CN100443165C - A catalyst for the synthesis of methyl mercaptan by the reaction of carbon monoxide and hydrogen sulfide - Google Patents

Abstract

It relates to a catalyst for synthesizing methyl mercaptan by reacting carbon monoxide (CO) and hydrogen sulfide (H ₂ S). The catalyst is a supported Mo-OK based composite catalyst. The catalyst contains at least one transition metal oxide and/or Or cerium oxide promoter, the carrier is SiO ₂ ; the Mo-OK group can be converted from K ₂ MoO ₄ or (NH ₄ ) ₆ Mo ₇ O ₂₄ ·H ₂ O plus a potassium salt. The reaction is carried out under the conditions of a temperature of 220-350° C., a pressure of 0.1-2.0 MPa, and a volume space velocity of the raw material gas of (2-5)×10 ³ h ^-1 . It has high activity and selectivity to produce methyl mercaptan, the conversion rate of CO is 45%-90%, the space-time yield of methyl mercaptan is 0.8g·h ^-1 ·ml _cat ^-1 , and the selectivity is as high as 99%.

Description

A catalyst for the synthesis of methyl mercaptan by the reaction of carbon monoxide and hydrogen sulfide

technical field

The invention relates to a catalyst for synthesizing methyl mercaptan by reacting carbon monoxide (CO) and hydrogen sulfide (H ₂ S). The catalyst is a supported Mo-OK based composite system with at least one transition metal oxide and/or cerium oxide as a promoter.

Background technique

Methyl mercaptan is the main chemical intermediate for the synthesis of methionine, pharmaceuticals and pesticides. The synthetic technical route of existing methyl mercaptan has: U.S. Patent US 5977011, US 6198003, European patent EP 0564706A, EP 1005906, disclosed by Japanese Patent Publication JP219673 (2000) etc. route, the main _catalyst system is WO ₃ -K ₂ O/γ-Al ₂ O ₃ , MgO+ZrO/γ-Al ₂ O ₃ systems; (CO+H ₂ ) is the route of directly synthesizing methyl mercaptan as raw material, and its catalyst is a supported Mo-SK based composite catalyst, which is characterized by higher methyl mercaptan selectivity and space-time yield; U.S. Patent US 4668825, US4570020 discloses a scheme for directly synthesizing methyl mercaptan from carbon monoxide and hydrogen sulfide. The catalyst system used is a catalyst in which oxides such as V, Nb, and Ta are supported on a _TiO2 carrier. The catalyst system is at 300 ° C. The highest conversion rate of CO is 36%.

Contents of the invention

The object of the present invention is to provide a kind of new catalyst system that is used for the direct synthesis of methyl mercaptan of carbon monoxide and hydrogen sulfide. The catalyst system is a supported Mo-O-K based composite system with at least one transition metal oxide and/or cerium oxide as a promoter.

Said catalyst of the present invention is a kind of catalyst system that is used for the direct synthesis of methyl mercaptan of carbon monoxide and hydrogen sulfide, is made up of active component, promotor and carrier, and said active component is Mo-OK base compound, promotes The agent is an oxide of at least one transition metal and/or cerium oxide (CeO ₂ ), and the support is SiO ₂ . The active component Mo-OK based complex can be converted from the precursor K ₂ MoO ₄ and metered by K ₂ MoO ₄ , or from (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O plus a potassium salt conversion and measured by MoO ₃ +K ₂ O, said potassium salt can be selected from KOH, K ₂ CO ₃ , KAc, K ₂ C ₂ O ₄ , or KNO ₃ ; said transition metal oxide The oxides of Fe, Co, Ni or Mn, the precursors of transition metal oxides and ceria are the respective nitrates or acetates; the oxide promoter is measured in MO _x (weight), if the oxide is more than one species, then MO _x represents the sum of several oxides. The weight ratio of each component of the catalyst is K ₂ MoO ₄ /MO _x /support=(0.05-0.80)/(0.01-0.10)/1, preferably (0.1-0.5)/(0.01-0.06)/1 or MoO ₃ /K ₂ O/MO _x /carrier=(0.10-0.50)/(0.10-0.30)/(0.01-0.10)/1, preferably (0.10-0.30)/(0.10-0.25)/(0.01-0.06) /1.

The preparation of catalyst adopts step-by-step impregnation method, and its method is as follows:

1) The selected and measured soluble salts of transition metals and/or Ce are dissolved with quantitative distilled water to make an aqueous solution of a certain concentration, and a certain volume of known concentration of transition metals and/or Ce soluble salt solutions can also be measured , and then use this solution to impregnate the metered carrier. If there are more than one accelerator, each aqueous solution should be prepared first, and then combined into a mixed aqueous solution, and then this solution is used to impregnate the metered carrier. The immersion time is 4 to 6 hours. Then dry at 100-135° C. for 2-4 hours, and finally calcinate at 500-600° C. for 4-6 hours to prepare an intermediate modified by transition metal oxide and/or cerium oxide.

2) When the precursor of the active component is K ₂ MoO ₄ , dissolve the quantitative K ₂ MoO ₄ in quantitative distilled water to prepare a certain concentration of K ₂ MoO ₄ aqueous solution, and then use this solution to impregnate the step (1) The prepared carrier modified by transition metal oxide and/or cerium oxide is impregnated for 5-8 hours, then dried at 110-130°C for 2-4 hours, and finally calcined at 400-550°C for 3-5 hours;

When the precursor of the active component is (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O plus a potassium salt, first dissolve the selected and measured potassium salt with quantitative distilled water to prepare a certain concentration of potassium salt solution, and then use this solution to impregnate the carrier modified by transition metal oxide and/or cerium oxide prepared in step (1) for 4-6h, then dry at 100-130°C for 2-4h, and use the same method to Measured (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O is dissolved in quantitative distilled water to prepare a certain concentration of (NH ₄ ) ₆ Mo ₇ O ₂₄ aqueous solution, and then use this solution to impregnate transition metal oxides and/or Or the carrier modified by cerium oxide and potassium salt, the impregnation time is 5-8 hours, then dried at 110-130°C for 2-4 hours, and finally calcined at 400-550°C for 3-5 hours.

The catalyst must be reduced with H ₂ or H ₂ +CO gas at 300-350°C for 8 hours before use. The service condition of catalyst of the present invention is: the volume ratio of each component in the feed gas is CO: H ₂ S=1/(3～0.1), preferably 1/(3～1), reaction temperature is 220～350 ℃, The pressure is 0.1-2.0 MPa, and the reaction gas volume space velocity (GHSV) is (2-5)×10 ³ h ^-1 .

The invention is evaluated in a fixed bed tubular flow reaction system. The raw material gas and reaction products were analyzed by gas chromatography, and samples were taken for analysis 2 hours after the reaction proceeded and reached a steady state. The present invention has high activity and selectivity for generating methyl mercaptan. Under the evaluation conditions of the present invention, the conversion rate of CO is 45% to 90%, and the space-time yield of methyl mercaptan is 0.8g·h ^-1 ·ml ^{- 1} _cat , the selectivity is as high as 99%.

Detailed ways

Further illustrate the present invention with embodiment below.

Example 1

Take 20ml of Fe(NO ₃ ) ₃ aqueous solution with a concentration of 0.25M and impregnate 10.0g SiO ₂ (80-100 mesh) for 4 hours, then dry at 110°C for 3 hours, and calcinate at 550°C for 4 hours to prepare Fe ₂ O ₃ /SiO ₂ intermediate; 5.025g of K ₂ MoO ₄ dissolved in 20ml of distilled water was impregnated with the prepared Fe ₂ O ₃ /SiO ₂ intermediate for 8 hours, then dried at 110°C for 3 hours, and calcined at 500°C for 4 hours. The weight composition of the components was K ₂ MoO ₄ /Fe ₂ O ₃ /SiO ₂ =0.5/0.04/1.

Example 2

Put 0.5 g _of the catalyst produced in Example 1 into a stainless steel tubular reactor, reduce it with H at 350° C. for 8 h, and then pass the feed gas to react. The volume ratio of each component of the feed gas is CO:H ₂ S=1/ 1. Reaction temperature: 295°C; pressure: 0.2Mpa; space velocity: 3×10 ³ h ^-1 , take a sample for chromatographic analysis 2 hours after the reaction reaches a steady state, and the analysis results are shown in Table 1 (code A).

Example 3

Put 0.5 g _of the catalyst manufactured in Example 1 into a stainless steel tubular reactor, reduce it with H at 330° C. for 8 h, and then pass the feed gas to react. The volume ratio of each component of the feed gas is CO: H ₂ S=1/ 3. Reaction temperature: 300°C; pressure: 0.6Mpa; space velocity: 3×10 ³ h ^-1 , take a sample for chromatographic analysis 2 hours after the reaction reaches a steady state, and the analysis results are shown in Table 1 (code B).

Example 4

"0.20M Mn(NO ₃ ) ₂ solution 18ml" replaces "concentration is 0.25M Fe(NO ₃ ) ₃ aqueous solution 20ml" in embodiment 1, all the other ways are the same as embodiment 1, and the catalyst 0.5g prepared in this way is carried out The method of example 2 and 3 is evaluated, and the composition of catalyst and activity evaluation result are shown in Table 1.

Embodiment 5-7

In Example 1, "20ml of Fe(NO ₃ ) ₃ solution with a concentration of 0.25M" was changed to weigh 1.20g Ni(NO ₃ ) ₂ ·6H ₂ O, 1.20g Co(NO ₃ ) ₂ ·6H ₂ O, 0.65g Ce(NO ₃ ) ₃ ·6H ₂ O was dissolved in 20ml of distilled water and combined to form a mixed solution. The rest of the preparation method and steps were the same as in Example 1. Each 0.5 g of the catalysts prepared in this way was evaluated according to the method of Examples 2 and 3, and the composition and activity evaluation results of the catalysts are shown in Table 1.

Example 8

Dissolve 0.500g Ce(NO ₃ ) ₃ ·6H ₂ O in 15ml of distilled water to make Ce(NO ₃ ) ₃ aqueous solution, then combine it with 10ml of 0.5M Fe(NO ₃ ) ₃ aqueous solution to form a mixed solution, and the rest Method and steps are the same as in Example 1. 0.5 g of the catalyst prepared in this way was evaluated according to the method of Examples 2 and 3, and the composition and activity evaluation results of the catalyst are shown in Table 1.

Example 9

Combine the solution of 1.250g Fe(NO ₃ ) ₃ .9H ₂ O dissolved in 10ml distilled water and the solution of 0.500g Ni(Ac) ₂ .4H ₂ O dissolved in 15ml distilled water, and impregnate 10.0g SiO ₂ with this solution for 5h, Then dry at 110°C for 4 hours, calcined at 550°C for 4 hours to make Fe ₂ O ₃ /NiO/SiO ₂ intermediate, and then immerse this intermediate in a solution of 2.505g K ₂ MoO ₄ dissolved in 20ml of distilled water for 6 hours, and then 120 ℃ drying for 3 hours, calcination at 500 ℃ for 4 hours, 0.5 g of the catalyst prepared in this way was evaluated according to the methods of Examples 2 and 3, and the composition and activity evaluation results of the catalyst are shown in Table 1.

Example 10

Ni(Ac) in embodiment 9 ₂ 4H ₂ O is changed into Co(Ac) ₂ 4H ₂ O, all the other are the same as embodiment 9, the catalyst 0.5g prepared in this way is evaluated by the method of embodiment 2 and 3, the catalyst's The composition and activity evaluation results are shown in Table 1.

Example 11

Dilute 10ml of 0.25M Fe(NO ₃ ) ₃ solution with 10ml of distilled water to prepare another concentration of ferric nitrate aqueous solution, then use this solution to impregnate 10.0g of SiO ₂ (80-100 mesh) for 4 hours, at 110°C Dry for 3 hours, then calcinate in a muffle furnace at 550°C for 4 hours to produce Fe ₂ O ₃ /SiO ₂ intermediate; 3.50g of K ₂ CO ₃ dissolved in 20ml of distilled water is used to impregnate the Fe ₂ O ₃ /SiO ₂ prepared in the previous step Intermediate for 4 hours, then dried at 120°C for 4 hours for later use; the next step is to dissolve 3.71g (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O in 25ml of distilled water and impregnate Fe ₂ O ₃ prepared in the first two steps. K ₂ CO ₃ modified Fe ₂ O ₃ /K ₂ CO ₃ /SiO ₂ intermediate for 7 hours, then dried at 110°C for 4 hours, and calcined at 500°C for 3 hours, 0.5g of the catalyst thus prepared according to the methods of Examples 2 and 3 Evaluation is carried out, and the composition and activity evaluation results of the catalyst are shown in Table 2.

Examples 12-14

Change K ₂ CO ₃ in Example 11 to 2.52g KOH, 3.08g KAc, and 3.64g K ₂ C ₂ O ₄ . All the other steps and methods are the same as in Example 11, and each 0.5 g of the catalyst prepared in this way is evaluated according to the method of Examples 2 and 3, and the composition and activity evaluation results of the catalyst are shown in Table 2.

Example 15

Dissolve 0.500g Ce(NO ₃ ) ₃ ·6H ₂ O in 15ml of distilled water to make Ce(NO ₃ ) ₃ aqueous solution, then combine it with 5ml of 0.5M Fe(NO ₃ ) ₃ aqueous solution to form a mixed solution, and then Use this solution to impregnate 10.0g SiO ₂ (80-100 mesh) for 4 hours, dry at 110°C for 3 hours, and then calcinate in a muffle furnace at 550°C for 4 hours to produce Fe ₂ O ₃ /CeO ₂ /SiO ₂ intermediate; the intermediate Immerse with 2.50g K ₂ CO ₃ dissolved in 20ml distilled water for 4 hours, then dry at 120°C for later use; the next step is to immerse with 2.28g (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O dissolved in 25ml distilled water The Fe ₂ O ₃ /CeO ₂ /K ₂ CO ₃ /SiO ₂ carrier modified with Fe ₂ O ₃ , CeO ₂ , and K ₂ CO ₃ prepared in the first two steps was dried for 8 hours at 130°C for 2 hours, then dried at 500°C After calcining for 3 hours, 0.5 g of the catalyst prepared in this way was evaluated according to the methods of Examples 2 and 3. The composition and activity evaluation results of the catalyst are shown in Table 2.

Example 16, 17

Change the 0.500g Ce(NO ₃ ) ₃ .6H ₂ O in Example 15 to 0.500g Ni(Ac) ₂ .4H ₂ O and 0.500g Co(Ac) ₂ .4H ₂ O respectively, and the remaining steps and methods are carried out in the same way Example 15, 0.5 g of the catalyst prepared in this way was evaluated according to the methods of Examples 2 and 3, and the composition and activity evaluation results of the catalyst are shown in Table 2.

Catalyst composition and activity evaluation result of table 1 embodiment 1-10

Catalyst composition and activity evaluation result of table 2 embodiment 11-17

^* Press the evaluation condition evaluation result of embodiment 2

^** According to the evaluation condition evaluation result of embodiment 3

^*** _CO2 does not count towards selectivity

Claims (3)

1, a kind of Mo-O-K of load is catalyst based, and it comprises at least a promoter that is selected from transition metal oxide, the method preparation of described catalyst by may further comprise the steps:

(a) nitrate or the acetate of the metal of chosen from Fe, manganese, cobalt, nickel and/or Ce is soluble in water, make the aqueous solution;

(b) with described aqueous solution impregnation of silica carrier, dip time is 4～6h, dries resulting impregnated carrier 2～4h down at 100～135 ℃;

(c) calcine described infusion product 4～6h down at 500～600 ℃, make intermediate;

(d) use K ₂MoO ₄The aqueous solution floods described intermediate 4～6h, then dries 2～4h down at 110～130 ℃; And

(e) calcine described dry products 3～5h down at 400～550 ℃ at last,

Described catalyst consist of K ₂MoO ₄/ MO _x/ carrier=(0.05～0.80)/(0.01～0.10)/1, wherein MO _xThe oxide of representing the metal of at least a chosen from Fe, manganese, cobalt, nickel and/or Ce.

2. the catalyst of claim 1, wherein said transition metal oxide is CeO ₂

3, a kind of method of in the presence of the catalyst of claim 1 or 2, coming synthesis of methyl mercaptan by the unstripped gas that comprises carbon monoxide and hydrogen sulfide, reaction temperature is 200-350 ℃, pressure is 0.1-2MPa, reaction gas volume air speed (2～5) * 10 ³h ^-1, it is CO that the mole in the unstripped gas is formed: H ₂S=1/ (3～0.1).