阅读说明：本技术 一种乙二胺预处理柠条的方法 (Method for pretreating caragana microphylla by using ethylenediamine ) 是由 钟成 韩琳洁 刘其敬 贾士儒 李文超 于 2019-09-29 设计创作，主要内容包括：本发明提供了一种乙二胺预处理柠条的方法。将粉碎后的柠条与乙二胺混匀置于密闭反应容器中,在120-230℃的条件下进行反应,得到预处理的柠条。该方法能够有效去除木质素、保留纤维素、降低纤维素结晶度,提高柠条中纤维素和半纤维素的酶解效率。本发明操作简单,对设备腐蚀性小,乙二胺可后续回收,适合工业化生产。(The invention provides a method for pretreating caragana microphylla by using ethylenediamine. And uniformly mixing the pulverized caragana microphylla and ethylenediamine, placing the mixture into a closed reaction container, and reacting at the temperature of 120-230 ℃ to obtain the pretreated caragana microphylla. The method can effectively remove lignin, retain cellulose, reduce cellulose crystallinity, and improve enzymolysis efficiency of cellulose and hemicellulose in Caragana microphylla. The method has the advantages of simple operation and small corrosion to equipment, and the ethylenediamine can be subsequently recovered, so the method is suitable for industrial production.)

1. A method for pretreating caragana microphylla by ethylenediamine comprises the following steps:

and uniformly mixing the pulverized caragana microphylla and ethylenediamine, placing the mixture in a closed reactor, heating for reaction, taking out the reactor after a certain time, quickly cooling, and taking out the material to obtain the caragana microphylla pretreated by the ethylenediamine.

2. The pretreatment method of claim 1, wherein the caragana microphylla is selected to have a size capable of passing through a 20-mesh screen.

3. The pretreatment method as claimed in claim 1, wherein the temperature of the heating reaction is 120-230 ℃.

4. The pretreatment method according to claim 1, wherein the heating reaction time is 10 to 60 min.

5. The pretreatment method according to claim 1, wherein the mass-to-volume ratio of caragana microphylla to ethylenediamine is 1 g: (1-5) ml.

6. The pretreatment method of claim 1, wherein the caragana microphylla is pretreated with ethylenediamine, washed with water, filtered or heated to recover ethylenediamine, to obtain pretreated solid, and dried. The glucose yield is obviously improved after enzymolysis, and the ethylenediamine can be recovered by adopting a proper recovery device in the subsequent process.

Technical Field

The invention belongs to the technical field of biomass refining, and particularly relates to a method for pretreating caragana microphylla by using ethylenediamine.

Background

With the gradual depletion of petroleum resources and the increasing deterioration of the environment, environmental-friendly renewable resources are receiving more and more attention. Renewable biomass with abundant reserves and wide sources is an important component of a novel resource system. Lignocellulosic biomass feedstock is composed mainly of cellulose, hemicellulose and lignin. In plant cell walls, lignin is filled between cellulose and hemicellulose, and is linked to carbohydrate polymers through hydrogen bonds and covalent bonds. This dense structure can help plants resist the invasion of microorganisms, but it seriously increases the difficulty of their development and utilization. The main functions of the pretreatment process are to separate hemicellulose and/or lignin, reduce the crystallinity of cellulose, increase gaps and the like, and improve the enzymolysis accessibility of the cellulose and the hemicellulose by destroying the stable structure of plant cell walls.

In the field of biomass refining, it is important to develop a raw material source and search for a cheap alternative raw material. The caragana microphylla is an important vegetation which is widely planted in arid and semiarid regions in northwest of China, has wind-proof and sand-fixing capabilities and improves the ecological environment. The planting area of the caragana microphylla in China is 300 ten thousand mu, and as the caragana microphylla needs to be cut down for about 3 years, about 3 tons of caragana microphylla stems can be obtained per mu, and 300 ten thousand tons of caragana microphylla resources are urgently needed to be developed and utilized every year. Cellulose, hemicellulose and the like in caragana microphylla can be converted into fuel ethanol through biological fermentation, so that the caragana microphylla becomes a substitute of the first generation of fuel ethanol taking grains as raw materials, and considerable economic and environmental benefits can be generated if the caragana microphylla is efficiently utilized. However, caragana microphylla belongs to perennial woody plants, the lignification degree of caragana microphylla is high, the cellulose release is difficult, the utilization rate is low, and the lignification degree is higher and higher along with the increase of the tree age, and the processing difficulty is increased. Therefore, the efficient separation of lignin and the efficient utilization of cellulose are key technologies for the resource utilization of caragana microphylla.

The existing pretreatment methods mainly comprise physical methods, such as mechanical crushing, microwave pretreatment, freezing pretreatment, ultrasonic treatment and the like; chemical methods such as acid, base, organic solvent and ionic liquid pretreatment; physical and chemical methods, such as steam explosion pretreatment, ammonia fiber explosion pretreatment, high-temperature liquid water pretreatment and the like; biological methods, such as biological enzyme pretreatment, brown rot fungus pretreatment, white rot fungus pretreatment, and the like. However, due to the large difference of chemical compositions and structures of different substrates (herbs and woody), different action mechanisms and limited application ranges of different pretreatment methods, an effective pretreatment mode needs to be explored for the woody plant, caragana microphylla, and the resource utilization level of the woody plant is improved.

Ethylenediamine is an organic base having a boiling point of 119 ℃ and can be recovered by heating or the like. The organic alkali can open ether bonds connected between the lignin and the hemicellulose, so that the lignin is removed, the cellulose and the hemicellulose are retained to a greater extent, and the crystal form of the cellulose can be changed. The ethylenediamine pretreatment can effectively improve the enzymolysis yield of herbaceous lignocellulose such as corn straws and the like. Publication No. CN104561183A provides a pretreatment method of corn stalks, which can effectively improve the enzymolysis efficiency of the corn stalks by using ethylenediamine, but due to the difference in chemical composition and structure between woody plants and herbaceous plants, the biological resistance of the woody plants is stronger than that of herbaceous plants.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a method for pretreating caragana microphylla with ethylenediamine, wherein the pretreatment method of the present invention can significantly improve the conversion rate of cellulose and hemicellulose of caragana microphylla of woody plants.

The invention provides a method for pretreating caragana microphylla by using ethylenediamine, which comprises the following steps:

and uniformly mixing the pulverized caragana microphylla and ethylenediamine, placing the mixture in a closed reactor, heating for reaction, taking out the reactor after a certain time, quickly cooling, and taking out the material to obtain the caragana microphylla pretreated by the ethylenediamine.

Preferably, the caragana microphylla selected by the invention has a size capable of passing through a 20-mesh sieve.

Preferably, the temperature for heating the reaction is 120-230 ℃.

Preferably, the heating reaction time is 10 to 60 min.

Preferably, the mass volume ratio of the caragana microphylla to the ethylenediamine is 1 g: (1-5) mL.

Preferably, the caragana microphylla is pretreated by ethylenediamine, washed by water, filtered or heated to recover ethylenediamine, so as to obtain pretreated solid, and then dried. The ethylenediamine can be recovered in a subsequent process using a suitable recovery unit. The invention provides a method for pretreating caragana microphylla by using ethylenediamine, which comprises the following steps: and (3) placing the pulverized caragana microphylla and ethylenediamine in a closed reactor, and carrying out heating reaction at the temperature of 120-230 ℃ to obtain the caragana microphylla pretreated by the ethylenediamine. The ethylenediamine pretreatment method provided by the invention can remove lignin, retain cellulose and hemicellulose to a greater extent, change the crystal form of cellulose, and improve the enzymolysis efficiency of pretreated caragana microphylla to a great extent. And the ethylenediamine can be recycled after being heated and recovered, so that the cost is saved. The results of the implementation case of the invention show that the yield of glucose obtained after the pretreatment and enzymolysis of the caragana microphylla ethylenediamine is 88.03%, and is obviously improved compared with the yield of glucose obtained after the enzymolysis of the untreated caragana microphylla, which is 9.63%.

Detailed Description