CN107126948B

CN107126948B - Molybdenum-based catalyst

Info

Publication number: CN107126948B
Application number: CN201710253506.7A
Authority: CN
Inventors: 权恒道; 张呈平; 张小玲; 庆飞要
Original assignee: Beijing Institute of Technology BIT; Beijing Yuji Science and Technology Co Ltd
Current assignee: Quanzhou Yuji New Material Technology Co.,Ltd.; Beijing Institute of Technology BIT
Priority date: 2017-04-18
Filing date: 2017-04-18
Publication date: 2020-07-10
Anticipated expiration: 2037-04-18
Also published as: CN107126948A

Abstract

The invention discloses a molybdenum-based catalyst, belonging to the field of chemical synthesis. The molybdenum-based catalyst consists of molybdenum ions and an auxiliary agent, wherein the mass percentage of the molybdenum ions and the auxiliary agent is 80-95% and 5-20%, the molybdenum ions are one or more of trivalent molybdenum ions, tetravalent molybdenum ions and pentavalent molybdenum ions, and the auxiliary agent is other metal elements. The total amount of fluorine gas or molybdenum hexafluoride introduced in the activation stage is equal to the precursor consumption fluorine gas or molybdenum hexafluoride theoretical amount of molybdenum ions plus the metal element auxiliary agent consumption fluorine gas or molybdenum hexafluoride theoretical amount, and because hexavalent molybdenum is easy to lose, the molybdenum ions are reduced to be controlled in a trivalent, tetravalent or pentavalent state as much as possible when the fluorine gas dosage is calculated. The molybdenum-based catalyst has high use temperature, high catalytic activity and long service life, and is mainly used for preparing fluorine-containing olefin by gas-phase catalysis of halogenated olefin at high temperature to generate fluorine-chlorine exchange reaction.

Description

Molybdenum-based catalyst

Technical Field

The invention relates to a molybdenum-based catalyst, in particular to a method for preparing fluorine-containing olefin by gas-phase catalysis of halogenated olefin to generate fluorine-chlorine exchange reaction at high temperature.

Background

To fulfill the montreal protocol aimed at protecting the earth's ozone layer, Hydrofluorocarbons (HFCs) and Hydrofluoroolefins (HFOs) with zero ODP values have been introduced in countries around the world, thus eliminating chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) with ODP values other than zero. At present, HFCs and HFOs have been widely used as refrigerants, cleaning agents, foaming agents, fire extinguishing agents, etching agents, and the like.

At present, most of HFCs or HFOs produced industrially adopt a method of gas phase catalysis fluorine-chlorine exchange reaction of halogenated organic matters, and the method has the advantages of simple process, easy continuous large-scale production, safe operation and the like. The fluorine-chlorine exchange catalyst plays a central role in the gas phase catalytic fluorine-chlorine exchange reaction of halogenated organic matters. Currently, the common fluorine-chlorine exchange catalyst is a chromium-based catalyst, the main active component of which is chromium.

U.S. Dupont reports an Al modified chromium-based catalyst for the catalytic preparation of trifluoropropene in U.S. Pat. No. 4,4465786.

U.S. DuPont reports in U.S. Pat. No. 5,20100051853 that monochloromonofluoromethane and tetrafluoropropene as raw materials react under the action of aluminum halide to obtain 1-chloro-2, 2,3,3, 3-pentafluoropropane (HCFC-235cb), and then HCFC-235cb reacts in Cr₂O₃In the presence of the catalyst, dehydrofluorination reaction is carried out to obtain E/Z-1-chloro-2, 3,3, 3-tetrafluoropropene (E/Z-HCFC-1224yd), and finally the E/Z-HCFC-1224yd and hydrogen fluoride are subjected to gas-phase fluorine-chlorine exchange reaction under the action of a Zn element modified chromium-based catalyst to obtain the E/Z-1, 1,1, 2, 3-pentafluoropropene (E/Z-HFC-1225ye), wherein the content of trans-configuration and cis-configuration is respectively 95% and 5%.

Modified chromium-based catalysts of the Zn element for the catalytic preparation of difluoromethane (HFC-32) are reported in patent US5763704 by the company Imperial chemical industries, England.

The uk empire chemical industry company reported in patent US5763707 that chromium-based catalysts modified with Zn and Ni elements are used for the catalytic production of HFC-125.

The preparation of 1-chloro-3, 3, 3-trifluoropropene (HCFO-1233zd), 1,3,3, 3-tetrafluoropropene (HFO-1234ze) and 1,1,1, 3, 3-pentafluoropropane (HFC-245fa) by the company Elvator chemical, France, in patent US5811603, chromium-based catalyst catalyzed HCO-1233 za.

The french er-vogue chemical company reported in patent US6184172 that a chromium-based catalyst co-modified with Al element and Ni element was used to catalyze 1-chloro-3, 3, 3-trifluoroethane (HCFC-133a) to produce 1,1,1, 3-tetrafluoroethane (HFC-134 a).

Japanese Dajin company reported in U.S. Pat. No. 5,6300531 that a specific surface area S is 170-300 m²The chromium-based catalyst is used for catalyzing 1,1, 1-trichloroethane to generate fluorine-chlorine exchange reaction to synthesize HFC-134a, and can also be used for catalyzing tetrachloroethylene to generate fluorine-chlorine exchange reaction to obtain pentafluoroethane (HFC-125).

Japanese Dajin company reported in U.S. Pat. No. 6,989,928 that a chromium-based catalyst catalyzes a vapor phase fluorine-chlorine exchange reaction of 2-chloro-3, 3, 3-trifluoropropene (HCFO-1233xf) with HF to give 2,3,3, 3-tetrafluoropropene (HFO-1234 yf).

The use of chromium-based catalysts for the catalytic preparation of 1,1, 1-trifluoro-3, 3-dichloroacetone from pentachloroacetone is reported in patent US5905174 by the company Central glass, japan.

Japanese Raynaud and Senso-Dow company in patent CN1192995C report a fluorine-chlorine exchange catalyst prepared by impregnating Cr (NO) with Cr₃)₃Loaded on active carbon, dried, roasted and activated by hydrogen fluoride, and is used for catalyzing cyclo-CF at 330 DEG C₂CF₂CF₂Preparation of cyclo-CF by fluoro-chloro exchange reaction of CCl ═ CCl and hydrogen fluoride₂CF₂CF₂CF ═ CCl, which has very low catalytic activity, with a conversion of only 26% and a selectivity of 91%.

China Xian gold bead modern chemical industry finite responsibility company reports that one element of Mn, Co or Zn and the other element of Mg or Ni in a patent CN1408476, a chromium-based catalyst modified by the two elements is used for catalyzing trichloroethylene, and HFC-134a is synthesized by two-step gas-phase fluorine-chlorine exchange reaction through an intermediate HCFC-133 a.

China-chemical modern environmental protection chemical industry (Xian) limited company reports that a rare earth element modified chromium-based catalyst is used for catalyzing HCFC-133a and HF to perform gas-phase fluorine-exchange reaction to synthesize HFC-134a in patent CN 102580767A.

In patent CN1145275 of the national institute of Seaman chemistry, a cobalt and magnesium modified chromium catalyst is reported, wherein a carrier is aluminum fluoride and is used for catalyzing trichloroethylene, and a two-step gas-phase fluorine-chlorine exchange reaction is carried out to synthesize HFC-134a through an intermediate HCFC-133 a.

The chromium-based catalyst has attracted research interest of scientists all over the world due to the advantages of easy availability of raw materials and high activity. However, with the progress of research, people find that the chromium catalyst still has the defects of low use temperature, low catalytic activity, short service life and difficult recycling, and more importantly, chromium has toxicity and can cause great harm to people, and particularly, high-valence chromium has strong carcinogenicity. Research suggests that hexavalent chromium is 100 times more toxic than trivalent chromium, is easily absorbed by the human body and accumulates in the body, and is slowly metabolized and eliminated. Under certain conditions, trivalent chromium and hexavalent chromium can be interconverted. Hexavalent chromium has been identified as a cause of respiratory cancer in humans. Hexavalent chromium, once absorbed and metabolized by the ubiquitous reducing agents in the cell, forms chromium-promoted DNA-damage cancers in the cells of the human digestive system. Hexavalent chromium is listed as a "human carcinogen" by the world health organization international agency for research on cancer (IARC).

Disclosure of Invention

The invention aims to solve the problem that non-chromium-based catalysts which are always searched for are used as fluorine-chlorine exchange catalysts. The catalyst of the invention provides a non-chromium catalyst, namely a molybdenum-based catalyst which is safe, environment-friendly, harmless, high in catalytic activity and long in service life. The invention has milestone effect in gas phase catalysis of fluorine-chlorine exchange reaction and search of non-chromium-based catalyst.

Another technical problem to be solved by the present invention is to provide a method for preparing the above molybdenum-based catalyst.

The invention provides a molybdenum-based catalyst, which consists of molybdenum ions and an auxiliary agent, wherein the molybdenum ions are one or more of trivalent molybdenum ions, tetravalent molybdenum ions or pentavalent molybdenum ions, the auxiliary agent is at least one or more of Al, Mg, Ni, Co, Ti, Zr, V, Fe, Zn, In, Cu, Ag, Cd, Hg, Ga, Sn, Pb, Mn, Ba, Re, Sc, Sr, Ru, Nb, Ta, Ca, Ce, Sb, Tl and Hf, the mass percent of the molybdenum ions and the auxiliary agent is 60-100% and 0-40%, and the molybdenum-based catalyst is prepared by the following preparation method:

(1) uniformly mixing a precursor of the molybdenum ions and a precursor of the auxiliary agent according to the mass percentage of the molybdenum ions and the auxiliary agent, and performing compression molding to obtain a catalyst precursor;

(2) roasting the catalyst precursor obtained in the step (1) for 6-15 hours at 300-500 ℃ in a nitrogen atmosphere;

(3) vacuumizing the roasted product obtained in the step (2) at 220-500 ℃, and then activating in fluorine gas for 6-15 hours under a closed condition to prepare a molybdenum-based catalyst, wherein the total amount of fluorine gas introduced is equal to the sum of the theoretical amount of consumed fluorine gas of a precursor of molybdenum ions and the theoretical amount of consumed fluorine gas of a metal element auxiliary agent; the theoretical amount of fluorine consumed by the precursor of molybdenum ions is greater than the theoretical amount of fluorine consumed by the precursor of molybdenum ions for conversion of molybdenum ions to molybdenum trifluoride and less than the theoretical amount of fluorine consumed by the precursor of molybdenum ions for reduction of molybdenum ions to molybdenum pentafluoride.

Or (3) firstly vacuumizing the roasted product obtained in the step (2) at 220-500 ℃, and then activating in molybdenum hexafluoride for 6-15 hours under a closed condition to prepare the molybdenum-based catalyst, wherein the total amount of introduced molybdenum hexafluoride is equal to the sum of the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions and the theoretical amount of molybdenum hexafluoride consumed by the metal element auxiliary agent; the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions is greater than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for conversion to molybdenum trifluoride and less than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for reduction to molybdenum pentafluoride.

The precursor of the molybdenum ions is at least one or more of molybdenum simple substance, molybdenum trioxide, molybdenum dioxide or molybdenum pentoxide, and the precursor of the auxiliary agent is at least one or more of oxide, hydroxide, nitrate, acetate or carbonate of the corresponding auxiliary agent.

The precursor of the molybdenum ion in the invention is preferably molybdenum simple substance.

The auxiliary agent of the invention is preferably nickel or cobalt.

The mass percentage of the molybdenum ions and the auxiliary metal elements is 80-95% and 5-20%.

The precursor of the promoter is preferably nickel nitrate or cobalt nitrate.

The precursor of the molybdenum-based catalyst of the present invention is preferably a mixture of elemental molybdenum and nickel nitrate, wherein the mass percentages of molybdenum ions and nickel elements are 90% and 10%.

The precursor of the molybdenum-based catalyst of the present invention is preferably a mixture of elemental molybdenum and cobalt nitrate, wherein the mass percentages of molybdenum ions and cobalt elements are 90% and 10%.

The molybdenum-based catalyst is prepared by the following preparation method:

The molybdenum hexafluoride provided by the invention can be prepared by the following method: at the temperature of 20-50 ℃, the molybdenum simple substance reacts with fluorine gas to obtain molybdenum hexafluoride, and the reaction equation is as follows: mo +3F₂→MoF₆. The boiling point of the molybdenum hexafluoride is 35.0 ℃/760 mmHg.

The precursor of the molybdenum ion is at least one or more of molybdenum simple substance, molybdenum trioxide, molybdenum dioxide or molybdenum pentoxide, and the precursor of the auxiliary agent is at least one or more of metal oxide, hydroxide, nitrate, acetate or carbonate.

The precursor of the molybdenum ion is a molybdenum simple substance, the ventilation amount of the fluorine gas is 3/2 times or more of the ratio of the theoretical amount of the fluorine gas consumed by the molybdenum simple substance to the amount of the molybdenum simple substance, and is 5/2 times or less, and the residual fluorine gas is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is molybdenum trioxide, the ventilation amount of the fluorine gas is 3 times or more and 5 times or less of the ratio of the theoretical amount of the fluorine gas consumed by the molybdenum trioxide to the amount of the molybdenum trioxide, and the residual fluorine gas is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ion is molybdenum dioxide, the ventilation amount of the fluorine gas is more than or equal to 2 times of the ratio of the theoretical amount of the consumed fluorine gas of the precursor of the molybdenum ion to the amount of the molybdenum dioxide substance and is less than or equal to 5/2 times, and the residual fluorine gas is absorbed by dried soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is molybdenum pentoxide, the ventilation amount of the fluorine gas is 5 times or more of the ratio of the theoretical amount of the consumed fluorine gas of the precursor of the molybdenum ions to the amount of molybdenum pentoxide substances, and the residual fluorine gas is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is a molybdenum simple substance, the ventilation amount of the molybdenum hexafluoride is 1 time or more of the ratio of the theoretical amount of the molybdenum hexafluoride consumed by the precursor of the molybdenum ions to the amount of the molybdenum simple substance, and is less than or equal to 5 times, and the residual molybdenum hexafluoride is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is molybdenum trioxide, the ventilation amount of the molybdenum hexafluoride is 2 times or more of the ratio of the theoretical amount of the molybdenum hexafluoride consumed by the precursor of the molybdenum ions to the amount of the molybdenum trioxide substances and is less than or equal to 10 times, and the residual molybdenum hexafluoride is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is molybdenum dioxide, the ventilation amount of the molybdenum hexafluoride is 2 times or more of the ratio of the theoretical amount of the molybdenum hexafluoride consumed by the precursor of the molybdenum ions to the amount of the molybdenum dioxide substances, and is less than or equal to 5 times, and the residual molybdenum hexafluoride is absorbed by dry soda lime to prepare the molybdenum-based catalyst; or

The precursor of the molybdenum ions is molybdenum pentoxide, the ventilation quantity of the molybdenum hexafluoride is 10 times of the ratio of the theoretical quantity of the molybdenum hexafluoride consumed by the precursor of the molybdenum ions to the quantity of the molybdenum pentoxide substances, and the residual molybdenum hexafluoride is absorbed by dry soda lime to prepare the molybdenum-based catalyst.

In the molybdenum-based catalyst, the precursor of the molybdenum ion is preferably a molybdenum simple substance, the precursor of the auxiliary agent is preferably a compound containing nickel or cobalt, and the mass percentage content of the molybdenum ion and the mass percentage content of the auxiliary agent metal element are 80-95% and 5-20% in sequence.

The precursor of the promoter is preferably nickel nitrate or cobalt nitrate.

The molybdenum-based catalyst is prepared by the following preparation method:

The precursor of the molybdenum ion of the molybdenum-based catalyst is selected from molybdenum simple substance, the auxiliary agent is preferably nickel or cobalt, and the precursor of the auxiliary agent is preferably oxide, hydroxide, nitrate, acetate or carbonate of corresponding metal elements.

The molybdenum-based catalyst is applied to preparing fluorine-containing olefin by carrying out gas-phase catalysis on halogenated olefin to generate fluorine-chlorine exchange reaction under the high-temperature condition.

The halogenated olefin is cyclo-CF₂CF₂CF₂Preparation of Cyclo-CF from CCl ═ CCl₂CF₂CF₂CF＝CCl；

Or the halogenated olefin is 2-chloro-3, 3, 3-trifluoropropene (abbreviated as HCFO-1233xf) to produce 2,3,3, 3-tetrafluoropropene (abbreviated as HFO-1234 yf);

or the halogenated olefin is E/Z-1-chloro-2, 3,3, 3-tetrafluoropropene, producing E/Z-1,2,3,3, 3-pentafluoropropene (abbreviated as E/Z-HFO-1225 ye);

or the haloolefin is E-1-chloro-3, 3, 3-trifluoropropene, to produce E/Z-1,3,3, 3-tetrafluoropropene (abbreviated as E/Z-HFO-1234 ze);

or the halogenated olefin is Z-1-chloro-3, 3, 3-trifluoropropene, to produce E/Z-HFO-1234 ze.

The total amount of fluorine gas or molybdenum hexafluoride introduced by the method is equal to the theoretical amount of fluorine gas consumed by the precursor of molybdenum plus the theoretical amount of fluorine gas or molybdenum hexafluoride consumed by the metal element auxiliary agent, and because the molybdenum hexafluoride is easy to run away due to the low boiling point (35.0 ℃/760mmHg), molybdenum ions are reduced to be controlled to be in a trivalent state, a tetravalent state or a pentavalent state as much as possible when the amount of the fluorine gas or the molybdenum hexafluoride is calculated.

The catalyst is prepared by adopting a blending method, according to the percentage composition of molybdenum ions and an auxiliary agent, a precursor of the molybdenum ions and a precursor of the auxiliary agent are uniformly mixed and pressed to form to prepare a catalyst precursor, when the precursor is roasted at high temperature, the precursor (hydroxide, nitrate, acetate or carbonate) of the auxiliary agent is pyrolyzed to obtain an oxide of the auxiliary agent, and the precursor of the molybdenum ions basically does not react and still exists in the original valence state; when the precursor enters the activation stage of fluorine gas or molybdenum hexafluoride, the specific process is as follows:

(1) when the precursor of the molybdenum ion is a molybdenum simple substance, the ratio of the amount of fluorine gas to the amount of molybdenum ion can be controlled to realize the quantitative conversion of the molybdenum ion into molybdenum fluoride, when F₂3/2 (molar ratio), the following reaction occurs: 2Mo +3F₂→2MoF₃(ii) a When F is present₂5/2 (molar ratio), the following reaction occurs: 2Mo +5F₂→2MoF₅(ii) a Controlling the ratio of fluorine gas (the amount of fluorine gas consumed by metal element auxiliary agent is deducted from the total amount of fluorine gas) consumed by molybdenum ions to the amount of molybdenum simple substance to be greater than or equal to 3/2 and less than or equal to 5/2;

(2) when the precursor of molybdenum ion is molybdenum trioxide, the fluorine gas and molybdenum ion can be controlledThe amount of the substance is in proportion to achieve quantitative conversion of molybdenum ions into molybdenum fluorides when F₂/Mo₂O₃3/2 (molar ratio), the following reaction occurs: mo₂O₃+3F₂→2MoF₃+3O₂(ii) a When F is present₂/Mo₂O₃At 5 (molar ratio), the following reaction occurs: mo₂O₃+5F₂→2MoF₅+3O₂(ii) a Controlling the ratio of fluorine gas consumed by molybdenum ions (the amount of fluorine gas consumed by metal element additives is deducted from the total amount of fluorine gas) to molybdenum trioxide to be more than or equal to 3 and less than or equal to 5;

(3) when the precursor of the molybdenum ion is molybdenum dioxide, the ratio of the amount of fluorine gas to the amount of molybdenum ion can be controlled to realize the quantitative conversion of molybdenum ion into molybdenum fluoride, when F₂/MoO₂2 (molar ratio), the following reaction occurs: MoO₂+2F₂→2MoF₄+O₂(ii) a When F is present₂/MoO₂5/2 (molar ratio), the following reaction occurs: 2MoO₂+5F₂→2MoF₅+2O₂(ii) a Controlling the ratio of fluorine gas (the amount of fluorine gas consumed by metal element auxiliary agent is subtracted from the total amount of fluorine gas) consumed by molybdenum ions to the amount of molybdenum dioxide substance to be more than or equal to 2 and less than or equal to 5/2;

(4) when the precursor of the molybdenum ion is molybdenum pentoxide, the ratio of the amounts of fluorine gas and molybdenum ion can be controlled to achieve quantitative conversion of molybdenum ion into molybdenum fluoride, when F₂/Mo₂O₅At 5 (molar ratio), the following reaction occurs: mo₂O₅+5F₂→2MoF₅+5O₂(ii) a The ratio of fluorine gas consumed by molybdenum ions (the amount of fluorine gas consumed by the metal element additive is subtracted from the total amount of fluorine gas) to the amount of molybdenum pentoxide substance was controlled to be 5.

(5) When the precursor of the molybdenum ion is a molybdenum simple substance, the ratio of the amount of the molybdenum hexafluoride to the molybdenum ion can be controlled to realize the quantitative conversion of the molybdenum ion into the molybdenum fluoride, when MoF₆1 (molar ratio), the following reaction occurs: mo + MoF₆→2MoF₃(ii) a When MoF₆5 (molar ratio), the following reaction occurs: mo +5MoF₆→6MoF₅(ii) a Controlling the ratio of molybdenum hexafluoride consumed by molybdenum ions (the amount of molybdenum hexafluoride consumed by metal element additives is deducted from the total amount of molybdenum hexafluoride) to the amount of molybdenum simple substance to be more than or equal to 1 and less than or equal to 5;

(6) when the precursor of the molybdenum ion is molybdenum trioxide, the ratio of the amount of the molybdenum hexafluoride to the molybdenum ion can be controlled to realize the quantitative conversion of the molybdenum ion into the molybdenum fluoride, when the MoF is used₆/Mo₂O₃2 (molar ratio), the following reaction occurs: mo₂O₃+2MoF₆→4MoF₃+3/2O₂(ii) a When MoF₆/Mo₂O₃At 10 (molar ratio), the following reaction occurs: mo₂O₃+10MoF₆→12MoF₅+3/2O₂(ii) a Controlling the ratio of the molybdenum hexafluoride consumed by molybdenum ions (the amount of the molybdenum hexafluoride consumed by deducting the metal element additive from the total amount of the molybdenum hexafluoride) to the amount of the molybdenum trioxide to be more than or equal to 2 and less than or equal to 10;

(7) when the precursor of the molybdenum ion is molybdenum dioxide, the ratio of the amount of the molybdenum hexafluoride to the molybdenum ion can be controlled to realize the quantitative conversion of the molybdenum ion into the molybdenum fluoride, when MoF₆/MoO₂2 (molar ratio), the following reaction occurs: MoO₂+2MoF₆→3MoF₄+O₂(ii) a When MoF₆/MoO₂5/2 (molar ratio), the following reaction occurs: MoO₂+5MoF₆→6MoF₅+O₂(ii) a Controlling the ratio of molybdenum hexafluoride consumed by molybdenum ions (the amount of molybdenum hexafluoride consumed by metal element additives is deducted from the total amount of molybdenum hexafluoride) to the amount of molybdenum dioxide substances to be more than or equal to 2 and less than or equal to 5;

(8) when the precursor of the molybdenum ions is molybdenum pentoxide, the ratio of the amount of the molybdenum hexafluoride to the molybdenum ions can be controlled to realize the quantitative conversion of the molybdenum ions into molybdenum fluorides, when MoF₆/Mo₂O₅At 5 (molar ratio), the following reaction occurs: mo₂O₅+10MoF₆→12MoF₅+5/2O₂(ii) a The ratio of the molybdenum hexafluoride consumed by controlling the molybdenum ions (the amount of the molybdenum hexafluoride consumed by deducting the metal element additive from the total amount of the molybdenum hexafluoride) to the amount of the molybdenum pentoxide substance, and the likeAt 10.

In the activation stage of fluorine gas or molybdenum hexafluoride, molybdenum in low valence state can be converted into molybdenum ion in high valence state, such as trivalent molybdenum ion, tetravalent molybdenum ion, pentavalent molybdenum ion and hexavalent molybdenum ion from zero valence state, and since hexavalent molybdenum ion is easy to be lost, F can be controlled₂Or the dosage of the molybdenum hexafluoride quantitatively converts low-valence chromium ions into trivalent molybdenum ions, tetravalent molybdenum ions or pentavalent molybdenum ions. The molybdenum-based catalyst has strong catalytic activity due to the existence of a large amount of trivalent molybdenum ions, tetravalent molybdenum ions or pentavalent molybdenum ions, and other metal elements are used as auxiliaries, so that the stability of the molybdenum-based catalyst is enhanced. The whole effect is that the molybdenum-based catalyst prepared by the scheme has high use temperature, high catalytic activity and long service life.

The molybdenum-based catalyst is suitable for catalyzing halogenated olefin to generate fluorine-chlorine exchange reaction at high temperature in gas phase to prepare fluorine-containing olefin. The starting halogenated olefin may or may not contain a fluorine atom, but must contain one or more halogen atoms other than a fluorine atom, such as a chlorine atom, a bromine atom or an iodine atom. For example: Cyclo-CF₂CF₂CF₂Preparation of Cyclo-CF by gas phase catalytic fluorination of CCl ═ CCl₂CF₂CF₂CF ═ CCl, 2-chloro-3, 3, 3-trifluoropropene (abbreviated as HCFO-1233xf) gas-phase catalytic fluorination to produce 2,3,3, 3-tetrafluoropropene (abbreviated as HFO-1234yf), E/Z-1-chloro-2, 3,3, 3-tetrafluoropropene (abbreviated as E/Z-HCFO-1224yd), E/Z-1,2,3,3, 3-pentafluoropropene (abbreviated as E/Z-HFO-1225ye), E-1-chloro-3, 3, 3-trifluoropropene (abbreviated as E/Z-HFO-1234ze), Z-1-chloro-3, gas phase catalytic fluorination of 3, 3-trifluoropropene to produce E/Z-HFO-1234ze, and the like.

Compared with the prior art, the invention has the following advantages:

(1) for human beings, molybdenum is the only known element essential to human beings in the second and third transition elements, and compared with the transition elements of the same type, the molybdenum has extremely low toxicity and can be considered as basically nontoxic. Researches show that the incidence rate of cancer is low in areas with high molybdenum content in soil. Therefore, compared with the chromium-based catalyst, the molybdenum-based catalyst has the characteristics of safety, environmental protection and harmlessness.

(2) When the molybdenum-based catalyst is activated by fluorine gas or molybdenum hexafluoride, the precursor of molybdenum ions can generate one or more of molybdenum trifluoride, molybdenum tetrafluoride or molybdenum pentafluoride with the fluorine gas or molybdenum hexafluoride, so that the molybdenum-based catalyst has stronger catalytic activity, and the molybdenum-based catalyst is modified by metal elements, so that the stability of the molybdenum-based catalyst is greatly improved.

(3) The molybdenum-based catalyst is suitable for gas-phase catalysis of halogenated olefin at high temperature to generate fluorine-chlorine exchange reaction to prepare fluorine-containing olefin, and the use temperature can reach 450 ℃, which is obviously higher than 330 ℃ in the prior art.

Detailed Description

The present invention will be described in further detail below by way of examples, but is not limited to the examples.

An analytical instrument: shimadzu GC-2010, DB-VRX caliper column (i.d. 0.32mm; length30 m; J & Mo Scientific Inc.).

GC analysis method: and washing, alkali washing and drying the reaction product, and then taking a gas sample for GC analysis. The temperature of the detector is 250 ℃, the temperature of the vaporization chamber is 250 ℃, the initial temperature of the column is 40 ℃, the temperature is kept for 10 minutes, the temperature is increased to 230 ℃ at the speed of 15 ℃/min, and the temperature is kept for 8 minutes.

The preparation method of the molybdenum hexafluoride comprises the following steps: at the temperature of 20-50 ℃, the molybdenum simple substance reacts with fluorine gas to obtain molybdenum hexafluoride, and the reaction equation is as follows: mo +3F₂→MoF₆. The boiling point of the molybdenum hexafluoride is 35.0 ℃/760mmHg

Example 1

According to the percentage composition of 90 percent and 10 percent of molybdenum ions and nickel elements, uniformly mixing molybdenum elementary substances with nickel nitrate, tabletting and forming to obtain a catalyst precursor, filling 10m L of the catalyst precursor into a tubular reactor made of Monel material with the inner diameter of 1/2 inches and the length of 30cm, introducing nitrogen, roasting for 8 hours at 450 ℃, wherein the space velocity of the nitrogen is 200h^-1Cooling to 300 ℃, then sealing the tubular reactor, vacuumizing, and introducing fluorine gas, wherein the ventilation rate of the fluorine gas is more than or equal to the theoretical amount of fluorine gas consumed by molybdenum elementary substance substances and molybdenumThe ratio of the amount of the simple substance is 3/2 times and 5/2 times or less, the activation is carried out for 12 hours, and the residual fluorine gas is absorbed by dry soda lime to prepare the molybdenum-based catalyst.

Example 2

The catalyst was prepared by substantially the same procedure as in example 1, except that the percentage composition of molybdenum ions and nickel elements was 100% and 0.

Example 3

The catalyst was prepared by substantially the same procedure as in example 1, except that the percentage composition of molybdenum ions and nickel elements was 80% and 20%.

Example 4

The catalyst was prepared by substantially the same procedure as in example 1, except that the percentage composition of molybdenum ions and nickel elements was 70% and 30%.

Example 5

The catalyst was prepared by substantially the same procedure as in example 1, except that the percentage composition of molybdenum ions and nickel elements was 60% and 40%.

Example 6

The catalyst was prepared by essentially the same procedure as in example 1, except that nickel nitrate was changed to aluminum nitrate and the percentage composition of molybdenum ions and aluminum elements was 90% and 10%.

Example 7

The catalyst was prepared by the same procedure as in example 1, except that nickel nitrate was changed to magnesium nitrate, and the percentage composition of molybdenum ions and magnesium elements was 90% and 10%.

Example 8

The catalyst was prepared by the same procedure as in example 1, except that nickel nitrate was changed to manganese nitrate, and the percentage composition of molybdenum ions and manganese elements was 90% and 10%.

Example 9

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to cobalt nitrate and the percentage composition of molybdenum ions and cobalt elements was 90% and 10%.

Example 10

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to titanium nitrate, and the percentage composition of molybdenum ions and titanium elements was 90% and 10%.

Example 11

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to zirconium nitrate and the percentage composition of molybdenum ions and zirconium elements was 90% and 10%.

Example 12

The catalyst was prepared by a process substantially the same as that of example 1, except that nickel nitrate was changed to vanadyl nitrate and the percentage composition of molybdenum ions and vanadium elements was 90% and 10%.

Example 13

The catalyst was prepared by the same procedure as in example 1, except that nickel nitrate was changed to ferric nitrate and the percentage composition of molybdenum ions and iron elements was 90% and 10%.

Example 14

The catalyst was prepared by the same procedure as in example 1, except that nickel nitrate was changed to zinc nitrate and the percentage composition of molybdenum ions and zinc elements was 90% and 10%.

Example 15

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to indium nitrate, and the percentage composition of molybdenum ions and indium elements was 90% and 10%.

Example 16

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to copper nitrate and the percentage composition of molybdenum ions and copper elements was 90% and 10%.

Example 17

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to silver nitrate and the percentage composition of molybdenum ions and silver elements was 90% and 10%.

Example 18

The preparation process of the catalyst was substantially the same as in example 1, except that nickel nitrate was changed to cadmium nitrate, and the percentage composition of molybdenum ions and cadmium elements was 90% and 10%.

Example 19

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to mercury nitrate and the percentage composition of molybdenum ions and mercury elements was 90% and 10%.

Example 20

The preparation process of the catalyst was substantially the same as in example 1, except that nickel nitrate was changed to gallium nitrate, and the percentage composition of molybdenum ions and gallium elements was 90% and 10%.

Example 21

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to tin nitrate, and the percentage composition of molybdenum ions and tin elements was 90% and 10%.

Example 22

The preparation process of the catalyst was substantially the same as in example 1, except that nickel nitrate was changed to lead nitrate, and the percentage composition of molybdenum ions and lead elements was 90% and 10%.

Example 23

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to strontium nitrate and the percentage composition of molybdenum ions and strontium elements was 90% and 10%.

Example 24

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to barium nitrate and the percentage composition of molybdenum ions and barium elements was 90% and 10%.

Example 25

The catalyst was prepared by essentially the same procedure as in example 1, except that the nickel nitrate was changed to rhenium nitrate, with the molybdenum ions and rhenium elements having a percentage composition of 90% and 10%.

Example 26

The catalyst was prepared by a process substantially identical to that of example 1, except that nickel nitrate was changed to scandium nitrate, and the percentage composition of molybdenum ions and scandium elements was 90% and 10%.

Example 27

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to ruthenium nitrate, and the percentage composition of molybdenum ions and ruthenium elements was 90% and 10%.

Example 28

The catalyst was prepared by essentially the same procedure as in example 1, except that the nickel nitrate was changed to niobium nitrate and the percentage composition of the molybdenum ions and niobium elements was 90% and 10%.

Example 29

The catalyst was prepared by a process substantially the same as that of example 1, except that nickel nitrate was changed to tantalum nitrate, and the percentage composition of molybdenum ions and tantalum elements was 90% and 10%.

Example 30

The catalyst was prepared by the same procedure as in example 1, except that nickel nitrate was changed to calcium nitrate and the percentage composition of molybdenum ions and calcium elements was 90% and 10%.

Example 31

The preparation process of the catalyst was substantially the same as in example 1, except that nickel nitrate was changed to cerium nitrate, and the percentage composition of molybdenum ions and cerium elements was 90% and 10%.

Example 32

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to antimony nitrate and the percentage composition of molybdenum ions and antimony elements was 90% and 10%.

Example 33

The catalyst was prepared by essentially the same procedure as in example 1, except that the nickel nitrate was changed to thallium nitrate and the percentage composition of the molybdenum ions and thallium elements was 90% and 10%.

Example 34

The catalyst was prepared by essentially the same procedure as in example 1, except that nickel nitrate was changed to hafnium nitrate, and the percentage composition of molybdenum ions and hafnium elements was 90% and 10%.

Example 35

The catalyst was prepared by a process substantially the same as in example 1, except that nickel nitrate was changed to nickel oxide, and the percentage composition of molybdenum ions and nickel elements was 90% and 10%.

Example 36

The catalyst was prepared by the same procedure as in example 1 except that nickel nitrate was changed to nickel hydroxide, and the percentage composition of molybdenum ions and nickel elements was 90% and 10%.

Example 37

The preparation process of the catalyst was substantially the same as in example 1, except that the molybdenum element was changed to molybdenum trioxide, the percentage composition of molybdenum ions and nickel elements was 90% and 10%, the aeration amount of fluorine gas was 3 times or more the theoretical amount of fluorine gas consumed by the molybdenum trioxide substance and 5 times or less the amount of the molybdenum trioxide substance, and the residual fluorine gas was absorbed by dry soda lime to prepare the molybdenum-based catalyst.

Example 38

The preparation process of the catalyst was substantially the same as in example 1, except that the molybdenum element was changed to molybdenum dioxide, the percentage composition of molybdenum ions and nickel elements was 90% and 10%, the aeration amount of fluorine gas was 2 times or more the theoretical amount of fluorine gas consumed as a precursor of molybdenum ions to the amount of molybdenum dioxide substance and 5/2 times or less, and the residual fluorine gas was absorbed by dried soda lime to prepare a molybdenum-based catalyst.

Example 39

The preparation process of the catalyst was substantially the same as in example 1, except that the molybdenum element was changed to molybdenum pentoxide, the percentage composition of molybdenum ions and nickel elements was 90% and 10%, the aeration amount of fluorine gas was 5 times or more the ratio of the theoretical amount of fluorine gas consumed as a precursor of molybdenum ions to the amount of molybdenum pentoxide, and the residual fluorine gas was absorbed by dry soda lime to obtain a molybdenum-based catalyst.

Example 40

The preparation process of the catalyst is basically the same as that of the example 1, except that the fluorine gas in the activated atmosphere is changed into molybdenum hexafluoride, the ventilation rate of the molybdenum hexafluoride is 1 time or more of the ratio of the theoretical amount of the molybdenum hexafluoride consumed by the precursor of the molybdenum ions to the amount of the molybdenum simple substance, and is 5 times or less, and the residual molybdenum hexafluoride is absorbed by dry soda lime to prepare the molybdenum-based catalyst.

Application example 1

The fluoro-chloro exchange catalyst prepared in example 1 was used in the following reaction to synthesize a series of fluorine-containing olefins:

after 20 hours of reaction, the reaction product was washed with water and then washed with alkali to remove HF, and the organic composition was analyzed by GC, and the results are shown in Table 1. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 1

The fluoroolefin selectivity refers to the ratio of the target products, and refers to the sum of the selectivities to E-HFO-1225ye and Z-HFO-1225ye for reaction (3), and to the sum of the selectivities to E-HFO-1234ze and Z-HFO-1234ze for reactions (4) and (5), and the selectivities to the single target product for the other reactions are all the same.

Application example 2

The catalyst prepared in example 2 was used in the reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 2. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 2

Application example 3

The catalyst prepared in example 3 was used in the reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 3. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 3

Application example 4

The catalyst prepared in example 4 was used in the reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 4. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 4

Application example 5

The catalyst prepared in example 5 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 5. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 5

Application example 6

The catalyst prepared in example 6 was used in the reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 6. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 6

Application example 7

The catalyst prepared in example 7 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 7. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 7

Application example 8

The catalyst prepared in example 8 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 8. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 8

Application example 9

The catalyst prepared in example 9 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 9. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 9

Application example 10

The catalyst prepared in example 10 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 10. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 10

Application example 11

The catalyst prepared in example 11 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 11. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 11

Application example 12

The catalyst prepared in example 12 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 12. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 12

Application example 13

The catalyst prepared in example 13 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 13. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 13

Application example 14

The catalyst prepared in example 14 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 14. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 14

Application example 15

The catalyst prepared in example 15 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 15. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 15

Application example 16

The catalyst prepared in example 16 was used in the reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 16. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 16

Application example 17

The catalyst prepared in example 17 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 17. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 17

Application example 18

The catalyst prepared in example 18 was used in a reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 18. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 18

Application example 19

The catalyst prepared in example 19 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 19. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 19

Application example 20

The catalyst prepared in example 20 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 20. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 20

Application example 21

The catalyst prepared in example 21 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 21. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 21

Application example 22

The catalyst prepared in example 22 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 22. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 22

Application example 23

The catalyst prepared in example 23 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 23. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 23

Application example 24

The catalyst prepared in example 24 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 24. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 24

Application example 25

The catalyst prepared in example 25 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 25. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

TABLE 25

Application example 26

The catalyst prepared in example 26 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 26. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 26

Application example 27

The catalyst prepared in example 27 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 27. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 27

Application example 28

The catalyst prepared in example 28 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 28. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 28

Application example 29

The catalyst prepared in example 29 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 29. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 29

Application example 30

The catalyst prepared in example 30 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 30. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 30

Application example 31

The catalyst prepared in example 31 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 31. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 31

Application example 32

The catalyst prepared in example 32 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 32. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 32

Application example 33

The catalyst prepared in example 33 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 33. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 33

Application example 34

The catalyst prepared in example 34 was used in a reaction for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 34. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 34

Application example 35

The catalyst prepared in example 35 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 35. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 35

Application example 36

The catalyst prepared in example 36 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 36. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 36

Application example 37

The catalyst prepared in example 37 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 37. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 37

Application example 38

The catalyst prepared in example 38 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 38. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 38

Application example 39

The catalyst prepared in example 39 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 39. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 39

Application example 40

The catalyst prepared in example 40 was used in reactions for synthesizing a series of fluorine-containing olefins under substantially the same conditions as in application example 1, and the results are shown in table 40. The catalyst is continuously operated for 1000 hours, and the catalytic activity of the catalyst is basically unchanged.

Watch 40

Claims

1. A molybdenum-based catalyst is composed of molybdenum ions and an auxiliary agent, wherein the molybdenum ions are a combination of trivalent molybdenum ions, tetravalent molybdenum ions and pentavalent molybdenum ions, the auxiliary agent is at least one or more of Al, Mg, Ni, Co, Ti, Zr, V, Fe, Zn, In, Cu, Ag, Cd, Hg, Ga, Sn, Pb, Mn, Ba, Re, Sc, Sr, Ru, Nb, Ta, Ca, Ce, Sb, Tl and Hf, and the mass percent of the molybdenum ions and the auxiliary agent is 80-95% and 5-20%, and the preparation method of the catalyst comprises the following steps:

(3) vacuumizing the roasted product obtained in the step (2) at 220-500 ℃, and then activating in fluorine gas for 6-15 hours under a closed condition to prepare a molybdenum-based catalyst, wherein the total amount of fluorine gas introduced is equal to the sum of the theoretical amount of consumed fluorine gas of a precursor of molybdenum ions and the theoretical amount of consumed fluorine gas of a metal element auxiliary agent; the theoretical amount of fluorine consumed by the precursor of the molybdenum ion is larger than the theoretical amount of fluorine consumed by the precursor of the molybdenum ion for reducing the molybdenum ion into molybdenum trifluoride and smaller than the theoretical amount of fluorine consumed by the precursor of the molybdenum ion for reducing the molybdenum ion into molybdenum pentafluoride;

or (3) firstly vacuumizing the roasted product obtained in the step (2) at 220-500 ℃, and then activating in molybdenum hexafluoride for 6-15 hours under a closed condition to prepare the molybdenum-based catalyst, wherein the total amount of introduced molybdenum hexafluoride is equal to the sum of the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions and the theoretical amount of molybdenum hexafluoride consumed by the metal element auxiliary agent; the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions is greater than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for reduction to molybdenum trifluoride and less than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for reduction to molybdenum pentafluoride.

2. The molybdenum-based catalyst of claim 1, wherein the precursor of the molybdenum ion is at least one or more of elemental molybdenum, molybdenum trioxide, molybdenum dioxide, or molybdenum pentoxide, and the precursor of the promoter is at least one or more of an oxide, hydroxide, nitrate, acetate, or carbonate of the metal.

3. The molybdenum-based catalyst according to claim 2, wherein the precursor of molybdenum ion is elemental molybdenum, the fluorine gas is introduced in an amount of 3/2 times or more and 5/2 times or less the ratio of the theoretical amount of fluorine gas consumed by elemental molybdenum species to the amount of elemental molybdenum species, and the residual fluorine gas is absorbed by dried soda lime to obtain a molybdenum-based catalyst; or

4. The molybdenum-based catalyst according to claim 2, wherein the precursor of the molybdenum ion is elemental molybdenum, the precursor of the promoter is a compound containing nickel or cobalt, and the mass percentages of the molybdenum ion and the promoter metal element are 80-95% and 5-20%.

5. The molybdenum-based catalyst of claim 4, wherein the promoter precursor is nickel nitrate or/and cobalt nitrate.

6. The molybdenum-based catalyst according to claim 5, wherein the precursor of the molybdenum-based catalyst is a mixture of elemental molybdenum and nickel nitrate, wherein the mass percentage composition of molybdenum ions and nickel elements is 90% and 10%; or

The precursor of the molybdenum-based catalyst is a mixture of a molybdenum simple substance and cobalt nitrate, wherein the mass percentage of molybdenum ions and cobalt elements is 90% and 10%.

7. A process for the preparation of the molybdenum-based catalyst according to any one of claims 1 to 6, comprising the steps of:

(1) uniformly mixing the molybdenum simple substance and the precursor of the auxiliary agent according to the mass percentage of the molybdenum ions and the auxiliary agent, and performing compression molding to obtain a catalyst precursor;

or activating the roasted product obtained in the step (2) in molybdenum hexafluoride for 6-15 hours at 220-500 ℃ under a closed condition to prepare a molybdenum-based catalyst, wherein the total amount of introduced molybdenum hexafluoride is equal to the sum of the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions and the theoretical amount of molybdenum hexafluoride consumed by the metal element auxiliary agent; the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions is greater than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for reduction to molybdenum trifluoride and less than the theoretical amount of molybdenum hexafluoride consumed by the precursor of molybdenum ions for reduction to molybdenum pentafluoride.

8. The method according to claim 7, wherein the molybdenum hexafluoride is prepared by:

and reacting the molybdenum simple substance with fluorine gas at the temperature of 20-50 ℃ to obtain the molybdenum hexafluoride.

9. Use of the molybdenum-based catalyst according to any one of claims 1 to 6 for the gas-phase catalysis of halogenated olefins at elevated temperature for the fluorine-chlorine exchange reaction to give fluoroolefins.

10. The use according to claim 9, wherein the halogenated olefin is cyclo-CF₂CF₂CF₂Preparation of Cyclo-CF from CCl ═ CCl₂CF₂CF₂CF＝CCl；

Or the halogenated olefin is 2-chloro-3, 3, 3-trifluoropropene, and 2,3,3, 3-tetrafluoropropene is prepared;

or the halogenated olefin is E/Z-1-chloro-2, 3,3, 3-tetrafluoropropene to prepare E/Z-1,2,3,3, 3-pentafluoropropene;

or the halogenated olefin is E-1-chloro-3, 3, 3-trifluoropropene, and E/Z-1,3,3, 3-tetrafluoropropene is prepared;

or the halogenated olefin is Z-1-chloro-3, 3, 3-trifluoropropene, and E/Z-1,3,3, 3-tetrafluoropropene is prepared.