.

(3) Preferably, the molar ratio of silicon atoms to aluminum atoms in the acidic EMT zeolite molecular sieve used in the present invention is in a range from 1.5 to 30. Preferably, the molar ratio of silicon atoms to aluminum atoms in the acidic EMT zeolite molecular sieve of the present invention is in a range from 2 to 15.

(4) Preferably, the acidic EMT zeolite molecular sieve used in the present invention contains a catalyst promoter which is one or more metals selected from gallium, iron, copper and silver (which may exist in the form of metal elementary substance or metal compounds such as metal oxides). For instance, the catalyst promoter is introduced to the acidic EMT zeolite molecular sieve by a method selected from in-situ synthesis, metal ion exchange or impregnation loading. Preferably, based on the total weight of the catalyst, the weight fraction of the catalyst promoter calculated by weight of metal elementary substance is in a range from 0.01 wt % to 10 wt %. More preferably, the weight fraction of the catalyst promoter calculated by weight of metal elementary substance is in a range from 0.05 wt % to 1.0 wt %.

(5) Preferably, the acidic EMT molecular sieve used in the present invention contains a binder which is one or more compounds selected from alumina, silicon dioxide and magnesium oxide. Preferably, the weight fraction of the binder in the total weight of the catalyst is in a range from 0 wt % to 50 wt %.

(6) Preferably, the raw gas containing carbon monoxide used in the present invention contains carbon monoxide, hydrogen and one or more inactive gases selected from nitrogen, helium, argon, carbon dioxide, methane and ethane. Preferably, based on the total volume of the raw gas containing carbon monoxide, the volume fraction of carbon monoxide is in a range from 50% to 100%, and the volume fraction of hydrogen is in a range from 0% to 50%, and the volume fraction of the inert gas is in a range from 0% to 50%.

(7) Preferably, the carbonylation reaction in the present invention is carried out in a fixed bed reactor, a fluidized bed reactor or a moving bed reactor.

EXAMPLES

(8) The present invention will be described in details by Examples, but the present invention is not limited to these Examples.

(9) In the examples, the calculation of percent conversion of dimethyl ether and selectivity of methyl acetate was based on the carbon mole number:

(10) Percent conversion of dimethyl ether=[(the carbon mole number of dimethyl ether in the feed gas)(the carbon mole number of dimethyl ether in the product)](the carbon mole number of dimethyl ether in the feed gas)(100%)

(11) Selectivity of methyl acetate=(2/3)(the carbon mole number of methyl acetate in the product)[(the carbon mole number of dimethyl ether in the feed gas)(the carbon mole number of dimethyl ether in the product)](100%)

(12) Four samples of Na-EMT zeolite molecular sieve whose molar ratios of silicon atom to aluminum atom respectively are 2, 4, 15 and 25, a sample of Na-EMT zeolite molecular sieve containing Ga whose molar ratio of silicon atom to aluminum is 4, and a sample of Na-EMT zeolite molecular sieve containing Fe whose molar ratio of silicon atom to aluminum is 4 have been used in the Examples. All of them were produced and provided by Dalian Institute of Chemical Physics.

(13) Examples for Preparing the Catalyst

(14) H-EMT Catalyst

(15) 100 g of a sample of Na-EMT zeolite molecular sieve was exchanged with 0.5 mol/L of ammonium nitrate for three times and each time was for 2 hours. And then the solid product was washed with deionized water, dried, calcined at 550 C. for 4 h, pressed, crushed and sieved to 20-40 mesh used as the catalyst sample. Four samples of Na-EMT zeolite molecular sieve with molar ratios of silicon atom to aluminum atom of 2, 4, 15 and 25 were used, to obtain the samples of Catalyst 1#, Catalyst 2#, Catalyst 3# and Catalyst 4#, respectively.

(16) Ga-EMT Catalyst

(17) 100 g of the sample of Na-EMT zeolite molecular sieve containing Ga (the molecular ratio of silicon atom to aluminum is 4) was exchanged with 0.5 mol/L of ammonium nitrate for three times and each time was for 2 hours. And then the solid product was washed with deionized water, dried, calcined at 550 C. for 4 h, pressed, crushed and sieved to 20-40 mesh to obtain the sample of Catalyst 5#.

(18) Fe-EMT Catalyst

(19) 100 g of the sample of Na-EMT zeolite molecular sieve containing Fe (the molecular ratio of silicon atom to aluminum is 4) was exchanged with 0.5 mol/L of ammonium nitrate for three times and each time was for 2 hours. And then the solid product was washed with deionized water, dried, calcined at 550 C. for 4 h, pressed, crushed and sieved to 20-40 mesh to obtain the sample of Catalyst 6#.

(20) Supported Catalyst of M/EMT

(21) The supported catalyst of M/EMT was prepared using equivalent-volume impregnation method. 4.32 g of Fe(NO.sub.3).sub.3, 4.32 g of Cu(NO.sub.3).sub.2.3H.sub.2O and 3.04 g of AgNO.sub.3.3H.sub.2O were respectively dissolved in 18 mL of deionized water to form the Fe(NO.sub.3).sub.3 aqueous solution, Cu(NO.sub.3).sub.2 aqueous solution and AgNO.sub.3 aqueous solution. 20 g of Catalyst 2# (H-EMT zeolite molecular sieve catalyst) was added into the Fe(NO.sub.3).sub.3 aqueous solution, Cu(NO.sub.3).sub.2 aqueous solution and AgNO.sub.3 aqueous solution, respectively. After standing for 24 hours, the solid products were separated by filtration, washed by deionized water, dried in the oven at 120 for 12 hours, and then the samples obtained were put into a muffle furnace whose temperature was heated to 550 at a heating rate of 2 C./min, calcined at 550 C. in air for 4 h to obtain the samples of Catalyst 7#, Catalyst 8# and Catalyst 9#.

(22) Ion Exchange Catalyst of M-EMT

(23) 20 g of Catalyst 2# (H-EMT zeolite molecular sieve catalyst) and 300 mL of 0.15 mol ferric nitrate aqueous solution were placed in a flask, being stirred for 2 hours at 80 under the condition of cooling and refluxing with solid-liquid ratio of 1:15. The solid product was separated by filtration and washed by deionized water. Repeating the above steps for 2 times, the sample obtained was dried at 120 for 12 hours, and the dried sample was put into a muffle furnace whose temperature was heated to 550 at a heating rate of 2 C./min, calcined at 550 C. in air for 4 h to obtain the sample of Catalyst 10#.

(24) Molded Catalyst of H-EMT

(25) 80 g of Na-EMT zeolite molecular sieve with molar ratio of silicon atom to aluminum of 4, 28 g of pseudo-boehmite and 10% of diluted nitric acid were uniformly mixed, and then the mixture was molded through extrusion. After being calcined at 550 for 4 hours, the molded sample was exchanged with 0.5 mol/L of ammonium nitrate for three times (2 hours/time). And then the solid product was washed by deionized water, dried, calcined at 550 C. for 4 h to obtain the sample of Catalyst 11#.

(26) 80 g of Na-EMT zeolite molecular sieve with molar ratio of silicon atom to aluminum of 4, 20 g of magnesium oxide and 10% of diluted nitric acid were uniformly mixed, and then the mixture was molded through extrusion. After being calcined at 550 for 4 hours, the molded sample was exchanged with 0.5 mol/L of ammonium nitrate for three times and each time was for 2 hours. And then the solid product was washed by deionized water, dried, calcined at 550 C. for 4 h to obtain the sample of Catalyst 12#.

(27) 80 g of Na-EMT zeolite molecular sieve with molar ratio of silicon atom to aluminum of 4, 50 g of silicon sol and 10% of diluted nitric acid were uniformly mixed, and then the mixture was molded through extrusion. After being calcined at 550 for 4 hours, the molded sample was exchanged with 0.5 mol/L of ammonium nitrate for three times (2 hours/time). And then the solid product was washed by deionized water, dried, calcined at 550 C. for 4 h to obtain the sample of Catalyst 13#.

Examples of Synthesis

Comparative Example

(28) H-MOR (molar ratio of silicon atom to aluminum atom Si/A1=6.7) was used as a comparative catalyst. 10 g of the comparative catalyst was put into a tubular fixed bed reactor with inner diameter of 28 mm, and then was heated to 550 at a heating rate of 5 /min under nitrogen gas. After being kept at 550 for 4 hours, the temperature was reduced to the reaction temperature of 190 in nitrogen gas, and then the pressure was increased to the reaction pressure of 5 MPa by introducing CO. The space velocity of feeding dimethyl ether was 0.10 h.sup.1, and the molar ratio of carbon monoxide to dimethyl ether was 6:1, and the molar ratio of carbon monoxide to hydrogen in the raw gas containing carbon monoxide was 2:1. The results at the reaction times when the catalytic reaction ran on for 1 h, 50 h and 100 h, are shown in Table 1.

(29) TABLE-US-00001 TABLE 1 Results of the comparative catalyst Time on stream (h) 1 50 100 Percent conversion of dimethyl ether (%) 35.7 23.8 9.8 Selectivity of methyl acetate (%) 99.8 78.2 25.3

Example 1

(30) According to Table 2, 10 g of the catalyst was put into a tubular fixed bed reactor with inner diameter of 28 mm, and then was heated to 550 at a heating rate of 5/min under nitrogen gas. After being kept at 550 for 4 hours, the temperature was reduced to the reaction temperature of 190 in nitrogen gas, and then the pressure was increased to the reaction pressure of 5 MPa by introducing CO. The raw material went through the catalyst bed from top to bottom. The space velocity of feeding dimethyl ether was 0.10 h.sup.1, and the molar ratio of dimethyl ether to carbon monoxide was 1:6, and the molar ratio of carbon monoxide to hydrogen in the raw gas containing carbon monoxide was 2:1, and the reaction temperature was 190 . The results at the reaction time when the catalytic reaction ran on for 100 h are shown in Table 2.

(31) TABLE-US-00002 TABLE 2 Evaluation results of catalyst for dimethyl ether carbonylation Percent conversion Selectivity of of dimethyl ether ether methyl acetate Catalyst (%) (%) 1# 7.5 95.3 2# 17.5 95.3 3# 23.5 97.7 4# 24.5 96.3 5# 27.5 91.6 6# 31.5 91.6 7# 24.5 91.6 8# 25.3 91.6 9# 24.2 91.6 10# 26.8 91.6 11# 17.5 98.3 12# 15.5 97.3 13# 14.2 97.3

Example 2

(32) Reaction Results of Dimethyl Ether Carbonylation at Different Reaction Temperatures

(33) 10 g of Catalyst 3# was used. The reaction temperatures were 70 , 210 and 240 , respectively, and other experimental conditions were same as Example 1. The results at the reaction time when the catalytic reaction ran on for 100 h are shown in Table 3.

(34) TABLE-US-00003 TABLE 3 Reaction results at different reaction temperatures Inlet temperature of reactor () 170 200 230 240 Percent conversion of dimethyl ether (%) 15.7 42.1 76.0 87.8 Selectivity of methyl acetate (%) 97.8 99.7 94.5 90.4

Example 3

(35) Reaction Results of Dimethyl Ether Carbonylation at Different Reaction Pressures

(36) The Catalyst 4# was used. The reaction pressures were 1 MPa, 6 MPa, 10 MPa and 15 MPa, respectively, and the reaction temperature was 190 , and other experimental conditions were same as Example 1. The results at the reaction time when the catalytic reaction ran on for 100 h are shown in Table 4.

(37) TABLE-US-00004 TABLE 4 Reaction results at different reaction pressures Reaction pressure (MPa) 1 6 10 15 Percent conversion of dimethyl ether (%) 18.3 29.3 41.8 52.3 Selectivity of methyl acetate (%) 98.7 99.1 99.4 99.8

Example 4

(38) Reaction Results of Dimethyl Ether Carbonylation at Different Space Velocities of Dimethyl Ether

(39) The Catalyst 6# was used. The space velocities of dimethyl ether were 0.25 h.sup.1, 1 h.sup.1 and 2 h.sup.1, respectively, and the reaction temperature was 190 , and other experimental conditions were same as Example 1. The results at the time on stream of 100 h are shown in Table 5.

(40) TABLE-US-00005 TABLE 5 Reaction results at different space velocities of dimethyl ether Space velocity of dimethyl ether (h.sup.1) 0.25 1 2 Percent conversion of dimethyl ether (%) 18.3 14.3 10.8 Selectivity of methyl acetate (%) 99.7 99.1 97.9

Example 5

(41) Reaction Results of Dimethyl Ether Carbonylation Under Different Molar Ratio of Carbon Monoxide to Dimethyl Ether

(42) The Catalyst 5# was used. The molar ratios of carbon monoxide to dimethyl ether were 12:1, 8:1, 4:1 and 2:1, respectively, and the reaction temperature was 190 , and other experimental conditions were same as Example 1. The results at the reaction time when the catalytic reaction ran on for 100 h are shown in Table 6.

(43) TABLE-US-00006 TABLE 6 Reaction results under different molar ratio of dimethyl ether to carbon monoxide Mole ratio of carbon monoxide/dimethyl ether 12 8 4 2 Percent conversion 40.6 31.7 16.7 11.7 of dimethyl ether (%) Selectivity of 97.8 98.1 99.5 99.4 methyl acetate (%)

Example 6

(44) Reaction Results of Dimethyl Ether Carbonylation when the Raw Gas Containing Carbon Monoxide Also Contains an Inactive Gas

(45) The Catalyst 9# was used. The molar ratios of carbon monoxide to hydrogen was 12 and 1.5, respectively, and the space velocities of dimethyl ether was 0.1 h.sup.1, and the molar ratio of dimethyl ether to carbon monoxide was 1:9, and the reaction temperature was 190 , and other experimental conditions were same as Example 1. The results at the reaction time when the catalytic reaction ran on for 200 h are shown in Table 7.

(46) TABLE-US-00007 TABLE 7 Reaction results of dimethyl ether on H-EMT catalyst when the raw gas containing carbon monoxide also contains an inactive gas Volume Volume Percent conversion Selectivity of fraction of fraction of of dimethyl ether methyl acetate inert gas CO (%) (%) 1% (H.sub.2) 99% 33.5 96.8 48% (H.sub.2) 52% 13.9 97.8 1% (N.sub.2) 99% 33.5 96.5 48% (N.sub.2) 52% 12.6 95.2 20% (N.sub.2) + 52% 13.1 96.7 28% (H.sub.2) 20%(CO.sub.2) + 52% 13.2 96.7 28% (H.sub.2)

Example 7

(47) Reaction Results in Different Type of Reactors

(48) The Catalyst 6# was used. The reaction temperature was 230 , and the reactors were a fluidized bed reactor and a moving bed reactor, respectively, and other experimental conditions were same as Example 1. The reaction results are shown in Table 8.

(49) TABLE-US-00008 TABLE 8 Reaction results on H-EMT catalyst in different type of reactors Type of reactor fluidized bed moving bed Percent conversion of of dimethyl ether (%) 95.2 94.5 Selectivity of methyl acetate (%) 98.7 98.5

Example 8

(50) Methyl Acetate Hydrolysis to Acetic Acid

(51) The carbonylation product methyl acetate was hydrolyzed to acetic acid in the presence of hydrolyzing catalyst. The ratio of water to ester was 4, and space velocity of methyl acetate was 0.4 h.sup.1, and loading amount of the catalyst was 10 g. The reaction results are shown in Table 10.

(52) TABLE-US-00009 TABLE 9 Reaction result of methyl acetate hydrolysis to acetic acid Reaction temperature () 50 60 70 Percent conversion of methyl acetate (%) 55.7 72.1 89.0

Example 9

(53) Methyl Acetate Hydrogenation to Ethanol

(54) The carbonylation product methyl acetate was hydrogenated to ethanol in the presence of hydrogenation catalyst. The reaction pressure was 5.5 MPa, and the molar ratio of hydrogen tp methyl acetate in raw gas was 20:1, and the molar ratio of hydrogen to carbon monoxide was 20:1, and the space velocity of methyl acetate was 3 h.sup.1, and loading amount of the catalyst was 10 g. The reaction results are shown in Table 11.

(55) TABLE-US-00010 TABLE 10 Reaction results of methyl acetate hydrogenation to ethanol Reaction Methyl acetate hydrogenation temperature Percent conversion of Selectivity of Selectivity of () methyl acetate (%) Ethanol (%) Methanol (%) 180 68.1 39.7 53.2 200 77.4 41.0 51.8 220 88.3 43.3 50.1 240 96.2 45.2 50.3

(56) The present invention has been described in detail as above, but the invention is not limited to the detailed embodiments described in this text. Those skilled in the art will understand that other changes and deformations can be made without deviating from the scope of the invention. The scope of the invention is limited by the appended claims.