34 results about "Levoglucosan" patented technology

The invention belongs to the field of utilization of biomass energy, and in particular relates to a method for preparing levoglucosan from cellulose by catalytic pyrolysis. The method comprises the following steps of: mechanically mixing copper powder serving as a catalyst and cellulose powder; performing fast pyrolysis under an oxygen-free condition at the temperature of between 280 and 450 DEG C; condensing pyrolysis gas to obtain a levoglucosan-rich liquid product; and burning solid residues to recover the copper powder catalyst. In the product prepared from the cellulose by the catalytic pyrolysis of the copper powder, the levoglucosan has high yield and purity and is convenient to subsequently separate and extract; in addition, the solid copper powder is used as the catalyst, is veryconvenient to recover, does not substantially have the problem such as inactivation and the like and can be repeatedly recycled.

The invention provides recombinant bacteria capable of synthesizing 3-hydracrylic acid by using glucan as well as a construction method and application of the recombinant bacteria, and belongs to the field of gene engineering and fermentation engineering. Klebsiella pneumoniae is host bacteria for expressing a gene lgk capable of encoding levodextran kinase and a gene aldH capable of encoding aldehyde dehydrogenase. The construction method comprises the following steps: obtaining a recombinant carrier puC18-lgk-aldH, converting the recombinant carrier puC18-lgk-aldH into a competent cell of the host Klebsiella pneumoniae, and obtaining the recombinant bacteria. By use of the levodextran kinase gene lgk and the aldehyde dehydrogenase gene aldH which are optimized through a codon, in combination with the whole scheme, the substrate use rate is increased, and the yield is increased.

The invention provides a method for preparing levoglucosan through rapid pyrolysis of coupling pretreatment biomass, which comprises the following steps: mixing a biomass raw material with alkali liquor, and carrying out alkali pretreatment to obtain an alkali pretreatment product; carrying out solid-liquid separation on the alkali pretreatment product to obtain solid filter residues, mixing the solid filter residues with a Fenton reagent, and carrying out Fenton pretreatment to obtain a Fenton pretreatment product; carrying out solid-liquid separation on the Fenton pretreatment product to obtain filter residues, washing the filter residues to be neutral, and drying the filter residues to obtain a coupling pretreatment product; and quickly pyrolyzing the coupling pretreatment product, and condensing and pyrolyzing the volatile product to obtain bio-oil containing levodextran. According to the method disclosed by the invention, alkali liquor pretreatment is firstly carried out to mainly remove a large amount of lignin in the biomass, then Fenton pretreatment is carried out to mainly break cellulose and hemicellulose as well as glucosidic bonds between the cellulose and degrade part of hemicellulose, and finally a porous short-chain cellulose enriched substrate is formed, so that higher levoglucosan yield can be achieved.

The invention relates to a method for promoting growth of Nannochlorisoculata and increasing contents of chlorophyll and single-cell protein of the Nannochlorisoculata. The method comprises the step that levoglucosan from biomass pyrolysis or cellulose pyrolysis liquid subjected to detoxification treatment is added to a Nannochlorisoculata culture solution, wherein the additive amount of levoglucosan is 5-50mM, and the additive amount of the cellulose pyrolysis liquid is 0.25-2% by weight. By taking a cellulosic biomass high-temperature pyrolysis product, namely levoglucosan or the pyrolysis liquid as an accelerant, a result shows that levoglucosan or the pyrolysis liquid can promote the growth of the Nannochlorisoculata obviously; a promoting rate reaches up to 194%; and the contents of chlorophyll and mycoprotein can be increased significantly, so that a use value of a cellulosic biomass can be increased.

The invention relates to photosynthetic bacteria and applications thereof. Cellulose pyrolytical liquid and levoglucosan are utilized to culture the photosynthetic bacteria, and the obtained photosynthetic bacteria can be used for producing carotinoid and single-cell protein and also can be used as a water quality improving agent for aquaculture and sewage treatment or can be used as a leaf fertilizer and the like. The levoglucosan or the cellulose pyrolytical liquid is prepared to form a culture solution, under the conditions of certain loading volume and transformation temperature, the culture solution is cultured for certain time to obtain carotinoid-rich photosynthetic bacteria thallus, and the thallus which is subjected to carotinoid extraction can be used as a single-cell protein feed. The photosynthetic bacteria are utilized to effectively use the high-temperature pyrolysis products of cellulose biomass and the levoglucosan to prepare the carotinoid and the photosynthetic bacteria single-cell protein, the cellulose biomass is effectively utilized, the cellulose biomass with rich sources can be transformed into products with high additional values, wastes are turned into wealth, and the method has good economic and environmental application potentials and a social benefit.

The invention discloses a method for improving the quality of pyrolytic oil by pretreating a biomass raw material by using a freezing-thawing-assisted low cosolvent and application of the method. The method comprises the following steps: (1) adding a biomass raw material into water, uniformly stirring and mixing, freezing in a liquid nitrogen environment at-196 DEG C for 1-4 hours, taking out, recovering to room temperature, melting, repeating the freezing and thawing operation for 0-4 times, separating solids, washing and drying to obtain a biomass raw material subjected to freezing and thawing pretreatment; (2) mixing imidazole and choline chloride, heating, stirring and dissolving to obtain an imidazole-eutectic solvent system, then adding the freeze-thaw pretreated biomass raw material, stirring and reacting, separating solids after the reaction, washing and drying to obtain solid residues; and (3) pyrolyzing the solid residues in a protective gas atmosphere at 450-600 DEG C to obtain pyrolyzed bio-oil. According to the method, the content of levoglucan in the pyrolysis bio-oil can be remarkably increased, and the quality of the pyrolysis oil is improved.

The invention provides recombinant bacteria capable of synthesizing 3-hydracrylic acid by using glucan as well as a construction method and application of the recombinant bacteria, and belongs to the field of gene engineering and fermentation engineering. Klebsiella pneumoniae is host bacteria for expressing a gene lgk capable of encoding levodextran kinase and a gene aldH capable of encoding aldehyde dehydrogenase. The construction method comprises the following steps: obtaining a recombinant carrier puC18-lgk-aldH, converting the recombinant carrier puC18-lgk-aldH into a competent cell of the host Klebsiella pneumoniae, and obtaining the recombinant bacteria. By use of the levodextran kinase gene lgk and the aldehyde dehydrogenase gene aldH which are optimized through a codon, in combination with the whole scheme, the substrate use rate is increased, and the yield is increased.

The invention provides an MXene-based catalyst and its preparation method and application. The MXene-based catalyst includes MXene and graphene oxide, and the mass ratio of MXene and graphene oxide is (0.5-5):1. Add graphene oxide dispersion liquid into MXene dispersion liquid, mix uniformly to obtain mixed liquid A, and freeze-dry mixed liquid A to obtain MXene-based catalyst. As a catalyst, it has good selectivity for the generation of levoglucosan, and can overcome the existing problems of poor selectivity of the catalyst, corrosion of equipment, difficult recovery, environmental pollution and the like.

The invention discloses a method for separating levoglucosan from wood vinegar. The method uses wood vinegar as a raw material. The separation process includes: adding an alkaline compound to adjust the wood vinegar to alkaline, and adding flocculation After flocculation, the liquid is filtered to remove the precipitate; after filtration, the clear liquid is added with a decolorizing agent for heat preservation and decolorization; after decolorization, the clear liquid is separated by ion exchange resin, and pure water is selected as the eluent for elution, and the levoglucosan The eluate was concentrated and precipitated with methanol to obtain the product levoglucosan. The invention can remove a large amount of impurities in the stock solution of the wood vinegar through pretreatment, and effectively separate the levoglucosan component in the wood vinegar.

The invention discloses a method for producing levoglucosan by using agricultural and forest waste. The method for producing the levoglucosan by using the agricultural and forest waste comprises the following steps of (1) adding the crushed agricultural and forest waste and water into a hydrothermal reaction kettle according to a mass volume ratio of (1 to 1) to (5 to 20); (2) filling the hydrothermal reaction kettle with CO2, sealing the hydrothermal reaction kettle to make the hydrothermal reaction kettle heated to 150-250 DEG C with stirring, and maintaining the temperature for 10-50 minutes; (3) cooling the hydrothermal reaction kettle, collecting a reaction product, and conducting vacuum filtration, separation and drying on the reaction product to obtain a solid product subjected to hydrothermal pre-treatment; (4) placing the solid product in a pyrolysis reactor to make the solid product subjected to pyrolysis in a CO2 atmosphere; and (5) obtaining a liquid product with a high levoglucosan concentration after conducting fractional condensation on the solid product. According to the method for producing the levoglucosan by using the agricultural and forest waste, hydrothermal pre-treatment under the CO2 atmosphere and pyrolysis under the CO2 atmosphere are combined to promote maximum conversion from the agricultural and forest waste to the levoglucosan, and the defect of alow yield of levoglucosan in bio-oil obtained by directly conducting pyrolysis on biomass is overcome.

A method for synchronously measuring levoglucosan, mannan and galactosan in aerosol for high performance liquid chromatography-tandem quadrupole mass spectrometry combination includes the steps that levoglucosan, mannan and galactosan in an aerosol sample are subjected to ultrasonic extraction with ultrapure water and detected by means of a high performance liquid chromatography-tandem quadrupolemass spectrometer; ammonia water is adopted as a mobile phase; an electrospray ionization mode suitable for polar molecule analysis is adopted as an ion source of a mass spectrometry, ion source parameters and compound parameters optimized many times are adopted in a mass spectrometric method, and qualitative and quantitative analysis is conducted in an anion and multiple-reaction monitoring mode.By means of the external standard curve method, the linear relation of L, M and G is good in the range of 0.01<-1> microgramme per milliliter, the correlation coefficient is larger than 0.99, the detection limit of L is smaller than 0.005 microgramme per milliliter, the detection limits of M and G are both smaller than 0.01 microgramme per milliliter, experiment repeatability is good, relative standard deviations of repetitive experiments of L, M and G are 1.31%, 4.48% and 1.31% respectively, and the adding standard recovery rates of L, M and G all reach 97% or above.

The invention belongs to the field of utilization of biomass energy, and in particular relates to a method for preparing levoglucosan from cellulose by catalytic pyrolysis. The method comprises the following steps of: mechanically mixing copper powder serving as a catalyst and cellulose powder; performing fast pyrolysis under an oxygen-free condition at the temperature of between 280 and 450 DEG C; condensing pyrolysis gas to obtain a levoglucosan-rich liquid product; and burning solid residues to recover the copper powder catalyst. In the product prepared from the cellulose by the catalytic pyrolysis of the copper powder, the levoglucosan has high yield and purity and is convenient to subsequently separate and extract; in addition, the solid copper powder is used as the catalyst, is veryconvenient to recover, does not substantially have the problem such as inactivation and the like and can be repeatedly recycled.

The invention provides a method for preparing levoglucosan by rapid pyrolysis of coupled pretreatment biomass, comprising: mixing biomass raw materials with alkali solution, performing alkali pretreatment to obtain alkali pretreatment products; solidifying the alkali pretreatment products liquid separation to obtain a solid filter residue, mix the solid filter residue with Fenton's reagent, and perform Fenton pretreatment to obtain a Fenton pretreated product; perform solid-liquid separation on the Fenton pretreated product to obtain a filter residue, wash the filter residue with water until neutral, The coupling pretreatment product is obtained after drying; the coupling pretreatment product is quickly pyrolyzed, and the pyrolysis volatile product is condensed to obtain bio-oil containing levoglucosan. The method of the present invention firstly carries out lye pretreatment, mainly removes a large amount of lignin in biomass, and then carries out Fenton pretreatment, mainly interrupts cellulose and hemicellulose, and the glucosidic bond between cellulose and cellulose, Degrading part of the hemicellulose and finally forming a porous short-chain cellulose-rich substrate can result in a higher yield of levoglucosan.

The present invention belongs to the field of biopharmaceuticals, specifically relating to a bound selenium polysaccharide. The polysaccharide uses as a carrier a polysaccharide substance having a 3,6-levoglucosan structure, and a selenium atom connects to a carbon atom at position 6 of a polysaccharide 3,6-inner ether structure by means of a selenoester structure. By means of oxidizing the carbon atom at position 6 of the polysaccharide 3,6-inner ether bond, converting same to a 3,6-lactone, then undergoing ring-opening esterification by reacting with selenocysteine, the prepared structure is well-defined, being a bound selenium polysaccharide product containing a controllable amount of selenium. The prepared bound selenium product is able to noticeably improve the immunity of test subjects by means of increasing blood-selenium content.

The invention discloses a method for low-temperature complete combustion of bio-oil heavy components by the use of a Cu-Mn base supported monolithic catalyst. By a technological condition that an xCuyMnzM / SBA-15 composite oxide cordierite ceramic monolithic catalyst with a low-temperature activity is used to catalyze a model of a bio-oil heavy components mixture including guaiacol, levoglucosan, methanol and water mixed solution (guaiacol represents benzene oxygenate in the heavy components, levoglucosan represents carbohydrate in the heavy components, and methanol and water are used as solvents for homogeneous mixing of two model compounds), exploration and research are performed to obtain a catalyst system and technological conditions suitable for low-temperature oriented conversion of methanol-soluble viscous real bio-oil heavy components to CO2 and H2O, and low-temperature complete conversion of bio-oil heavy components is realized.