阅读说明：本技术 将合成气转化为异丁醇的方法 (Process for the conversion of syngas to isobutanol ) 是由 R.龙 阮畋 周麓波 郭锦标 于 2018-02-28 设计创作，主要内容包括：提供了改进的异丁醇合成方法,其通过从合成气形成混合醇来进行。所述两步方法避免了常规的一步直接异丁醇合成方法中最慢的α碳加成反应。一旦在第一个反应区中生产了乙醇和丙醇,它们可以在第二个反应区中与甲醇和/或合成气反应,以在催化剂的存在下通过快速的β碳加成反应生产异丁醇,导致异丁醇生产能力显著地提高。(Improved isobutanol synthesis processes are provided by forming mixed alcohols from syngas. The two-step process avoids the slowest alpha carbon addition reaction in conventional one-step direct isobutanol synthesis processes. Once ethanol and propanol are produced in the first reaction zone, they can be reacted with methanol and/or syngas in the second reaction zone to produce isobutanol by a rapid beta carbon addition reaction in the presence of a catalyst, resulting in a significant increase in isobutanol production capacity.)

1. A method of making isobutanol comprising:

introducing syngas into a first reaction zone in the presence of a first heterogeneous catalyst to produce a reaction mixture comprising a mixture of alcohols, the alcohols comprising methanol and a major amount of ethanol and propanol;

separating the reaction mixture into at least a first stream comprising methanol and a second stream comprising ethanol and propanol;

the synthesis gas and at least a portion of the second stream are introduced into a second reaction zone in the presence of a second heterogeneous catalyst to produce isobutanol.

2. The process of claim 1, wherein the second heterogeneous catalyst comprises elements from groups IA, IIA, IIIA, IV, IB, IIB, IIIB, VIB, VIIB and VIIIB of the periodic Table.

3. The process of any of claims 1-2, wherein the second heterogeneous catalyst comprises an alkali and alkaline earth promoted ZnO or CuO catalyst.

4. The process of any of claims 1-3, wherein the first heterogeneous catalyst comprises one or more of: Cu-Co containing catalysts, Cu-Fe containing catalysts, Cu-Ni containing catalysts, promoted Mo catalysts and noble metal catalysts, and combinations thereof.

5. The process of any one of claims 1-4, wherein the reaction mixture is separated by a distillation or adsorption desorption process.

6. The method of any one of claims 1-5, wherein H is in the syngas₂The molar ratio to CO is in the range of 10:1 to 0.1: 1.

7. The method of any one of claims 1-6, further comprising:

introducing at least a portion of said first stream and at least a portion of said second stream, and optionally a portion of said syngas, into a third reaction zone in the presence of a third heterogeneous catalyst to produce a second portion of isobutanol.

8. The process of claim 7, wherein the third heterogeneous catalyst comprises elements from groups IA, IIA, IIIA, IVA, VA, IV, IB, IIB, VIB, VIIB and VIIIB of the periodic Table.

9. The method of any one of claims 1-8, further comprising:

introducing at least a portion of the first stream into a methanol to olefins process to convert the methanol to at least one of ethylene or propylene.

10. The method of any one of claims 1-9, further comprising:

at least a portion of the first stream is introduced into a methanol to gasoline process to convert the methanol to gasoline.

11. The process of any one of claims 1-10, wherein the weight ratio of ethanol and propanol to methanol is greater than 0.2.

12. The process of any one of claims 1-11, wherein the weight ratio of ethanol and propanol to methanol is greater than 0.5.

13. The process of any of claims 1-12, wherein the weight ratio of ethanol and propanol to methanol is greater than 1.0.

14. The method of any one of claims 1-13, wherein the reaction mixture further comprises isobutanol.

15. The method of claim 14, wherein separating the reaction mixture into at least the first stream comprising methanol and the second stream comprising ethanol and propanol comprises separating the reaction mixture into at least the first stream comprising methanol, the second stream comprising ethanol and propanol, and a third stream comprising isobutanol.

Background

Isobutanol is an organic solvent and is the starting material for the manufacture of isobutyl acetate and isobutyl ester. It can also be blended directly with gasoline to improve octane and combustion efficiency, or used as a pure alternative fuel. Isobutanol has a relatively higher energy density and lower volatility than ethanol. In addition, it does not readily absorb moisture in the air, which prevents corrosion of the engine and the pipes. It also has a higher octane number than ethanol, which results in less knock on the engine.

Despite its many potential uses, isobutanol is currently being synthesized only to a limited extent. Isobutanol can be produced by the hydroformylation of propylene: a process comprising reacting propylene with carbon monoxide and hydrogen to produce isobutyraldehyde, and then hydrogenating isobutyraldehyde to isobutanol. For example, U.S. Pat. No. 2,564,130 discloses a catalyst prepared from propylene, CO and H in the presence of a cobalt-containing catalyst at 225-300 deg.C₂A process for the preparation of n-butanol and isobutanol from the mixture of (a). While this hydroformylation process is currently used to produce butanol, it is not energy efficient due to the high energy required for the production of propylene and synthesis gas (syngas). Further, when isobutanol is used as a gasoline additive, its demand is expected to significantly increase the demand for propylene, resulting in increased costs for the process.

Alternatively, much research has been directed to richer and moreInexpensive synthesis gas performs the synthesis of isobutanol. Syngas, comprising carbon monoxide and hydrogen, is produced mainly from the reforming or partial oxidation of natural gas and light hydrocarbons, or the gasification of coal and biomass at high temperatures. It can also be produced from gasification of municipal solid waste. Carbon monoxide and hydrogen are reacted at high temperature and high pressure to produce methanol and isobutanol over alkali metal promoted ZnO and CuO-ZnO based catalysts with methane and light hydrocarbons as the major by-products. For example, U.S. patent No. 5,767,166 discloses a process for the synthesis of isobutanol from synthesis gas over an alkali metal promoted Zn-Cr oxide catalyst in one reactor. H at 420 ℃, 18MPa, 1.0₂165g/kg-cat/h of isobutanol were achieved with a molar/CO ratio and a gas hourly space velocity of 20,000 per hour. A similar process is disclosed in Chinese patent publication No. 103,272,609, in which CuO-ZnO-ZrO is promoted in alkali and rare earth oxides₂Over the catalyst, a carbon monoxide conversion of 32-61% was achieved with 25-45 wt% isobutanol in liquid alcohol.

While this direct isobutanol synthesis from syngas has been extensively studied, it is generally associated with poor isobutanol selectivity and productivity. During operation, lower temperatures result in higher methanol selectivity, however higher temperatures tend to produce more methane and light hydrocarbons. Therefore, it is difficult to achieve high isobutanol selectivity and yield on alkali metal promoted ZnO and CuO-ZnO catalysts.

Therefore, a process that overcomes the above obstacles and improves isobutanol selectivity and productivity would be desirable.