阅读说明：本技术 一种温和且快速分离木质素的方法 (A method of mild and quick separating lignin ) 是由 张学铭 陈天影 许凤 朱若楠 黄剑波 于 2019-09-30 设计创作，主要内容包括：本发明涉及一种温和且快速分离木质素的方法,其包括以下步骤：1)氯化锌/乳酸溶剂体系的配置；2)生物质的前处理；3)无抽提物生物质原料的反应；4)木质素的分离；5)木质素的沉淀析出；和6)溶剂体系的回收再利用。根据本发明的方法采用有机酸乳酸替代传统上分离木质素使用的无机强酸,危险系数较低,对设备要求较低,且可来源于生物质,并且在利用过程中可循环使用,绿色环保。并且氯化锌和乳酸可以充分混合,形成均一溶液,且两者会通过金属锌和乳酸中的氧形成络合,进一步促进木质素的快速分离。(The present invention relates to a kind of mild and quick separating lignin methods comprising following steps: 1) zinc chloride/lactic acid dicyandiamide solution configuration；2) pre-treatment of biomass；3) reaction without extract biomass material；4) separation of lignin；5) Precipitation of lignin；With the recycling and reusing of 6) dicyandiamide solution.The inorganic acid that lignin uses is traditionally isolated using organic acid lactic acid substitution according to the method for the present invention, danger coefficient is lower, and it is lower to equipment requirement, and biomass can be derived from, and can be recycled during utilization, it is environmentally protective.And zinc chloride and lactic acid can be sufficiently mixed, and form uniform solution, and the two can be formed by the oxygen in metallic zinc and lactic acid and is complexed, and the quick separating of lignin is further promoted.)

1. a kind of mild and quick separating lignin method comprising following steps:

1) zinc chloride/lactic acid (ZnCl₂/ Lac) dicyandiamide solution configuration: zinc chloride and lactic acid are mixed with certain molar ratio, And it continues stirring until dissolution and obtains homogeneous and transparent liquid；

2) pre-treatment of biomass: biomass is ground up, sieved to obtain 40-60 mesh powder, and with toluene and ethyl alcohol with 2:1's The Benzene-ethanol extraction liquid of volume ratio mixing is continuously extracted, and until the extract into Soxhlet extractor is colourless, obtains no extracting The biomass material of object；

3) reaction without extract biomass material: will consolidate without extract biomass material according to certain obtained in step 2) Liquor ratio is added to above-mentioned ZnCl₂In/Lac dicyandiamide solution, at a constant temperature, with the mixing speed of 300rpm to 600rpm into Row stir process for a period of time, obtains the solidliquid mixture of brown；

4) separation of lignin: in step 3) after reaction, ethyl alcohol is added and is diluted, and filter realization and be separated by solid-liquid separation；

5) Precipitation of lignin: filtrate obtained in step 4) being concentrated by evaporation after removing ethyl alcohol plus deionized water precipitating analysis Lignin out filters, is washed with deionized to neutral, freeze-drying and obtains lignin；

6) recycling and reusing of dicyandiamide solution: it will be obtained in step 5) and filter out the concentration removing of the liquid evaporation after removing lignin Whole moisture, i.e., recyclable zinc chloride/lactic acid dicyandiamide solution, the recycling zinc chloride/lactic acid dicyandiamide solution can utilize again.

2. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 1), The zinc chloride and lactic acid are mixed with the molar ratio of 1:5 to 1:15, more preferably 1:8 to 1:12, most preferably 1:10.

3. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 2), The biomass is agricultural-forestry biomass, such as can be selected from needlebush, leaf wood and careless class etc., preferably red red Poplar Powder.

4. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 3), The biomass and the zinc chloride/lactic acid dicyandiamide solution solid-liquid mass ratio are 1:10 to 1:40, preferably 1:15 to 1:30, More preferably 1:20.

5. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 3), The steady temperature is 70-120 DEG C, time 1-4h, it is highly preferred that the steady temperature is 90-110 DEG C.

6. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 4), The volume that ethyl alcohol is added is 1 to 1.5 times of solidliquid mixture volume obtained in step 2).

7. mild and quick separating lignin method according to claim 1, which is characterized in that in the step 5), After removing ethyl alcohol, the amount of the deionized water of addition is about 8 to 12 times, preferably from about 10 times of concentrate.

8. according to claim 1 mild and quick separating lignin method, which is characterized in that the step 5) and 6) In, it is concentrated by evaporation and is carried out under about 60 DEG C of vacuum condition using Rotary Evaporators, concentration can be fast implemented.

Technical field

The invention belongs to lignin separation technical fields, and in particular to a kind of using zinc chloride/lactic acid mixed system processing Wood fiber biomass, the method for mild quick separating lignin.

Background technique

Lignin is widely present in higher plant, is the second largest biomass resource for being only second to cellulose, is accounted for plant The 20%~30% of gross mass.Lignin can be applied to the energy and chemicals neck as a kind of fragrant cyclopolymer abundant In domain, its higher value application is sufficiently realized.However, in plant cell wall, intercellular layer, three positions of primary wall and secondary wall Degree of lignification is different, and lignin structure is different, and lignin is connected in the form of chemical bond with hemicellulose, cellulose with There are the cellulosic structures of hydrogen bond and highly crystalline to together constitute the " natural complicated of cell wall structure between lignin Property ".Therefore, in the obstacle for breaking through the research of biomass lignin, the separation of lignin is particularly important.

Inorganic fused salt hydrate is a type ion liquid system, cheap, is easily obtained.Salt hydrate is melted to fibre Tieing up the polysaccharide such as element, hemicellulose has good swollen, dissolution, hydrolysis ability.Wherein, zinc chloride is a kind of common melting Salt, its zinc ion (Zn²⁺) and chloride ion (Cl^-) be able to and the oxygen atom (O) and hydrogen atom (H) phase in cellulose hydroxyl group Interaction, and hydrogen bond is formed with cellulose, to destroy the hydrogen bond network between cellulose between cellulose and lignin.Together When zinc chloride presence can destroy the crystalline texture of cellulose, make cellulose that swollen occur.This performance of fuse salt is in life Apparent effect can be played during preprocessing substance.

Fuse salt is usually to carry out during preprocessing biomass under the conditions of acid (mostly inorganic acid).Carbon Chemical bond between hydrate and lignin can be broken under the action of an acid while exposure.Acid condition is to several The removal of lignin is all in all types of lignocellulose biomass (corncob, straw, wheat stalk, poplar, pine tree) There is very much effect.However inorganic acid danger coefficient is high, and to the more demanding of equipment, and after use can not recycling and reusing, hold It is also easy to produce a series of environmental problem.Therefore need to develop the method for new separating lignin.

Summary of the invention

In view of the above-mentioned problems of the prior art, the purpose of the present invention is to provide a kind of mild and quick separating is wooden Element method, this method by using zinc chloride and lactic acid combination effectively and rapidly separating lignin, and mild condition, wherein Zinc chloride plays the role of the removal to the run-inflation effect and acid condition of biomass to lignin, and zinc chloride and lactic acid can lead to It crosses metal ion and oxygen atom forms complexing and generates collective effect, promote the quick separating of lignin.

To achieve the goals above, the present invention provides a kind of mild and quick separating lignin methods comprising with Lower step:

1) zinc chloride/lactic acid (ZnCl₂/ Lac) dicyandiamide solution configuration: by zinc chloride and lactic acid with certain molar ratio Mixing, and continue stirring until dissolution and obtain homogeneous and transparent liquid.

2) pre-treatment of biomass: biomass is ground up, sieved to obtain 40-60 mesh powder, and with toluene and ethyl alcohol with 2: The Benzene-ethanol extraction liquid of 1 volume ratio mixing is continuously extracted, and until the extract into Soxhlet extractor is colourless, obtains no pumping The biomass material of extract.

3) reaction without extract biomass material: by obtained in step 2) without extract biomass material according to certain Solid-to-liquid ratio be added to above-mentioned ZnCl₂In/Lac dicyandiamide solution, at a constant temperature, with the stirring speed of 300rpm to 600rpm Degree is stirred a period of time, obtains the solidliquid mixture of brown.

4) separation of lignin: in step 3) after reaction, ethyl alcohol is added and is diluted, and filters and realizes solid-liquid point From.

5) Precipitation of lignin: filtrate obtained in step 4) is concentrated by evaporation after removing ethyl alcohol plus deionized water is heavy Precipitation goes out lignin, filters, is washed with deionized to neutral, freeze-drying and obtains lignin.

6) recycling and reusing of dicyandiamide solution: it will be obtained in step 5) and filter out the concentration of the liquid evaporation after removing lignin Whole moisture are removed, i.e., recyclable zinc chloride/lactic acid dicyandiamide solution, which can be sharp again With.

Preferably, in the step 1), zinc chloride and lactic acid are mixed with the molar ratio of 1:5 to 1:15, and more preferably 1:8 is extremely 1:12, most preferably 1:10.

Preferably, in the step 2), the biomass is agricultural-forestry biomass, such as can be selected from needlebush, leaf wood With careless class etc., preferably red red Poplar Powder.

Preferably, in the step 3), the biomass is with the zinc chloride/lactic acid dicyandiamide solution solid-liquid mass ratio 1:10 to 1:40, preferably 1:15 are to 1:30, more preferably 1:20.

Preferably, in the step 3), the steady temperature is 70-120 DEG C, time 1-4h, it is highly preferred that the perseverance Determining temperature is 90-110 DEG C.

Preferably, in the step 4), the volume that ethyl alcohol is added is solidliquid mixture volume obtained in step 2) 1 to 1.5 times.

Preferably, in the step 5), after removing ethyl alcohol, the amount of the deionized water of addition is about 8 to 12 times of concentrate, Preferably from about 10 times.

The step 5) and 6) in, be concentrated by evaporation and carried out under about 60 DEG C of vacuum condition using Rotary Evaporators, can be fast Speed realizes concentration.

The utility model has the advantages that

The present invention compared with prior art, has the advantages that (1) present invention using organic acid lactic acid substitution traditionally The inorganic acid that separating lignin uses, danger coefficient is lower, lower to equipment requirement, and can derive from biomass, and It is environmentally protective using can be recycled in the process.(2) zinc chloride and lactic acid can be sufficiently mixed in the present invention, be formed uniform molten Liquid, and the two can form complexing by metal zinc ion and oxygen atom, further promote the quick separating of lignin.(3) this hair Bright treatment conditions are mild, short processing time, and extraction process is simple, lower to equipment requirement, react easily controllable.

Detailed description of the invention

Fig. 1 be two kinds of dicyandiamide solutions of lactic acid and zinc chloride/lactic acid hydrogen spectrum (¹H-NMR) nuclear magnetic spectrogram；

Fig. 2 is optical microscope photograph (wherein, the cell corner of cell wall swollen situation after the pretreatment of different solvents system Labeled as CCML, compound middle lamella is labeled as CML, and secondary wall is labeled as S)

Illustrate: Fig. 2 photo using cross section be 40 × 50mm the red poplar block of pellet as raw material, cut using Lycra EMUC7 ultra micro Piece machine is sliced, and the ultra micro slice of 10 μ m-thicks is obtained.Slice is mixed with lactic acid, zinc chloride and zinc chloride/lactic acid mixed system Close (about 10/1mL) and simultaneously handle 15min at 110 DEG C, treated slice cleans with deionized water with remove dicyandiamide solution and The removing object on cell wall surface layer, then flattens film-making on glass slide and (object lens select × 100 oil under an optical microscope Mirror) observation.Control group is the ultra micro slice without any processing.

It is compared with raw material, through single lactic acid or zinc chloride treated cell wall there are slight swollen, and zinc chloride/ Treated that cell wall swollen is obvious for lactic acid mixed solvent system, and due to the removing cell corner (CCML) of lignin and compound Intercellular layer (CML) is high-visible.

Specific embodiment

Hereinafter, the preferred embodiment of the disclosure is described in detail with reference to the accompanying drawings.Before describing, should The term that solution uses in the description and the appended claims, and should not be interpreted as limited to general and dictionary meaning, but answer When the principle for suitably defining term based on the explanation for allowing inventor best, based on the meaning for corresponding to the technology of the present invention level Justice and concept explain.Therefore, the preferred embodiment of description in this only for illustration purpose, and not refer to the limitation present invention Range, it is therefore to be understood that, other can be made without departing from the spirit and scope of the invention and equally implement and repair Change.

The present invention uses fuse salt zinc chloride, cheap and easy to get as a type ion liquid system, and is known as very to fiber The effect of good swollen and dissolution.In addition organic acid lactic acid is also used, acidity is weaker and can derive from biomass, and in benefit It is environmentally protective with can be recycled in the process.Meanwhile the presence of organic acid can also effectively remove lignin.Zinc chloride and lactic acid Mixing is broken carbon hydrate using lactic acid before zinc chloride swollen wood fiber biomass, destruction cellulose while hydrogen bond Connection between object and lignin, to realize efficiently separating for lignin.

In method according to the present invention, it is preferable that in the step 1), zinc chloride and lactic acid are with 1:5 to 1:15 Molar ratio mixing, more preferably 1:8 to 1:12, most preferably 1:10.When the molar ratio of zinc chloride and lactic acid is greater than 1:5, That is chlorination zinc overdose, then zinc chloride/lactic acid dicyandiamide solution setup time increases, and solution viscosity increases, and is unfavorable for subsequent Lignin separation；And when being less than 1:15, it due to the excess of lactic acid, is easy to make lignin that depolymerization occur, is unfavorable for subsequent lignin Precipitation and separation.

Preferably, in the step 3), the biomass is with the zinc chloride/lactic acid dicyandiamide solution solid-liquid mass ratio 1:10 to 1:40, preferably 1:15 are to 1:30, more preferably 1:20.When solid-liquid mass ratio is greater than 1:10, since reaction substrate accounts for Than increasing, solvent reaches saturation to the extraction separating capacity of lignin from biomass, so that lignin separation efficiency can reduce.Gu When liquor ratio is less than 1:40, excessive solvent is easy to aggravate the requirement to tankage and increases production cost.

Preferably, in the step 3), the steady temperature is 70-110 DEG C, time 1-4h, it is highly preferred that the perseverance Determining temperature is 90-110 DEG C.Within this temperature range, the separation of most of lignin can be realized with the short time, and to instrument and equipment It is required that low, less energy consumption, can be rapidly completed the operation of whole flow process in the industrial production, production cost is reduced.

Preferably, in the step 4), the volume that ethyl alcohol is added is solidliquid mixture volume obtained in step 2) 1 to 1.5 times.The viscosity that gained mixture can be effectively reduced within this range, is conducive to subsequent separation of solid and liquid, more greatly Although the ethyl alcohol of amount can reach identical effect, but in subsequent removing and recycle ethyl alcohol during can increasing energy consumption.

Preferably, in the step 5), after removing ethyl alcohol, the amount of the deionized water of addition is about 8 to 12 times of concentrate, Preferably from about 10 times.If be added deionized water it is very few, be easy to keep lignin deposit insufficient, and be added excessively then make it is wooden In element in opposite small molecular mass moieties dissolved aqueous solution, it is unfavorable for precipitation and separation.

Following embodiment is enumerated only as the example of embodiment of the present invention, does not constitute any limit to the present invention System, it will be appreciated by those skilled in the art that modification in the range of without departing from essence and design of the invention each falls within the present invention Protection scope.Unless stated otherwise, reagent and instrument used in the following embodiment are commercially available product.