Method for preparing allyl alcohol by isomerizing epoxypropane

Abstract

The invention provides a method for preparing allyl alcohol through epoxypropane isomerization, and relates to the technical field of chemical synthesis. According to the method, propylene oxide is subjected to an isomerization reaction in the presence of a polymerization inhibitor to prepare allyl alcohol; wherein the polymerization inhibitor is a phenol polymerization inhibitor and / or a quinone polymerization inhibitor. The technical scheme of the invention can effectively reduce the deactivation rate of the catalyst and prolong the service life of the catalyst. The method for preparing allyl alcohol through epoxypropane isomerization is high in production efficiency and low in production cost, and has important industrial application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, in particular to a method for preparing allyl alcohol by isomerization of propylene oxide. BACKGROUND

[0002] Allyl alcohol (propenyl alcohol) is a colorless flammable liquid, with a melting point of -129℃, a boiling point of 97.1℃, and a flash point of 28℃. It is soluble in water, ethanol, diethyl ether, petroleum ether, and chloroform, and is an important chemical raw material. Due to the presence of double bonds and hydroxyl groups in its molecular structure, allyl alcohol can participate in various reactions such as oxidation, reduction, esterification, and addition, and can be used to synthesize a series of downstream products with wide applications in agricultural chemicals, pharmaceuticals, fragrances, and organic synthesis.

[0003] The main industrial production methods for allyl alcohol include hydrolysis of chloropropene, isomerization of propylene oxide, reduction of propenal, hydrolysis of propenyl acetate (prepared by oxidation of propylene using a noble metal Pd catalyst), and glycerol method. In the early stage, allyl alcohol was mainly synthesized by hydrolysis of allyl chloride. However, this process generates a large amount of wastewater and waste liquid containing chlorine. The production processes of propenyl acetate and other methods generate a large amount of wastewater and waste liquid, and the overall atomic economy is low, making it difficult to meet the increasingly stringent environmental requirements. A low-cost, high-yield, and low-pollution production process has become an inevitable trend for the development of future chemical industry. Therefore, there is an urgent need to develop a low-cost, high-yield, and environmentally friendly green synthesis method for allyl alcohol.

[0004] The equation for the preparation of allyl alcohol by isomerization of propylene oxide is as follows:

[0005]

[0006] US4720598 discloses a gas-phase synthesis and regeneration process with a reaction temperature of 255-275℃. Propylene oxide is isomerized to allyl alcohol under the catalysis of a lithium phosphate catalyst. This process has the characteristics of short process flow and high yield of allyl alcohol. However, the catalyst deactivates very quickly, with a 50% loss of activity after 30h of use. Therefore, the catalyst needs to be frequently replaced and regenerated, which not only reduces the production efficiency and makes it impossible to produce continuously, but also greatly increases the process cost, making it unsuitable for industrial production.

[0007] Patent CN107537526A discloses a method for preparing a fluidized bed isomerization catalyst. A fluidized bed reactor is used for the preparation of allyl alcohol, which has the advantages of high gas-solid mass transfer efficiency and fast reaction rate without solvent loss. However, due to the strength of the catalyst and other reasons, this process has not been applied. Based on the technical solution of this patent, the research and development team of the company has replicated the catalyst and successfully developed a small-scale test technology for allyl alcohol. The small-scale test results show that the catalyst in this isomerization process still deactivates quickly (lifetime <48h), which is not conducive to further industrialization. SUMMARY

[0008] In order to solve the problems of short service life of catalyst, frequent switching and regeneration, and difficulty in industrial production in the existing propylene oxide isomerization process, the application discloses a method for preparing allyl alcohol by propylene oxide isomerization.

[0009] In order to achieve the above technical purposes, the application provides a method for preparing allyl alcohol by propylene oxide isomerization, which comprises the following steps: in the presence of a polymerization inhibitor, propylene oxide is subjected to isomerization reaction to obtain propylene alcohol; wherein the polymerization inhibitor is a phenolic polymerization inhibitor and / or a quinone polymerization inhibitor.

[0010] The research and development team of the application found through exploration experiments that the carbon deposition caused the deactivation of the isomerization reaction catalyst. Further exploration experiments found that the carbon deposition was not from the common by-products (propionaldehyde, acetone and propanol) in the isomerization reaction, but a small amount of allyl alcohol with carbon-carbon double bond inevitably self-polymerized to form heavy recombination by-products under high temperature in the propylene oxide isomerization reaction process. These heavy recombination by-products adhere to the surface of the catalyst and cannot be quickly desorbed, causing the active sites of the catalyst to be covered and the active pores to be blocked, and then rapidly deactivating. In the above technical solution, the phenolic polymerization inhibitor and / or the quinone polymerization inhibitor is added to combine with the free radicals of allyl alcohol in the form of gas during the isomerization reaction, effectively preventing a small amount of self-polymerization of the product allyl alcohol on the surface of the catalyst, promoting the timely desorption of propylene alcohol in the form of small molecules on the surface of the catalyst, delaying the blockage of the catalyst pores under the premise of ensuring the yield of the existing product, and prolonging the service life of the catalyst.

[0011] The application illustrates the above exploration experiment process.

[0012] In further examples of the application, the catalyst can be selected as a solid acid catalyst, further selected as a lithium phosphate-based catalyst, further selected as a modified lithium phosphate catalyst or a supported lithium phosphate catalyst.

[0013] In further examples of the present application, the types of the phenolic polymerization inhibitor and the quinone polymerization inhibitor are explored and optimized. Optionally, the phenolic polymerization inhibitor is selected from one or more of hydroquinone, o-phenol, p-tert-butyl hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl hydroquinone, and 2-tert-butyl hydroquinone. Optionally, the quinone polymerization inhibitor is selected from one or more of p-benzoquinone, naphthoquinone, and chloranil. The optional polymerization inhibitor of the present application has a boiling point of 210-310°C, and can combine with the free radicals on the unsaturated bond of allyl alcohol in a gaseous phase in the isomerization reaction to form stable free radicals, thereby preventing the self-polymerization of allyl alcohol caused by further activation of the free radicals. Because the difference between the boiling point of the polymerization inhibitor (about 210-310°C) and the boiling point of allyl alcohol (about 96-98°C) is large, the polymerization inhibitor and allyl alcohol can be separated by simple treatment of the post-reaction material, such as condensation or distillation to separate the polymerization inhibitor from the post-reaction material, and the polymerization inhibitor can be recycled. The examples of the present application show the process of preparing allyl alcohol by isomerization of propylene oxide using different polymerization inhibitors.

[0014] In further examples of the present application, the polymerization inhibitor can be a complex polymerization inhibitor of a phenolic polymerization inhibitor and a quinone polymerization inhibitor, and the molar ratio of the phenolic polymerization inhibitor to the quinone polymerization inhibitor in the complex polymerization inhibitor is (0.1-10):1. In optional examples of the present application, the molar ratio of the phenolic polymerization inhibitor to the quinone polymerization inhibitor in the complex polymerization inhibitor is (1-5):1. Further optionally, the phenolic polymerization inhibitor is selected from one or more of hydroquinone, o-phenol, p-tert-butyl hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl hydroquinone, and 2-tert-butyl hydroquinone; and the quinone polymerization inhibitor is selected from one or more of p-benzoquinone, naphthoquinone, and chloranil.

[0015] In further examples of the present application, the amount of the polymerization inhibitor added is 0.01wt%-1wt% of the propylene oxide, and the appropriate or small amount of the polymerization inhibitor can inhibit the self-polymerization of allyl alcohol and improve the service life of the catalyst. In optional examples of the present application, the amount of the polymerization inhibitor added is 0.1wt%-0.5wt% of the propylene oxide.

[0016] The method of the present application for preparing allyl alcohol by isomerization of propylene oxide has wide applicability in reaction systems. In further examples of the present application, the method is a method for preparing allyl alcohol by a gas phase method, which comprises the following steps:

[0017] Step (1), dissolving the polymerization inhibitor in the propylene oxide to obtain a solution of propylene oxide to be reacted;

[0018] Step (2), preheating and vaporizing the solution of propylene oxide to be reacted, and contacting the vaporized solution with a catalyst in the presence of a carrier gas to occur isomerization reaction, thereby obtaining the allyl alcohol.

[0019] In the isomerization reaction, the polymerization inhibitor is one or more of hydroquinone, pyrocatechol, p-tert-butyl pyrocatechol, p-benzoquinone, preferably one or more of hydroquinone, p-benzoquinone, p-tert-butyl pyrocatechol; further preferably, the polymerization inhibitor is a mixture of hydroquinone and p-benzoquinone.

[0020] In the isomerization reaction, the preheating temperature in step (2) is selected from 150-250℃; the isomerization reaction temperature in step (2) is 275-300℃, and the reaction pressure is 0-1 MPa; the reaction temperature is controlled to be higher than the critical temperature of the raw material propylene oxide and allyl alcohol (the critical temperature of propylene oxide is 209.1℃, and the critical temperature of allyl alcohol is 271.9℃), so that the raw material propylene oxide and the polymerization inhibitor are in a gaseous phase and contact with the catalyst, thereby preventing the polymerization of allyl alcohol and avoiding the adhesion of carbon deposition.

[0021] In the isomerization reaction, the feed mass space velocity of the propylene oxide solution to be reacted is selected from 0.5-5 h -1 The carrier gas is an inert gas; the molar ratio of the feed amount of the carrier gas to propylene oxide is (0.5-10):1, and the contact time of propylene oxide and the catalyst can be adjusted according to the actual working condition by optimizing the molar ratio of the carrier gas to propylene oxide.

[0022] It should be noted that the inert gas in the present application refers to a gas that does not chemically interact with the reactants, for example: nitrogen and group zero element gases in the periodic table (such as argon). The inert atmosphere refers to a gaseous environment composed of inert gases.

[0023] The isomerization reaction can be carried out in a fixed bed reactor, and a catalyst bed is arranged in the fixed bed reactor. In the actual reaction process, the preheated propylene oxide solution to be reacted can be input from the feed port at the upper part of the fixed bed, and the reacted material can be output from the discharge port at the top of the reactor and then enter the post-treatment process.

[0024] In a further example of the present application, the method is a method for preparing allyl alcohol by a liquid phase method, comprising the following steps:

[0025] Step S1, dissolving the polymerization inhibitor in the propylene oxide to obtain a propylene oxide solution to be reacted;

[0026] Step S2, after preheating the propylene oxide solution to be reacted, the isomerization reaction occurs in the solvent with the catalyst to obtain the allyl alcohol.

[0027] Further, the feed mass space velocity of the propylene oxide solution to be reacted in step (2) is selected from 0.5-5 h - 1.

[0028] Further, the preheating temperature in step S2 can be selected as 150-250℃.

[0029] Further, the solvent is selected from one or more of triphenyl, p-phenol, and hydrogenated triphenyl, and the present embodiment shows the isomerization reaction process of propylene oxide using different solvents. Further, in step S2, the mass ratio of the solvent to the catalyst is (5-20):1. The isomerization catalyst of the present application is a solid catalyst, and by optimizing the mass ratio of the solvent to the catalyst, a reaction liquid with a solid content of about 5%-20% can be obtained, which promotes the effective contact of propylene oxide with the catalyst.

[0030] Further, the temperature of the isomerization reaction in step S2 is 275-300℃, and the reaction pressure is 0-1 MPa.

[0031] Further, the isomerization reaction in step S2 is carried out in an inert atmosphere.

[0032] Further, the isomerization reaction in step S2 is carried out in a suspension bed reactor. In the continuous reaction process, the propylene oxide solution to be reacted containing the polymerization inhibitor continuously enters the reactor, and then the propylene oxide is in contact with the catalyst in the solvent to undergo isomerization reaction. The allyl alcohol, unreacted propylene oxide, polymerization inhibitor, and by-products and impurities generated in the reaction are continuously removed from the reaction system and enter the post-treatment process.

[0033] Further, in the above isomerization reaction process, the polymerization inhibitor is one or more of p-dihydroxybenzene, o-dihydroxybenzene, p-tert-butyl-o-dihydroxybenzene, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-p-dihydroxybenzene, 2-tert-butyl-p-dihydroxybenzene, p-benzoquinone, naphthoquinone, and tetrachlorobenzoquinone; preferably one or more of p-dihydroxybenzene, p-benzoquinone, and p-tert-butyl-o-dihydroxybenzene; and further preferably a p-dihydroxybenzene and p-benzoquinone compound polymerization inhibitor.

[0034] Compared with the prior art, the present application has the beneficial effect that the isomerization reaction of propylene oxide to prepare allyl alcohol in the presence of a phenolic polymerization inhibitor and / or a quinone polymerization inhibitor can effectively reduce the deactivation rate of the catalyst and prolong the service life of the catalyst. The method for preparing allyl alcohol by isomerization of propylene oxide has high process production efficiency, low production cost, and important industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0035] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0036] Figure 1TG-Mass thermogravimetric analysis results of the newly prepared metal-doped catalyst in the present application exploration example are shown.

[0037] Figure 2 TG-Mass thermogravimetric analysis results of the metal-doped catalyst after catalysis for 96h in the present application exploration example are shown. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the preferred embodiments of the application. It should be understood, however, that these embodiments are merely set forth in order to illustrate rather than to limit the application, and it will be apparent that modifications and / or

[0039] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which the present application pertains. The test reagents used in the following examples are all conventional biochemical reagents unless otherwise specified; and the experimental methods used are all conventional methods unless otherwise specified. In addition, it should be noted that, although the steps of the preparation method of the present application are described in a specific order in the description of the present application, these orders are not limiting, and those skilled in the art can perform the steps in different orders without deviating from the basic principles of the present application.

[0040] When a value, a concentration, or other value or parameter is expressed in a range, a preferred range, or a range having an upper preferred value and a lower preferred value, it is understood that the disclosure specifically encompasses all ranges formed from any pair of an upper limit or a preferred value and a lower limit or a preferred value, whether the range is expressly disclosed or not. When numerical ranges are described herein, unless otherwise stated, the range is intended to include both the upper and lower values and all intervening values, as well as the integers within the range.

[0041] It should be noted that the catalyst for isomerization of propylene oxide in the present application is not limited, and can be selected from solid acid catalysts, and further can be selected from lithium phosphate-based catalysts, such as modified lithium phosphate catalysts or supported lithium phosphate catalysts, etc. The catalyst used in the following examples can be prepared by the following method:

[0042] (1) Na3PO4 and LiOH are configured in a ratio of n(P):n(Li)=3.0-4.0, LiOH is put into a container and added with desalted water to configure solution A, and Na3PO4 is dissolved in desalted water to configure phosphate solution B; the two solutions are maintained at 65°C or above to maintain sufficient dissolution, and the molar concentration of the substances in the two solutions is controlled at 0.05-0.1 mol / mL;

[0043] (2) phosphate solution B is added to solution A under sufficient stirring at a speed of 100 mL / min, and the same stirring state is maintained during the dropping process, and the solid is completely precipitated;

[0044] (3) After the co-precipitation is completed, solid-liquid separation is performed, the solid is washed several times at 80℃ until the pH of the filtrate is 12.5, and after drying, the metal-doped catalyst is obtained by calcining at 500℃ for 18h.

[0045] Exploration example

[0046] The research and development team of the present application explored the reasons for the deactivation of the catalyst in the process of preparing allyl alcohol by isomerization of propylene oxide.

[0047] Exploration example 1

[0048] Specifically, the above metal-doped catalyst is used to catalyze the isomerization reaction of propylene oxide: 100ml of solvent is added to a 250ml stainless steel reaction kettle, 15g of isomerization catalyst powder is added, the reactor is heated to 300℃ after nitrogen is fully replaced, the preheater is heated to 230℃, and the propylene oxide solution is heated by the preheater, then enters the reaction kettle from the bottom of the reaction kettle at a flow rate of 1.0ml / min through the inner tube of the reaction kettle and is subjected to isomerization reaction to obtain allyl alcohol; after 96h of reaction, the product is collected by condensation through a cold trap, and the final product is analyzed by gas chromatography, and the results are shown in Table 1.

[0049] After the catalyst is thoroughly cleaned, the research and development team respectively performs TG-Mass thermal gravimetric analysis on the newly prepared metal-doped catalyst (without catalytic reaction) and the catalyst after 96h of catalysis, and the results are shown in Figure 1 , Figure 2 ; see Figure 1 , the TG-Mass result of the newly prepared metal-doped catalyst shows that four molecular mass spectrum peaks are detected at 335-355℃ (33-35min), indicating that CO2 is generated in this time period, which is speculated to be the decomposition of lattice carbonate in the metal-doped catalyst; see Figure 2 , the TG-Mass of the metal-doped catalyst after 96h of use shows that, compared with the isomerization catalyst without use, the catalyst not only releases CO2 at 335-355℃ (33-35min), but also releases CO2 at the beginning of the temperature rise segment (0-330℃), indicating that the catalyst surface is attached to adsorptive carbon after use, and these carbon is continuously removed in the thermal gravimetric test as the temperature rises, and when the temperature reaches about 335℃, the lattice CO2 begins to be removed.

[0050] In addition, the research and development team also tested the specific surface area, pore volume and pore volume of the two catalysts: the specific surface area of the newly prepared metal-doped catalyst is 26.1749m 2cm3 / g, pore volume 0.111305 cm3 / g 3 cm3 / g, pore volume 0.06497 cm3 / g 2 cm3 / g, pore volume 0.06497 cm3 / g 3 cm3 / g, pore volume 0.06497 cm3 / g

[0051] Exploratory Example 2

[0052] Based on the experimental results of Exploratory Example 1, the research and development team attempted to conduct isomerization reaction exploration by preparing an isopropyl oxide solution containing hydroquinone, adding a trace amount of hydroquinone to isopropyl oxide (taking 0.01 g of hydroquinone and dissolving it in 100 g of isopropyl oxide, after sufficient stirring and dissolution, preparing a 0.01 wt% isopropyl oxide solution), and the other parameters and condition controls in this exploratory example were the same as in Exploratory Example 1. Table 1 shows the reaction results of Exploratory Example 1 and Exploratory Example 2 at different reaction times. It should be noted that, in order to avoid sampling loss of raw material isopropyl oxide, the reaction accumulated products of 0-48 h (reaction time marked as 48 h) and 48-96 h (reaction time marked as 96 h) were collected respectively, and then the products were analyzed by gas chromatography, and the conversion rate and selectivity were calculated by the correction normalization method. The "yield reduction rate" is the percentage of the yield (conversion rate x selectivity) at 96 h compared to the yield at 48 h, and thus the effect of the polymerization inhibitor on the service life of the catalytic reaction is calculated by the reduction rate of the yield and conversion rate twice.

[0053] Table 1

[0054]

[0055] The experimental results shown in Table 1 are surprising:

[0056] After adding trace amounts of polymerization inhibitors in the exploration example 2, the amount of by-products (propionaldehyde, acetone and propanol) generated in the isomerization reaction of propylene oxide did not change significantly compared to the exploration example 1 without adding polymerization inhibitors, and the difference in selectivity was also small, such as 48h: the difference in the content of by-products propionaldehyde, acetone and propanol in exploration example 1 and exploration example 2 was within ±0.5%; such as 96h: the difference in the content of by-products propionaldehyde, acetone and propanol in exploration example 1 and exploration example 2 was within ±1.16%. In the isomerization reaction of propylene oxide, propionaldehyde, acetone and propanol are common small molecule by-products. The comparison results of the by-products shown in Table 1 show that the difference in selectivity is not large under the same catalyst, but the service life of the catalyst shows a significant difference. The research and development team speculates that the generation of carbon deposition in the isomerization reaction catalyst is not related to the common by-products of isomerization reaction. In addition, it is worth noting that the selectivity of allyl alcohol in exploration example 1 and exploration example 2 also does not change significantly.

[0057] However, when the isomerization reaction is carried out for 96h, the addition of polymerization inhibitors shows a significant difference in the catalytic activity of the catalyst, which is reflected in the fact that the yield reduction rate of exploration example 2 (10.78%) is significantly lower than that of exploration example 1 (28.36%) without adding polymerization inhibitors, that is, the catalyst in exploration example 2 still maintains high catalyst performance in the same reaction time, which can be inferred that the addition of trace amounts of polymerization inhibitors in exploration example 2 effectively delays the deactivation of the catalyst and improves the service life of the catalyst.

[0058] Subsequently, the research and development team took out the catalysts after 96h reaction in exploration example 1 and exploration example 2 respectively, and thoroughly cleaned the catalysts to exclude the influence of solvents, and then determined the specific surface area, pore volume and pore volume of the two used catalysts by BET (results as shown in Table 2), and found that the specific surface area, pore volume and pore volume of the catalyst in exploration example 1 were significantly lower than those of the catalyst in exploration example 2.

[0059] Table 2

[0060] Sample Specific surface area Pore volume Pore volume Exploratory Example 1 Catalyst 16.8931m 2 / g]]> 0.06497 cm 3 / g]] 10.3782 nm Exploratory Example 2 Catalyst 22.1873m 2 / g]]> 0.93568 cm 3 / g]] 12.2570 nm

[0061] Based on the experimental results of the exploration example 1 and the exploration example 2, the research and development team speculates that in the process of isomerization of propylene oxide to allyl alcohol, the target product allyl alcohol with carbon-carbon double bond inevitably self-polymerizes to generate viscous and non-volatile heavy component impurities, which adhere to the surface of the catalyst to cover the active sites and block the active pores, and then rapidly deactivates. Based on Table 1 and Table 2, in the 48h reaction stage, the addition of the polymerization inhibitor in the exploration example 2 does not obviously affect the conversion rate and the selectivity, but in the 96h reaction stage, the exploration example 2 shows obvious advantages in the catalytic life, thereby confirming that the addition of the polymerization inhibitor in the existing propylene oxide isomerization process can reduce the self-polymerization degree of the allyl alcohol and the unsaturated by-products thereof, and improve the service life of the catalyst; the research and development team speculates that in the continuous catalytic reaction, the hydroquinone added in the exploration example 2 may be oxidized to p-benzoquinone in the reaction system, and combined with the free radicals in the allyl alcohol, so as to avoid the re-polymerization of the allyl alcohol on the surface of the catalyst, prevent or slow down the reaction rate of the carbon chain increasing reaction, promote the allyl alcohol to maintain the small molecule state in the pores of the catalyst surface and desorb in time, and then delay the plugging of the pores of the catalyst, thereby increasing the life of the isomerization catalyst.

[0062] Based on the above findings, the research and development team proposes the technical scheme of the present application for preparing allyl alcohol by isomerization of propylene oxide.

[0063] Example 1

[0064] A method for preparing allyl alcohol by isomerization of propylene oxide, specifically:

[0065] (1) hydroquinone is used as a polymerization inhibitor, the hydroquinone is dissolved in raw material propylene oxide, and after being fully stirred and dissolved, a propylene oxide solution with a hydroquinone content of 0.3wt% is prepared.

[0066] (2) the lithium phosphate catalyst is pressed into particles with a particle size of 20-40 mesh, 15g of which is loaded into a fixed bed reactor with a diameter of 10mm, and 250sccm of nitrogen is introduced for protection; the reactor is heated to 300℃, and the reaction pressure is 0.1MPa; the preheater is heated to 230℃, and the propylene oxide solution is heated by the preheater and then enters the fixed bed from the top at a flow rate of 1.0ml / min (the mass hourly space velocity is 4h -1 ) and nitrogen (the molar ratio of nitrogen to propylene oxide is 0.79), and the isomerization reaction of the catalyst is carried out to obtain allyl alcohol; after the reaction is completed, the product is collected by condensation in a cold trap.

[0067] It should be noted that, in order to avoid the loss of raw material propylene oxide at the time of sampling, the reaction accumulated products of 0-48h and 48-96h were collected respectively, the products were analyzed by gas chromatography, the conversion rate and selectivity were calculated by correction normalization method, the influence of polymerization inhibitor on the catalytic reaction life was calculated by the decline ratio of the conversion rate and selectivity of the products twice, and the reaction results are shown in Table 3.

[0068] Example 2

[0069] A method for preparing allyl alcohol by isomerization of propylene oxide, specifically:

[0070] (1) A complex polymerization inhibitor containing hydroquinone and p-benzoquinone (the molar ratio of hydroquinone to p-benzoquinone is 1:4) was used, the complex polymerization inhibitor was dissolved in the raw material propylene oxide, and after sufficient stirring and dissolution, a propylene oxide solution with a polymerization inhibitor content of 0.1wt% was prepared.

[0071] (2) The lithium phosphate catalyst was pressed into 20-40 mesh particles, 15g was weighed and loaded into a fixed bed reactor with a diameter of 10mm, and 250sccm of nitrogen was introduced for protection; the reactor was heated to 300℃, and the reaction pressure was 0.1MPa; the preheater was heated to 230℃, and the propylene oxide solution was heated by the preheater, then entered the fixed bed from the top at a flow rate of 1.0ml / min and contacted with the catalyst to occur isomerization reaction to obtain allyl alcohol; after the reaction was completed, the product was collected by condensation in a cold trap. The reaction results are shown in Table 3.

[0072] Example 3

[0073] A method for preparing allyl alcohol by isomerization of propylene oxide, the operation process and parameter control of this embodiment are the same as those of Example 2, the difference is that the molar ratio of hydroquinone to p-benzoquinone in the complex polymerization inhibitor is 1:2; the reaction results of this embodiment are shown in Table 3. In addition, the catalytic activity of the catalyst was continuously evaluated for a long time, and it was found that the isomerization reaction yield of the catalyst in this embodiment only decreased by 10% after 430h of use.

[0074] Example 4

[0075] A method for preparing allyl alcohol by isomerization of propylene oxide, the parameters and condition control of this method are the same as those of Example 3, the difference is that the complex polymerization inhibitor is hydroquinone and p-tert-butylcatechol, and the molar ratio of hydroquinone to p-tert-butylcatechol is 1:2; in addition, the concentration of the polymerization inhibitor is 0.4wt%; after vaporization by preheating, propylene oxide is input into the top of the fixed bed reactor at a flow rate of 0.125ml / min. The reaction results of this embodiment are shown in Table 3.

[0076] Example 5

[0077] A method for preparing allyl alcohol by isomerization of propylene oxide, in particular:

[0078] (1) Dissolve the polymerization inhibitor p-benzoquinone in the raw material propylene oxide, and after fully stirring and dissolving, prepare a propylene oxide solution with a p-benzoquinone content of 0.01wt%.

[0079] (2) Crush the lithium phosphate catalyst tablets into 20-40 mesh particles, take 15g and load into a fixed bed reactor with a diameter of 10mm, and introduce 250sccm of nitrogen for protection; heat the reactor to 275°C and the reaction pressure to 0.1MPa; heat the preheater to 200°C, and after heating the propylene oxide solution in the preheater, introduce it into the fixed bed from the top at a flow rate of 1.0ml / min and contact the catalyst to produce allyl alcohol by isomerization; after the reaction is completed, the product is collected by condensation in a cold trap. The reaction results are shown in Table 3.

[0080] Example 6

[0081] A method for preparing allyl alcohol by isomerization of propylene oxide, in particular:

[0082] (1) Dissolve the polymerization inhibitor p-benzoquinone in the raw material propylene oxide, and after fully stirring and dissolving, prepare a propylene oxide solution with a p-benzoquinone content of 0.01wt%.

[0083] (2) Crush the lithium phosphate catalyst tablets into 20-40 mesh particles, take 15g and load into a fixed bed reactor with a diameter of 10mm, and introduce 250sccm of nitrogen for protection; heat the reactor to 275°C and the reaction pressure to 0.1MPa; heat the preheater to 200°C, and after heating the propylene oxide solution in the preheater, introduce it into the fixed bed from the top at a flow rate of 1.0ml / min and contact the catalyst to produce allyl alcohol by isomerization; after the reaction is completed, the product is collected by condensation in a cold trap. The reaction results are shown in Table 3.

[0084] Comparative Example 1

[0085] A method for preparing allyl alcohol by isomerization of propylene oxide, the specific process and parameter control are the same as in Example 1, except that no polymerization inhibitor is added, and the reaction results are shown in Table 3.

[0086] Comparative Example 2

[0087] A method for preparing allyl alcohol by isomerization of propylene oxide, the specific process and parameter control are the same as in Example 1, except that an equal amount of nitrobenzene is added as a polymerization inhibitor, and the reaction results are shown in Table 3.

[0088] Comparative Example 3

[0089] The process for preparing allyl alcohol by isomerization of propylene oxide is the same as that in Example 1, except that an equal amount of copper sulfate is added as a polymerization inhibitor. It is found in the specific experimental process that copper sulfate is difficult to dissolve in propylene oxide, and the reaction results are shown in Table 3.

[0090] Example 7

[0091] A process for preparing allyl alcohol by isomerization of propylene oxide, specifically:

[0092] Step S1: Hydroquinone is used as a polymerization inhibitor, and the hydroquinone is dissolved in the raw material propylene oxide. After sufficient stirring and dissolution, a 0.01wt% propylene oxide solution is prepared.

[0093] Step S2: 100ml of solvent triphenyl and hydrogenated triphenyl (volume ratio 1:1) are added to a 250ml stainless steel reaction kettle, 15g of isomerization catalyst powder is added, and the reactor is heated to 300℃ after nitrogen replacement. The reaction pressure is controlled at 0.1MPa, the preheater is heated to 230℃, and the propylene oxide solution is heated by the preheater. The solution is then introduced into the reaction kettle at a flow rate of 1.0ml / min through the inner tube from the bottom of the reaction kettle and contacts the isomerization catalyst to produce allyl alcohol. After the reaction is completed, the product is collected by condensation in a cold trap, and the final product is analyzed by gas chromatography. The reaction results are shown in Table 3.

[0094] Example 8

[0095] A process for preparing allyl alcohol by isomerization of propylene oxide, the operation process and parameter control of this embodiment are the same as those of Example 7, except that a compound polymerization inhibitor of hydroquinone and p-benzoquinone is used in this embodiment, and the molar ratio of hydroquinone to p-benzoquinone is 10:1. In addition, the concentration of the polymerization inhibitor in this embodiment is 0.5wt%. The solvent used is hydrogenated triphenyl. The reaction results of this embodiment are shown in Table 3.

[0096] Example 9

[0097] A process for preparing allyl alcohol by isomerization of propylene oxide, the operation process and parameter control of this embodiment are the same as those of Example 8, except that the molar ratio of hydroquinone to p-benzoquinone in the compound polymerization inhibitor used in this embodiment is 1:4. In addition, the concentration of the polymerization inhibitor is 0.1wt%. The reaction results of this embodiment are shown in Table 3.

[0098] Example 10

[0099] A method for preparing allyl alcohol by isomerization of propylene oxide, the operation process and parameter control of this embodiment are the same as those of example 9, the difference is that the complex inhibitor used in this embodiment is a complex inhibitor of hydroquinone and p-tert-butyl hydroquinone, and the molar ratio of hydroquinone to p-tert-butyl hydroquinone is 1:10; in addition, the solvent used in this embodiment is terphenyl; the rate of propylene oxide input into the reaction kettle is 0.125 ml / min. The reaction results of this embodiment are shown in Table 3.

[0100] Example 11

[0101] A method for preparing allyl alcohol by isomerization of propylene oxide, specifically:

[0102] Step S1: hydroquinone is used as a polymerization inhibitor, hydroquinone is dissolved in raw material propylene oxide, and after sufficient stirring and dissolution, a 0.05wt% propylene oxide solution is prepared.

[0103] Step S2: 100ml of solvent p-phenol is added to a 250ml stainless steel reaction kettle, 15g of isomerization catalyst powder is added, and after nitrogen is fully replaced, the reactor is heated to 275℃, the reaction pressure is controlled at 0MPa, the preheater is heated to 200℃, and the propylene oxide solution is heated through the preheater, then enters the reaction kettle from the bottom of the reaction kettle through the inner tube at a flow rate of 1.25ml / min and contacts the isomerization reaction catalyst to generate isomerization reaction to obtain allyl alcohol; after the reaction is completed, the product is collected by condensation through a cold trap, and the final product is analyzed by gas chromatography, and the reaction results are shown in Table 3.

[0104] Comparative Example 4

[0105] A method for preparing allyl alcohol by isomerization of propylene oxide, the specific process and parameter control are the same as those of example 7, but no polymerization inhibitor is added, and the experimental results are shown in Table 3.

[0106] Table 3

[0107]

[0108]

[0109] As can be seen from Table 3, compared with the scheme of not adding a polymerization inhibitor or using nitrobenzene and copper sulfate as a polymerization inhibitor, the method for preparing allyl alcohol by gas phase method of propylene oxide of the present application can significantly reduce the rate of catalyst deactivation, which is reflected in that the yield reduction ratio of example 1 is significantly less than that of comparative examples 1-3 within 96h reaction stage. In addition, the method for preparing allyl alcohol by liquid phase method of the present application can also significantly reduce the rate of catalyst deactivation, and the yield reduction ratio of example 7 is lower than that of comparative example 4 within 96h reaction stage. The above examples and comparative examples verify that the method for preparing allyl alcohol by isomerization of propylene oxide of the present application has the technical advantage of prolonging the service life of the catalyst.

[0110] It should be noted that the above content is a further detailed description of the present application in combination with specific embodiments, and cannot be considered as limiting the specific embodiments of the present application. For ordinary skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple improvements can be made, which should be considered as belonging to the protection scope of the present application.

Claims

1. A process for the isomerization of propylene oxide to allyl alcohol, characterized in that Propylene oxide is isomerized in the presence of a polymerization inhibitor to obtain allyl alcohol; wherein the polymerization inhibitor is a phenolic polymerization inhibitor and / or a quinone polymerization inhibitor.

2. The process for isomerization of propylene oxide to allyl alcohol according to claim 1, characterized in that, The phenolic polymerization inhibitor is selected from one or more of hydroquinone, catechol, p-tert-butylcatechol, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone; And / or, the quinone polymerization inhibitor is selected from one or more of p-benzoquinone, naphthoquinone, chloranil.

3. The process for isomerization of propylene oxide to allyl alcohol according to claim 1, characterized in that, The polymerization inhibitor is a complex polymerization inhibitor of the phenolic polymerization inhibitor and the quinone polymerization inhibitor, and the molar ratio of the phenolic polymerization inhibitor to the quinone polymerization inhibitor in the complex polymerization inhibitor is (0.1-10):1, preferably (1-5):

1. Preferably, the phenolic polymerization inhibitor is selected from one or more of hydroquinone, catechol, p-tert-butylcatechol, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl-hydroquinone, 2-tert-butyl-hydroquinone; The quinone polymerization inhibitor is selected from one or more of p-benzoquinone, naphthoquinone, chloranil.

4. The process for isomerization of propylene oxide to allyl alcohol according to claim 1, characterized in that, The addition amount of the polymerization inhibitor is 0.01wt%-1wt%, preferably 0.1wt%-0.5wt%, of the amount of propylene oxide.

5. The method for preparing allyl alcohol by isomerization of propylene oxide according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: Step (1), dissolving the polymerization inhibitor in the propylene oxide to obtain a propylene oxide solution to be reacted; Step (2), preheating and vaporizing the propylene oxide solution to be reacted, and contacting with a catalyst in the presence of a carrier gas to isomerize to obtain the allyl alcohol.

6. The process for isomerization of propylene oxide to allyl alcohol according to claim 5, characterized in that, The mass space velocity of the propylene oxide solution to be reacted in step (2) is 0.5-5 h -1 ; And / or, the preheating temperature in step (2) is 150-250°C; And / or, the carrier gas is an inert gas; and the molar ratio of the carrier gas to propylene oxide is (0.5-10):1; And / or, the isomerization reaction temperature in step (2) is 275-300°C, and the reaction pressure is 0-1MPa; And / or, the isomerization reaction in step (2) is carried out in a fixed bed reactor.

7. The process for isomerization of propylene oxide to allyl alcohol according to claim 5, characterized in that, The polymerization inhibitor is one or more of hydroquinone, catechol, p-tert-butylcatechol, p-benzoquinone, preferably one or more of hydroquinone, p-benzoquinone, p-tert-butylcatechol.

8. The method for preparing allyl alcohol by isomerization of propylene oxide according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: Step S1, dissolving the polymerization inhibitor in the propylene oxide to obtain a propylene oxide solution to be reacted; Step S2, after preheating, the propylene oxide solution to be reacted is contacted with a catalyst in a solvent to isomerize to obtain the allyl alcohol.

9. The process for isomerization of propylene oxide to allyl alcohol according to claim 8, characterized in that, The feed mass space velocity of the propylene oxide solution to be reacted in step (2) is 0.5-5 h -1 ; And / or, the preheating temperature in step S2 is 150-250°C; And / or, the solvent is selected from one or more of terphenyl, p-phenol, and hydrogenated terphenyl; Preferably, in step S2, the mass ratio of the solvent to the catalyst is (5-20):1; And / or, the isomerization reaction temperature in step S2 is 275-300°C, and the reaction pressure is 0-1MPa; And / or, the isomerization reaction in step S2 is carried out in an inert atmosphere; And / or, the isomerization reaction in step S2 is carried out in a suspension bed reactor.

10. The process for isomerization of propylene oxide to allyl alcohol according to claim 8, characterized in that, The polymerization inhibitor is one or more of hydroquinone, catechol, p-tert- butylcatechol, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl- hydroquinone, 2-tert-butyl-hydroquinone, p-benzoquinone, naphthoquinone, chloranil; preferably one or more of hydroquinone, p-benzoquinone, p-tert- butylcatechol. The polymerization inhibitor is one or more of hydroquinone, catechol, p-tert- butylcatechol, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butyl- hydroquinone, 2-tert-butyl-hydroquinone, p-benzoquinone, naphthoquinone, chloranil; preferably one or more of hydroquinone, p-benzoquinone, p-tert- butylcatechol. The polymerization inhibitor is one or more of hydroquinone, catechol, p-tert- butylcatechol, p-hydroxyanisole, 2,6-di-

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