CN1724151A - A kind of catalyst that is used for the synthetic c_2-oxygen compound of CO hydrogenation - Google Patents

Abstract

The invention provides a catalyst composed of Rh-Mn-Ti-M ₁ -M ₂ /SiO ₂ , M ₁ is an alkali metal such as Li and Na; M ₂ is one or two of Ru, Fe and Ir. According to the present invention, the loading of Rh is 0.1% to 3%, the weight ratio of Mn/Rh is 0.5 to 12, the weight ratio of Ti/Rh is 0.001 to 3, the weight ratio of M ₁ /Rh is 0.01 to 1.0, M The weight ratio of ₂ /Rh is 0.1 to 1.0. The catalyst has the advantages of low Rh loading, high overall catalytic activity, and significantly improved catalytic efficiency per unit Rh.

Description

A catalyst for CO hydrogenation to synthesize two-carbon oxygenated compounds

technical field

The invention relates to a catalyst for CO hydrogenation to synthesize two-carbon oxygen-containing compounds.

The present invention also relates to a method for preparing the above-mentioned catalyst.

The invention also relates to the use of the catalysts described above.

technical background

Two-carbon oxygenated compounds such as ethanol and acetaldehyde are important chemical raw materials, especially ethanol as a gasoline additive and fuel to increase the octane value has received extensive attention. Rh-based catalysts for selectively synthesizing two-carbon oxygenates such as ethanol have received special attention because of their unique selectivity to the formation of two-carbon oxygenates. Has applied for a large number of Rh-based catalyst patents for the synthesis of two-carbon oxygenates at home and abroad. Its purpose is to improve the activity and selectivity of synthesizing two-carbon oxygen-containing compounds on the Rh-based catalyst by adding various additives. For example, GB1501891 is a supported Rh-Fe catalyst with Fe as a promoter. US4096164 is a supported Rh-Mo catalyst. J59227831 invented a Rh-based catalyst improved with three additives of Mn, Ir and Li, using 5% Rh-1.17% Ir-0.11% Mn-0.021% Li/SiO ₂ catalyst, with CO/H ₂ =9 The mixed gas is used as the raw material gas, reacted at 10.0Mpa, 280-300°C, and the product mainly synthesized with acetic acid is obtained. The selectivity of acetic acid reaches 67.1%, and the space-time yield reaches 347 g/lh. J6032733 is a catalyst with basic components of Rh, Mn, Li and Fe. The common feature of these catalysts is the high loading of Rh, generally 4-5%, or higher than 5%. Since Rh is a noble metal, the high loading of Rh limits the industrial application of these catalysts. In CN1177521A, a catalyst composed of Rh-Ti-Mn-M ₁ -M ₂ /SiO ₂ was applied, where M ₁ is Ru, Fe, Ir or Ni, and M ₂ is K, Li or Mg. The Rh loading of this catalyst is 1%, and the catalytic efficiency of Rh has been greatly improved compared with the previous catalysts, but from the perspective of industrialization requirements, there is still a need for further improvement in order to minimize the amount of Rh and Reduce catalyst costs.

Contents of the invention

The purpose of the present invention is to provide a multi-component and low Rh loading catalyst with high activity and selectivity, and the process of CO hydrogenation to synthesize two-carbon oxygenated compounds on this catalyst.

The catalyst provided by the invention has the advantages of low Rh loading, high overall catalytic activity, and significantly improved catalytic efficiency per rhodium.

The composition of this catalyst is Rh-Mn-Ti-M ₁ -M ₂ /SiO ₂ , M ₁ is an alkali metal such as Li and Na; M ₂ is one or two of Ru, Fe and Ir. According to the present invention, the loading of Rh is 0.1% to 3%, the more suitable loading is 0.3% to 2%, and the most suitable loading is 0.7% to 1.5%. The weight ratio of Mn/Rh is 0.5 to 12, a more suitable weight ratio is 0.5 to 10, and the most suitable weight ratio is 1 to 8. The weight ratio of Ti/Rh is 0.001 to 3, a more suitable weight ratio is 0.001 to 2, and the most suitable weight ratio is 0.001 to 0.5. The weight ratio of M ₁ /Rh is 0.01 to 1.0, more suitably 0.02 to 0.5, most suitably 0.04 to 0.2. The weight ratio of M ₂ /Rh is 0.1 to 1.0, more suitably 0.1 to 0.9, most suitably 0.2 to 0.8.

According to the present invention, the preparation method of catalyst is as follows:

The catalyst is prepared by step-by-step impregnation or co-impregnation. The Rh, Mn, _M1 and _M2 components in the catalyst can be chloride, nitrate or other soluble compounds. The compound of Ti component can be organic titanate, such as ethyl titanate, butyl titanate, titanium chloride such as TiCl ₄ or other soluble compounds. The solvent used may be water or a non-aqueous solvent such as methanol, ethanol and the like.

When using the co-impregnation method to prepare the catalyst, the required amount of compounds of various components are dissolved in the solvent to make a solution with a certain concentration, and then impregnated on the catalyst. The amount of impregnating liquid should at least ensure that all supports are submerged. The drying temperature of the impregnation can be from room temperature to 200°C, and the drying time can be from 2 hours to 20 days. The length of drying time is related to the height of drying temperature. When the drying temperature is 100°C to 120°C, the drying time is 4 hours to 50 hours, preferably 4 hours to 30 hours. The dried catalyst can be calcined at 200° C. to 400° C. for 1 to 20 hours, and can also be directly used as a standby catalyst after drying.

When using the step-by-step impregnation method, one or several components of the compound are prepared together into a certain concentration of impregnating solution, which is first impregnated on the silica, dried or re-roasted, and then impregnated with other components of the compound. The drying and roasting conditions of the impregnation are related to the step-by-step impregnation procedure. The drying temperature of the impregnation can be from room temperature to 200° C., and the drying time is from 2 hours to 20 days. The length of drying time is related to the height of drying temperature. When the drying temperature is 100°C to 120°C, the drying time is 4 hours to 50 hours, preferably 4 hours to 30 hours. The dried catalyst can be calcined at 200°C to 700°C for 1 to 20 hours. The calcination temperature and time vary with the impregnation procedure and the amount of catalyst components added. After impregnation and drying, all the components are directly used as backup catalysts, or after being recalcined, used as backup catalysts.

These spare catalysts were placed in the reactor for in situ reduction with pure _H2 or _H2 -containing gas for at least 1 h before the reaction. However, when necessary, the standby catalyst is used in an off-line reduction reactor before being loaded into the reactor with pure H ₂ or a gas containing H ₂ to be reduced in situ for at least 1 hour under normal pressure or pressurized conditions, and the reduced catalyst is After passivation treatment in the reactor, it is unloaded and stored for later use. The passivation treatment refers to that when the reduction is completed and the temperature of the reactor is lowered to room temperature or close to room temperature, the residual H ₂ in the reactor is blown off with an inert gas such as N ₂ , Ar or CO ₂ , and then in an inert gas Add a small amount of O ₂ or air to slowly absorb O ₂ on the active surface of the catalyst, and avoid the burning and damage of the catalyst in a highly active state after reduction due to sudden contact with air.

The catalyst prepared by the invention has higher activity and higher space-time yield of the two-carbon oxygen-containing compound during the reaction process of CO hydrogenation to synthesize the two-carbon oxygen-containing compound.

Detailed ways

The invention is further illustrated by the following examples.

Example 1: impregnate a 20-40 mesh silica gel carrier with a certain concentration of Ti(OC ₂ H ₅ ) ₄ ethanol solution, dry at 110°C for 5 hours after the solvent ethanol volatilizes, and bake at 700°C for 4 hours to obtain a Ti containing 0.0025 wt.% TiO ₂ /SiO ₂ . Impregnate the above TiO ₂ /SiO ₂ with a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ and H ₂ IrCl ₆ aqueous solution, and dry at 110°C for 20 hours to obtain the spare 1%Rh-2%Mn-0.0025 %Ti-0.075%Li-0.5%Ir/ _SiO2 catalyst.

Example 2: impregnate a 20-40 mesh silica gel carrier with a certain concentration of Ti(OC ₂ H ₅ ) ₄ ethanol solution, dry at 110°C for 5 hours after the solvent ethanol volatilizes, and bake at 600°C for 4 hours to obtain a titanium-containing 0.005% TiO ₂ /SiO ₂ . The rest are the same as in Example 1 to obtain the standby 1%Rh-2%Mn-0.005%Ti-0.075%Li-0.5%Ir/SiO ₂ catalyst.

Example 3: Using the same method as in Example 1, first prepare TiO ₂ /SiO ₂ containing 0.0025 wt% Ti, and then use a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ and Fe(NO ₃ ) ₂ The above TiO ₂ /SiO ₂ was impregnated with aqueous solution, and dried at 110° C. for 20 hours to obtain a spare 1%Rh-2%Mn-0.0025%Ti-0.075%Li-0.05%Fe/ _SiO2 catalyst.

Example 4: TiO ₂ /SiO ₂ with a Ti content of 0.0025wt% was prepared by the same method as in Example 1, and then impregnated with a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ and RuCl ₃ aqueous solution TiO ₂ /SiO ₂ was dried at 110°C for 20 hours to obtain a spare 1%Rh-2%Mn-0.0025%Ti-0.075%Li-0.3%Ru/SiO ₂ catalyst.

Example 5: TiO ₂ /SiO ₂ with a Ti content of 0.0025wt% was prepared using the same method as in Example 2, and then a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ , H ₂ IrCl ₆ and Fe (NO ₃ ) ₂ aqueous solution impregnated the above TiO ₂ /SiO ₂ , and dried at 110°C for 20 hours to obtain the spare 1%Rh-2%Mn-0.005%Ti-0.1%Li-0.5%Ir-0.05%Fe/SiO ₂ catalysts.

Example 6: Impregnate a 20-40 mesh silica gel carrier with a certain concentration of Ti(OC ₂ H ₅ ) ₄ ethanol solution, dry at 110°C for 5 hours after the solvent ethanol volatilizes, and bake at 500°C for 4 hours to obtain a Ti-containing 0.01 wt% TiO ₂ /SiO ₂ , then impregnate the above TiO ₂ /SiO ₂ with a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , NaNO ₃ and H ₂ IrCl ₆ aqueous solution, and dry at 110°C for 20 hours to obtain 1%Rh-1%Mn-0.01%Ti-0.1%Na-0.5%Ir/ _SiO2 catalyst.

Example 7: TiO ₂ /SiO ₂ with a Ti content of 0.0025wt% was prepared by the same method as in Example 2, and then impregnated with a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ and H ₂ IrCl ₆ aqueous solution The above TiO ₂ /SiO ₂ was dried at 110° C. for 20 hours to obtain a spare 1.3% Rh-2% Mn-0.005% Ti-0.075% Li-0.5% Ir/SiO ₂ catalyst.

Comparative example 1: impregnate the above-mentioned SiO ₂ with a certain concentration of RhCl ₃ , Mn(NO ₃ ) ₂ , LiNO ₃ and H ₂ IrCl ₆ aqueous solution, and dry at 110°C for 6 hours to obtain a spare 1%Rh-2%Mn- 0.075% Li-0.5% Ir/ _SiO2 catalyst.

Comparative Example 2: TiO ₂ /SiO ₂ containing 0.0025wt% Ti was prepared by the same method as in Example 1, and then impregnated with a certain concentration _of RhCl ₃ , LiNO ₃ and H ₂ IrCl ₆ aqueous solution _. , dried at 110° C. for 20 hours to obtain a spare 1% Rh-0.0025% Ti-0.075% Li-0.5% Ir/SiO2 catalyst.

Comparative Example 3: TiO ₂ /SiO ₂ containing 0.0025wt% Ti was first prepared by the same method as in Example 1, and then the TiO 2 /SiO 2 was impregnated with a certain concentration _of RhCl ₃ , Mn(NO ₃ ) ₂ and LiNO ₃ aqueous solution. SiO ₂ , dried at 110°C for 20 hours to obtain a spare 1%Rh-2%Mn-0.0025%Ti-0.075%Li/SiO ₂ catalyst.

Table 1 lists the evaluation results of the CO hydrogenation reaction performed on the catalysts of Examples and Comparative Examples at 320° C., 3.0 MPa, 12500 h ⁻¹ , and feed gas with H ₂ /CO volume ratio = 2.

Find out from the reaction result of table 1, the Rh loading capacity of catalyst of the present invention is low, the active selectivity of synthesizing two-carbon oxygen-containing compounds such as ethanol and acetaldehyde is high, and the catalytic effectiveness of synthesizing two-carbon oxygen-containing compounds on the unit metal Rh of catalyst Significantly higher than previous catalysts and has better industrial application prospects.

The CO hydrogenation reaction result of the embodiment of table 1 Example Catalyst composition wt% space-time yield g/kg.h Selectivity C% 1 1Rh-2Mn-0.0025Ti-0.075Li-0.5Ir 453.4 57.2 2 1Rh-2Mn-0.005Ti-0.075Li-0.5Ir 449.3 56.4 3 1Rh-2Mn-0.0025Ti-0.075Li-0.05Fe 438.7 54.9 4 1Rh-2Mn-0.0025Ti-0.075Li-0.3Ru 442.6 54.4 5 1Rh-2Mn-0.005Ti-0.1Li-0.5Ir-0.05Fe 468.2 58.2 6 1Rh-1Mn-0.01Ti-0.1Na-0.5Ir 451.3 56.8 7 1.3Rh-2Mn-0.005Ti-0.075Li-0.5Ir 487.8 59.3 comparative example 1 1Rh-2Mn-0.075Li-0.5Ir 340.0 55.4 2 1Rh-0.0025Ti-0.075Li-0.5Ir 158.4 46.1 3 1Rh-2Mn-0.0025Ti-0.075Li 317.2 53.3

Claims (13)

1, a kind of catalyst that is used for the synthetic c_2-oxygen compound of CO hydrogenation, its expression formula is:

Rh-Mn-Ti-M ₁-M ₂/ SiO ₂, in the formula:

M ₁Be Li or Na; M ₂Be that Ir, Ru are or/and Fe; The Rh carrying capacity is 0.1-3%; The weight ratio of Mn/Rh is 0.5-12; The weight ratio of Ti/Rh is 0.001-3; M ₁The weight ratio of/Rh is 0.01-1.0; M ₂The weight ratio of/Rh is 0.1-1.0.

2, the catalyst of claim 1 is characterized in that, wherein: the Rh carrying capacity is 0.7-1.5%; The weight ratio of Mn/Rh is 1-8; The weight ratio of Ti/Rh is 0.001-0.5; M ₁The weight ratio of/Rh is 0.04-0.2; M ₂The weight ratio of/Rh is 0.2-0.8.

3, a kind of method for preparing the described catalyst of claim 1, its key step is:

Compound titanium solution is impregnated on the silica-gel carrier, and the macerate drying is or/and Rh is flooded in roasting more respectively, and Mn, Li or Na, Ir, Ru be or/and the Fe compound solution, and macerate is room temperature to 200 ℃ drying 2 hours to 20 days, catalyst.

4, the preparation method of claim 3 is characterized in that, floods Rh respectively, Mn, and Li or Na, Ir, Ru are or/and the order of Fe compound solution is arbitrarily.

5. the preparation method of claim 3 is characterized in that, compound titanium solution is impregnated on the silica-gel carrier, and the macerate drying is or/and Rh and Mn are flooded in roasting again, Li or Na, and Ir, Ru are or/and Fe compound solution formulated together; Macerate is normal temperature to 200 ℃ drying 2 hours to 20 days, catalyst.

6. claim 3 or 5 preparation method is characterized in that when described baking temperature was 100 to 120 ℃, be 4 hours to 30 hours drying time.

7. claim 3 or 5 preparation method is characterized in that the catalyst that obtains was 150 ℃ to 700 ℃ roastings 1 to 20 hour.

8, claim 3 or 5 preparation method is characterized in that titanium compound is Ti (OC ₂H ₅) ₄, Ti (OC ₄H ₉) ₄, TiCl ₄Or the compound of other solubility; The compound of Rh, Mn, Ru, Ir and Fe is the compound of chloride, nitrate or other solubility.

9, claim 3 or 5 preparation method is characterized in that the used solvent of described solution is water, methyl alcohol or ethanol.

10, claim 3 or 5 preparation method is characterized in that the catalyst that makes places the pure H of reduction reactor before use ₂Or contain H ₂Gas in-situ reducing at least 1 hour under normal pressure or pressurized conditions.

11, claim 3 or 5 preparation method is characterized in that, the catalyst that obtains is used pure H in the reduction reactor outside online before the reactor of packing into ₂Or contain H ₂Gas in-situ reducing at least 1 hour under normal pressure or pressurized conditions, the catalyst after the reduction in reduction reactor after Passivation Treatment, draw off preserve standby.

12, the preparation method of claim 11 is characterized in that, described Passivation Treatment refers to, and reduction finishes that temperature of reactor reduced to room temperature or during near room temperature, uses inert gas N ₂, Ar or CO ₂Blow down remaining H in the reactor ₂, in inert gas, add O then ₂Or air, make the catalyst activity surface adsorb O lentamente ₂, and be in the operating process that the catalyst under the high activity state burns and damages because of unexpected ingress of air after avoiding reducing.

13, the application of the catalyst of claim 1 in the synthetic c_2-oxygen compound reaction of CO hydrogenation reaction.