Method for producing diol compound by synthesis gas one-step method

Abstract

The invention discloses a method for producing a diol compound from synthesis gas by a one-step method, and belongs to the technical field of catalytic chemistry. The method comprises the following steps: contacting and reacting raw material gas containing water, carbon monoxide and hydrogen with a catalyst to obtain the diol compound, the catalyst is selected from at least one of mordenite, ZSM-5, ZSM-23, a Na-type Y molecular sieve and an H-type Y molecular sieve. According to the method disclosed by the invention, one-step continuous production of the diol compound can be realized in the fixed bed reactor by taking the synthesis gas and the water as raw materials, and the conversion rate of carbon monoxide and the selectivity of the diol compound are effectively improved by adjusting the ratio of the synthesis gas to the water, the catalyst activation condition and the catalytic reaction condition; according to the present invention, the continuous production of one or more diol compounds such as methylene glycol, ethylene glycol and 1, 4-butanediol, and one or more alcohol products such as methanol and ethanol can be achieved, and the high selectivity is provided.

Description

Technical Field

[0001] This application relates to a one-step method for producing diol compounds from syngas, belonging to the field of catalytic chemistry technology. Background Technology

[0002] Glycols are a class of organic compounds containing two hydroxyl groups, widely used in polyester synthesis, antifreeze, pharmaceutical intermediates, and cosmetics. The mainstream glycols on the market mainly include ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Currently, the production of glycols primarily uses low-carbon olefins, such as ethylene and propylene, as raw materials through oxidation and hydration. However, with the dwindling global oil resources and persistently high crude oil prices, the cost of preparing glycols from olefins is increasing. Given the growing market demand for glycols, finding methods to produce them from inexpensive raw materials is crucial.

[0003] Given my country's abundant coal and natural gas resources, syngas is an ideal industrial raw material for synthesis. Researchers have also found that, theoretically, syngas possesses the feasibility and potential for preparing diol compounds. For example, existing technologies disclose a method for preparing dimethyl oxalate from syngas, followed by hydrogenation of dimethyl oxalate to ethylene glycol. However, this method has many shortcomings, including the difficulty and purity of intermediates and byproducts in the multi-step reaction process, which significantly affect the separation of ethylene glycol products. Meanwhile, some studies have reported on one-step synthesis of diol compounds from syngas, but these all require the use of transition metal carbonyl compounds with ligands under high pressure (100–1700 atm) homogeneous reaction conditions, limiting their industrial application to laboratory settings. Currently, the production methods for diol compounds are all stepwise processes, leading to issues such as the impact of reaction intermediates and byproducts on product purity, and raw material losses at each step. Summary of the Invention

[0004] To address at least one of the problems in existing technologies for producing diols from syngas—namely, reliance on precious metals, harsh high-pressure conditions, or multi-step reactions leading to difficulties in industrialization, high costs, and complex processes—this application provides a one-step process for producing diols from water using syngas. It employs a commercially available silica-alumina molecular sieve catalyst to catalyze the carbonylation hydrogenation reaction of water, carbon monoxide, and hydrogen to synthesize diols. This method enables the thermocatalytic carbonylation reaction of water under fixed-bed reaction conditions, and the preparation of diols from water and syngas. This method, used in the one-step syngas production of diols, offers advantages such as high carbon monoxide conversion and strong selectivity for diols.

[0005] The technical solution adopted in this application is as follows: According to a first aspect of this application, a method for producing diol compounds from syngas in a one-step process is provided, comprising: The feed gas containing water, carbon monoxide and hydrogen is contacted with a catalyst to react and obtain diol compounds. The catalyst is selected from at least one of mordenite, ZSM-5, ZSM-23, Na-type Y molecular sieve, and H-type Y molecular sieve.

[0006] The water, after being heated and vaporized, is mixed with carbon monoxide and hydrogen to form the raw material gas.

[0007] Diol compounds include methane glycol, ethylene glycol, and 1,4-butanediol, as well as other alcohols such as methanol and ethanol.

[0008] Optionally, the molar ratio of carbon monoxide, hydrogen and water in the raw gas is (1~400):(1~400):1.

[0009] Optionally, the molar ratio of carbon monoxide to water in the raw material is 20 to 100:1.

[0010] Optionally, the molar ratio of hydrogen to water in the raw material is 20 to 100:1.

[0011] Optionally, the silicon-to-aluminum ratio of the catalyst is 20 to 100:1.

[0012] Optionally, the reaction temperature is 100~400 °C.

[0013] Optionally, the reaction temperature is 150~300 °C.

[0014] Optionally, the reaction pressure is 0.5~10.0 MPa.

[0015] Optionally, the reaction pressure is 0.5~6.0 MPa.

[0016] Optionally, the total space velocity of the raw material is 3-8 h. -1 .

[0017] Optionally, the total space velocity of the raw material is 3-6 h. -1 .

[0018] Optionally, the catalyst may be activated before the feedstock containing water, carbon monoxide and hydrogen is brought into contact with the catalyst. The activation step includes: purging the catalyst with a reducing gas and then purging it with a carrier gas at the activation temperature.

[0019] Optionally, the reducing gas is selected from at least one of hydrogen, carbon monoxide, and pyridine.

[0020] Optionally, the reducing gas is selected from hydrogen and / or carbon monoxide.

[0021] Optionally, the carrier gas is selected from at least one of nitrogen, helium, and argon.

[0022] Optionally, the activation temperature is 100~400 °C.

[0023] Optionally, the activation time is 2 to 48 hours.

[0024] Optionally, the activation temperature is 150~250 °C.

[0025] Optionally, the apparatus used for the reaction is a fixed-bed reactor or a batch reactor.

[0026] The beneficial effects of this application include: (1) This method uses widely available syngas and water as raw materials. With specific commercial molecular sieves as catalysts, it can achieve one-step production of diols from syngas under relatively mild temperature and pressure conditions, which is far lower than the ultra-high pressure homogeneous reaction conditions previously reported, which require the use of transition metal carbonyl compound ligand systems. It also completely eliminates the multi-step oxidation and hydration process that relies on petroleum-based olefins. Furthermore, the reaction path is short and energy consumption is low, which makes this technical solution have a solid feasibility and safety foundation for moving from the laboratory to industrial production.

[0027] (2) The technical solution of this application can efficiently promote the carbonylation hydrogenation pathway of water by optimizing parameters such as catalyst type, raw material ratio, temperature, pressure and space velocity, and directionally generate target products such as ethylene glycol. The selectivity of ethylene glycol can reach up to 98.9%, while effectively inhibiting the generation of by-products such as methanol and ethanol, simplifying the separation of subsequent products, improving the utilization efficiency of raw materials, and replacing petroleum raw materials to produce high value-added glycols. It has important strategic significance and economic value. Detailed Implementation

[0028] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0029] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0030] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0031] The testing conditions for this application are as follows: The composition of the products was qualitatively analyzed using an AVANCE III 500 NMR spectrometer manufactured by Bruker GmbH, Germany. Test conditions: detection temperature 25 °C, deuterated reagent: deuterated water, test mode: 1H NMR.

[0032] The product composition was quantitatively analyzed using the area normalization method with an Agilent 8860A gas chromatograph manufactured by Agilent Technologies, Inc. Test conditions: detection temperature 270 °C, vaporization temperature 250 °C; HP-5 capillary column (0.25 mm × 50 m); column temperature was controlled by a programmed temperature ramp method, holding at 60 °C for 3 min, then ramping to 200 °C at a rate of 7 °C / min and holding for 5 min.

[0033] In the embodiments of this application, the carbon monoxide conversion rate and the selectivity of the diol compound are calculated based on molar numbers: Carbon monoxide conversion rate % = (number of carbon moles of carbon monoxide in feed gas – number of carbon moles of diol compounds in product) / number of carbon moles of carbon monoxide in feed gas × 100% (calculated based on the number of carbon moles). Diol selectivity % = (number of carbon moles of diol compounds in the product) / (number of carbon moles of carbon monoxide in the feed gas – number of carbon moles of diol compounds in the product) × 100% (calculated based on the number of carbon moles).

[0034] According to one embodiment of this application, a method for one-step production of diol compounds from syngas includes: The feed gas containing water, carbon monoxide and hydrogen is contacted with a catalyst to react and obtain diol compounds. The water, after being heated and vaporized, is mixed with carbon monoxide and hydrogen to form the raw material gas.

[0035] The catalyst is selected from at least one of mordenite, ZSM-5, ZSM-23, Na-type Y molecular sieve, and H-type Y molecular sieve.

[0036] In one embodiment, the diol compound product includes methane glycol, ethylene glycol, and 1,4-butanediol, as well as other alcohol products including methanol and ethanol.

[0037] In one embodiment, the molar ratio of carbon monoxide, hydrogen and water in the raw gas is (1~400):(1~400):1.

[0038] In one embodiment, the molar ratio of carbon monoxide to water in the raw material is 20 to 100:1.

[0039] In one embodiment, the molar ratio of carbon monoxide to water in the raw material is selected from any value or a range between 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, and 100:1, preferably 20 to 70:1.

[0040] In one embodiment, the molar ratio of hydrogen to water in the raw material is 20 to 100:1.

[0041] In one embodiment, the molar ratio of hydrogen to water in the raw material is selected from any value or a range between 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, and 100:1, preferably 20 to 70:1.

[0042] In one embodiment, the molar ratio of carbon monoxide to hydrogen is 0.5:1 to 2:1.

[0043] In one embodiment, the molar ratio of carbon monoxide to hydrogen is any value selected from 0.5:1, 1:1, 1.5:1, 2:1, or any range between two of them.

[0044] In one embodiment, the silicon-to-aluminum ratio of the catalyst is 20 to 100:1.

[0045] In one embodiment, the silicon-to-aluminum ratio of the catalyst is selected from any value of 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, or a range between any two.

[0046] In one embodiment, the catalyst is preferably one of mordenite, ZSM-23, or H-type Y molecular sieve with a strength of 40-100.

[0047] In one embodiment, the reaction temperature is 100~400 °C.

[0048] In one embodiment, the reaction temperature is preferably 150~300 °C.

[0049] In one embodiment, the reaction pressure is 0.5~10.0 MPa.

[0050] In one embodiment, the reaction pressure is preferably 0.5 to 6.0 MPa, more preferably 1.0 to 6.0 MPa.

[0051] In one embodiment, the total space velocity of the raw material is 3-15 h. -1 .

[0052] In one embodiment, the total space velocity of the raw material is preferably 5 to 10 h. -1 .

[0053] In one embodiment, the catalyst is further activated before the raw material containing water, carbon monoxide and hydrogen is contacted with the catalyst. The activation step includes: purging the catalyst with a reducing gas and then purging it with a carrier gas at the activation temperature.

[0054] In one embodiment, the reducing gas is selected from at least one of hydrogen, carbon monoxide, and pyridine.

[0055] In one embodiment, the reducing gas is selected from hydrogen and / or carbon monoxide.

[0056] In one embodiment, the carrier gas is selected from at least one of nitrogen, helium, and argon.

[0057] In one embodiment, the activation temperature is 100~400 °C.

[0058] In one embodiment, the activation time is 2 to 48 hours.

[0059] In one embodiment, the activation temperature is preferably 150~250 °C.

[0060] In one embodiment, the apparatus used for the reaction is a fixed-bed reactor or a batch reactor.

[0061] Examples 1-18 (1) Catalyst activation: 1 g of catalyst is packed into a fixed bed reactor, and activation gas is introduced at the activation temperature for 12 hours. Then, nitrogen gas is purged at the same temperature for 2 hours to complete the activation of the catalyst. (2) Synthesis of diol compounds: Under reaction conditions, carbon monoxide, hydrogen and water are introduced into a fixed bed reactor (carbon monoxide is directly introduced as a gas sample, and water is introduced after heating and vaporization) to react with the activated catalyst. The tail gas is analyzed by gas chromatography online, the conversion rate of carbon monoxide and the selectivity of diol compounds are calculated, and the condensate is collected. The product type is determined by nuclear magnetic resonance hydrogen spectroscopy. The catalyst, activation conditions, reaction conditions, raw material ratio, and test data are shown in Table 1.

[0062] Table 1

[0063] In summary, the data in the table shows that, for a new one-step method for producing diols from water and syngas, the proven conclusions include: (1) Using commercially available molecular sieve catalysts, under relatively mild reaction conditions of 190~210℃ and 4.5 MPa, water, carbon monoxide and hydrogen can be converted into ethylene glycol with higher value and have high ethylene glycol selectivity, achieving a technical effect of ethylene glycol selectivity ≥90%.

[0064] (2) This method is not limited to being carried out in a single catalytic reactor; the catalytic reaction can be carried out in both fixed-bed reactors and batch reactors.

[0065] (3) The silicon-to-aluminum ratio of commercial molecular sieve catalysts has a significant impact on the selectivity of catalytic reaction products. Among them, the molecular sieve catalyst with a silicon-to-aluminum ratio of 40:1 exhibits the highest ethylene glycol selectivity.

[0066] (4) Among various molecular sieve catalysts, mordenite catalysts exhibit higher carbon monoxide conversion and ethylene glycol selectivity compared to other types of catalysts.

[0067] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for one-step production of diol compounds from syngas, characterized in that, include: The feed gas containing water, carbon monoxide and hydrogen is contacted with a catalyst to react and obtain diol compounds. The water is heated and vaporized, then mixed with carbon monoxide and hydrogen to form the raw material gas. The catalyst is selected from at least one of mordenite, ZSM-5, ZSM-23, Na-type Y molecular sieve, and H-type Y molecular sieve.

2. The method according to claim 1, characterized in that, The molar ratio of carbon monoxide, hydrogen and water in the raw gas is (1~400):(1~400):1; Preferably, the molar ratio of carbon monoxide to water in the raw gas is 20~100:1; Preferably, the molar ratio of hydrogen to water in the raw material gas is 20~100:

1.

3. The method according to claim 1, characterized in that, The catalyst has a silicon-to-aluminum ratio of 20 to 100:

1.

4. The method according to claim 1, characterized in that, The reaction temperature is 100~400 °C; Preferably, the reaction temperature is 150~300 °C.

5. The method according to claim 1, characterized in that, The reaction pressure is 0.5~10.0 MPa; Preferably, the reaction pressure is 0.5~6.0 MPa.

6. The method according to claim 1, characterized in that, The total space velocity of the raw material is 3-15 h. -1 ; Preferably, the total space velocity of the raw material is 5-10 h⁻¹. -1 .

7. The method according to claim 1, characterized in that, The process also includes activating the catalyst before contacting the feedstock containing water, carbon monoxide, and hydrogen with the catalyst. The activation step includes: purging the catalyst with a reducing gas and then purging it with a carrier gas at the activation temperature.

8. The method according to claim 7, characterized in that, The reducing gas is selected from at least one of hydrogen, carbon monoxide, and pyridine; The carrier gas is selected from at least one of nitrogen, helium, and argon; Preferably, the reducing gas is hydrogen and / or carbon monoxide.

9. The method according to claim 7, characterized in that, The activation temperature is 100~400 °C, and the activation time is 2~48 h; Preferably, the activation temperature is 150~250 °C.

10. The method according to claim 1, characterized in that, The apparatus used for the reaction is a fixed-bed reactor or a batch reactor.

Images