阅读说明：本技术 一种催化剂及其在七氟丙烷制备中的应用 (Catalyst and application thereof in preparation of heptafluoropropane ) 是由 何建明 裴文 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种催化剂,该催化剂由金属氟化物或金属氧化物中任选至少三种的混合物、用氢氟酸充分浸泡并干燥粉碎后的黏土、用氢氟酸充分浸泡并干燥后的稻壳炭按质量比1：1～3：1～3制得。以及该催化剂在七氟丙烷制备中的应用。本发明的氟化催化体系所用的原料价廉易得,成本低,反应过程中无聚合物富集,催化剂的使用寿命大大延长；催化剂制备工艺简单,对设备要求低,反应条件温和,原料的转化率达到了95％以上；该氟化催化体系在干燥的环境下不分解、不易燃,可连续使用。(The invention discloses a catalyst, which is prepared by mixing at least three of metal fluoride or metal oxide, clay which is fully soaked by hydrofluoric acid and dried and crushed, and rice hull carbon which is fully soaked by hydrofluoric acid and dried according to the mass ratio of 1: 1-3: 1-3. And the application of the catalyst in the preparation of heptafluoropropane. The raw materials used by the fluorination catalytic system are cheap and easily available, the cost is low, no polymer is enriched in the reaction process, and the service life of the catalyst is greatly prolonged; the catalyst has simple preparation process, low requirement on equipment, mild reaction conditions and high conversion rate of raw materials up to over 95 percent; the fluorination catalytic system is not decomposed and is not flammable in a dry environment, and can be continuously used.)

1. A catalyst, characterized by: the catalyst is prepared by mixing at least three selected from metal fluoride or metal oxide, clay which is fully soaked by hydrofluoric acid and dried and crushed, and rice hull carbon which is fully soaked by hydrofluoric acid and dried according to the mass ratio of 1: 1-3: 1-3.

2. The catalyst of claim 1, wherein: the metal fluoride or the metal oxide is weighed and then burned for 1-5 hours at 300-600 ℃, and the mixture is crushed for use.

3. The catalyst of claim 2, wherein: adding the raw materials into a stirring container, introducing hydrogen fluoride gas, fully stirring and mixing until the hydrogen fluoride gas is absorbed to be saturated, and pressing into a strip catalyst.

4. The catalyst of claim 1, wherein: the metal oxide is one of sodium fluoride, potassium fluoride, magnesium fluoride and aluminum fluoride, and the metal oxide is one of magnesium oxide, aluminum oxide and chromium oxide.

5. The catalyst of claim 1, wherein: the mass concentration of hydrofluoric acid for soaking the clay and the rice husk carbon is 30-50%, and the soaking time is 1-5 hours.

6. The catalyst according to claim 1 or 3, characterized in that: the rice husk carbon is obtained by fully carbonizing rice husk by concentrated sulfuric acid.

7. Use of a catalyst according to any one of claims 1 to 6 in the preparation of heptafluoropropane.

8. Use according to claim 7, characterized in that: pumping 150kg/h of hexafluoropropylene and 20-40 kg/h of hydrogen fluoride into a preheating reactor by a pump, preheating to the reaction temperature of 100-220 ℃, and then preheating at 6kg/cm²The reaction is carried out in a pipeline reaction kettle filled with a strip catalyst under absolute pressure, and after the reaction is finished, the material is distilled into a condensation separation tower for separation to obtain the product.

Technical Field

The invention relates to a catalyst and application thereof, belonging to the technical field of industrial catalysis.

Background

Heptafluoropropane (HFC-227) has gradually become the main variety of indoor fire extinguishing agents as a substitute for Halon 1301. The heptafluoropropane is colorless and tasteless gas at normal temperature, is non-conductive, non-corrosive, free of environmental protection limitation and short in atmospheric persistence. Although heptafluoropropane is relatively stable at room temperature, it decomposes at high temperatures to generate hydrogen fluoride, which is harmful to the human body. Other combustion products also include carbon monoxide and carbon dioxide. Since heptafluoropropane does not contain chlorine or bromine and does not have a destructive effect on the atmospheric ozone layer, halon 1301 and halon 1211 which are harmful to the environment are replaced to serve as raw materials of the fire extinguishing agent. Therefore, from the purposes of reducing cost and improving process, the research and development of the novel heptafluoropropane catalyst and the application thereof in production have important significance for the sustainable development of enterprises.

The conventional processes for producing heptafluoropropane mainly include a perfluoropropene fluorination process, a propane (propene or a derivative thereof) bio-electrolysis process, a heptafluorochloropropane catalytic hydrogenation process, a propylene/propane catalytic chlorofluorination process, and the like. Wherein the direct use of propane (propylene or its derivatives) for the biological electrolysis of HFC-227ea has great difficulty, quite complex side reactions and low yield. The method for synthesizing HFC-227ea by catalytic hydrogenation of heptafluoropropane is a newly developed method in the nineties, breaks through the limitation of using perfluoropropene as a raw material, is relatively advanced in process, has the problem that the raw material cannot be matched, and is difficult to realize industrial production. The catalytic chlorofluorination method of propylene and propane uses propylene and propane as raw material, and utilizes them to simultaneously catalyze chlorofluorination with hydrogen fluoride and chlorine gas so as to synthesize series of valuable CF₃CCl₂CCl₃、CF₃CClFCF₃Intermediates which are then fluorinated to directly produce HFC-227 ea. However, the catalytic chlorofluorination process in this method is relatively complicated, and it is difficult to industrially produce the catalyst by recycling the raw materials, which makes the process difficult. In addition, chinese patent CN102731245B, a method for producing heptafluoropropane, adopts a direct liquid phase addition process of perfluoropropene and hydrogen fluoride. The perfluoropropene fluorination method has the advantages of short process route, sufficient raw material source, high conversion rate, high selectivity and small catalyst manufacturing difficulty, reactors, compressors, rectifying towers and the like used in the production process are all conventional chemical equipment, equipment import is not needed, an ionic liquid catalytic system consisting of alkali metal fluoride and amide ionic liquid is utilized, the stable temperature range is large, the chemical stability is good, and the catalytic system is easy to recycle. However, as is well known to the applicant, the technology has been found for a long time to produce, in the case of a liquid phase addition process, an ionic liquid catalyst system in which a part of hexafluoropropylene polymer is adhered to or retained in the reaction process during completion of the reaction, and which is composed of an alkali metal fluoride and an amide ionic liquid, and in spite of the above advantages, it is necessary to develop the catalyst system for sustainable developmentFurther improvements to the process are desired.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a novel catalyst, which can be used for preparing heptafluoropropane by a gas phase method, has long service life and low cost, and improves the conversion rate of raw materials.

In order to solve the technical problems, the invention firstly discloses a catalyst, which is prepared by mixing at least three optional components of metal fluoride or metal oxide, clay which is fully soaked by hydrofluoric acid and dried and crushed, and rice hull carbon which is fully soaked by hydrofluoric acid and dried according to the mass ratio of 1: 1-3: 1-3.

Furthermore, the metal fluoride or the metal oxide is weighed and then burned for 1-5 hours at 300-600 ℃, and the mixture is crushed for use.

Further, the raw materials are added into a stirring container, hydrogen fluoride gas is introduced, then the raw materials are fully stirred and mixed until the hydrogen fluoride gas is absorbed and saturated, and the mixture is pressed into a strip catalyst.

Further, the metal oxide is one of sodium fluoride, potassium fluoride, magnesium fluoride and aluminum fluoride, and the metal oxide is one of magnesium oxide, aluminum oxide and chromium oxide, and optionally at least three of the metal oxide and the chromium oxide are mixed in any ratio.

Furthermore, the mass concentration of hydrofluoric acid for soaking the clay and the rice husk carbon is 30-50%, and the soaking time is 1-5 hours.

Further, the rice husk carbon is obtained by fully carbonizing rice husks by concentrated sulfuric acid.

The invention also discloses an application of the catalyst in preparation of heptafluoropropane.

Further, pumping 150kg/h of hexafluoropropylene and 20-40 kg/h of hydrogen fluoride into a preheating reactor by a pump, preheating to the reaction temperature of 100-220 ℃, and then preheating at 6kg/cm²The reaction is carried out in a pipeline reaction kettle filled with a strip catalyst under absolute pressure, and after the reaction is finished, the material is distilled into a condensation separation tower for separation to obtain the product.

Namely, the catalyst of the invention is used for preparing heptafluoropropane by a gas phase method. The chemical reaction formula is as follows:

HF+C₃F₆→CF₃CHFCF₃。

the invention has at least the following advantages:

1) the raw materials used by the fluorination catalytic system are cheap and easily available, the cost is low, no polymer is enriched in the reaction process, and the service life of the catalyst is greatly prolonged;

2) the fluorination catalyst has the advantages of simple preparation process, low requirement on equipment, mild reaction conditions and high conversion rate of raw materials up to more than 95%;

3) the fluorination catalytic system is not decomposed and is not flammable in a dry environment, and can be continuously used.

Detailed Description

The present invention will be described more specifically with reference to examples. The practice of the present invention is not limited to the following examples, and any modification or variation of the present invention is within the scope of the present invention.