Comprehensive utilization method of rectification heavy component of 2-methyl furan byproduct

Abstract

The invention discloses a comprehensive utilization method of a rectification heavy component of a 2-methyl furan byproduct, which comprises the following steps: 1) carrying out reduced pressure distillation on the heavy component of the 2-methyl furan byproduct to obtain a heavy component removal solution, and supplementing a small amount of n-amyl alcohol; 2) mixing the de-heavy liquid obtained in the step 1) with furfuryl alcohol in proportion, reacting in the presence of a catalyst to generate an intermediate furfuryl amyl ether, and further hydrolyzing to obtain amyl levulinate; and 3) filtering or neutralizing and filtering the reaction liquid obtained in the step 2), and then carrying out catalytic hydrogenation reaction to obtain gamma-valerolactone, 4, the reaction liquid obtained in the step 3 is subjected to vacuum rectification, and an n-amyl alcohol product and a gamma-valerolactone product are obtained.By means of the process, the effective utilization rate of n-amyl alcohol, furfuryl alcohol and gamma-valerolactone in heavy components can reach 80% or above, the process is simple and easy to operate, industrialization is facilitated, the purity of prepared n-amyl alcohol is larger than or equal to 99.5%, and the purity of prepared gamma-valerolactone is larger than or equal to 98.0%.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a method for comprehensively utilizing distillation heavy components of 2-methylfuran byproduct. Background Art

[0002] 2-methylfuran is mainly used for preparing medicines such as vitamin B1, chloroquine phosphate and primaquine phosphate, synthesizing pyrethroid pesticides and flavors and fragrances, and is also a good solvent. Bio-based production technology can be prepared by furfural or furfuryl alcohol hydrogenation reaction, for example, furfuryl alcohol hydrogenation carries out gas phase fixed bed reaction production 2-methylfuran, reaction ends, and continuous distillation is carried out after multi-stage cooling, first removes heavy components, then removes light components, and finally distillation obtains 2-methylfuran product. In the production process, when producing one ton of 2-methylfuran, also by-product about 150kg of heavy components, the distillation heavy components of the by-product generally mainly include furfuryl alcohol, gamma-valerolactone, high boiling point (generally refers to the material that can not be steamed under vacuum degree 2kp or so, bottom temperature 150 degree conditions) and a small amount of n-amyl alcohol, tetrahydrofurfuryl alcohol, water and other impurities etc.

[0003] Since furfuryl alcohol and γ-valerolactone in the by-product heavy components have similar boiling points, it is difficult to purify them into industrial qualified products by distillation. Therefore, the heavy components are often incinerated in industry to recover the calorific value, which results in a huge waste of resources. The failure to effectively utilize furfuryl alcohol and γ-valerolactone will also increase production costs.

[0004] Current research is mostly focused on how to efficiently and greenly produce 2-methylfuran, but there has been no report on the research on the heavy by-products in the production process of 2-methylfuran.

[0005] Based on this, this application was developed. Summary of the invention

[0006] The present invention aims to overcome the defects of the prior art and provide a method for comprehensive utilization of the distillation heavy components of 2-methylfuran byproduct. The method uses the heavy components after removing high boiling points as a solvent to produce γ-valerolactone, effectively utilizes furfuryl alcohol and γ-valerolactone therein, and n-pentanol also plays an important role as a raw material participating in the intermediate reaction. A reaction liquid rich in n-pentanol and γ-valerolactone is obtained by alcoholysis and hydrogenation, and then distilled to obtain n-pentanol and γ-valerolactone products, thereby realizing the comprehensive utilization of effective components in the heavy components.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A method for comprehensive utilization of distillation heavy components of 2-methylfuran byproduct, comprising the following steps:

[0009] 1) Recombinant components produced by 2-methylfuran are subjected to vacuum distillation to remove a portion of high-boiling substances (the purpose of vacuum distillation is to remove the self-polymers of furfuryl alcohol and leave useful substances with relatively low boiling points), to obtain a de-heavy liquid, and a small amount of n-pentanol is added;

[0010] 2) mixing the deweighted liquid obtained in step 1) with furfuryl alcohol in proportion, reacting in the presence of a catalyst to generate an intermediate furfuryl pentyl ether, and further hydrolyzing to obtain pentyl levulinate;

[0011] 3) filtering, or neutralizing and filtering the reaction solution obtained in step 2), and then performing a catalytic hydrogenation reaction to obtain γ-valerolactone;

[0012] 4) The reaction solution obtained in step 3) is subjected to vacuum distillation to obtain qualified n-pentanol product and γ-valerolactone product respectively.

[0013] Specifically, in step 1), the 2-methylfuran by-product heavy components contain, by weight percentage, 1-5% n-pentanol, 15-40% furfuryl alcohol, 20-40% γ-valerolactone, 0.1-1.0% water, 10-20% high boiling substances, 1-3% tetrahydrofurfuryl alcohol, and 5-10% other impurities.

[0014] Furthermore, in step 1), the temperature of the bottom of the kettle during the vacuum distillation is 70-120° C., the vacuum degree is 0.3-2.0 kPa, and the vacuum distillation is performed until no more fraction is produced. n-Pentanol is added until the content of n-pentanol is 10-90%, preferably 30-50%, and the added n-pentanol can be the n-pentanol recovered by the method.

[0015] Specifically, in step 2), the deweighting liquid and furfuryl alcohol are mixed in a mass ratio of (50-1):1, preferably (30-10):1, and further preferably (10-5):1; the reaction can be a batch reaction in a kettle or a continuous reaction in a kettle, and the reaction can be performed for 2-8 hours.

[0016] Further, in step 2), the catalyst used may include commonly used inorganic or organic strong acids, such as hydrochloric acid, sulfuric acid, methanesulfonic acid, dodecylbenzenesulfonic acid, phosphotungstic acid, etc., or may be one or more solid acids (such as HND-8, Amberlyst-15, etc.) including Lewis acids such as ferric chloride, ferric sulfate, zinc chloride, zinc sulfate, and molecular sieves (such as ZSM-5). In step 2), the reaction temperature is 90 to 180°C, preferably 110 to 150°C, and the reaction is carried out until the contents of furfuryl alcohol and furfuryl pentyl ether are both ≤0.1%. The reaction process is: furfuryl alcohol and n-pentanol first react to form an intermediate furfuryl pentyl ether, and then furfuryl pentyl ether is further hydrolyzed to obtain pentyl levulinate.

[0017] Specifically, in step 3), the catalytic hydrogenation reaction uses Raney nickel as a catalyst, the reaction pressure is 3-7 MPa, the reaction temperature is 110-230°C, preferably 150-190°C, and the reaction generally takes 4-20 hours. If a solid acid catalyst is used in step 2), the obtained reaction liquid can be directly filtered and then subjected to catalytic hydrogenation reaction; if a liquid acid catalyst such as an inorganic or organic strong acid is used in step 2), the obtained reaction liquid is firstly neutralized with alkali to produce a precipitate, and then filtered for catalytic hydrogenation reaction.

[0018] Furthermore, in step 4), the vacuum distillation conditions are: vacuum degree 0.3-2.0 kPa, kettle bottom temperature 70-150°C, reflux ratio (1-5): 1, firstly distilling out the n-pentanol product, and then distilling out the γ-valerolactone product. The distillation is a vacuum kettle intermittent distillation, the distillation column has an inner diameter of 24 mm, a length of 60 cm, and is filled with 316L triangular spiral packing.

[0019] Compared with the prior art, the beneficial effects of the method of the present invention are as follows:

[0020] The present invention provides a method for comprehensive utilization of the distillation heavy components of 2-methylfuran by-product, which mainly contain furfuryl alcohol, γ-valerolactone, n-pentanol, tetrahydrofurfuryl alcohol, high boiling substances, water and other impurities. After removing the components that are unfavorable to the catalyst, the present invention uses it as a solvent for preparing pentyl levulinate by alcoholysis of furfuryl alcohol and further hydrogenating it to prepare γ-valerolactone, and can also convert the furfuryl alcohol therein into γ-valerolactone. γ-Valerolactone is an important solvent and can also be used to produce 2-methyltetrahydrofuran. The process of this method can achieve an effective utilization rate of n-pentanol, furfuryl alcohol and γ-valerolactone in the heavy components of more than 80%, and the process is simple and easy to operate, which is convenient for industrialization. The purity of the prepared n-pentanol is ≥99.5%, and the quality meets the T / CPCIF 000X-2021 industrial n-pentanol synthesis grade standard, and the purity of the prepared γ-valerolactone is ≥98.0%. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited thereto.

[0022] The moisture content involved in the embodiments was determined by Karl Fischer moisture meter, and the organic matter content was determined by gas chromatography external standard method, the equipment model is Agilent 8860, and the chromatographic column model is DB-624.

[0023] The quality of the prepared n-pentanol meets the T / CPCIF 000X-2021 industrial n-pentanol synthesis grade standard, and the purity of the prepared γ-valerolactone is ≥98.0%.

[0024] In the following examples, the raw materials used are all common commercially available products or can be prepared by conventional methods in the art.

[0025] The raw material furfuryl alcohol and the distillation heavy components of 2-methylfuran by-product are provided by Puyang Hongye High-tech Development Co., Ltd. The quality of furfuryl alcohol meets the national standard GB / T 14022.1-92 quality requirements of industrial furfuryl alcohol premium products.

[0026] The composition information of the distillation heavy components of the by-product 2-methylfuran is: 2.5% n-pentanol, 34.9% furfuryl alcohol, 1.7% tetrahydrofurfuryl alcohol, 36.2% γ-valerolactone, 0.5% water, 16.6% high boiling substances, and 7.6% other impurities.

[0027] The provided 2-methylfuran by-product is subjected to vacuum distillation (the vacuum distillation temperature is 90-100° C. and the vacuum degree is 0.5-0.7 kPa), and the vacuum distillation is performed until no more fractions are produced to obtain a de-weighted liquid. The de-weighted liquid is composed of: 3.0% of n-pentanol, 42.1% of furfuryl alcohol, 1.9% of tetrahydrofurfuryl alcohol, 43.7% of gamma-valerolactone, 0.4% of water, and 8.9% of impurities.

[0028] The deweighted liquid obtained in the above preparation is then used to carry out subsequent steps to produce n-pentanol and γ-valerolactone products.

[0029] Embodiment 1:

[0030] 1000 g of the deweighted liquid was added with 800 g of n-pentanol (purity 99.6%), and then mixed with 150 g of furfuryl alcohol to obtain a mixture.

[0031] First, 200 g of the above mixture was added to a three-necked flask, 60 g of HND-8 solid acid catalyst was added, a reflux device was added, the temperature was raised to 130° C. under magnetic stirring and then kept warm, and the remaining 1750 g of the raw material was continuously added dropwise to the reactor at a rate of 2.0 ml / min. After the addition was completed, the reaction was continued to be kept warm for 1 h, and then samples were taken and analyzed every 1 h until furfuryl alcohol and furfuryl pentyl ether were completely converted (i.e., the contents of both were ≤0.1%), and pentyl levulinate was prepared.

[0032] After cooling down, the sample is analyzed by gas chromatography. It should be noted that if a solid acid catalyst is used, the sample needs to be filtered after sampling and then analyzed. If a liquid acid catalyst is used, such as inorganic or organic strong acid, hydrochloric acid, sulfuric acid, methanesulfonic acid, dodecylbenzenesulfonic acid, phosphotungstic acid, etc., a base needs to be added after sampling for neutralization, then filtered, and finally analyzed. The results are shown in the table below.

[0033] Embodiments 2 to 9:

[0034] Referring to the method of Example 1, the difference is that the catalyst is replaced with hydrochloric acid, sulfuric acid, molecular sieve ZSM-5, solid acid Amberlyst-15 (A-15), methanesulfonic acid (MSA), phosphotungstic acid, iron sulfate, and zinc sulfate, respectively, and the corresponding reaction is carried out to prepare amyl levulinate. At the same time, the reaction solution is analyzed, and the results are compared as follows.

[0035]

[0036]

[0037] Considering that chloride ions are highly corrosive to stainless steel reactors, we subsequently selected the reaction solution of alcoholysis catalyzed by the solid acid catalyst HND-8 used in Example 1 for the next catalytic hydrogenation reaction to prepare γ-valerolactone, and also gave the experimental results of other examples.

[0038] The reaction solutions prepared in Examples 1, 4, 5, 8, and 9 were directly filtered; the reaction solutions prepared in Examples 2, 3, 6, and 7 (using a liquid acid catalyst in the above step) were neutralized with sodium carbonate and then filtered. 700 g of the filtrate of each example was added to a 1000 ml high pressure reactor, 10 g of Raney nickel was added, the reactor was sealed and tested for leaks with nitrogen at 7 MPa, and after confirming that there was no leak, nitrogen was replaced three times, and then hydrogen was replaced four times, and finally 1 MPa of hydrogen was filled, stirring was turned on, the temperature was slowly raised to 170 ° C, the reaction pressure was maintained at 6 MPa, and the temperature was kept for 30 minutes until there was no pressure drop, the temperature was lowered, and sampling was performed for detection. The test results are shown in the table below.

[0039]

[0040] Summary: The alcoholysis liquid with better alcoholysis reaction is used for hydrogenation reaction, the reaction speed is faster, the conversion rate of pentyl levulinate is 100%, and the selectivity is more than 99%. We choose the hydrogenation liquid of Example 1 for distillation.

[0041]

[0042] The catalyst in the catalytic hydrogenation reaction liquid was filtered out, and the filtrate was rectified in a distillation tower (the conditions of vacuum distillation were: vacuum degree 0.5-0.7 kPa, kettle bottom temperature 100-120°C, reflux ratio about 3:1), and the n-pentanol product was first distilled out, and then the γ-valerolactone product was distilled out. 239.2 g of n-pentanol with a purity of ≥99.5% was obtained, with a recovery rate of 81.8%, and 329.3 g of γ-valerolactone with a purity of ≥98.0% was obtained, with a distillation yield of 90.2%, and the recovery rates of furfuryl alcohol and γ-valerolactone in the de-heavy liquid were 85.23%.

[0043]

[0044] Conclusion: Using the distillation de-heavy liquid produced as a by-product of 2-methylfuran as solvent and alcoholysis with furfuryl alcohol in a certain mass ratio, 100% conversion of furfuryl alcohol including the furfuryl alcohol in the de-heavy liquid as solvent can be achieved, and the selectivity of amyl levulinate is more than 90%. The alcoholysis reaction liquid is subjected to catalytic hydrogenation and then distillation to separate and purify n-pentanol and γ-valerolactone products that meet industry standards, and the recovery rates of n-pentanol, furfuryl alcohol and γ-valerolactone in the de-heavy liquid are all above 80%.

[0045] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for comprehensive utilization of distillation heavy components of 2-methylfuran by-product, characterized in that: The steps include: 1) The heavy components of the by-product 2-methylfuran are distilled under reduced pressure to obtain a de-heavy liquid, and a small amount of n-pentanol is added; 2) mixing the deweighted liquid obtained in step 1) with furfuryl alcohol in proportion, reacting in the presence of a catalyst to generate an intermediate furfuryl pentyl ether, and further hydrolyzing the mixture to obtain pentyl levulinate; 3) filtering, or neutralizing and filtering, the reaction solution obtained in step 2) and then performing a catalytic hydrogenation reaction to obtain γ-valerolactone; 4) The reaction solution obtained in step 3) is subjected to vacuum distillation to obtain n-pentanol product and γ-valerolactone product respectively.

2. The comprehensive utilization method of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 1), the 2-methylfuran by-product heavy components contain, by weight percentage, 1-5% n-pentanol, 15-40% furfuryl alcohol, 20-40% γ-valerolactone, 0.1-1.0% water, 10-20% high boiling substances, 1-3% tetrahydrofurfuryl alcohol, and 5-10% other impurities.

3. The comprehensive utilization method of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 1), the temperature of the reduced pressure distillation is 70-120° C., the vacuum degree is 0.3-2.0 kPa, and the reduced pressure distillation is performed until no more distillate is produced.

4. The comprehensive utilization method of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 1), n-pentanol is added until the content of n-pentanol is 10 to 90%.

5. The comprehensive utilization method of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 2), the de-weighting liquid and furfuryl alcohol are mixed in a mass ratio of (50-1):

1.

6. The method for comprehensive utilization of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 2), the catalyst used includes one or more of hydrochloric acid, sulfuric acid, methanesulfonic acid, dodecylbenzenesulfonic acid, phosphotungstic acid, ferric chloride, ferric sulfate, zinc chloride, zinc sulfate, and molecular sieves.

7. The method for comprehensive utilization of the distillation heavy components of the 2-methylfuran byproduct as claimed in claim 1, characterized in that: In step 2), the reaction temperature is 90-180° C., and the reaction is carried out until the contents of furfuryl alcohol and furfuryl pentyl ether are both ≤0.1%.

8. The method for comprehensive utilization of the distillation heavy components of the 2-methylfuran by-product as claimed in claim 1, characterized in that: In step 3), Raney nickel is used as a catalyst for the catalytic hydrogenation reaction, the reaction pressure is 3-7 MPa, and the reaction temperature is 110-230°C.

9. The method for comprehensive utilization of the distillation heavy components of the 2-methylfuran byproduct as claimed in claim 1, characterized in that: In step 4), the vacuum distillation conditions are: vacuum degree 0.3-2.0 kPa, kettle bottom temperature 70-150° C., reflux ratio 1-(5:1), firstly distilling out the n-pentanol product, and then distilling out the γ-valerolactone product.

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