CN1123389C - Preparation of catalyst for preparing low-carbon alcohol by low-carbon oleffine hydration and its application - Google Patents

Abstract

A catalyst for preparing low-carbon alcohols by hydration of low-carbon olefins is characterized in that: the catalyst is composed of modified β molecular sieves and binders, and the modifying elements are selected from La, B, Fe, Ge, Ni, Cr, Co, At least one of Cu, Mg, Ca, Sr, Ge, the binder is selected from one of silica sol, water glass, aluminum hydroxide, boehmite, kaolin, zirconium hydroxide, titanium oxide, clay; catalyst The composition is (percentage by weight): 1-5% of modifying elements, 40-80% of beta zeolite molecular sieve, and the balance of binder. The invention has no requirement on the purity of the raw materials, has good low-temperature activity, long single-pass life, and can be regenerated repeatedly.

Description

Preparation and Application of Catalyst for Low-carbon Alcohols by Hydration of Low-carbon Olefins

The invention relates to catalytic technology, and in particular provides a catalyst for producing low-carbon alcohols by hydration of low-carbon olefins, and its preparation and application.

Olefin hydration is one of the most important organocatalytic reactions. Among the hydration reactions, the most representative and practical one is the hydration of alkenes to prepare alcohols. For example, ethanol, isopropanol, and sec-butanol are widely used as important organic chemical raw materials and solvents. Ethanol can be used to make dyes, paints, drugs, synthetic rubber, and detergents. Isopropanol can be used not only for the synthesis of glycerin and acetone, but also for the synthesis of fine products such as pesticides and spices. Second-butanol is mostly used as methyl ethyl ketone, or as a raw material for plasticizers, herbicides, and mineral dressing agents.

The hydration of the above-mentioned olefins to produce the corresponding alcohols, the traditional industrial method is the indirect hydration method of sulfuric acid, which has been gradually replaced by the catalytic direct hydration method due to its strong corrosion effect on equipment and problems such as waste acid treatment. The direct hydration of ethylene is the latest method adopted in the industry at present. This method requires high purity of ethylene. Due to the mature development of the ethylene industry, it is not difficult to provide high-purity ethylene. This method uses phosphoric acid/carrier as a catalyst, and the corrosion of the equipment is much lighter than that of the indirect method. Although the single-pass conversion rate of ethylene is low, only about 5%, the process is mature and can adapt to the requirements of large-scale and modernization, and the labor productivity is high. Production The cost is also lower than the sulfuric acid indirect method. The industrial production of isopropanol is widely used at present by using phosphoric acid/diatomaceous earth as a catalyst and reacting propylene with water at 180-260°C and 2.5-6.5 MPa. The production process of direct hydration of n-butene is a butene-butane mixture containing 80-85% n-butene. After preheating with water to the reaction temperature, it is added from the bottom of the tank reactor for direct hydration. When the reaction temperature of butene is 150-170°C and 6.0 MPa, the conversion rate per pass is about 6%, and the conversion rate in circulation reaches 90%.

Zeolite molecular sieve catalyst is an excellent solid acid without acid loss. Due to its unique properties, it is of great significance in petrochemical industry. In order to overcome the shortcomings of the above-mentioned catalysts, researchers have devoted themselves to developing zeolite catalysts for hydration of low-carbon olefins in recent years. There are many types of zeolites studied, such as Y-zeolite, β-zeolite, γ-zeolite, X-zeolite, ultra-stable Y-zeolite (USY), dealuminated Y-zeolite, mordenite, ZSM series.

There are many foreign research reports on zeolite molecular sieve catalysts used in olefin hydration, such as US4857664, 4727977, 5012014, European patents EP210793, 1986, EP323268, 1988, EP323137, 1989, EP458048, 1991. It is shown from the above documents that among the zeolites used in the preparation of isopropanol/isopropyl ether by hydration of propylene, beta zeolite has the best effect. ZSM-5 zeolite has a good effect on hydration of ethylene, and the conversion rate and selectivity of ZSM series are very high for the hydration of n-butene to sec-butanol.

The purpose of the present invention is to provide a catalyst for producing low-carbon alcohols by hydration of low-carbon olefins, which has no requirement on the purity of raw materials, has good low-temperature activity, long single-pass life, and can be regenerated repeatedly.

The invention provides a catalyst for producing low-carbon alcohols by hydration of low-carbon olefins, which is characterized in that: the catalyst is composed of modified β molecular sieve and binder, and the modifying elements are selected from La, B, Fe, Ge, Ni, At least one of Cr, Co, Cu, Mg, Ca, Sr, Ge, the binder is selected from silica sol, water glass, aluminum hydroxide, boehmite, kaolin, zirconium hydroxide, titanium oxide, clay A kind; Catalyst consists of (be weight percent in the present invention except special specification)

Modified element 1～5%

Beta zeolite molecular sieve 40～80%

Binder Balance

In the present invention, the modifying elements preferably account for 2-4%. Beta zeolite molecular sieve preferably accounts for 50-70%.

The present invention also provides a method for preparing the above-mentioned low-carbon olefin hydration catalyst for producing low-carbon alcohol, which is characterized in that: the modification of the β molecular sieve is carried out by ion exchange or impregnation, and then mixed with a binder, a pore-forming agent and a diluent to form; The pore-forming agent is selected from squash powder and hydroxymethyl cellulose, and the addition amount is 1-10% of the catalyst amount; the diluent is selected from water and dilute HNO ₃ , and the addition amount is suitable for forming.

Among them, the diluent is preferably 0.5N HNO ₃ solution.

The present invention is applicable to hydration of ethylene, propylene, 1-butene, cis, trans-2-butene and isobutene to produce ethanol, isopropanol, sec-butanol and tert-butanol.

The present invention adopts modified β zeolite molecular sieve as the catalyst for hydration of propylene to prepare isopropanol. The propylene involved can be polymerized, or dilute propylene such as a mixture of propylene and propane, or propylene in catalytic cracking, without special purification. deal with.

The invention adopts modified ZSM-5 zeolite as a catalyst for hydrating ethylene to produce ethanol and n-butene to produce sec-butanol. The raw materials used can be pure ethylene, pure n-butene-1, dilute ethylene and n-butene-1.

The present invention is described in detail below by way of examples.

Example 1

Weigh 100g of β zeolite raw powder (Si/Al=27), roast at 350°C for 2 hours, and at 550°C for 2 hours, burn off the phase-conducting agent tetraethylammonium hydroxide, and then use 1N NH ₄ NO ₃ solution at 85 Exchanged four times under the condition of ℃, the solid-liquid ratio was 1:10. Finally, it was washed four times with deionized water, dried in air, baked at 120°C for 12 hours, and calcined at 500°C for 4 hours to convert Naβ into Hβ molecular sieve for future use. Sample A is obtained.

Example 2

From sample A, take out 10 grams of H-type molecular sieve powder, 4.3 g of industrial aluminum hydroxide and 0.15 g of scallop powder with 1N HNO ₃ to make a paste, and use an extruder to extrude strips with a diameter of about Φ2 mm, and dry them in air. Baked at 120°C for 12 hours, and then baked at 500°C for 4 hours to obtain catalyst B.

Example 3

Take 10g of sample A, 0.5g of nickel nitrate, 4g of Al(OH) ₃ , 0.12g of turnip powder, make a paste with 0.5N HNO ₃ , extrude into strips with a diameter of 2mm, dry in the air, and dry at 120°C for 12 hours , Calcined at 500°C for 4 hours to obtain catalyst C.

Example 4

Adopt the same method of example 3, just change nickel nitrate into lanthanum nitrate, make catalyst D.

Example 5

Take 3 grams of catalyst B, crush it to 20-40 meshes, impregnate it with 4ml of dilute H ₃ BO ₃ solution (containing 0.06 g of B ₂ O ₃ ), dry it in air, dry it at 120°C, and bake it at 500°C for 4 hours to prepare catalyst E.

Example 6

Take 5 grams of sample A, add 28% SiO ₂ content of silica sol and 0.05 g of safflower powder, extrude into a rod, the diameter is also Φ2 mm, then air-dry, oven dry, and roast at 500 ° C for 4 hours to obtain catalyst F.

Example 7

Weigh 100 grams of organic amine method to synthesize ZSM-5 former powder (Si/Al=48), through 350 DEG C for 1 hour, 450 DEG C for 2 hours, 550 DEG C for 2 hours roasting, obtain the molecular sieve powder that removes phase-conducting agent, press molecular sieve: Al (OH) ₃ : Sesame powder = 69:29:2 Mix evenly, then use 1N HNO ₃ to make a paste, extrude into strips with a diameter of about 2mm with an extruder, dry at room temperature, and bake at 120°C After 12 hours, raise the temperature to 550°C at 60°C/hour in a muffle furnace, and keep the temperature constant for 4 hours to obtain a ZSM-5/Al ₂ O ₃ mixture; break it to 20-40 mesh, weigh 30g, and reflux with 1N HCl Exchange 4 times under the same conditions, each exchange time is 1 hour, finally wash 4 times with deionized water, dry at room temperature, dry at 120°C for 12 hours, and rise to 550°C in a muffle furnace at 60°C/hour ℃ and kept constant for 4 hours to obtain the molded HZSM-5. Weigh 10g of the molded HZSM-5, impregnate it with 10ml of calcium nitrate solution containing 0.2gCa, heat and dry it on a water bath, and then bake it at 550℃ for 4 hours to get CaHZSM-5 Sample, denoted as Catalyst G.

Embodiment 8-catalyst application example 1

Catalyst B was evaluated on a self-built continuous microreactor. The size of the reactor was φ16×5×300mm, and 3g of 20-40 mesh catalyst B was installed inside. The bed type used a trickle bed, that is, both propylene and water were fed from the top of the reactor. Before the reaction, it was activated with N ₂ at 400°C for 1 hour. When the temperature dropped to 130°C, the ionized water was fed in, and the propylene was fed when the water pressure reached the reaction pressure of 7.0MPa. Both water and propylene were fed by a high-pressure micro piston pump. The molecular ratio is 30, the liquid space velocity of propylene is 0.30h ^-1 , the reaction temperature is 140-200°C, the reaction product liquid is detected by OV-17 capillary column and hydrogen flame identifier, the gas is analyzed by Qs column and TCD identifier, and the chromatography used is Shanghai Analytical Instrument Factory 103 and Shanghai Kechuang Chromatography Company GC8810A chromatographic instrument, the chromatographic microprocessor adopts CR-1A produced by Shimadzu Corporation of Japan. At 150 ° C, the conversion rate of propylene is 38-50%, and the selectivity of isopropanol is 95%. Diisopropyl ether selectivity 5%.

Embodiment 9-catalyst application example 2

Catalysts B, C, D, E, and F were evaluated on the apparatus of Example 8, and the catalyst apparatuses were all 6 g. Evaluation conditions are: reaction pressure 7.0MPa, temperature 150°C, water/propylene (mol) = 30, propylene liquid space velocity 0.30h ^-1 , see Table 1 for specific reaction results.

The results of hydration of propylene to isopropanol over different catalysts catalyst Propylene conversion % Isopropanol selectivity % other% BCDEF 3842.342.640.337.5 93.696.697.097.294.2 6.43.43.02.85.8

Embodiment 10-catalyst application example 3

Take out the deactivated catalyst D, rise to 550 DEG C with 60 DEG C/hour in muffle furnace, and constant temperature 2 hours, then evaluate on embodiment 8 apparatus, reaction pressure 7.0MPa, temperature 150 DEG C, water/propylene ( mol)=30, the liquid space velocity of propylene is 0.30h ^-1 , the conversion rate of propylene can reach 42.5%, and the selectivity of isopropanol is >97.0%.

Embodiment 11-catalyst application example 4

Weigh 6 g of the catalyst G prepared in Example 7, and evaluate its reaction performance on the apparatus of Example 8, the feed is 1-butene and water, the liquid space velocity of 1-butene is 0.30h ^-1 , water/propylene (mol) =20, reaction pressure 7.0MPa, temperature 180°C, 1-butene conversion rate 27.0%, sec-butanol selectivity 99.6% (wt).

Claims (6)

1. a low-carbon olefin hydration catalyst for producing low-carbon alcohols is characterized in that: the catalyst is made up of modified β molecular sieves and binders, and the modifying elements are selected from La, B, Fe, Ge, Ni, Cr, At least one of Co, Cu, Mg, Ca, Sr, Ge, and the binder is selected from one of silica sol, water glass, aluminum hydroxide, boehmite, kaolin, zirconium hydroxide, titanium oxide, and clay ; Catalyst consists of (weight percent) Modified element 1～5% Beta zeolite molecular sieve 40～80% Binder Balance 2. The catalyst for preparing low-carbon alcohols by hydration of low-carbon olefins according to claim 1, characterized in that: modifying elements account for 2 to 4%. 3. The catalyst for preparing low-carbon alcohols by hydration of low-carbon olefins according to claim 1, characterized in that: zeolite beta molecular sieve accounts for 50-70%. 4. A method for preparing a catalyst for low-carbon alcohols by hydration of low-carbon olefins as claimed in claim 1, characterized in that: the modification of β molecular sieves is carried out by ion exchange or impregnation, and then mixing binder, pore-forming agent and dilution The pore-forming agent is selected from squash powder and hydroxymethyl cellulose, and the addition amount is 1-10% of the catalyst amount; the diluent is selected from water and dilute HNO ₃ , and the addition amount is suitable for molding. 5. according to the preparation method of the catalyst for preparing low-carbon alcohols by the hydration of low-carbon olefins described in claim 4, it is characterized in that: the diluent is selected from _0.5N HNO solution. 6. The catalyst of claim 1 is used for hydration of ethylene, propylene, 1-butene, cis, trans-2-butene, isobutene to produce ethanol, isopropanol, sec-butanol, tert-butanol.