阅读说明：本技术 一种乳糖转化合成羟甲基糠醛方法 (Method for synthesizing hydroxymethylfurfural by lactose conversion ) 是由 贾松岩 姜玉坤 纪婷婷 蒋万东 于 2021-11-01 设计创作，主要内容包括：一种乳糖转化合成羟甲基糠醛方法,涉及替代能源领域一种生物质资源转化方法,本发明为在液相体系中催化合成羟甲基糠醛(HMF)的方法。涉及乳糖的催化转化工艺,目标是获得HMF,属于生物质资源转化与利用领域。本方法采用金属盐作为催化剂,在高含水量的离子液体体系中,能够将乳糖有效地转化为HMF。本方法操作简单,获得HMF的产率较高,溶剂中离子液体的用量比现存研究工艺中的用量明显下降。本方法提供的信息可为富含乳糖的生物质资源的转化提供了有用参考。(The invention discloses a method for synthesizing Hydroxymethylfurfural (HMF) by lactose conversion, relates to a biomass resource conversion method in the field of alternative energy, and provides a method for catalytically synthesizing Hydroxymethylfurfural (HMF) in a liquid phase system. Relates to a catalytic conversion process of lactose, aims to obtain HMF, and belongs to the field of biomass resource conversion and utilization. The method adopts metal salt as a catalyst, and can effectively convert lactose into HMF in an ionic liquid system with high water content. The method is simple to operate, the yield of the HMF is high, and the dosage of the ionic liquid in the solvent is obviously reduced compared with the dosage in the existing research process. The information provided by the method can provide a useful reference for the conversion of lactose-rich biomass resources.)

1. The method for synthesizing the hydroxymethylfurfural by lactose conversion is characterized by comprising the following preparation processes:

a. adding raw materials, a catalyst, ionic liquid and water into a reaction bottle;

b. putting the reaction bottle filled with the raw materials, the catalyst, the ionic liquid and the water into a reaction module with a preset temperature, heating and stirring to generate HMF;

the catalyst in the step a comprises chromium trichloride, or chromium nitrate or a mixture of the two metal salts;

the molar weight ratio of the catalyst to the lactose in the step a is 1: 5-1: 2;

the ionic liquid in the step a comprises 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium bromide, or the ionic liquid mixture;

in the step a, the high-water-content ionic liquid system means that the mass fraction of water in a mixture of the ionic liquid and water is 30-55%.

2. The method for synthesizing hydroxymethylfurfural by lactose conversion according to claim 1, wherein lactose is efficiently converted into Hydroxymethylfurfural (HMF) in an ionic liquid system with high water content by using metal salt as a catalyst.

Technical Field

The invention relates to a biomass resource conversion synthesis method in the field of alternative energy, in particular to a method for synthesizing hydroxymethyl furfural by lactose conversion.

Background

The traditional fossil energy mainly comprises petroleum, coal and natural gas, and the energy plays an important role in promoting the development process of the world, and the global development is seriously dependent on the fossil energy. However, these three kinds of energy are non-renewable, and with the rapid development of the world for many years, a great amount of greenhouse gases are emitted while a great amount of fossil energy is consumed, which is a serious challenge for the sustainable development in the future. The development and utilization of new renewable energy sources are effective means for relieving global serious dependence on fossil energy sources and reducing greenhouse gas emission.

Biomass resources have been considered in recent years as a very promising alternative energy source. The reserves of the biomass are very abundant, mainly land and aquatic plants, widely distributed and low in pollution. These plants are capable of storing solar energy in the form of chemical energy through photosynthesis. The biomass resource used in the research field at present mainly refers to lignocellulose, and the main components of the biomass resource are cellulose, hemicellulose and lignin respectively. Lignocellulose is fully utilized and converted into some commodities with the potential of replacing petrochemicals, and the important supporting effect on sustainable development is achieved.

Hydroxymethylfurfural (HMF) is a popular platform compound in recent years, attracting extensive research attention. First, HMF has different kinds of functional groups in its chemical structure, for example, hydroxymethyl and aldehyde groups at positions 2 and 5 of its chemical structure, respectively, and it itself has a furan ring, which makes its chemical properties flexible. Second, HMF can be converted to a range of high value-added downstream chemicals through a number of different processes. For example, 2, 5-dimethylfuran obtained by selective hydrogenation can be used as a liquid fuel, 2, 5-furandicarboxylic acid obtained by selective oxidation can be used for preparing a high molecular compound, and a series of products obtained by reductive amination can be used for synthesis of pharmaceutical intermediates or high molecular compounds. Finally, HMF can be obtained by conversion of six-carbon sugars or their polymers by selective dehydration. These sugars are renewable biomass resources, which is a realistic basis for advancing biomass conversion processes represented by HMF.

Currently, the research field mainly relates to the selective conversion of fructose and glucose into HMF. The conversion of fructose is relatively easy, and the fructose can be converted into HMF in various solvent systems and under the action of various catalysts, so that the yield of HMF is high. The conversion of glucose is difficult compared to fructose because glucose exists mainly in a six-membered pyran ring structure, which has a low conversion activity. Fructose is generally present in about 30% of five-membered furan ring structures, which have a high conversion activity. The conversion of glucose generally requires first undergoing an isomerization process to form fructose, which is then subjected to subsequent conversions to yield HMF. In addition to fructose and glucose, research has also been focused on using their polymers as raw materials with the aim of reducing raw material costs.

However, many carbohydrate resources have not been studied in nature. The full and efficient utilization of the resources can effectively promote the important support effect of the biomass resources in the field of future alternative energy. In nature, various saccharides do not exist in a single form, they often exist in a polymer form with a complex structure, and the saccharide units often have completely different conversion activities due to slight changes of a steric structure of a functional group. Therefore, the detailed research on the conversion process of various carbohydrate resources has important significance for the comprehensive utilization of biomass resources. As mentioned above, fructose and glucose are six-carbon sugar materials mainly involved in the present research field, and disaccharides such as sucrose, cellobiose, maltose, etc. corresponding thereto have also been widely studied. However, carbohydrate resources similar to them but still of interest are also present in nature. Lactose is a disaccharide whose chemical structure is composed of one molecule of galactose and one molecule of glucose. Among them, galactose is a C4 site epimer of glucose, which results in a significant difference in chemical conversion activity from glucose. According to current studies, the yield of HMF obtained by galactose conversion is generally low. As such, lactose also has low conversion activity due to the presence of galactose building blocks and has not received much attention. Lactose is widely found in the milk of mammals in nature and can be obtained by feeding large numbers of livestock. In addition, a large amount of dairy product waste can be generated in daily life of the human society, the pollution possibly caused by the waste is solved by fully utilizing the resources, the high-value utilization of renewable resources is improved, and the method has important significance for supporting sustainable development.

In recent years, reaction systems for synthesizing HMF by converting saccharides mainly include water, a water-organic solvent two-phase system, a polar organic solvent, an ionic liquid, a supercritical fluid, and the like. Among them, ionic liquids have recently received much attention. The conversion of saccharides in various ionic liquids to obtain HMF has high yield, and is generally superior to the conversion performance in other solvent systems. However, ionic liquids also have some disadvantages. First, the cost of ionic liquids remains a consideration. Second, ionic liquids can be potentially toxic. Thirdly, the ionic liquid has strong water absorption, and additional drying treatment is often needed, so that the operation steps and the process cost are increased. Finally, it has been reported that the absorption of large amounts of water in ionic liquids also significantly inhibits the conversion of carbohydrates to HMF, resulting in a substantial reduction in their yield. Therefore, how to reduce the dosage of the ionic liquid and how to overcome the problems that the ionic liquid greatly reduces the conversion performance of the saccharides due to absorbing water are some key challenges for synthesizing the HMF by converting the saccharides currently.

Disclosure of Invention

The invention aims to provide a method for synthesizing hydroxymethylfurfural by lactose conversion, which takes metal salt as a catalyst, effectively converts lactose into Hydroxymethylfurfural (HMF) in an ionic liquid system with high water content and has high yield.

The purpose of the invention is realized by the following technical scheme:

a method for synthesizing hydroxymethylfurfural by lactose conversion comprises the following preparation processes:

a. adding raw materials, a catalyst, ionic liquid and water into a reaction bottle;

b. putting the reaction bottle filled with the raw materials, the catalyst, the ionic liquid and the water into a reaction module with a preset temperature, heating and stirring to generate HMF;

the catalyst in the step a comprises chromium trichloride, or chromium nitrate or a mixture of the two metal salts;

the molar ratio of the catalyst to the lactose in the step a is 1:5 to 1: 2.

The ionic liquid in the step a comprises 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium bromide, or a mixture of the ionic liquids.

In the step a, the high-water-content ionic liquid system means that the mass fraction of water in a mixture of the ionic liquid and water is 30-55%.

According to the method for synthesizing hydroxymethylfurfural by lactose conversion, the lactose is effectively converted into Hydroxymethylfurfural (HMF) in an ionic liquid system with high water content by taking metal salt as a catalyst.

The invention has the advantages and effects that:

1. the method effectively converts lactose resources widely existing in nature into the important chemical intermediate of the hydroxymethyl furfural, adopts an ionic liquid system with high water content, can reduce the cost of using the ionic liquid and potential pollution possibly caused by using a large amount of the ionic liquid, can effectively obtain the hydroxymethyl furfural in the system, and emphasizes the water-free property of the system when the ionic liquid system is used. The invention solves the problem that the effective conversion of lactose and the water content in the ionic liquid generate negative influence. The transformation prospect is good.

2. The water content in the system is higher, the using amount of the ionic liquid can be correspondingly reduced, and the using cost of the ionic liquid is reduced. The water content in the system is higher, so that the using amount of the ionic liquid can be correspondingly reduced, and the potential toxicity and potential pollution caused by the ionic liquid system are reduced.

3. The drying step of the ionic liquid can be reduced because more water needs to be added into the system.

4. The conversion of lactose to HMF is better and the product yield is higher.

Detailed Description

The present invention will be described in detail with reference to examples.

Example 1

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 560 mg of ionic liquid 1-ethyl-3-methylimidazole chloride and 240 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose, at 150%^oAnd C, reacting for 1 h at the stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 52%.

Example 2

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-ethyl-3-methylimidazole chloride and 320 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose, at 150%^oAnd C, reacting for 1 h at the stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 56%.

Example 3

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-ethyl-3-methylimidazole chloride and 320 mg of water, CrCl₃The molar amount of (b) is 30% of the molar amount of lactose and is in the range of 150^oAnd C, reacting for 1 h at the stirring speed of 300 r/min, and testing the sample by using an ultraviolet-visible spectrophotometer after the reaction is finished, wherein the yield of the HMF is 59%.

Example 4

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-ethyl-3-methylimidazole chloride and 320 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose at 140^oAnd C, reacting for 2 hours at the stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 58%.

Example 5

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-butyl-3-methylimidazolium bromide and 320 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose, at 150%^oAnd C, reacting for 1 h at the stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 58%.

Example 6

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into trace amount480 mg of ionic liquid 1-butyl-3-methylimidazole chloride and 320 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose at 160%^oAnd C, reacting for 0.5 h at the stirring speed of 300 r/min, and testing the sample by using an ultraviolet-visible spectrophotometer after the reaction is finished, wherein the yield of the HMF is 54%.

Example 7

60 mg of lactose and catalyst chromium trichloride (CrCl)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-hexyl-3-methylimidazole chloride and 320 mg of water, CrCl₃The molar amount of (b) is 20% of the molar amount of lactose at 160%^oAnd C, reacting for 0.5 h at a stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 52%.

Example 8

60 mg lactose and catalyst chromium nitrate (Cr (NO)₃)₃) Adding into a micro reaction bottle, adding 480 mg of ionic liquid 1-butyl-3-methylimidazole chloride and 320 mg of water, Cr (NO)₃)₃The molar amount of (b) is 20% of the molar amount of lactose, at 150%^oAnd C, reacting for 1 h at the stirring speed of 300 r/min, and after the reaction is finished, testing the sample by using an ultraviolet-visible spectrophotometer, wherein the yield of the HMF is 57%.

While the invention has been described with reference to specific preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.