Method for efficiently recycling light components of rearrangement reaction

Abstract

The application provides a light component efficient recovery method, through controlling the rectification separation condition of a Saucy-Marbet reaction liquid, a light component fraction without 2,2-dimethoxypropane or heavier components is obtained, the light component fraction is mixed with a certain amount of a cracking auxiliary, and then is directly introduced into a cracking reactor, 2,2-dimethoxypropane is converted into 2-methoxypropylene and methanol through high-temperature cracking, and then the mixture obtained through cracking is subjected to rectification separation, and the useful component, 2-methoxypropylene, is recycled and utilized. The application simplifies the separation and recycling process of the light component byproduct of the Saucy-Marbet reaction, improves the recycling rate of raw materials, and reduces the operation cost of the project.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of fine chemicals for perfumery, nutraceuticals, daily chemicals, etc., and particularly relates to a method for efficient recovery and utilization of light components in rearrangement reaction. BACKGROUND

[0002] The Saucy-Marbet reaction refers to a reaction of propargyl alcohol and 2-methoxy propene under the action of a catalyst to obtain a ketone allene, and the product ketone allene is also called allene ketone. The Saucy-Marbet reaction was first reported by chemists Saucy and Marbet (R. Marbet, G. Saucy, Helv. Chim. Acta. 1967, 50, 1158-1167; US3029287, US6184420), and in the initial report, the chemists used strong acids such as p-toluenesulfonic acid, methanesulfonic acid, and sulfuric acid for catalysis, and the rearrangement product was obtained in a high yield. The Saucy-Marbet reaction has the advantages of easy availability of starting materials, fast reaction speed, and high yield, and has been widely used in the synthesis of chemicals for perfumery, nutraceuticals, and daily chemicals.

[0003]

[0004] In the Saucy-Marbet rearrangement reaction, an excess of 2-methoxy propene is generally required relative to the propargyl alcohol substrate, and sometimes the amount is as much as 3-5 equivalents, because when the propargyl alcohol and 2-methoxy propene react, one equivalent of alkyl alcohol is produced, and under the Saucy-Marbet rearrangement reaction conditions, the alkyl alcohol will react with another molecule of 2-methoxy propene to form 2,2-dimethoxypropane or a dialkoxy acetal, so in order to make the Saucy-Marbet reaction proceed completely, the amount of 2-methoxy propene is at least 2 equivalents of the alkyl alcohol. In addition to the above reason, 2-methoxy propene is not stable under acidic conditions and is prone to self-polymerization, electrophilic substitution, and other side reactions; an excess of 2-methoxy propene can improve the reaction rate and improve the reaction selectivity; therefore, in actual application, the amount of 2-methoxy propene added is far in excess. Although the excess addition reduces the economy of the reaction, since the price of 2-methoxy propene is relatively low, this is also acceptable in terms of economy.

[0005]

[0006] However, the excessive addition of 2-methoxypropene also brings some problems. If the excessive 2-methoxypropene is not recovered at all, the atomic economy of the reaction is poor, and the production cost is also increased accordingly. From the production and cost point of view, it is better to recycle the excessive 2-methoxypropene. Generally speaking, the Saucy-Marbet reaction uses a Bronsted acid catalyst, and the raw materials propargyl alcohol and 2-methoxypropene are sensitive to acid. In addition, the reaction temperature is relatively high, and a certain amount of side reactions such as dehydration, dimerization, and cyclization will occur in the two raw materials. According to our experience, there are more than twenty kinds of by-products in the light components of the Saucy-Marbet reaction, and they are all components with very similar boiling points. A very high plate number rectification column is needed to better recover useful components such as 2-methoxypropene and 2,2-dimethoxypropane in the light components. Such separation method consumes a large amount of steam and manpower, and additionally increases the production cost (CN105384615A, US20020161263A1).

[0007] In summary, the Saucy-Marbet rearrangement reaction is a very efficient method for synthesizing ketone-based allenes from propargyl alcohol. In normal production, a large excess of 2-methoxypropene is generally added to promote the reaction to proceed quickly and improve the yield of allene ketone. In order to improve the atomic economy and reduce the production cost, it is necessary to recover the light components of the Saucy-Marbet reaction. However, the components of the light components are complex and have similar boiling points. A large amount of steam is generally consumed for rectification to recover relatively pure 2-methoxypropene and 2,2-dimethoxypropane. Therefore, there is an urgent need to develop a new Saucy-Marbet reaction light component recovery process and flow to reduce separation cost and improve project economy. SUMMARY

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0009] On the one hand, the present application provides a method for efficient recovery and utilization of light components of rearrangement reaction. The rearrangement reaction is a Saucy-Marbet reaction, that is, propargyl alcohol and 2-methoxypropene react under the action of a catalyst to obtain a ketone-based allene.

[0010] S1: The light components are separated from the rearrangement reaction liquid obtained by reacting propargyl alcohol and 2-methoxypropene under the action of a catalyst by rectification;

[0011] S2: A cracking aid is added to the separated light components for vaporization and cracking, and the cracking is completed and then cooled;

[0012] S3: The cracking liquid is subjected to azeotropic rectification and extractive rectification in sequence to separate pure 2-methoxypropene.

[0013] In the present application, first, by controlling the rectification separation conditions of Saucy-Marbet reaction liquid, the components with higher boiling point than 2,2-dimethoxypropane in the reaction liquid, including isopropylidene acetone, ketone alkyne, etc. are left in the tower kettle, and the light components are collected at the top of the tower; the rectification is carried out in a rectification tower, and the operation conditions of the rectification tower are as follows: the number of plates is 30-35, the top temperature is 35-40℃, the kettle temperature is 138-140℃, the reflux ratio is 1.5:1-3.0:1, and the top pressure is 30-40kPa; the typical light component obtained by the above method is composed of the following (mass percentage): 2-methoxypropylene (21.2-26.7%), 2,2-dimethoxypropane (62.5-67.5%), and the rest is methanol, acetone, isoprene, isoamyl alcohol and other impurities (10.8-11.3%).

[0014] In the present application, after the above light component is separated, a cracking aid is added to it, and the cracking aid is selected from one or more of water, methanol, ethanol, ammonia, trimethylamine, triethylamine, dimethyl ethylamine, and pyridine, and the addition amount of the cracking aid is 0.1-1.5wt% of the mass of the light component.

[0015] In the present application, the vaporization and cracking process is carried out in a vaporization tank and a high-temperature cracking reaction tube. Specifically, after the light component is mixed with the cracking aid, it is directly introduced into the vaporization tank, the vaporization temperature is 220-260℃, and after complete vaporization, it is introduced into the high-temperature cracking reaction tube for cracking, the cracking temperature is 280-320℃, the mass space velocity is 0.5-20h -1 , and the reaction pressure is 0.1-0.2MPaG.

[0016] In the present application, the cracking process is carried out in the presence of a cracking catalyst, and the cracking catalyst is preferably ZSM molecular sieve, magnesium pyrophosphate, aluminum phosphate salt, etc. as the catalyst; the amount of the cracking catalyst is not particularly limited, and is preferably 1%-10wt% of the mass of the light component. The reactor is preferably a tubular reactor, and the material feeding mode is top-in and bottom-out.

[0017] In the present application, the cooling process after the completion of the cracking is carried out by using circulating water for quenching, and the temperature of the circulating water used is 5-11℃, and after quenching, the material changes from gaseous state to liquid state, and the temperature is controlled to be not more than 15℃.

[0018] In the present application, after cooling, the cracked liquid is separated by azeotropic rectification and extractive rectification in turn to obtain pure 2-methoxypropylene, so as to realize the recycling of 2-methoxypropylene.

[0019] In the present application, the azeotropic distillation conditions are as follows: the number of plates is 18-25, the top temperature is 32-33℃, the bottom temperature is 58-62℃, the reflux ratio is 2:1-4:1, and the top pressure is 90-110kPa; the cracking liquid is continuously fed into the bottom of the column, and the azeotrope of 2-methoxy propene and methanol is taken out from the top, wherein the content of 2-methoxy propene is 91.9-92.5%.

[0020] In the present application, the extractive distillation conditions are as follows: the number of plates is 18-25, the top temperature is 33-34℃, the bottom temperature is 98-115℃, the reflux ratio is 0.5:1-2:1, the top pressure is 90-110kPa, the azeotrope of 2-methoxy propene and methanol is continuously fed into the bottom of the column, and 2-methoxy propene is taken out from the top, wherein the purity of 2-methoxy propene is 99.2-99.5%.

[0021] In the present application, the extractant of extractive distillation is selected from one or more of N-methyl pyrrolidone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and water, preferably N-methyl pyrrolidone or water; and the feed amount of extractant is 0.3-0.4 times that of the cracking liquid.

[0022] The present application has the following positive effects by adopting the above technical scheme:

[0023] 1. The recovery and separation scheme of light components is simplified. The original process is to separate 2-methoxy propene and 2,2-dimethoxy propane by distillation and then crack them. The present scheme omits this step, and the mixture is directly cracked, thus simplifying the process.

[0024] 2. A certain amount of cracking aid is added to the light components to prevent coking on the surface of the high-temperature cracking catalyst. The main reason for coking on the surface of the catalyst is that 2-methoxy propene is dimerized, trimerized or even polymerized after being de-methylated on the surface of the catalyst, and then dehydrated and coked. By adding a certain amount of aid such as trimethylamine, triethylamine, pyridine, water, etc., the occurrence of the side reaction can be effectively prevented. The aid water can even react with the oligomers to generate acetone and methanol, thereby reducing the content of oligomers and improving the selectivity of the cracking reaction and prolonging the service life of the catalyst.

[0025] 3. The reaction liquid after cracking is separated by azeotropic distillation and extractive distillation, which saves the energy consumption of separation and reduces the project cost. DETAILED DESCRIPTION

[0026] The present application will be described in detail below by examples, but the present application is not limited to the following examples.

[0027] The main raw material information is as follows:

[0028] Saucy-Marbet reaction solution, self-made by Wanhua, which can be prepared by referring to the method in the published patent (Patent Application No. 201910519957.X Example 6); methanol, purity > 99.9%, Nantong Runfeng; triethylamine, pyridine, purity 99%, Bailingwei; deionized water, self-made; ZSM-5 molecular sieve, Zhongjie Energy Wanrun, pore size 0.53-0.58 nm, SSA > 300, silicon aluminum ratio 70; magnesium pyrophosphate, aluminum pyrophosphate, Anhui Zesheng, reagent grade. 50% aqueous solution of trimethylamine, dimethyl ethylamine, Anjige, AR.

[0029] The gas chromatography test conditions of the present application are as follows:

[0030] Instrument model: Agilent 7890B; chromatographic column: HP-VOC / (6% -cyanopropyl phenyl)-polymethylsiloxane (60m x 0.32mm x 1.8μm); carrier gas: nitrogen, carrier gas flow rate: 1.5mL / min; column temperature: initial temperature 50℃, hold for 2min, then increase the temperature to 80℃ at 5℃ / min, increase the temperature to 250℃ at 30℃ / min, hold for 10min; vaporization chamber temperature 160℃, detector temperature 260℃; split injection, split ratio 100:1; injection amount: 0.2μL; hydrogen flow rate: 40mL / min; air flow rate: 400mL / min, tail gas flow rate 30mL / min. Carrier gas nitrogen, purity not less than 99.99%; fuel gas hydrogen, purity not less than 99.99%; auxiliary gas (spacer purge and tail): nitrogen with the same properties as the carrier gas. The retention time of 2-methoxypropene is 7.43min, and the retention time of 2,2-dimethoxypropane is 10.54min.

[0031] Example 1

[0032] The light component was separated from the rectification rearrangement reaction solution

[0033] A 2L three neck flask equipped with magnetic stirrer was charged with a small amount of Saucy-Marbet reaction liquid (150 mL) at room temperature. A 1 m long rectifying column was attached to the top of the 2L three neck flask and a reflux ratio controller. The column was packed with 3*3 spiral packing and the total number of plates was 30. The three neck flask was placed in an oil bath and the oil bath was turned on with stirring and heating. The stirring was controlled at 600 rpm and the oil bath temperature was controlled at 145°C, so that the temperature in the three neck flask was maintained at 138-140°C. The water condenser and vacuum system were turned on and the condensing temperature was controlled at 5°C and the overhead pressure was controlled at 30 kPa. After the temperature and pressure of the overhead and the bottom were stable, the Saucy-Marbet reaction liquid was continuously fed and the heavy components were continuously removed from the bottom by a laminar flow pump and the light components were removed from the overhead. The overhead condensing temperature was 35°C and the reflux ratio was 1.5:1. The overhead and the bottom samples were taken at regular intervals and the sample composition was analyzed by GC. The results are shown in the following table. By using the above conditions, the components heavier than 2,2-dimethoxypropane were basically removed from the bottom and the overhead light components were basically free of them. The overhead composition was as follows: 2-methoxypropene (26.7%), 2,2-dimethoxypropane (62.4%), and the rest was dimethyl ether, acetone, methanol, isoprene and other impurities (10.8%).

[0034] Table-1 Saucy-Marbet reaction liquid distillation separation data 1

[0035]

[0036] Example 2

[0037] Distillation of rearrangement reaction liquid to separate light components

[0038] A 2 L three-necked flask equipped with magnetic stirrer was charged with a small amount of Saucy-Marbet reaction liquid (150 mL) at room temperature. A 1.2 m long rectifying column was connected to the top of the 2 L three-necked flask, and a reflux ratio controller was connected to the top of the column. The column was filled with 3*3 spiral packing with a total plate number of 35. The three-necked flask was placed in an oil bath, and the oil bath was stirred and heated. The stirring speed was controlled at 600 rpm, and the oil bath temperature was controlled at 145 °C, so that the temperature in the three-necked flask was maintained at 140 °C. The water-cooled condenser and vacuum system were started, and the condensing temperature was controlled at 5 °C, and the pressure at the top of the column was controlled at 40 kPa. After the temperature and pressure at the top and bottom of the column were stabilized, the Saucy-Marbet reaction liquid was continuously fed, and heavy components were continuously removed from the bottom of the column by a laminar flow pump, and light components were removed from the top of the column. The temperature of the light components before condensation was 40 °C, and the reflux ratio at the top of the column was 3:1. The samples at the top and bottom of the column were taken at regular intervals, and the composition of the samples was analyzed by GC. The results are shown in the following table. By using the above conditions, the components heavier than 2,2-dimethoxypropane were basically removed from the bottom of the column, and only a small amount of light components were removed from the top of the column. The composition of the light components at the top of the column was as follows: 2-methoxypropene (21.2%), 2,2-dimethoxypropane (67.5%), and the rest were dimethyl ether, acetone, methanol, isoprene and other impurities (11.3%).

[0039] Table-2 Saucy-Marbet reaction liquid distillation separation data 2

[0040]

[0041] Example 3

[0042] High-temperature cracking of light components after mixing with cracking aids

[0043] The light components obtained in Example 1 were taken as 310 g, and triethylamine was first added to the light components at a dosage of 1.6 g. The resulting mixture was uniform and clear, and no phase separation occurred. A tubular reactor with a length of 1 m and a diameter of 2.5 cm was used for the cracking reaction. The middle part of the reaction tube was filled with ZSM-5 molecular sieve catalyst with a mass of 10 g, and quartz sand (particle size 0.5-0.8 mm) was filled above and below the catalyst to stabilize and support the catalyst. The light components mixed with triethylamine were fed into the vaporization tank at a flow rate of 30.0 g / h through a flowmeter, and the temperature of the vaporization tank was controlled at 220-230 °C, and the pressure was 0.1 MPaG. After the light components were completely vaporized, they entered the reaction tube from the top of the reaction tube, and the temperature of the catalyst layer was maintained at 300 °C. After the light components were in contact with the catalyst for a short time, they were quickly discharged from the reaction tube, and were liquefied after being rapidly cooled to 5 °C, and then entered the collection tank. The average collection rate of the collection tank was measured to be 29.9 g / h, and the GC analysis composition is shown in Table 3. The calculation of 2,2-dimethoxypropane cracking conversion rate was 99.7%, and the selectivity was 98.0%. The reaction was continuously carried out for 30 h, and no conversion rate decrease and catalyst deactivation were found.

[0044] Table-3 Pyrolysis data of light component

[0045]

[0046] Example 4

[0047] Pyrolysis of light component after mixing with pyrolysis aids

[0048] Take 280g of light component obtained in Example 1, first add 22.4g of pyridine to it, mix well, the obtained mixture is clear and homogeneous, no phase separation occurs. Use a tubular reactor with length of 1m and diameter of 2.5cm to carry out the pyrolysis reaction, fill the middle part of the reactor tube with catalyst magnesium pyrophosphate, the filling mass is 5g, fill quartz sand (particle size 0.5-0.8mm) above and below the catalyst, for stabilizing and supporting the catalyst. The light component mixed with pyridine enters the vaporization tank through the flow meter at a flow rate of 25.0g / h, control the temperature of the vaporization tank at 230-240℃, the pressure is 0.2MPaG. After the light component is completely vaporized, it enters the reactor tube from the top of the reactor tube, the temperature of the catalyst layer is maintained at 320℃, the light component contacts the catalyst for a short time, then quickly discharges from the reactor tube, after rapid cooling to 5℃, it is liquefied, then enters the collection tank. The average production rate of the collection tank is 24.5g / h, the GC analysis composition is shown in Table 3, the calculated 2,2-dimethoxypropane pyrolysis conversion rate is 98.3%, the selectivity is 97.6%, the reaction is continuously carried out for 10h, no conversion rate decrease and catalyst deactivation phenomenon is found.

[0049] Table-4 Pyrolysis data of light component

[0050]

[0051] Example 5

[0052] Pyrolysis of light component after mixing with pyrolysis aids

[0053] Take the light component 370g obtained in Example 1, first to it add 5.55g (50% aqueous solution) of trimethylamine aqueous solution, mixed evenly, the resulting mixture is uniform and clear, no phase separation. Using a length of 1 m, a diameter of 2.5 cm tube reactor for cracking reaction, the middle part of the reaction tube is filled with catalyst ZSM-5 molecular sieve, the filling mass is 10 g, the catalyst is filled with quartz sand (particle size 0.5-0.8 mm) at the top and bottom, which is used to stabilize and support the catalyst. The mixed methanol and water light component enters the vaporization tank through the flowmeter at a flow rate of 30.0 g / h, the temperature of the vaporization tank is controlled at 210℃, and the pressure is 0.1 MPaG. After the light component is completely vaporized, it enters the reaction tube from the top of the reaction tube, and the temperature of the catalyst layer is maintained at 280℃. The light component contacts the catalyst for a short time and is quickly discharged from the reaction tube, then it is liquefied after rapid cooling, and then it enters the collection tank. The average production rate of the collection tank is 5.0 g / h, and the GC analysis composition is shown in Table 3. The calculated 2,2-dimethoxypropane cracking conversion rate is 99.5%, the selectivity is 98.5%, and the reaction is continuously carried out for 60 h, without finding the conversion rate decrease and catalyst deactivation phenomenon.

[0054] Table-5 High temperature cracking data of light component

[0055]

[0056]

[0057] Example 6

[0058] High temperature cracking of light component mixed with cracking aid

[0059] Take the light component 410g obtained in Example 1, first to it add 4.1g of dimethylethylamine, mixed evenly, the resulting mixture is uniform and clear, no phase separation. Using a length of 1 m, a diameter of 2.5 cm tube reactor for cracking reaction, the middle part of the reaction tube is filled with catalyst ZSM-5 molecular sieve, the filling mass is 12 g, the catalyst is filled with quartz sand (particle size 0.5-0.8 mm) at the top and bottom, which is used to stabilize and support the catalyst. The mixed dimethylethylamine light component enters the vaporization tank through the flowmeter at a flow rate of 60.0 g / h, the temperature of the vaporization tank is controlled at 210-220℃, and the pressure is 0.1 MPaG. After the light component is completely vaporized, it enters the reaction tube from the top of the reaction tube, and the temperature of the catalyst layer is maintained at 290℃. The light component contacts the catalyst for a short time and is quickly discharged from the reaction tube, then it is liquefied after rapid cooling, and then it enters the collection tank. The average production rate of the collection tank is 58.9 g / h, and the GC analysis composition is shown in Table 6. The calculated 2,2-dimethoxypropane cracking conversion rate is 99.3%, the selectivity is 98.3%, and the reaction is continuously carried out for 6 h, without finding the conversion rate decrease and catalyst deactivation phenomenon.

[0060] Table-6 Pyrolysis data of light fraction with methanol

[0061]

[0062] Example 7

[0063] Pyrolysis of light fraction mixed with methanol

[0064] Take the light fraction 460g obtained in Example 2, first add 6.9g of anhydrous methanol to it, the resulting mixture is uniform and clear, no phase separation occurs. Use a tubular reactor with a length of 1m and a diameter of 2.5cm to carry out the pyrolysis reaction, the middle part of the reaction tube is filled with ZSM-5 molecular sieve catalyst, the filling mass is 15g, and quartz sand (particle size 0.5-0.8mm) is filled above and below the catalyst to stabilize and support the catalyst. The light fraction mixed with methanol and water is introduced into the vaporization tank through the flowmeter at a flow rate of 25.1g / h, the temperature of the vaporization tank is controlled at 250-260℃, and the pressure is 0.1MPaG. After the light fraction is completely vaporized, it enters the reaction tube from the top of the reaction tube, the temperature of the catalyst layer is maintained at 320℃, and after the light fraction is in brief contact with the catalyst, it is quickly discharged from the reaction tube, then it is liquefied after being rapidly cooled to 11℃, and then it is introduced into the collection tank. The average production rate of the collection tank is 25.1g / h, the GC analysis composition is shown in Table 3, the calculation of 2,2-dimethoxypropane pyrolysis conversion rate is 99.6%, the selectivity is 93.2%, and the reaction is continuously carried out for 15h, no conversion rate decrease and catalyst deactivation phenomenon is found.

[0065] Table-7 Pyrolysis data of light fraction with methanol

[0066]

[0067] Example 8

[0068] Pyrolysis of light fraction directly

[0069] Take the light fraction 305g obtained in Example 2, use a tubular reactor with a length of 1m and a diameter of 2.5cm to carry out the pyrolysis reaction, the middle part of the reaction tube is filled with ZSM-5 molecular sieve catalyst, the filling mass is 15g, and quartz sand (particle size 0.5-0.8mm) is filled above and below the catalyst to stabilize and support the catalyst. The light fraction is introduced into the vaporization tank through the flowmeter at a flow rate of 25.1g / h, the temperature of the vaporization tank is controlled at 250-260℃, and the pressure is 0.1MPaG. After the light fraction is completely vaporized, it enters the reaction tube from the top of the reaction tube, the temperature of the catalyst layer is maintained at 320℃, and after the light fraction is in brief contact with the catalyst, it is quickly discharged from the reaction tube, then it is liquefied after being rapidly cooled to 11℃, and then it is introduced into the collection tank. The average production rate of the collection tank is 25.1g / h, the GC analysis composition is shown in Table 3, the calculation of 2,2-dimethoxypropane pyrolysis conversion rate is 83.5%, the selectivity is 78.6%, and the reaction is continuously carried out for 10h.

[0070] Table-8 Light components pyrolysis data at high temperature

[0071]

[0072] Example 9

[0073] azeotrope distillation separation of pyrolysis liquid

[0074] Take the pyrolysis liquid obtained in Example 3, 280 g, at room temperature, into a 2L three-necked flask equipped with a magnetic stirrer, connect a 0.6m long rectifying column and reflux ratio controller above the three-necked flask, fill the column with 3*3 tri-leg spiral packing, and the total number of plates is about 18. Put the three-necked flask into an oil bath, turn on the oil bath stirring, and control the stirring speed at 600 rpm; turn on the oil bath to control the oil bath temperature at about 64°C, so that the temperature in the three-necked flask is maintained at 58°C. Turn on the condenser water at the top of the column, control the condenser water temperature at 5-11°C, and the column top pressure is atmospheric pressure 90 kPa. After the column top and column bottom temperature and pressure are stable, turn on the continuous feeding of the pyrolysis liquid, and the feeding position is in the middle of the column; at the same time, continuously take out the heavy components from the column bottom through a laminar pump, and the product liquid is taken out through the column top, and the temperature of the light components before condensation at the top of the column is 32°C, and the reflux ratio at the top of the column is 2:1. Take samples of the column top and column bottom liquid at regular intervals, and analyze the sample composition by GC. The azeotrope distillation results are shown in the following table, and under the above separation conditions, the heavy components of pyrolysis are basically taken out from the column bottom, and the light components at the top of the column are 2-methoxy propylene and methanol azeotrope, the azeotrope composition is 91.0:7.9, and the others are some light component impurities.

[0075] Table-9 Azeotrope distillation separation data of pyrolysis reaction liquid

[0076]

[0077] Example 10

[0078] azeotrope distillation separation of pyrolysis liquid

[0079] Take the cleavage solution 300g obtained in Example 6, room temperature is added to the 2L three-necked flask with magnetic stirring, connected to the top of the three-necked flask 0.8m long rectifying column and reflux ratio controller, the column is filled with 3*3 tri-leg spiral fillers, the total number of plates is about 25. The three-necked flask is placed in the oil bath, open oil bath stirring, stirring speed control at 600rpm; open oil bath to add, so that the oil bath temperature control at 64°C, so that the temperature in the three-necked flask is maintained at 58°C. Open the overhead condenser water, condenser water temperature control at 5-11°C, the tower top pressure is atmospheric pressure 100kPa. After the tower top and tower kettle temperature and pressure is stable, open the cleavage liquid continuous feeding, feeding position is located in the middle of the tower; feeding at the same time by constant from the tower kettle to extract heavy components, product liquid through the tower top, the tower top light components before condensation temperature is 33°C, the tower top reflux ratio is 4:1. Timely sampling of the tower top and tower kettle to extract liquid, GC analysis of sample composition. Azeotropic distillation results are shown in the following table, using the above separation conditions, cleavage of heavy components are basically from the tower kettle to extract, the tower top light components to obtain 2-methoxy propylene and methanol azeotrope, azeotrope composition of 91.1:7.9, the other is some light component impurities.

[0080] Table-10 azeotropic distillation separation data of cleavage reaction liquid

[0081]

[0082] Example 11

[0083] N-methyl pyrrolidone extractive distillation separation to obtain pure 2-methoxy propylene

[0084] Take the cleavage solution 220 g obtained in Example 3, at room temperature into a 2L three-necked flask equipped with magnetic stirring, connect a 0.6m long rectifying column and reflux ratio controller on the top of the three-necked flask, fill the column with 3*3 tri-leg spiral packing, the total number of plates is about 18. Put the three-necked flask into the oil bath, start the oil bath stirring, control the stirring speed at 600 rpm; start the oil bath to control the oil bath temperature at about 120°C, so that the temperature in the three-necked flask is maintained at 115°C. Start the condenser water, control the condenser water temperature at 5-11°C, the tower top pressure is atmospheric pressure 100 kPa. After the tower top and tower kettle temperature and pressure are stable, start the continuous feeding of the cleavage solution, the feeding position is in the middle of the column; at the same time, use a uniform flow pump to feed the extractant N-methyl pyrrolidone (NMP) from near the top of the column. The product 2-methoxy propene is taken out from the top of the column, the temperature before condensation of the light components at the top of the column is 34°C, the reflux ratio at the top of the column is 0.5:1. The feeding speed of the extractant in the middle of the column is 0.3 g / min, the feeding speed of the extractant NMP at the top of the column is 0.11 g / min, the discharge speed at the top of the column is 0.26 g / min, and the discharge speed at the bottom of the column is 0.15 g / min. Sample the column top and column kettle at regular intervals, analyze the sample composition by GC. The azeotropic distillation results are shown in the following table, using the above separation conditions, the cleavage heavy components are basically taken out from the bottom of the column, the qualified 2-methoxy propene product is taken out from the top of the column, the purity is 99.3%, containing a small amount of light component impurities.

[0085] Table-11 NMP extractive distillation separation of 2-methoxy propene data

[0086]

[0087] Example 12

[0088] Water extractive distillation separation of pure 2-methoxy propene

[0089] Take the cleavage solution 290g obtained in Example 3, room temperature is added to the 2L three-necked flask with magnetic stirring, connected to the top of the three-necked flask 0.8m long rectifying column and reflux ratio controller, the column is filled with 3*3 tri-leg spiral fillers, the total number of plates is about 25. The three-necked flask is placed in the oil bath, open oil bath stirring, stirring speed control at 600rpm; open oil bath to add, so that the oil bath temperature control at 105°C, so that the temperature in the three-necked flask is maintained at 98°C. Open the overhead condenser water, condenser water temperature control at 5-11°C, the tower top pressure is atmospheric pressure 110kPa. After the tower top and tower kettle temperature and pressure is stable, open the cleavage solution continuous feeding, feeding position is located in the middle of the tower; while using the uniform flow pump from near the top of the tower feed extractant deionized water. Product 2-methoxy propene is taken from the top of the tower, the temperature of the overhead light components before condensation is 33°C, the tower top reflux ratio is 1:1. Tower middle extraction liquid feed speed is 0.3g / min, the overhead extractant deionized feed speed is 0.10g / min, the tower top discharge speed is 0.26g / min, the tower kettle discharge speed is 0.15g / min. Timely sampling of the tower top and tower kettle, GC analysis of sample composition. Azeotropic distillation results are shown in the following table, using the above separation conditions, cleavage heavy components are basically from the tower kettle, the tower top take qualified 2-methoxy propene product, the purity is 99.3%, containing a small amount of light component impurities.

[0090] Table-12 water extractive distillation separation to obtain 2-methoxy propene data

[0091] .

Claims

1. A method for efficiently recycling light components in rearrangement reaction, the method comprising the following steps: S1: separating light components from rearrangement reaction liquid obtained by reacting propargyl alcohol and 2-methoxy propene in the presence of a catalyst through rectification; S2: adding a cracking aid to the separated light components to perform vaporization and cracking, and cooling after the cracking is completed; the cracking aid is selected from one or more of anhydrous methanol, trimethylamine, triethylamine, dimethyl ethylamine and pyridine; S3: the cracking liquid is sequentially subjected to azeotropic rectification and extractive rectification to separate pure 2-methoxy propene.

2. The method of claim 1, wherein, The rectification is performed in a rectification column, and the operation conditions of the rectification column are as follows: the number of plates is 30-35, the top temperature is 35-40℃, the bottom temperature is 138-140℃, the reflux ratio is 1.5:1-3.0:1, and the top pressure is 30-40kPa.

3. The method of claim 1, wherein, The cracking aid is added in an amount of 0.1-1.5wt% of the mass of the light components.

4. The method according to any one of claims 1 to 3, characterized in that, The vaporization temperature is 220-260℃; and / or, the cracking temperature is 280-320℃, mass space velocity is 0.5-20h -1 , reaction pressure 0.1-0.2MPaG.

5. The method according to any one of claims 1 to 3, wherein The cracking process is performed in the presence of a cracking catalyst, and the cracking catalyst is selected from ZSM molecular sieve, magnesium pyrophosphate and aluminum phosphate salt.

6. The method according to any one of claims 1 to 3, wherein The process of cooling after the cracking is completed adopts circulating water for quenching, and the temperature of the circulating water used is 5-11℃.

7. The method of any one of claims 1-3, wherein, The azeotropic rectification conditions are as follows: the number of plates is 18-25, the top temperature is 32-33℃, the bottom temperature is 58-62℃, the reflux ratio is 2:1-4:1, and the top pressure is 90-110kPa.

8. The method of any one of claims 1-3, wherein, The extractive rectification conditions are as follows: The number of plates is 18-25, the top temperature is 33-34℃, the bottom temperature is 98-115℃, the reflux ratio is 0.5:1-2:1, and the top pressure is 90-110kPa.

9. The method of any one of claims 1-3, wherein, The extractive agent for the extractive rectification is selected from one or more of N-methyl pyrrolidone, acetonitrile, N,N-dimethyl formamide, dimethyl sulfoxide and water; and / or, the feed amount of the extractive agent is 0.3-0.4 times of the feed amount of the cracking liquid.

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