CN110157473A - Method for synthesizing alkylate oil by catalyzing isopentane-propylene with double-acid ionic liquid - Google Patents

Abstract

The invention discloses a method for synthesizing alkylated oil from isopentane-propylene catalyzed by bi-acidic ionic liquid. Synthesis of alkylate oil; wherein the general structural formula of the double acid ionic liquid catalyst is as follows: Compared with the prior art, the catalyst used in the present invention has both ‑Lewis acidity, two types of acid active sites act synergistically, and have high catalytic activity; the catalyst is immiscible with the reaction raw materials and products, the separation is simple and can be reused; the reaction raw materials used in the present invention are cheap and easy to obtain, and the recovery is simple, It has important practical application value.

Description

A kind of method for catalyzing isopentane-propylene to synthesize alkylate by double acid ionic liquid

technical field

The invention belongs to the technical field of catalysis, and in particular relates to a method for synthesizing alkylated oil from isopentane-propylene catalyzed by a dual-acid ionic liquid.

Background technique

Alkylate is a mixture of isoparaffins and light olefins under the action of acid catalysts. Its components are mainly saturated hydrocarbons, so the combustion products are clean and the combustion calorific value is high. At the same time, the alkylate has Reid has a series of advantages such as low vapor pressure, non-volatile, high octane number, and is an ideal gasoline blending component. Trimethylpentanes (TMPs) are an alkane component in alkylated oils with a research octane number (RON) of up to 100. In the production of alkylated gasoline, the selectivity of TMPs is always desired The bigger the better. With the sharp increase in the number of domestic automobiles, the demand for high-quality gasoline is also increasing day by day. Therefore, it is of great practical significance to use cheap isoparaffins and low-carbon olefins to synthesize alkylate as a gasoline blending component.

The industrially used catalysts for the production of alkylated oil are mainly concentrated sulfuric acid and hydrofluoric acid. These two acid catalysis processes are relatively mature and have good catalytic performance, but these two catalysts still have many defects, such as acid consumption in the concentrated sulfuric acid process. The amount of waste acid is large and the waste acid is difficult to handle, while hydrofluoric acid itself is extremely volatile and highly toxic. Once leaked, it will cause great damage to the environment. In addition, both of the above two processes have the phenomenon of serious corrosion of equipment, so it is very important to develop new catalysts that are environmentally friendly, have no corrosion to equipment, and have low acid consumption.

At present, the most studied new catalysts for the synthesis of alkylate mainly include two categories: solid acid catalysts and ionic liquid catalysts. Among them, solid acid catalysts mainly include molecular sieves, solid superacids (such as heteropolyacids), etc., but these catalysts often have problems such as uneven distribution of acid strength and a small number of acid active sites, resulting in poor reaction performance. The catalyst is easily deactivated by carbon deposition during the reaction due to the limitation of the pore structure.

The reaction raw materials used in the traditional synthetic alkylate oil are isobutane and butene. Since isobutane is often excessive in the reaction process, the excess isobutane needs to be recovered by cryogenic cooling (below minus 25°C). Therefore, the energy consumption is large, and the production of C ₄ hydrocarbons in China also presents a situation of insufficient supply, so the process cost also increases, which is of great significance for the research of new alkylate synthesis process. In China's petroleum refining industry, a large amount of C ₃ and C ₅ hydrocarbons are produced every year. The separation of these substances often requires a lot of money. If these substances are rationally utilized to produce alkylated oil, It can realize the recovery and utilization of tail gas while saving the cost of refining tail gas recovery. At present, there is no report on the synthesis of alkylated oil with C3 and _C5 hydrocarbons. _The dual-acidic ionic liquid catalyst provided by the invention with multiple acid sites can effectively catalyze the alkylation reaction of isopentane-propylene, and the iso- Pentane is liquid at room temperature and does not require cryogenic recovery, which can save a lot of energy, open up a new way for the synthesis of alkylated oils, and has important economic value.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a method for synthesizing alkylated oil by catalyzing isopentane-propylene reaction by bi-acidic ionic liquid in view of the deficiencies of the prior art.

The technical scheme of the present invention is as follows: the reaction raw materials use isopentane and propylene to synthesize the alkylated oil in a high-pressure reaction kettle, and the catalyst used in the present invention simultaneously has -Lewis acidity, two types of acid active sites act synergistically, and have high catalytic activity; the reaction raw materials and products are immiscible with the catalyst used in the present invention, the separation is simple, and the catalyst can be reused; the reaction raw materials used in the present invention are cheap and easy to use It can be obtained, the recovery is simple, the synthesis conditions are mild, and the cost is low, which has important practical significance.

The specific technical scheme of the present invention is as follows: a method for catalyzing isopentane-propylene to synthesize alkylated oil by bi-acidic ionic liquid, characterized in that: using isopentane and propylene as reaction raw materials, bi-acidic ionic liquid as catalyst, Alkylated oil is synthesized by high-pressure alkylation; the general structural formula of the dual-acid ionic liquid catalyst is as follows:

The specific steps are: add isopentane and ionic liquid catalyst to the autoclave coated with polytetrafluoroethylene lining, fasten the lid of the autoclave, exhaust the air in the autoclave with _N2 , start the temperature control device, and use _N2 Press in the kettle, turn on the stirring device to fully mix the catalyst and isopentane, then inject propylene into the kettle with a micro metering pump, control the reaction pressure and stirring speed, and react to synthesize alkylated oil.

Preferably, the mass ratio of isopentane and propylene is 1:(0.05-0.2).

Preferably, the mass ratio of the amount of the bi-acidic ionic liquid catalyst to the propylene is 1:(0.2-1).

The preferred alkylation reaction temperature is 0-25°C; the preferred alkylation reaction time is 5-60 min; the preferred alkylation reaction pressure is 2-4 MPa.

Preferably, the stirring speed of the alkylation reaction is 200-1200 rpm.

The preferred biacidic ionic liquid catalysts are 1-sulfopropyl-3-methylimidazolium chloroaluminate, 1-sulfopropyl-3-methylimidazolium chlorozincate, 1-sulfopropyl-3-methylimidazole Ferric chloride, 1-sulfopropyl-3-methylimidazolium chlorostannate, 1-sulfobutyl-3-methylimidazolium chloroaluminate, 1-sulfobutyl-3-methylimidazolium chloride zinc acid salt, 1-sulfobutyl-3-methylimidazolium chloride ferric acid salt or 1-sulfobutyl-3-methylimidazolium chloride stannous acid salt.

Beneficial effects:

( ₁ ) In the method for synthesizing alkylated oil provided by the present invention, the reaction raw materials used can come from the C3 and _C5 tail gas which are difficult to be separated in petroleum refineries, and the direct utilization of the synthetic alkylated oil can effectively Improve the utilization value of refining tail gas, save the processing cost of refining tail gas, and relieve the demand pressure of _C4 hydrocarbon raw materials.

(2) The method for synthesizing alkylated oil using isopentane-propylene provided by the present invention, the excess isopentane in the reaction raw material does not need to be recovered by cryogenic recovery, thereby reducing energy consumption, and the synthesis conditions are mild, and the required matching Few facilities and easy to implement.

(3) The dual acid ionic liquid catalyst provided by the present invention has both Acidity and Lewis acidity, the synergistic effect of the two acid sites can significantly increase the protonation ability of propylene in the reaction raw materials, and at the same time increase the ability of isopentane to transfer hydride ions and improve the activity of alkylation.

Detailed ways

Example 1:

40g of isopentane and 6g of 1-sulfopropyl- ₃ -methylimidazolium chloroaluminate bis-acid ionic liquid catalyst were added to a 200ml autoclave coated with polytetrafluoroethylene lining, and the lid of the autoclave was quickly tightened. Exhaust the air in the kettle, start the temperature control device, when the temperature in the kettle is 5 ℃, press _N2 into the kettle, turn on the stirring device, first stir for 30min to fully mix the catalyst and isopentane, and then use a micrometering pump Into the kettle, 2g of propylene was injected, and the reaction pressure was 2MPa, the stirring speed was 1200rpm, and the reaction time was 20min. was 18.4%. After the catalyst was reused 4 times, the mass yield of alkylate was 90.4%, and the selectivity of TMPs was 17.7%.

Example 2:

Add 30g of isopentane and 10g of 1-sulfobutyl-3-methylimidazolium chlorozinc salt double acid ionic liquid catalyst to a 200ml autoclave coated with polytetrafluoroethylene lining, fasten the lid of the autoclave, use _N2 Exhaust the air in the kettle, start the temperature control device, when the temperature in the kettle is 0 °C, press _N2 into the kettle, turn on the stirring device, stir for 30 min to fully mix the catalyst and isopentane, and then use a micrometering pump Into the kettle, 2g of propylene was injected, the reaction pressure was 3MPa, the stirring speed was 1000rpm, and the reaction time was 5min. was 18.0%. After the catalyst was reused 6 times, the mass yield of alkylate was 84.7%, and the selectivity of TMPs was 17.2%.

Example 3:

20g of isopentane and 4g of 1-sulfopropyl- ₃ -methylimidazolium chlorostannate bis-acid ionic liquid catalyst were added into a 200ml autoclave coated with polytetrafluoroethylene lining, and the lid of the autoclave was quickly tightened. Exhaust the air in the kettle, start the temperature control device, when the temperature in the kettle is 15 ℃, press _N2 into the kettle, turn on the stirring device, stir for 30min to fully mix the catalyst and isopentane, and then use a micrometering pump Into the kettle, 2g of propylene was injected, and the reaction pressure was 3MPa, the stirring speed was 600rpm, and the reaction time was 40min. was 15.8%. After the catalyst was reused 5 times, the mass yield of alkylate was 78.8%, and the selectivity of TMPs was 15.3%.

Example 4:

Add 10g of isopentane and 2g of 1-sulfobutyl-3-methylimidazolium chloride ferric acid diacid ionic liquid catalyst to a 200ml autoclave coated with polytetrafluoroethylene lining, fasten the lid of the kettle, and use N ₂ The air in the kettle was exhausted, and the temperature control device was started. When the temperature in the kettle was 25 °C, _N2 was used to press into the kettle, the stirring device was turned on, and the catalyst was stirred for 30 min to fully mix the isopentane. When 2g of propylene was injected into the kettle, the reaction pressure was 4MPa, the stirring speed was 200rpm, and the reaction time was 60min, the mass yield of the alkylate (to the liquid yield of the feed propylene) was 66.2%, and the selectivity of TMPs was 11.3%. After the catalyst was reused four times, the mass yield of alkylate was 65.1%, and the selectivity of TMPs was 10.7%.

Claims (8)

1. a method for bi-acidic ionic liquid catalyzing isopentane-propylene to synthesize alkylated oil, it is characterized in that: take isopentane and propylene as reaction raw materials, bi-acidic ionic liquid is catalyzer, adopts high pressure alkylation method to synthesize Alkylate oil; wherein the general structural formula of the double acid ionic liquid catalyst is as follows: 2. method according to claim 1 is characterized in that the mass ratio of described isopentane and propylene is 1:(0.05～0.2). 3. method according to claim 1 is characterized in that the mass ratio of the consumption of biacidic ionic liquid catalyst and propylene is 1:(0.2～1). 4. The method according to claim 1, wherein the alkylation reaction temperature is 0-25°C. 5. method according to claim 1 is characterized in that the alkylation reaction time is 5～60min. 6. The method according to claim 1, wherein the alkylation reaction pressure is 2-4 MPa. 7 . The method according to claim 1 , wherein the stirring speed of the alkylation reaction is 200-1200 rpm. 8 . 8. method according to claim 1 is characterized in that biacidic ionic liquid catalyst is 1-sulfopropyl-3-methylimidazolium chloroaluminate, 1-sulfopropyl-3-methylimidazolium chlorozinc acid salt, 1-sulfopropyl-3-methylimidazolium chloroferric acid salt, 1-sulfopropyl-3-methylimidazolium chlorostannate, 1-sulfobutyl-3-methylimidazolium chloroaluminate, Any of 1-sulfobutyl-3-methylimidazolium chlorostannate, 1-sulfobutyl-3-methylimidazolium chloroferric acid or 1-sulfobutyl-3-methylimidazolium chlorostannate A sort of.