SINGLE-STAGE METHOD OF BUTADIENE PRODUCTION

Abstract

The invention relates to a gas-phase synthesis of butadiene from ethanol or from a mixture of ethanol and acetaldehyde. The method of production includes conversion of ethanol or a mixture of ethanol with acetaldehyde in the presence of a catalyst, wherein the reaction is carried out in the presence of a solid catalyst with a mesoporous Zr-containing zeolite having a BEA type structure and at least one metal in a zero oxidation state selected from the group: silver, copper and gold. The claimed method is suitable for carrying out the reaction under continuous flow conditions in the reactor with a fixed bed of catalyst. The invention makes possible to achieve a high yield of butadiene with high selectivity to butadiene and high stability of the catalyst.

Claims

1. A one-stage method for production of butadiene by conversion of ethanol or a mixture of ethanol with acetaldehyde in a gaseous phase in the presence of a solid catalyst, wherein the solid phase catalyst is comprised of a mesoporous Zr-containing zeolite having a BEA type structure and at least one metal in a zero oxidation state selected from the group consisting of silver, copper, gold and combinations of thereof.

2. The method according to claim 1, wherein the mesoporous zeolite having a BEA type structure is prepared by desilylation in an alkaline aqueous solution containing 0.1-0.7 mol/L of a water-soluble base.

3. The method according to claim 1, wherein introduction of Zr into the mesoporous zeolite is carried out by a direct hydrothermal synthesis, or by a post-synthetic modification of the aluminum-containing BEA type zeolite.

4. The method according to claim 1, wherein the mesoporous Zr-containing zeolite is modified by at least one alkali metal.

5. The method according to claim 1, wherein the solid phase catalyst is used with a binder selected from the group consisting of silicon oxide and aluminum oxide.

6. The method according to claim 1, wherein said conversion is carried out in conditions of gas-phase condensation at 200-400 C. under atmospheric pressure and the feed rate of 0.1-15 g/g.Math.h.

7. The method according to claim 1, wherein said conversion is carried out at a weight ratio of acetaldehyde to ethanol in a mixture of (0-3):10, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0027] In general, the claimed method for production of butadiene is carried out as follows.

[0028] Pre-treatment of the catalyst is carried out by its heating up to 300-500 C. in a flow of inert gas (nitrogen) with ramp rate of 500 C/h and dwelling at this temperature for 30 minutes, then the reactor is cooled to the reaction temperature, and the catalyst is reduced in a flow of hydrogen for 30 minutes. Ethanol or a mixture of ethanol and acetaldehyde are fed to the fixed-bed reactor. At the reactor outlet, the obtained products are separated into liquid and gaseous products. The composition of products is determined using gas chromatography. After the reaction, the adsorbed products and reagents are removed by purging with a flow of inert gas and regeneration is carried out in oxygen containing gas. Then the synthesis of butadiene is repeated, starting from the pre-treatment in a flow of dry inert gas at the temperature of 300-500 C.

[0029] Conversion and yield of the target product are calculated as follows:

Conversion (%)=n.sub.but/(n.sub.acet.inc.+n.sub.ethan.inc.).Math.200;

Yield (%)=n.sub.but/(n.sub.acet.tr.+n.sub.ethan.tr.).Math.200; [0030] where n.sub.butis a flow of butadiene, mol/hr; [0031] n.sub.acet.inc., n.sub.ethan.inc.is a flow of incoming acetaldehyde and ethanol, mol/hr; [0032] n.sub.acet.conv.,n.sub.ethan.conv.is a flow of converted acetaldehyde and ethanol, mol/hr.

[0033] Mesoporous Zr-containing zeolites with a BEA type structure used in the claimed method can be prepared according to the following procedures.

[0034] 1st method: Zr-containing BEA type zeolite (ZrBEA) is obtained by hydrothermal crystallization of the 1.0 SiO.sub.2: 0.005-0.01 ZrO.sub.2: 0.56 TEAOH: 6H.sub.2O: 0.56 HF composition gel, where TEA is a tetraethylammonium cation, at 140 C. for 10 days. The zeolite obtained after crystallization is washed with water, dried at 100 C. and calcined at 550 C. for 6 hours. Formation of mesopores is carried out by desilylation of the obtained ZrBEA zeolite by treatment for 2-24 h in 0.2-0.7 M alkaline solution (NaOH, KOH or similar water-soluble base) at room temperature. As a result of the treatment, a mesoporous zeolite catalyst is obtained which retains crystalline structure of the original microporous crystalline silicate.

[0035] 2nd method: Desilylated samples of BEA type zeolite are prepared by stirring of highly crystalline aluminosilicates having BEA type zeolite structure in 0.1-0.7 M alkaline solution (NaOH, KOH or similar water-soluble base) for 3-24 hours at room temperature. The obtained desilylated mesoporous zeolites (deSiAl-BEA) are dealuminated in a solution of nitric acid (70 wt %) at 80 C. for 12 hours until complete removal of aluminium. The resulting zeolite is treated in the solution of ZrOCl.sub.2 in dimethylsulfoxide at the temperature of 130 C. for 12 hours, which leads to the incorporation of Zr atoms into the zeolite framework. As the result, Zr-containing mesoporous zeolite Zr-(BEA) is obtained.

[0036] At the last stage, metals selected from the group of silver, copper, gold are introduced into the mesoporous zeolite catalyst with a BEA type structure obtained by 1st and 2nd methods.

[0037] The important feature of the mesoporous catalysts with a BEA type structure is the presence of two types of pores-micropores, which represent 60-90% of the total pore volume of zeolite, and mesopores formed in the desilylation process, which represent 10-40% of the total pore volume accordingly).

[0038] The following examples illustrate the invention and the obtained result in comparison with known methods for production of butadiene and do not limit the invention.

Example 1

[0039] 20.8 g of tetraethyl orthosilicate are mixed with 11.8 g of tetraethylammonium hydroxide and 7.8 g of water for the hydrolysis at 50 C. with gradual removal of forming ethanol. Then, 0.13 g of zirconyl chloride and 5 g of a 40% aqueous solution of hydrofluoric acid are added with stirring. The resulting gel is transferred to a Teflon-line autoclave and crystallization is carried out at 140 C. for 5 days. The zeolite obtained after crystallization is washed with water, dried at 100 C. and calcined at 550 C. for 6 hours.

[0040] 20 g of the microporous crystalline silicate with BEA type structure SiO2/ZrO2=200 obtained at the previous step are added to 120 ml of a 0.5 mol/L NaOH solution. The resulting suspension is stirred at room temperature for 0.5 hours. After the alkaline treatment, the material is filtered, washed with distilled water, dried at 100 C. for 24 hours, calcined at 550 C. for 24 hours. As the result, the mesoporous catalyst having a BEA type zeolite structure with the pore volume of 0.226 cm.sup.3/g, and the fraction of micropores and mesopores of 0.74 and 0.26, respectively, is synthesized. Then, the catalyst is impregnated according to its wetness capacity with an aqueous solution of silver nitrate until a silver concentration becomes 1% by weight (in terms of metal), dried and calcined at 500 C.

[0041] The resulting catalyst, having a 2Ag-1.5ZrO2-200SiO2 composition, is placed into the reactor, purged with nitrogen at 500 C. for 1 hour, then the temperature is decreased to 320 C. and the catalyst is purged with hydrogen for 0.5 hours. Then the gas flow is switched to nitrogen (10 ml/min) and ethanol is fed with the rate of 1.2 g/hr. The reaction is carried out for 3 hours. At the reactor outlet butadiene with an ethanol conversion of 42% and a yield of butadiene on the converted ethanol of 73% is obtained.

[0042] Unreacted ethanol is recycled. The results of the experiment are presented in Table 1.

Example 2

[0043] The process is carried out as described in the example 1 with process parameters measured after 100 hours in the stream. Parameters of the process are shown in Table 1.

Example 3 (Comparative)

[0044] The process is carried out as described in the example 1 with the catalyst based on zirconium oxide and silver supported on silica gel I and synthesized is according to the RU 2440962 prototype. Parameters of the process are shown in Table 1.

Example 4 (Comparative)

[0045] The process is carried out as described in the example 3 with the process parameters measured after 100 hours in the stream. Parameters of the process are shown in Table 1.

[0046] The analysis of the results obtained in examples 1-4 shows the advantages of the proposed method for production of butadiene from ethanol in comparison with the known methods. High conversion and yield of butadiene are not provided when using the known catalysts. High ethanol conversion, high butadiene yield and high stability of catalyst are achieved when catalysts containing mesoporous zeolite materials and the declared metals are used.

Example 5

[0047] 20 g of zeolite BEA type with SiO.sub.2/Al.sub.2O.sub.3=75 are added to 120 ml of 0.7 mol/L solution of NaOH. The obtained suspension is stirred at room temperature for 0.5 hours. Then, the material is filtered, washed with distilled water, dried at 100 C. for 24 hours, calcined at 550 C. for 24 hours. As the result, a mesoporous catalyst having a BEA type zeolite structure is obtained with the pore volume of 0.45 cm.sup.3/g, and the micropores and mesopores-fraction of 0.60 and 0.40, respectively.

[0048] 10 g of the obtained desilylated microporous crystalline aluminosilicate having BEA type structure with SiO2/Al.sub.2O.sub.3=3000 are added to 250 ml of nitric acid (65 wt %). The obtained mixture is heated at 80 C. for 12 hours. The obtained dealuminated zeolite is filtered, washed by water and dried.

[0049] 5 g of the obtained mesoporous dealuminated zeolite BEA type with SiO2/Al2O3=3000 are added to a solution of 20 g of ZrOC12 in 200 ml of dimethyl sulfoxide. The mixture is heated at 130 C. for 12 hours. Then the catalyst is filtered, washed with water, dried and calcined at a temperature of 500 C. that the resulting powder is impregnated according to its wetness capacity with an aqueous solution of silver nitrate to achieve silver loading of 1 wt %, dried and calcined at 500 C.

[0050] Testing of the obtained catalyst having 30Ag-70ZrO.sub.2Al.sub.2O.sub.3-3000SiO.sub.2 composition is carried out as described in the example 1.

Example 6

[0051] The process is carried out as described in the example 1 over the catalyst doped with sodium corresponding to the composition of 30Ag-70ZrO.sub.2Al.sub.2O.sub.3-5Na.sub.2O-3000SiO.sub.2. The process is carried out with the addition of acetaldehyde into the feed with the ratio acetaldehyde/ethanol=1/10. Parameters of the process are shown in Table 1.

[0052] in further examples, a possibility to carry out the processes with different catalysts from the declared under different process conditions is shown.

Example 7

[0053] The process is carried out as described in the example 1 over the catalyst containing copper instead of silver and addition of acetaldehyde into the feed with the ratio acetaldehyde/ethanol 1/10. Parameters of the process are shown in Table 1.

Example 8

[0054] The process is carried out as described in the example 5 over the catalyst containing gold instead of copper. Parameters of the process are shown in Table 1.

Example 9

[0055] The process is carried out as described in the example 1 with the addition of acetaldehyde with the ratio acetaldehyde/ethanol=1/10. Parameters of the process are shown in Table 1.

[0056] Examples 10-14 illustrate the possibility to use the method for production of butadiene in a wide range of process conditions.

Example 15

[0057] The process is carried out as described in the example lover the catalyst with a binder (aluminum oxide). Parameters of the process are shown in Table 1.

Example 16

[0058] The process is carried out as shown in the example 1 over the catalyst with a binder (silicon oxide). Parameters of the process are shown in Table 1.

Example 17

[0059] The process is carried out as described in the example 9 over the catalyst regenerated in a flow of air at 450 C. Parameters of the process are shown in Table 1.

[0060] Thus, the presented above examples show the production of butadiene in one step process achieving high ethanol conversion and high yield of butadiene with the stable operation of the catalyst.

[0061] Although this invention has been described in detail in the examples under preferred conditions, these examples of the invention are provided only for illustrative purposes. This description should not be regarded as limiting the scope of the invention, since changes not going beyond the scope of the formula of invention and directed to the adaptation to specific conditions or situations can be made to the described process stages. Variations and modifications, including equivalent solutions, defined by the claims are possible within the scope of the invention.

TABLE-US-00001 TABLE 1 Results Yield of Conditions butadiene Weight in terms of hourly the No Composition of space Duration converted of the the catalyst (by Temperature velocity, Acetaldehyde/ of the Conversion, reagents, example weight) C. g/g .Math. h ethanol experiment, h % mol. % 1. 2Ag-1,5ZrO.sub.2- 320 0.3 0 3 42 73 200SiO.sub.2 2 2Ag-1,5ZrO.sub.2- 320 0.3 0 100 42 73 200SiO.sub.2 3 1Ag-12ZrO.sub.2- 320 0.3 0 3 34 72 300SiO.sub.2 4 1Ag-12ZrO.sub.2- 320 0.3 0 100 29 71 300SiO.sub.2 5 30Ag-70ZrO.sub.2- 320 0.3 0 3 66 56 Al.sub.2O.sub.3-3000SiO.sub.2 6 30Ag-70ZrO.sub.2- 320 0.3 0 3 52 75 Al.sub.2O.sub.3-5Na.sub.2O- 3000SiO.sub.2 7 2Cu-1,5ZrO.sub.2- 320 0.3 1/10 3 69 34 200SiO.sub.2 8 2Au-1,5ZrO.sub.2- 320 0.3 1/10 3 46 73 200SiO.sub.2 9 2Ag-1,5ZrO.sub.2- 320 0.3 1/10 3 53 73 200SiO.sub.2 10 2Ag-1,5ZrO.sub.2- 200 0.3 1/10 3 5 55 200SiO.sub.2 11 2Ag-1,5ZrO.sub.2- 400 0.3 1/10 3 98 35 200SiO.sub.2 12 2Ag-1,5ZrO.sub.2- 320 0.1 1/10 3 78 60 200SiO.sub.2 13 2Ag-1,5ZrO.sub.2- 320 15 1/10 3 14 64 200SiO.sub.2 14 2Ag-1,5ZrO.sub.2- 320 0.3 3/10 3 75 55 200SiO.sub.2 15 2Ag-1,5ZrO.sub.2- 320 0.3 1/10 3 100 2 100Al.sub.2O.sub.3- 200SiO.sub.2 16 2Ag-1,5ZrO.sub.2- 320 0.3 1/10 3 48 72 300SiO.sub.2 17 2Ag-1,5ZrO.sub.2- 320 0.3 1/10 3 53 73 200SiO.sub.2