CN1101265C - Solid acid catalyst containing heteropoly acid and its preparing process - Google Patents

Abstract

The invention discloses a _solid acid catalyst containing heteropolyacid and its preparation method and application. The catalyst _contains heteropolyacid, zeolite and γ- _Al2O3 , and the _SiO2 / _Al2O3 molecular ratio of zeolite in the catalyst is 20 ～100, the content of zeolite is 30%～90%(w), the content of γ-Al ₂ O ₃ is 10～70%(w), and the content of heteropolyacid is 0.01～10%(w). The catalyst is prepared by mixing zeolite with the precursor of γ-Al ₂ O ₃ , adding nitric acid aqueous solution and an appropriate amount of deionized water for kneading and molding, and then drying and roasting to obtain the carrier of the catalyst of the present invention. The carrier is made of The aqueous solution of the heteropolyacid is impregnated, then dried and calcined to obtain the catalyst of the present invention. The catalyst is used in olefin amination reaction, olefin hydration reaction, etherification reaction, and has the characteristics of high conversion rate and selectivity, and long catalyst operation period. It is compatible with amorphous SiO ₂ -Al ₂ O ₃ , γ-Al ₂ O ₃ , zeolite-γ-Al ₂ O ₃ without heteropolyacid and heteropolyacid catalyst, the conversion rate is obviously increased under the same conditions, and the by-product rate is also reduced.

Description

A kind of solid acid catalyst containing heteropolyacid and preparation method thereof

The invention relates to a solid acid catalyst containing heteropolyacid and a preparation method thereof.

As a highly efficient catalyst with both acidic and oxidation-reduction properties, heteropolyacids have been widely used in petrochemical and organic synthesis reactions.

In US Patent 4175210 in 1979, Selwitz et al. applied silicotungstic acid to vapor phase synthesis of ethers. The catalyst was SiO ₂ ·12WO ₃ supported by SiO ₂ . It is suitable for the etherification of various olefins or olefin mixtures and 1-3 carbon alcohols or alcohol mixtures. The HPA content in the catalyst is 30%-100%, the gas phase, the liquid hourly space velocity is 0.1-0.5h ^-1 , the reaction temperature is 80-120°C, and the pressure is 0.01-1MPa or higher. The molar ratio of alcohol to enene is 2-5:1. The preparation method of the catalyst is as follows: Fisher scientific commercial silicotungstic acid is dissolved in water to obtain 422.9 g of a solution containing 21.82% SiO ₂ -12WO ₃ . The support was 215.3g of Davison 70 silica gel (10-20 mesh, calcined at 1000°F for 10h). The carrier was mixed with the heteropolyacid to obtain a solid with a net weight of 638.2 g, which was dried at 120° C. to obtain a dry product of 310 g. Then calcined at 400°C for 16 hours to obtain a catalyst containing 30% heteropolyacid. Most of the examples mentioned are etherification of olefins with 5-8 carbons and methanol, and propylene is not included.

In 1980, the ninth phase of the petrochemical industry document used heteropolyacid (mainly silicotungstic acid) and its soluble salt solution as catalysts to directly hydrate olefins to produce isopropanol. The catalyst concentration in the aqueous solution is 1×10 ^-3 gmol/l, the reaction temperature is 230° C., the reaction pressure is 20.0 MPa, the IPA yield is 200 g alcohol/catalyst·hour, and the HPA selectivity is 98%. The single-pass conversion rate of propylene is as high as 65% to 70%, and the catalyst has a long service life and can be used repeatedly. The disadvantage is the high reaction pressure.

In 1994 Chem Res, Chin, the tenth issue of University, Zhao Benliang and others studied the etherification of methanol and propylene oxide. It is considered that the HPA with Dawson structure is better than that with Keggin structure. Heteroplyblue is the best in HPA. Heteropoly acid salts generally have poor activity, indicating that the catalyst activity comes from the acidity of the catalyst. This process uses excess methanol to simulate the occurrence of polymerization, but there are still some olefins polymerized, so the selectivity is low.

The object of the present invention is to provide a kind of solid acid catalyst containing heteropolyacid and preparation method thereof, this catalyst is applied to olefin ammoniation reaction, olefin hydration reaction and etherification reaction etc. to show higher conversion rate and selectivity, It can reduce the unit consumption of raw materials, energy consumption and product cost.

Based on weight percent, the catalyst of the present invention contains:

1) 30% to 90% of zeolite, preferably 50% to 70%, zeolite can be one or more of USY, REUSY, Hβ, NTY, SSY, ZSM, mordenite, the SiO ₂ /Al ₂ The O ₃ molar ratio is 20-100.

2) _The content _of heteropolyacid is 0.01% to 10% _{, preferably} 0.5 _% to _{6 % .} (W ₂ O ₇ ) _5.5 (Mo ₂ O ₃ ) _0.5 ], H ₄ [Si(W ₃ O ₁₀ ) ₄ ], 20WO ₃ 2H ₃ PO ₄ 25H ₂ O, H ₄ S[Si(W ₃ O ₁₄ ) ₄ ] and its salts such as Cu _1.5 HS[Si(W ₃ O ₁₄ ) ₄ ], AlHS[Si(W ₃ O ₁₄ ) ₄ ], Zn _1.5 HS[Si(W ₃ O ₁₄ ) ₄ ], Na ₃ HS[Si(W ₃ O ₁₄ ) ₄ ], FeHS[Si(W ₃ O ₁₄ ) ₄ ], etc., preferably silicotungstic acid or phosphotungstic acid.

3) γ-Al ₂ O ₃ 10% to 70%, preferably 30% to 50%.

The preparation method of this catalyst is as follows:

(1) Mix and knead the zeolite and the precursor of γ-Al ₂ O ₃ , shape it, and dry it in the air; the specific process can be: mix the zeolite and the precursor of γ-Al ₂ O ₃ , add water and nitric acid aqueous solution (the concentration is best 10% to 20%) or phosphoric acid aqueous solution (the concentration is preferably 10% to 15%), then kneaded, shaped, and dried; (it is best to use deionized water and a nitric acid aqueous solution with a concentration of 10% to 15%); The amount of nitric acid or phosphoric acid can be added according to the molar ratio of nitric acid or phosphoric acid to γ-Al ₂ O ₃ is 0.1-0.5:1, preferably 0.2-0.3:1; the amount of water added is subject to kneading and molding;

(2) The molded product obtained in step (1) is dried, and can be dried at 100-170°C for 4-16 hours;

(3) calcining and drying the molded product can be calcined at 400-700°C for 5-12 hours to obtain the carrier of the catalyst of the present invention;

(4) impregnate the carrier prepared in step (3) with an aqueous solution containing a heteropolyacid, dry at 100-150°C for 8-12 hours, and then calcinate at 500-600°C for 4-8 hours to obtain Catalyst of the present invention.

The catalyst of the invention can be used in the process of producing aminated product by olefin amination reaction, producing alcohol by olefin hydration reaction, producing ether by etherification reaction and producing ether by olefin hydration reaction. For example, it can be used for hydration of propylene to prepare isopropanol, hydration of propylene to prepare diisopropyl ether, direct amination of isobutene to prepare tert-butylamine, and etherification of isobutene and methanol to prepare MTBE. In addition, the present invention can also be used to replace sulfuric acid in various acid-catalyzed reactions.

The catalyst prepared according to the present invention can be used directly.

Compared with prior art, the present invention has following advantage and effect:

Because catalyst of the present invention contains heteropolyacid and zeolite, compared with other acid catalysts such as amorphous silica-alumina, aluminum oxide and zeolite catalyst not containing heteropolyacid, equipment corrosion can be avoided, operating environment can be improved, and conversion rate can be improved. Obvious improvement, product selectivity also improves to some extent, by-product rate reduces to some extent.

Example 1

Take 30g of REUSY zeolite (SiO ₂ /Al ₂ O ₃ =50 and mix it with 36g of SB powder, add 54g of 15% dilute phosphoric acid, knead it on an extruder and extrude it to form a catalyst strip with a diameter of 1.5mm, and then dry it at 120°C 12 hours, and then calcined at 550°C for 6 hours in a muffle furnace, then impregnated with 40g of 5% silicotungstic acid aqueous solution, dried at 100°C for 10 hours, and then calcined at 600°C for 4 hours to obtain the catalyst A of the present invention. Its heteropolyacid content is 3% (w), γ-Al ₂ O ₃ content is 43% (w), and zeolite content is 54% (w).

Example 2

Get 30g Hβ zeolite (SiO ₂ /Al ₂ O ₃ =60.2) and mix with 20g of above-mentioned SB powder, add 14% nitric acid aqueous solution 30g, extrude molding after kneading on extruder, make the catalyst bar that diameter is 1.5mm, then Dry at 120°C for 12 hours, then bake in a muffle furnace at 550°C for 6 hours, then impregnate with 30g of 5% phosphotungstic acid aqueous solution, dry at 120°C for 10 hours, and then bake at 550°C for 8 hours to obtain this product Catalyst B is invented, its content of heteropolyacid is 3% (w), the content of γ-Al ₂ O ₃ is 30% (w), and the content of zeolite is 67% (w).

Embodiment 3～4

According to the method described in Example 1, the content of silicotungstic acid is 1% (w), 5% (w); γ-Al ₂ O Content is 40% (w), 35% (w); Zeolite _content is Catalysts C, D at 59% (w), 60% (w).

Comparative example 1

According to the method of Example 1, except that no heteropoly acid was added, a catalyst E with a content of γ-Al ₂ O ₃ of 60% (w) and a content of REUSY zeolite of 40% (w) was prepared.

Comparative example 2

According to the method of Example 2, except that no heteropoly acid was added, a catalyst F with a γ-Al ₂ O ₃ content of 40% and a Hβ content of 60% was prepared.

Embodiment 5-8

Catalysts in Examples 1 to 4 were broken into 8 to 20 meshes, and 20 g were respectively loaded into a stainless steel reactor with an internal diameter of 12 mm and a length of 650 mm. Isobutylene and ammonia were added to the upper part of the reactor with a metering pump, and the feed rate was 33 ml/ h (the weight space velocity is 1.0h ^-1 ), the ammonia/ene molar ratio is 2.0, the reaction temperature is 280°C, and the reaction pressure is 8.0MPa. Olefins and ammonia are discharged from the top of the separator, and the bottom liquid phase is weighed to calculate the conversion rate and analyzed by gas chromatography. The results are listed in Table 1 below.

Comparative example 3-6

According to the process of Examples 5-8, only E, F, amorphous SiO ₂ -Al ₂ O ₃ (Al ₂ O ₃ content 25% (w)) and γ-Al ₂ O ₃ are used as catalysts respectively, and the others are the same as in Examples 5 to 8, and the results are listed in Table 1.

Table 1 Example or Comparative Example Catalyst Per pass conversion of isobutene% Amine Selectivity % serial number Si-Al Ratio Heteropoly acid content (%) Example 5 A 50 3.0 11.5 97 Example 6 B 60.2 3.0 12.0 96 Example 7 C 50 1.0 9.5 95 Example 8 D. 50 5.0 10.0 93 Comparative example 3 E. 50 none 5.4 96 Comparative example 4 f 60.2 none 6.2 97 Comparative Example 5 Amorphous SiO ₂ -Al ₂ O ₃ 3.1 93 Comparative example 6 γ-Al ₂ O ₃ 2.3 90

It can be seen from the data in Table 1 that the catalyst of the present invention is obviously superior to zeolite-γ-Al ₂ O ₃ , amorphous SiO ₂ -Al ₂ O ₃ and γ-Al ₂ O ₃ without heteropolyacid.

Embodiment 9～12, comparative example 7～8

The catalysts in Examples 1-4 and Comparative Examples 1-2 were broken into 8-20 meshes, and 50ml of each was loaded into a stainless steel reactor with an inner diameter of 12mm and a length of 650mm. Propylene and water were added to the reactor with a metering pump, and the propene The feed volume space velocity is 0.3h ^-1 , the water/ene molar ratio is 13.6:1, the reaction temperature is 240°C, and the reaction pressure is 10.0MPa. Olefins were discharged from the top of the separator, and the composition of the bottom liquid phase was analyzed by gas chromatography, the results of which are listed in Table 2 below.

Table 2 Example or Comparative Example Catalyst Propylene conversion % Isopropanol selectivity % serial number Si-Al Ratio Heteropoly acid content (%) Example 9 A 50 3.0 35.5 95.5 Example 10 B 60.2 3.0 27.3 93 Example 11 C 50 1.0 35.5 97 Example 12 D. 50 5.0 40.5 90 Comparative Example 7 E. 50 none 11.8 92 Comparative Example 8 f 60.2 none 8.9 93

Examples 13-16, Comparative Examples 9-10

The catalysts in Examples 1-4 and Comparative Examples 1-2 were broken into 8-20 meshes, and 50ml of each was loaded into a stainless steel reactor with an inner diameter of 12mm and a length of 650mm. Propylene and water were added to the reactor with a metering pump, and the propene The feed volume space velocity is 0.5h ^-1 , the water/olefin molar ratio is 1.0, the reaction temperature is 155°C, and the reaction pressure is 8.0MPa. The top of the separator was discharged, and the composition of the liquid phase at the bottom was analyzed by gas chromatography, and the results are listed in Table 3 below.

table 3 Example Catalyst Propylene per pass conversion % Diisopropyl ether selectivity% serial number Si-Al Ratio Heteropoly acid content (%) 13 A 50 3.0 35.4 40 14 B 60.2 3.0 28.5 45 15 C 50 1.0 25.5 56 16 D. 50 5.0 54.0 36 Comparative Example 9 E. 50 none 18.0 39 Comparative Example 10 f 60.2 none 20.5 35.5

Examples 17-20, Comparative Examples 11-12

The catalysts in Examples 1 to 4 and Comparative Examples 1 to 2 were broken into 8 to 20 meshes, and 50 ml of each was loaded into a stainless steel reactor with an internal diameter of 12 mm and a length of 650 mm. Isobutene and methanol were added to the reactor with a metering pump, and isobutene The feed volume space velocity is 1.5h ^-1 , the reaction temperature is 100°C, the reaction pressure is 1.25MPa, and the ratio of alcohol/ene (mol) is 1.2:1. The reaction material flowing out from the reactor is cooled and put into a separator at normal pressure, unreacted olefins are discharged from the top of the separator, and the liquid phase at the bottom is analyzed by gas chromatography, and the results are shown in Table 4 below.

Table 4 Example Catalyst Isobutene conversion % MTBE selectivity % serial number Si-Al Ratio Heteropoly acid content (%) Example 17 A 50 3.0 90.5 99 Example 18 B 60.2 3.0 92.5 98 Example 19 C 50 1.0 90 100 Example 20 D. 50 5.0 95 95 Comparative Example 11 E. 50 none 56 97 Comparative Example 12 f 60.2 none 65 96.5

Claims (15)

1. A solid acid catalyst containing a heteropolyacid, based on weight percent, consists of: 1) Zeolite 30% to 90%; 2) The content of heteropoly acid is 0.01% to 10%; 3) 10% to 70% of γ-Al ₂ O ₃ . 2. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that the molecular ratio of the zeolite SiO ₂ /Al ₂ O ₃ is 20-100. 3. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that said heteropolyacid is HsO ₄ , H ₃ PO ₄ , 20MoO ₃ ·2H ₃ PO ₄ ·48H ₂ O, H ₂ [P(W ₂ O ₇ ) _5.5 (Mo ₂ O ₃ ) _0.5 ], H ₄ [Si(W ₃ O ₁₀ ) ₄ ], 20WO ₃ 2H ₃ PO ₄ 25H ₂ O, H ₄ S[Si(W ₃ O ₁₄ ) ₄ ] and one or more of its corresponding salts. 4. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that the content of said zeolite is 50%-70% based on the weight percentage of the catalyst. 5. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that the content of said heteropolyacid is 0.5%-6% based on the weight percentage of the catalyst. 6. The solid acid catalyst containing heteropoly acid according to claim 1, characterized in that the content of γ-Al ₂ O ₃ is 30%-50% based on the weight percentage of the catalyst. 7. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that said heteropolyacid is silicotungstic acid. 8. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that said heteropolyacid is phosphotungstic acid. 9. The solid acid catalyst containing heteropolyacid according to claim 1, characterized in that said zeolite is one or both of REUSγ and Hβ. 10. The solid acid catalyst containing heteropolyacid according to claim 3, characterized in that said corresponding salts are Cu _1.5 Hs[Si(W ₃ O ₁₄ ) ₄ ], AIHS[Si(W ₃ O ₁₄ ) ) ₄ ], one or more of Zn _1.5 HS[Si(W ₃ O ₁₄ ) ₄ ], Na ₃ HS[Si(W ₃ O ₁₄ ) ₄ ], FeHS[Si(W ₃ O ₁₄ ) ₄ ] . 11. A method for preparing the solid acid catalyst according to claim 1, comprising: 1) Kneading zeolite with the precursor of γ-Al ₂ O ₃ , water, nitric acid or phosphoric acid, molding, and drying; 2) drying the molded product obtained in step 1) at 100-170° C. for 4-16 hours; 3) Calcining the dried molded product at 400-700°C for 5-12 hours to obtain a catalyst carrier; 4) The carrier obtained in step 3) is impregnated with an aqueous solution containing heteropolyacid, then dried at 100-150° C. for 8-12 hours, and then calcined at 500-600° C. for 4-8 hours to obtain a catalyst. 12. An application of the solid acid catalyst as claimed in claim 1, characterized in that the catalyst is used in the process of producing amides by amination of olefins. 13. The application of the solid acid catalyst as claimed in claim 1, characterized in that the catalyst is used in the process of producing alcohol through hydration of olefins. 14. The application of the solid acid catalyst as claimed in claim 1, characterized in that the catalyst is used in the etherification reaction to prepare ether. 15. The application of the solid acid catalyst as claimed in claim 1, characterized in that the catalyst is used in the process of preparing ether from olefin hydration reaction.