CN105585406B - A kind of method that long-chain olefin is prepared by medium chain bio-based alkene - Google Patents

Abstract

The invention belongs to organic synthesis field, it is related to a kind of method that long-chain olefin is prepared by medium chain bio-based alkene, it using vegetable oil and small-numerator olefin is raw material by intersecting the medium chain bio-based alkene that olefin metathesis reactions obtain to particularly provide a kind of, the method that long-chain olefin is prepared through homogeneous catalyst catalytic reaction.Pass through technical scheme, to catalyst amount, feed postition, and proportioning of raw material etc. is explored, most suitable reaction condition is have found, the final long-chain olefin for obtaining higher degree so that long-chain olefin can be realized to be prepared from biomass material, solve the non-renewable problem of conventional raw material, expanded the application of long-chain olefin.

Description

A method for preparing long-chain olefins from medium-chain length bio-based olefins

technical field

The invention relates to the field of organic synthesis, in particular to a method for preparing long-chain olefins from medium-chain bio-based olefins.

Background technique

Long-chain olefins refer to C13-C24 non-α-linear olefins. Long-chain olefins have many uses, such as: as raw materials to produce surfactants, long-chain silanes, long-chain mercaptans, long-chain amines, long-chain alcohols, etc. ; It itself just can be directly used as biodegradable deep-sea drilling oil.

Currently, there are several well-known methods in the world that can be used to prepare long-chain olefins, for example: petroleum cracking method, olefin oligomerization method (SHOP method), Fischer-Tropsch method and olefin metathesis catalytic method.

The typical olefin metathesis catalytic method uses metal carbene compounds as catalysts to make long-chain olefins undergo self-metathesis or cross-metathesis reactions between olefins. It has the characteristics of high yield and high product selectivity. It is currently the most Attractive method for the preparation of long-chain olefins. Olefin metathesis catalysts can be divided into homogeneous catalysis and heterogeneous catalysis. Olefins used as raw materials generally come from petroleum-based products or mineral-based products produced by coal chemical industry.

Fred Chun-Chien Twu et al. disclosed in the patent US 2003/0224945A1 the use of a heterogeneous catalyst (solid state) and the use of α-olefins obtained by the Fischer-Tropsch method as raw materials to prepare long-chain olefins through olefin metathesis reactions. method. Twu Fred et al disclosed in the patent WO 03/101920A1 a method for preparing long-chain olefins through olefin metathesis reaction using a heterogeneous catalyst (solid state) and using α-olefins obtained by the SHOP method as a raw material. Using this method, Synthetic-based base oils that can be used in deep-sea drilling fluids were prepared.

The current research hotspots mainly focus on two major themes: the development of new catalysts and the search for cheaper and renewable sources of raw materials.

Compared with heterogeneous catalysts, the use of homogeneous olefin metathesis reaction catalysts to produce long-chain olefins has the advantages of high catalytic efficiency and less dosage, and also makes the reaction conditions milder, without the generation of three wastes, Production is easy to carry out.

However, using vegetable oil and small molecular olefins to obtain medium-chain bio-based olefins as raw materials for the preparation of long-chain olefins, since vegetable oil is a renewable resource and has a wide range of sources, compared with the petroleum cracking raw materials used in the SHOP method and the Fischer-Tropsch method. The raw materials for coal chemical production are more environmentally friendly and more in line with the concept of sustainable development; in addition, the cross-olefin metathesis reaction process between vegetable oil and small molecular olefins is simple, no three wastes are produced, and the reaction conditions are mild, which is an ideal medium for production Method for chain-length olefins.

Different vegetable oils and/or small molecular olefins are selected, and the bio-based olefins obtained through the cross-alkene metathesis reaction between vegetable oil and small molecular olefins are also different. Moreover, since vegetable oils contain not only saturated and monounsaturated components, but also diunsaturated The so-called polyunsaturated components such as saturated and tri-unsaturated, will cause the generated medium-chain-length olefins to contain di-unsaturated olefins, so that the olefin metathesis reaction is different from the raw materials obtained by the SHOP method or Fischer-Tropsch method. Compared with olefin metathesis reactions, it is more specific.

Contents of the invention

The purpose of the present invention is to invent a method of using metal carbene homogeneous olefin metathesis reaction catalyst to make medium-chain bio-based olefins undergo olefin metathesis reaction, thereby preparing long-chain olefins, which has the advantages of simple process, mild conditions, and obtained The product has the characteristics of high purity and wide source of raw materials.

Technical scheme of the present invention is:

The medium-chain-length (C7-C12) bio-based olefins obtained by the cross-olefin metathesis reaction of vegetable oil and small molecular olefins are used as raw materials, and the long-chain olefins are prepared through a catalytic reaction of a homogeneous catalyst.

In the following, the scheme will be described respectively according to raw materials, catalysts, reaction conditions and products.

1. Raw materials:

The raw material for the preparation of long-chain olefins involved in the present invention is medium-chain bio-based olefins, that is, vegetable oil and C2-C6 small molecular olefins. The olefins obtained by the catalyst of olefin metathesis reaction are listed in Chinese patent CN201510799475.6 Record in detail.

Mainly C7, C9, C10, C12, the molecular formula is as follows:

When C7 and C12 are used as mixed raw materials, the mixing ratio (equivalent ratio) is 1:1 to 100, preferably 1:3 to 20, and more preferably 1:5 to 10; when C9 and C10 are used as mixed raw materials, mix The ratio of C9 and C12 is 100:1～10000, preferably 100:20～500, more preferably 100:50～200; when C9 and C12 are used as mixed raw materials, the mixing ratio is 100:1～10000, preferably 100 : 20～500, more preferably 100:50～200; C10 can be used as a raw material alone; C12 can be used as a raw material alone.

Before use, it undergoes the following treatment: silica gel adsorption for 24 hours, high-purity nitrogen bubbling to remove most of the dissolved oxygen, and then CuCl oxygen scavenger for further oxygen removal for 24 hours.

2. Catalyst

The catalysts involved in this patent are homogeneous metal olefin displacement reaction catalysts, the more suitable ones are ruthenium metal ion catalysts, and the more suitable ones are the first and second generation Grubbs catalysts or novel N-heterocyclic carbene containing electron-pushing groups Ruthenium catalyst, the present invention mainly selects a self-made novel N-heterocyclic carbene ruthenium catalyst containing electron-pushing groups, and its preparation method is described in detail in the patent CN201510178654.8.

The dosage of the olefin metathesis reaction catalyst involved in the present invention is 1000ppm to 10ppm, preferably 500ppm-20ppm, more preferably 400ppm-30ppm, based on the weight of medium-chain length olefins.

First, the catalyst is made into a solution with a small amount of toluene or dichloromethane to facilitate addition. The catalyst can be added at one time or in stages. Adding in batches is to add the catalyst several times in different stages of the reaction, which is beneficial to the improvement of the conversion rate. Preferably, the catalyst is divided into two equal parts and added at the beginning of the reaction and 1/3 of the reaction time respectively.

3. Alkene metathesis reaction

The reaction temperature is 20-80°C, preferably 30-70°C, more preferably 35-60°C;

The reaction time is 1-72 hours, preferably 2-48 hours, more preferably 3-24 hours.

4. Product

Depending on the combination of medium-chain-length olefins, the resulting long-chain olefins will vary. Ignoring the accompanying isomerization reaction during the olefin metathesis reaction, when using a combination of different medium-chain length olefins as feedstock, the following higher olefins will be produced:

The small molecular olefins (1)-small molecular olefins (5) involved in the above reaction formula are different combinations of small molecular olefins of C2-C6, and the by-products (1)-by-products (5) are due to isomerization and Different combinations of alkenes with carbon numbers less than 13 produced by alkene metathesis.

The present invention also provides a method for removing the above-mentioned small molecular olefins: since in the reaction process, small molecular olefins such as ethylene and/or propylene and/or butene and/or pentene and/or hexene will be produced, it is necessary to remove The reaction system moves the reaction to the predetermined reaction direction and improves the conversion rate. Methods for removing small molecular olefins include: a) Bubbling method: when the reaction temperature is higher than the boiling point of small molecular olefins, an inert gas (such as nitrogen, argon, etc.) The gas quickly leaves the reaction system together; b) decompression method: the reaction system is decompressed to a certain vacuum degree, and according to the difference between the raw material and the reaction temperature, under the condition that the raw material is not lost, the vacuum degree is applied as large as possible to make the small molecule Olefins quickly leave the reaction system; c) Mixing method: the vacuum method and the bubbling method are used simultaneously to make small molecular olefins quickly leave the reaction system.

Through the technical scheme of the present invention, the amount of catalyst used, the way of adding, and the ratio of raw materials have been explored, and the most suitable reaction conditions have been found, and long-chain olefins with higher purity can be finally obtained, so that long-chain olefins can be realized from production It is prepared from raw materials, which solves the problem of non-renewable raw materials in the past and expands the application range of long-chain olefins.

detailed description

Operation method: In the glove box, add a certain weight of reactants (a single olefin or a mixture of several olefins in a certain weight ratio) into a reaction bottle with an electromagnetic stirrer, and add a certain amount of catalyst toluene with a micro syringe solution, so that the weight of the catalyst reaches a certain concentration (ppm w/w) of the weight of the reactant, and the catalyst can also be added in two times, that is, a part of the catalyst is added first, and the remaining catalyst is added when the reaction reaches a certain level. Install the suction joints of the feeding tube and the condenser tube on the two grinding ports of the reaction bottle respectively, then connect the suction joint to the upper end of the condenser tube, close the valves of the feeding tube and the suction joint, and take the reaction bottle out of the glove box.

The temperature of the condensing medium needs to be adjusted according to the difference of the raw material and the small molecule olefins produced by the reaction. When the boiling point of the raw material is low (such as C7, the boiling point is 80-90°C), in order to prevent the loss of the raw material, the condensing medium should be lower. When the molecular weight of small molecular olefins is relatively large (such as hexene), the temperature of the condensing medium needs to be higher in order to eliminate the reaction system. According to the different reaction systems, it can be adjusted within the range of 15-30°C.

When the reaction requires bubbling to remove small molecular olefins, connect the high-purity nitrogen input pipe to the gas feeding pipe, connect the oil bubble meter to the suction joint, first open the high-purity nitrogen valve, then open the suction joint valve, and adjust the high-purity Nitrogen intake (according to the size of the total amount of reactants, about 100-1 bubbles per second in the oil bubble meter). When the reaction needs to remove small molecular olefins under reduced pressure, start the vacuum pump and adjust the vacuum to the required vacuum degree with the gas feeding tube valve closed. When the reaction requires the mixing method to remove small molecule olefins, open the gas feeding pipe valve, start the vacuum pump, and adjust the feeding gas volume and vacuum degree at the same time, so that the inert gas entering amount and vacuum degree meet the requirements of the experiment.

In an oil bath at a certain temperature, start a magnetic stirrer, and react for a specified time. Samples were taken for gas chromatographic analysis.

Preparation of gas chromatographic samples: add absorbent cotton to a 1 ml syringe, seal the outlet of the syringe, add sorbent at a height of 1 cm into the syringe, seal the upper part with absorbent cotton and compact the absorbent. Take 0.5g of the sample to be tested and put it into the syringe, inject the sample into a 20mL glass bottle through the syringe, add 3mL of n-hexane, stir and dissolve, draw 0.25mL of the solution, and dilute it with n-hexane in the gas chromatography sample bottle to about 1.0mL for gas chromatographic determination. Its content is read as the percent peak area of the gas chromatogram.

Test instrument: Agilent 7890A gas chromatograph equipped with an automatic sampler. Gas chromatography test parameters are: Chromatographic column: Agilent HP-5 (30m×250μm×0.25μm), inlet temperature: 250°C, injection volume: 1μL, split ratio: 50:1, FID detector: 280°C , carrier gas: N2, column oven: keep at 100°C for 1min, rise to 250°C at 10°C/min, and keep for 15min. Diaphragm vacuum pump (GM-0.5B, Tianjin Jinteng Experimental Equipment Co., Ltd.).

Table 1 Retention time of different products

Example 1, C7-C12 Combination Raw Materials Preparation of Higher Olefins

Using different proportions of C7-C12 bio-based medium-chain-length olefins as raw materials, the total weight of reactants is 5g, and 200ppm of electron-pushing-based olefin metathesis reaction catalysts are added to remove small particles generated during the reaction process by high-purity nitrogen bubbling method. Molecular olefins, the temperature of the condensed liquid in the condenser tube is 20°C. Start electromagnetic stirring, and react at 30°C for 24h. Table 2 is the gas chromatography analysis result.

Table 2 Effects of different C7-C12 ratios on the conversion rate

The test results show that in addition to the olefin metathesis reaction, an isomerization reaction in which the double bond migrates along the carbon chain also occurs, making the product more complicated. The higher the proportion of C7 in the raw material, the higher the content of C15 in the product, the lower the content of C18, and the higher the total conversion rate.

Example 2, C9-C10 Combination Raw Materials Preparation of Higher Olefins

Using different proportions of C9-C10 bio-based medium-chain-length olefins as raw materials, the total weight of reactants is 5g, and 200ppm of electron-pushing olefin metathesis reaction catalyst is added to remove small molecular olefins generated during the reaction process by decompression. Adjust the vacuum degree to 120mmHg; the temperature of the condensed liquid in the condenser tube is 25°C. Start electromagnetic stirring and react at 50°C for 19h. Table 3 is the gas chromatography analysis result.

Table 3 Effects of different C9-C10 ratios on the conversion rate

It can be seen from Table 3 that when the ratio of C9:C10 is 1:2, the total conversion rate is the highest, and when the ratio of C9:C10 is 2:1, the conversion rate of C15 is the highest.

Example 3, C9-C12 Combined Raw Materials to Prepare Higher Olefins

Using different proportions of C9-C12 bio-based medium-chain-length olefins as raw materials, the total weight of reactants is 5g, adding electron-pushing-based olefin metathesis reaction catalyst toluene solution to make the catalyst concentration 50ppm of the raw material weight, and remove it by decompression method For small molecular olefins produced during the reaction, adjust the vacuum to 120mmHg; the temperature of the condensed liquid in the condenser tube is 25°C. Start electromagnetic stirring, and react at 50° C. for 10 h. Table 4 is the gas chromatography analysis result.

Table 4 Effect of different C9-C12 ratios on conversion rate

The test results show that when the proportion of C10 is higher, the total conversion is higher, at this time the yield of C15 is lower and the yield of C18 is higher.

Embodiment 4, C9 is raw material preparation high carbon olefin

Weigh 5g of bio-based C9 olefins, add electron-pushing olefin metathesis reaction catalyst toluene solution so that the catalyst concentration is 100ppm to 100ppm of the raw material weight, remove small molecule olefins generated during the reaction by decompression, adjust the vacuum to 120mmHg; condense The temperature of the condensed liquid in the tube was 25°C. Start electromagnetic stirring and react at 50°C for 7h. Table 5 is the gas chromatography analysis result.

Table 5 C9 as raw material for the preparation of higher olefins

Embodiment 5, C12 is raw material preparation high carbon olefin

Weigh 5g of bio-based medium chain length C12 olefins, add electron-pushing olefin metathesis reaction catalyst toluene solution to make the catalyst concentration 100ppm 100ppm of the raw material weight, remove the small molecular olefins produced in the reaction process by decompression method, adjust the vacuum to 120mmHg; the temperature of the condensed liquid in the condenser tube is 25°C. Start electromagnetic stirring and react at 50°C for 6h. Table 6 is the gas chromatography analysis result.

Table 6 Preparation of higher olefins from C12 as raw material

Example 6, C10 as raw material to prepare higher carbon olefins under different catalyst concentrations

Weigh 5g of bio-based C10 olefins in each of the two reaction flasks, add electron-pushing based olefin metathesis reaction catalysts respectively, so that the catalyst concentration reaches 100ppm and 40ppm respectively, and remove the small molecule olefins produced in the reaction process by decompression method, adjust The vacuum degree is up to 120mmHg; the temperature of the condensed liquid in the condenser tube is 25°C. Start electromagnetic stirring and react at 50°C for 19h. Table 7 is the gas chromatography analysis result.

Table 7 Preparation of higher olefins from C10 as raw material

The analysis results show that increasing the amount of catalyst will increase the total conversion rate and also make the isomerization reaction more serious, which is manifested by the increase in the content of high-carbon olefins produced by the isomerization reaction.

Example 7. Kilogram-scale experiment on the preparation of high carbon olefins from C9-C10 combined raw materials

It can be seen from Table 3 that when the ratio of C9:C10 is 1:2, the total conversion rate is the highest, so the combination of raw materials with this ratio is used to produce high-carbon olefins in large quantities.

Weigh 310g of C9 olefins and 690g of C10 olefins into the reactor respectively, add the catalyst toluene solution to make the catalyst concentration 25ppm of the raw material weight, keep the temperature of the cooling liquid in the condenser tube at room temperature, remove the small molecular olefins produced by the combined method, and adjust the vacuum degree To 120mmHg, the bubble volume is about 20 per minute. Start the strong magnetic stirrer, the number of revolutions is 800rpm. After reacting at 50° C. for 6 h, 25 ppm of catalyst was added again, and the reaction was continued for 14 h. The gas chromatography analysis results are shown in Table 8.

Table 8 Preparation of higher carbon olefins from C9-C10 combined raw materials in kilogram scale

Example 8, C12 as raw material preparation of high carbon olefins kilogram scale experiment

Weigh 1000g of C12 olefins into the reactor respectively, add catalyst toluene solution so that the catalyst concentration is 50ppm of the raw material weight, the temperature of the cooling liquid in the condenser tube is at room temperature, remove the small molecular olefins produced by the combined method, adjust the vacuum to 120mmHg, and the air bubbles The volume is about 20 per minute. Start the strong magnetic stirrer, the number of revolutions is 800rpm. React at 50°C for 24h.

Table 9 Preparation of higher carbon olefins from C12 feedstock in kilogram scale

From the comparison of the examples, it can be found that the conversion rate is higher when using a combination of olefins to prepare high-carbon olefins than when using a single olefin as a raw material.

The above-mentioned examples have carried out detailed analysis on the reaction products of different combinations of medium-chain-length bio-based olefins, and obtained a better combination.

An embodiment of the present invention has been described in detail above, but the content described is only a preferred embodiment of the present invention, and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the application scope of the present invention shall still belong to the scope covered by the patent of the present invention.

Claims (10)

1. A kind of 1. method that long-chain olefin is prepared by medium chain bio-based alkene, it is characterised in that：Utilize vegetable oil and small point Sub- alkene is raw material by intersecting the medium chain bio-based alkene that olefin metathesis reactions obtain, through homogeneous catalyst catalytic reaction To prepare long-chain olefin；Wherein, the small-numerator olefin has the small-numerator olefin of 2 to 6 carbon atoms；The long-chain olefin is Non-alpha-linear alpha-olefin with 13 to 24 carbon atoms；The medium chain alkene is the Medium chain with 7 to 12 carbon atoms Growth base alkene, and selected from following any group：

   (1) equivalent proportion is 1:1~100 C7 alkene and the mixture of C12 alkene；

   (2) equivalent proportion is 100:1~10000 C9 alkene and the mixture of C10 alkene；

   (3) equivalent proportion is 100:1~10000 C9 alkene and the mixture of C12 alkene；

   (4) C9 alkene；

   Wherein, the molecular formula difference of the C7 alkene, C9 alkene, C10 alkene and C12 alkene is as follows：

   a、C7

   b、C9

   c、C10

   d、C12
2. 2. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 1, its feature exist In：Before using the medium chain bio-based olefine reaction, through lower column processing：Silica gel absorption 24 hours, high pure nitrogen bubbling Method removes most of dissolved oxygen, then through the further deoxygenation of CuCl oxygen scavengers 24 hours.
3. 3. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 1, its feature exist In：From the novel N-heterocyclic carbenes ruthenium catalyst containing electron donating group, catalyst amount is medium chain olefin feed weight 1000ppm to 10ppm, catalyst can disposably be added or added by several times.
4. 4. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 3, its feature exist In：The catalyst amount is the 500ppm-20ppm of medium chain olefin feed weight, and catalyst is divided into two parts of equivalent, respectively at When starting the homogeneous catalyst catalytic reaction and reaction time of the homogeneous catalyst catalytic reaction carries out addition when 1/3.
5. 5. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 1, its feature exist In：The reaction temperature of the homogeneous catalyst catalytic reaction is 20-80 DEG C.
6. 6. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 5, its feature exist In：The reaction temperature of the homogeneous catalyst catalytic reaction is 35-60 DEG C.
7. 7. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 1, its feature exist In：The reaction time of the homogeneous catalyst catalytic reaction is 1-72 hours.
8. 8. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 7, its feature exist In：The reaction time of the homogeneous catalyst catalytic reaction is 3-24 hours.
9. 9. a kind of method that long-chain olefin is prepared by medium chain bio-based alkene according to claim any one of 1-8, It is characterized in that：The method for also including removing small-numerator olefin after the homogeneous catalyst catalytic reaction terminates, may be selected as follows Any one：

   A) Bubbling method：In the case where reaction temperature is higher than small-numerator olefin boiling point, inert gas is passed through in reaction solution, made small Molecular olefine departs from rapidly reaction system with inert gas；

   B) method is depressurized：Reaction system is decompressed to certain vacuum degree, according to raw material and the difference of reaction temperature, not lost in raw material In the case of, apply vacuum as big as possible, small-numerator olefin is departed from reaction system rapidly；

   C) mixing method：The vacuum method and the Bubbling method are used simultaneously, small-numerator olefin is departed from reaction system rapidly.
10. 10. a kind of method for preparing long-chain olefin by medium chain bio-based alkene according to claim 9, its feature exist In：The inert gas is nitrogen or argon gas.