CN103949268B - The synthesis copper Mn catalyst of methyl formate and method for making and application - Google Patents

Abstract

A copper-manganese catalyst for synthesizing methyl formate includes two types. Catalyst 1 is composed of copper-manganese oxide, and the molar ratio of each component is Cu:Mn=1:0.5-2 in terms of metal; catalyst 2 is composed of mesoporous The composition of ZrO ₂ -CaO or ZrO ₂ -MgO solid base is calculated as metal, and the molar ratio of each component is Zr:Ca or Mg=1:0.1-1.0, and the optimum value is 1:0.5-1.0. The invention has the advantages of good tolerance to water and carbon dioxide and high catalytic performance.

Description

Copper-manganese catalyst for synthesizing methyl formate and its preparation method and application

technical field

The invention belongs to a catalyst, a preparation method and an application, and in particular relates to a copper-manganese catalyst for synthesizing methyl formate, a preparation method and an application.

Background technique

As an emerging field of C1 chemistry, methyl formate (MeF) has the following advantages: (1) it can be produced economically and efficiently on a large scale; (2) it has a suitable boiling point (31.5 °C), and it is a liquid at room temperature, which is convenient for handling, storage and storage. Transportation; (3) There are many downstream products, especially large-tonnage products. In addition, methyl formate is used as the basic structural unit of C1 chemistry due to its high reactivity. Methyl formate can be used as an intermediate to derive more than 50 reactions, and many downstream chemical products can be synthesized, such as dimethyl carbonate. , ethylene glycol and diphosgene, and can also be used as insecticides, fungicides for cereal crops, fumigants and tobacco treatment agents. In addition, methyl formate can be derived into formic acid, dimethylformamide, acetic acid and high-purity CO through hydrolysis, ammonolysis, rearrangement and thermal decomposition.

At present, the methods for synthesizing methyl formate in the world mainly include: (1) Formic esterification method, formic esterification method is the earliest method for producing methyl formate. Due to its high cost and serious corrosion of equipment, it has long been eliminated abroad; (2) Formaldehyde dimerization method, this reaction is an intermolecular redox reaction, the catalytic reaction requires acid and alkali active centers, and the practicability is not strong; (3) The hydrogenation condensation method of methanol and carbon dioxide, this method is mainly used in the last century to reduce developed for the emission of greenhouse gases, but the yield of methyl formate is low, and the conversion rate of CO ₂ is only 3.8%-7.3%; (4) Methanol dehydrogenation method, which is a reaction limited by thermodynamic equilibrium, and its The rate is difficult to break through 50%. At present, there is no effective technical measure to break the limitation of this balance in the process. The activity and selectivity of the catalyst used are still low, so the application is limited; (5) Methanol carbonylation method, which is currently the The more advanced MeF production method has a lower cost. Using sodium methoxide as a catalyst, at a reaction temperature of 80°C and a pressure of 4-6MPa, the conversion rates of CO and methanol can reach 95% and 30%, respectively, and the selectivity of MeF is close to 100. %. However, this process has two major disadvantages: a) the catalyst is sensitive to moisture and CO ₂ , b) CO concentrations higher than 80% must be used; (6) direct syngas synthesis, the one-step synthesis of MeF from syngas is an efficient atomic The economical reaction is currently the most advanced MeF production method recognized in the world, conforms to the principle of low-carbon energy utilization technology advocated internationally, and is a true "zero emission" reaction. Therefore, the direct synthesis of MeF from syngas is extremely reasonable in terms of energy utilization and is one of the most promising technical routes.

In the research on the method of synthesizing methyl formate by one-step method of synthesis gas, the most researched at present is the synthesis of methyl formate in low temperature liquid phase. Patent US5384335 uses CO and _H2 to synthesize methanol and methyl formate in a catalytic system composed of Cu-Cr catalyst and alkali metal or alkaline earth metal compound, the reaction temperature is 100-160 ° C, the reaction pressure is 4.0-6.5 MPa, The patent mentions that the synthesis gas conversion rate is as high as 95%. Patent US4731386 also reports the one-step synthesis of methanol and methyl formate in low-temperature liquid phase with synthesis gas, and the catalysts used in this patent are alkyl salts of alkali metals or alkaline earth metals and copper catalysts. In addition, patents CN1050116 and CN1074305 have also reported the use of _CO and H in a copper chromium catalyst and sodium methylate system in a low-temperature liquid-phase synthesis of methyl formate. However, in these previous patents, the catalysts used alkali metal or alkaline earth metal alkoxides. These alkoxides are deactivated under the action of by-product water and carbon dioxide, and the overall performance of the catalyst is poor, requiring the addition of a co-catalyst. The bottleneck of the process development.

Contents of the invention

The present invention overcomes the problems existing in the above-mentioned catalytic system, develops a catalyst and a preparation method with good tolerance to water and carbon dioxide and high catalytic performance, and is used for the reaction of directly synthesizing methyl formate with _CO and H in a low-temperature liquid phase .

The catalyst of the present invention includes two kinds. Catalyst 1 is composed of copper-manganese oxide, and the molar ratio of each component is Cu:Mn=1:0.5-2 in terms of metal; catalyst 2 is composed of mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base composition, calculated as metal, the molar ratio of each component is Zr:Ca or Mg=1:0.1-1.0, the best value is 1:0.5-1.0.

The copper-manganese oxide catalyst preparation method provided by the invention comprises the following steps:

(1) According to the Cu:Mn molar ratio of 1:0.5-2, drop the 0.5-2mol/L manganese nitrate solution with pH=3-5 into the copper ammonia complex solution with pH=10-12 under vigorous stirring middle;

(2) Use concentrated nitric acid to adjust the pH of the solution to 5.5-7.5, keep the temperature between 30-50°C, and age for 2-9 hours;

(3) Filtrate, wash, dry at 100-120°C for 10-20h, and roast at 500-600°C for 2-6h to obtain the desired Cu-Mn oxide.

The preparation method of mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst provided by the present invention comprises the following steps:

(1) Dissolve the non-ionic template agent P123 (polyoxyethylene-polyoxypropylene-polyoxyethylene) in 3/5 of the total volume of absolute ethanol, and add calcium nitrate or magnesium nitrate after dissolving to form solution A;

(2) Add zirconium propoxide and acetylacetone to 2/5 of the total volume of absolute ethanol to form solution B;

(3) Add solution B to solution A, then add deionized water, and stir for 1-2 hours;

(4) After crystallization at 40-80°C for 12-48h, add 8-12L NaOH solution per 1mol Zr, reflux in 0.05-0.5mol/L NaOH solution for 24-48h, filter and wash, 60-120 After drying for 12-24 hours at ℃, calcining at 500-700℃ for 4-6 hours to obtain ZrO ₂ -CaO or ZrO ₂ -MgO;

The molar ratio of each additive in the catalyst preparation process is composed of Zr:P123:M: absolute ethanol: acetylacetone: H ₂ O=1:0.01-0.05:0.1-1.0:40-200:0.1-1.0:5-20 .

In the present invention, copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalysts catalyze CO and H ₂ to synthesize methyl formate in one step in a slurry bed reactor.

Catalyst of the present invention reacts used condition in slurry bed reactor:

(1) Activation conditions:

Catalyst 1: Copper-manganese oxide catalyst is activated with 5-10% H ₂ /N ₂ (volume fraction) at normal pressure and 200-300°C for 5-10 hours before the reaction, Passivation under %O ₂ /Ar (volume fraction) atmosphere for 2-8h;

Catalyst 2: ZrO ₂ -CaO or ZrO ₂ -MgO solid base is pretreated in N ₂ at 500-700°C for 1-4h.

(2) Reaction conditions: reaction temperature T=80-180°C, pressure 4.0-8.0MPa, gas volume space velocity 500-2000mL/h/g.cat, H ₂ /CO (molar ratio)=1.0-3.0; The relationship between catalyst 1 and solvent is (Cu-Mn): solvent = 5-20g: 1L, the relationship between catalyst 2 and solvent is ZrO ₂ -CaO or ZrO ₂ -MgO: solvent = 10-40g: 1L; the solvent used is alcohol A mixture with an aprotic organic solvent, the volume ratio of aprotic organic solvent: alcohol = 1-3, the alcohols can be methanol, ethanol, propanol, etc., and the aprotic organic solvent can be N, N dimethyl Methyl formamide (DMF), xylene, diphenyl ether, tetraethylene glycol dimethyl ether.

Compared with the prior art, the present invention has the following characteristics:

(1) The catalyst of the present invention has large specific surface area, strong alkalinity, good stability and long service life;

(2) Since the use of co-catalysts that are easily poisoned by CO ₂ and water is avoided, there is no poisoning problem, the catalyst can be directly activated and used, it is very easy to operate, and the catalyst can tolerate higher concentrations of CO ₂ and H ₂ O;

(3) The catalyst prepared by the present invention is used to synthesize methyl formate from syngas, with mild reaction conditions, strong adaptability and good performance;

(4) The by-products of the catalyst of the present invention in syngas one-step synthesis of methyl formate are methanol and ethanol, which are easily separated from the main product.

detailed description

Example 1:

Weigh 6.96g of P123 and dissolve it in 167.95mL of absolute ethanol, and add 10.63g of calcium nitrate after it is completely dissolved to form solution A; in addition, weigh 28.08g of zirconium propoxide (propanol solution, content 70wt.%) and 3.00mL of acetylacetone Add to 111.97mL of absolute ethanol to make solution B; add solution B to solution A, stir for 0.5h, add 10.80mL of deionized water, stir for 1h, and form a milky white gel; the resulting gel crystallizes at 80°C After 36h, reflux in 640mL of 0.1mol/L NaOH solution for 24h, filter, wash, dry at 80°C for 12h, and then roast at 600°C for 5h to obtain ZrO ₂ -CaO solid base, which is recorded as CatA, and the molar ratio of each component in CatA is Zr:Ca=1:0.75. The molar ratio of each additive in the preparation process is P123: Ca: absolute ethanol: zirconium propoxide: acetylacetone: deionized water = 0.02:0.75:80:1:0.5:10.

In the above steps, when the calcium nitrate added is replaced by magnesium nitrate, when the magnesium nitrate addition is 11.54g, ZrO2 _- MgO solid base is obtained, which is denoted as CatB, and the molar ratio of each component in CatB is Zr:Mg=1: 0.75.

Weigh 24.16g of Cu(NO ₃ ) ₂ .3H ₂ O solution in 100mL of deionized water, then adjust the pH of the solution to 10 with ammonia water, stir for 30min, and record it as solution A; weigh 35.79g of Mn(NO ₃ ) ₂ .4H ₂ O ( 50% aqueous solution) solution 75mL deionized water to make a 1moL/L solution, then use concentrated nitric acid to adjust pH=3, record it as solution B, then add solution B dropwise to solution A under vigorous stirring, and then use concentrated nitric acid Adjust the pH to 5.5, keep the temperature at 30°C, and age for 5 hours. Then the solution was filtered, washed, dried at 100°C for 15 hours, and calcined at 550°C for 4 hours to obtain a black powder, which was the Cu-Mn oxide catalyst, namely CatC, and the molar ratio of the components in CatC was Cu:Mn=1.

The one-step synthesis of methyl formate from synthesis gas was carried out in a 250mL magnetically stirred stainless steel reactor. Before the reaction, CatC was first activated with 5%H ₂ /N ₂ (volume fraction) at normal pressure and 200°C for 10h, and then passivated for 4h under 2%O ₂ /Ar (volume fraction) atmosphere after cooling down to room temperature; CatA Or CatB pretreatment in N ₂ at 600°C for 2h. Put the pretreated CatA and CatC catalysts or the pretreated CatB and CatC catalysts into the reactor, and then add xylene and methanol solvents to react, and investigate the two solids of ZrO ₂ -CaO or ZrO ₂ -MgO The effect of bases on the performance of catalytic reactions. The relationship between the catalyst and the solvent is CatA: solvent = 20.0g: 1L or CatB: solvent = 20.0g: 1L, CatC: solvent = 10.0g: 1L, and the total amount of solvent used is 100mL. Among them, V (xylene): V (methanol)=1.5, magnetic stirring speed r=1000r/min, pressure P=5.0MPa, temperature T=160℃, reaction time t=24h, space velocity MHSV=1000mL/h/g .cat, H ₂ /CO (molar ratio) = 2, the product after the reaction was analyzed by gas chromatography, and the analysis results are shown in Table 1.

Table 1 Catalytic Reaction Performance of Different Solid Bases

Example 2:

This example illustrates the influence of the solvent used on the catalytic performance when copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst catalyze CO and H ₂ to synthesize methyl formate in one step in a slurry bed reactor, The copper-manganese oxide catalyst is CatC, and the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst is CatA. Just change the amount of xylene and methanol in the solvent, and all the other reaction conditions are the same as in Example 1. The effect of xylene and methanol amount on catalytic performance is shown in Table 2.

The influence of table 2 solvent amount on catalytic performance

Example 3:

This example clarifies the effect of reaction temperature on the catalytic performance when copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst catalyze the synthesis of methyl formate from CO and H ₂ in a slurry bed reactor. The copper-manganese oxide catalyst is CatC, and the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst is CatA. Just change the temperature during reaction, all the other reaction conditions are with embodiment 1. The effect of reaction temperature on catalytic performance is shown in Table 3.

The influence of table 3 temperature on reaction performance

Example 4:

This example illustrates the influence of the solvent used on the catalytic performance when copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst catalyze CO and H ₂ to synthesize methyl formate in one step in a slurry bed reactor, The copper-manganese oxide catalyst is CatC, and the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst is CatA. Just change the pressure during reaction, all the other reaction conditions are with embodiment 1. The effect of reaction pressure on catalytic performance is shown in Table 4.

The impact of table 4 pressure on reaction performance

Example 5:

This example illustrates that when copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst catalyze CO and H ₂ to synthesize methyl formate in one step in a slurry bed reactor, copper-manganese oxide in solvent The influence of the amount on the catalytic performance, the copper-manganese oxide catalyst is CatC, and the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst is CatA. Just change the amount of copper-manganese oxide catalyst in the solvent, all the other reaction conditions are the same as embodiment 1. The effect of the amount of CatC in the solvent on the catalytic performance is shown in Table 5.

Table 5 The influence of the amount of catalyst in the solvent on the reaction performance

Embodiment 6:

This example clarifies the catalytic performance of hydrogen-carbon ratio of raw material gas when copper-manganese oxide and mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst catalyze the synthesis of methyl formate from CO and H ₂ in a slurry bed reactor The copper-manganese oxide catalyst is CatC, and the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst is CatA. Just change the hydrogen-to-carbon ratio of the feed gas used in the reaction, and all the other reaction conditions are the same as in Example 1. See Table 6 for the effect of feed gas hydrogen to carbon ratio on the catalytic performance.

Table 6 Effect of different H ₂ /CO on reaction performance

Embodiment 7:

The specific preparation process of the mesoporous ZrO ₂ -CaO or ZrO ₂ -MgO solid base catalyst in this example is according to Example 1, only the amount of calcium nitrate added in the preparation process is changed. When the amount of calcium nitrate added is 7.08g, each step in the preparation process The molar ratio of the additives is P123: Ca: absolute ethanol: zirconium propoxide: acetylacetone: deionized water = 0.02: 0.5: 80: 1: 0.5: 10, and the molar ratio in the obtained solid base is Zr: Ca = 1: 0.5 , The resulting solid base catalyst is denoted as CatD.

When the amount of calcium nitrate added in the above steps is 14.16g, the molar ratio Zr:Ca=1:1 in the obtained solid base, and the obtained solid base catalyst is denoted as CatE.

The one-step synthesis of methyl formate from synthesis gas was carried out in a 250mL magnetically stirred stainless steel reactor. Before the reaction, CatB was activated with 8%H ₂ /N ₂ (volume fraction) in a tube furnace at normal pressure and 280°C for 6h, and after cooling down to room temperature, it was passivated under 1%O ₂ /Ar (volume fraction) atmosphere for 8h ; CatA, CatD and CatE were pretreated in N ₂ at 500°C for 4h. Put pretreated CatA and CatC, CatD and CatC or CatE and CatC catalysts into the reactor, and then add tetraethylene glycol dimethyl ether and methanol solvent for reaction. The relationship between catalyst and solvent is CatA: solvent=30.0g:1L, CatD: solvent=30.0g:1L or CatE: solvent=30.0g:1L, CatC: solvent=5.0g:1L, the total amount of solvent used is 100mL, where V(tetraethylene glycol dimethyl ether): V(methanol)=2, magnetic stirring speed r=1000r/min, pressure P=6.0MPa, temperature T=160℃, reaction time t=24h, space velocity MHSV=2000mL /h/g.cat, H ₂ /CO (molar ratio) = 2.0, the product after the reaction was analyzed by gas chromatography. The influence of different component contents in the ZrO ₂ -CaO catalyst on the catalytic performance was investigated, and the specific analysis results are shown in Table 7.

Table 7 Effect of different Zr/Ca on reaction performance

Embodiment 8:

Weigh 24.16g Cu(NO ₃ ) ₂ .3H ₂ O solution in 100mL deionized water, then adjust the pH of the solution to 11 with ammonia water, stir for 30 minutes, and record it as solution A; weigh 17.89g Mn(NO ₃ ) ₂ .4H ₂ O ( 50% aqueous solution) solution 75mL deionized water to make a 1moL/L solution, then use concentrated nitric acid to adjust pH=4, record it as solution B, then add solution B dropwise to solution A under vigorous stirring, and then use concentrated nitric acid Adjust the pH to 6.5, keep the temperature at 50°C, and age for 5 hours. Then the solution was filtered, washed, dried at 110°C for 12h, and calcined at 550°C for 4h to obtain a black powder, which was the Cu-Mn oxide catalyst, which was CatF, and the molar ratio of the components in CatF was Cu:Mn=1:0.5 .

When the amount of Mn(NO ₃ ) ₂ .4H ₂ O (50% aqueous solution) added in the above steps is 71.58g, the molar ratio of Cu-Mn oxide components is Cu:Mn=1:2, denoted as CatG.

Example 6 1914 1652 1.14 0.93 81.5 2.6 Example 7 1527 1323 0.75 0.66 88 2.2 Example 8 1817 1552 1.01 0.82 81.1 2.0 Example 9 2141 1620 1.21 0.91 75.1 2.65

Claims (8)

1. synthesize a copper Mn catalyst for methyl formate, it is characterized in that catalyst is made up of catalyst 1 and catalyst 2, catalyst 1 is made up of copper-Mn oxide, and in metal, each component molar is than being Cu:Mn=1:0.5-2; Catalyst 2 is by mesoporous ZrO ₂-CaO or ZrO ₂-MgO solid base forms, and in metal, each component molar ratio is respectively Zr:Ca or Mg=1:0.1-1.0.

2. a kind of copper Mn catalyst synthesizing methyl formate as claimed in claim 1, is characterized in that catalyst 2 is by mesoporous ZrO ₂-CaO or ZrO ₂-MgO solid base forms, and in metal, each component molar ratio is respectively Zr:Ca or Mg=1:0.5-1.0.

3. a kind of copper Mn catalyst synthesizing methyl formate as claimed in claim 1 or 2, is characterized in that described catalyst 1 bronze medal-manganese oxide catalyst preparation method comprises the following steps:

(1) be 1:0.5-2 by Cu:Mn mol ratio, with vigorous stirring by the cupric ammine complex solution of the manganese nitrate solution of the 0.5-2mol/L of pH=3-5 instillation pH=10-12;

(2) pH value of solution=5.5-7.5 is regulated with red fuming nitric acid (RFNA), between temperature keeps 30 ~ 50 DEG C, aging 2-9h;

(3) filter, washing, dry 10-20h at 100-120 DEG C, at 500-600 DEG C of roasting 2-6h, obtains required Cu-Mn oxide.

4. a kind of copper Mn catalyst synthesizing methyl formate as claimed in claim 1 or 2, is characterized in that the mesoporous ZrO of described catalyst 2 ₂-CaO or ZrO ₂-MgO solid base catalyst is preparation method comprise the following steps:

(1) nonionic template P123 is dissolved in 3/5 of absolute ethyl alcohol cumulative volume, after dissolving, adds calcium nitrate or magnesium nitrate, form solution A;

(2) propyl alcohol zirconium and acetylacetone,2,4-pentanedione are joined wiring solution-forming B in 2/5 of absolute ethyl alcohol cumulative volume;

(3) solution B is added in solution A, then add deionized water, stir 1-2h;

(4) at 40-80 DEG C, after crystallization 12-48h, add the amount of 8-12LNaOH solution by every 1molZr, reflux 24-48h in the NaOH solution of 0.05-0.5mol/L, filter, washing, after 60-120 DEG C of dry 12-24h at 500-700 DEG C roasting 4-6h, obtain ZrO ₂-CaO or ZrO ₂-MgO;

Wherein in catalyst preparation process, each additive mol ratio consists of Zr:P123:Ca or Mg: absolute ethyl alcohol: acetylacetone,2,4-pentanedione: H ₂o=1:0.01-0.05:0.1-1.0:40-200:0.1-1.0:5-20.

5. a kind of application of synthesizing the copper Mn catalyst of methyl formate as described in any one of claim 1-4, is characterized in that copper-Mn oxide and mesoporous ZrO ₂-CaO or ZrO ₂-MgO solid base catalyst catalysis CO and H ₂one-step synthesis methyl formate carries out in paste state bed reactor;

(1) activation condition:

Catalyst 1: copper-manganese oxide catalyst first uses 5-10v%H before the reaction ₂/ N ₂under normal pressure, 200-300 DEG C condition, activate 5-10h, be down to after room temperature at 1-2v%O ₂passivation 2-8h under/Ar atmosphere;

Catalyst 2:ZrO ₂-CaO or ZrO ₂-MgO solid base is at N ₂middle 500-700 DEG C of pretreatment 1-4h;

(2) reaction condition:

Reaction temperature T=80-180 DEG C, pressure 4.0-8.0MPa, gas volume air speed 500-2000mL/h/g.cat, H ₂/ CO mol ratio=1.0-3.0; It is catalyst 1 that reaction used catalyst 1 closes with solvent: solvent=5-20g:1L, and it is ZrO that catalyst 2 and solvent close ₂-CaO or ZrO ₂-MgO: solvent=10-40g:1L.

6. a kind of application of synthesizing the copper Mn catalyst of methyl formate as claimed in claim 5, is characterized in that solvent for use is the mixture of alcohols material and non-proton organic solvent, non-proton organic solvent: the volume ratio=1-3 of alcohol.

7. a kind of application of synthesizing the copper Mn catalyst of methyl formate as claimed in claim 6, is characterized in that described alcohols is methyl alcohol, ethanol or propyl alcohol.

8. a kind of application of synthesizing the copper Mn catalyst of methyl formate as claimed in claim 6, is characterized in that described non-proton organic solvent is DMF, dimethylbenzene, diphenyl ether or tetraethyleneglycol dimethyl ether.