Anthocyanin is a kind of flavonoid which mainly exists in plants. It has strong biological activities such as anti-cancer and anti-oxidation, and is widely used in the field of nutrition and health care. Most anthocyanins are extracted directly from plants by physical or chemical means, but the yield is low, and the extracted anthocyanins are mostly mixtures due to the restrictions of time, region and season. Biosynthesis of anthocyanins have attracted much attention by researchers worldwide in recent years. As the biosynthesis of anthocyanins can be controlled artificially and the purity of the obtained products is high, it has been widely studied. Anthocyanins cannot exist stably in the environment, and need to be modified by glycosylation, acylation and methylation to increase their stability. The modified anthocyanins can be synthesized by microorganisms and significant color changes can be seen in the medium. The biosynthesis and modification of anthocyanins were reviewed in this paper, and the preparation technology of anthocyanin synthesis from plants and microorganisms was briefly introduced, the factors affecting anthocyanin synthesis were analyzed, and finally the future research direction of anthocyanin was predicted.
The effects of four kinds of driers, namely rare earth isooctanoate(REI), cobalt isooctanoate(CI), high-efficient drier M2203 and CQ-150B alone or in combination on the drying performance of tung oil and polymerized tung oil were investigated. The experimental results showed that the viscosity of polymerized tung oil at 10℃ was 15 520 mPa·s and higher than that of tung oil(160 mPa·s). The drying time of polymerized tung oil at 20℃ was 72 h and shorter than that of tung oil(168 h). When 0.6% of REI was used together with 0.010% of CI, the surface drying time and hard drying time of raw tung oil were 2 and 2.5 h, respectively, the hardness grade was 4 H, and the adhesion grade was 1; the surface drying time and hard drying time of polymerized tung oil were 0.67 and 1 h, hardness grade was 5 H, adhesion was grade 1. Compared with the high-efficient drier M2203 and CQ-150B drier, the composite drier had light color and good compatibility with tung oil. FI-IR and TGA analysis showed that the tung oil paint film prepared by drying with compound drier had high cross-linking degree and good heat stability. So the compound drier was proved to be an excellent tung oil drier.
Lignin is the most abundant renewable aromatic polymer in nature, which complex structure and compact connection with cellulose and hemicellulose through covalent bond and hydrogen bond make it difficult to be separated efficiently. Deep eutectic solvents (DES) is a novel kind of green ionic liquid, which has been successfully applied to lignin isolation due to its unique physical and chemical properties. The research progress of dissolution and extraction of lignin by deep eutectic solvents (DES) is reviewed in detail. From the point of view of the mechanism of dissolving lignin by DES, the effects of different factors(composition, proportion, pH value, functional groups of DES, water content of system, raw material, reaction time, temperature, catalyst, co-solvent, and so on) on lignin removal were emphatically expounded. Based on the research progress of DES in lignin extraction, the research progress and futuer application of lignin extraction were summarized and prospected.
Cellulose has been increasingly utilized in the area of flexible supercapacitor, biosensor, and electromagnetic shielding because of its unique advantages of lightweight, biocompatibility and flexibility. The polyhydroxy structure of cellulose is beneficial for the transmission of electrolyte ions, resulting in the good performance of the electric capacity and cyclical stability for flexible electrode materials. Furthermore, flexible cellulose-based electrode can be obtained by coating, compounding, layer-by-layer self-assembling and in situ chemical polymerization with electroconductive materials(e.g., graphene, carbon nanotubes, conductive polymer and so on). Resent researches of the cellulose-based flexible electrode materials from different cellulose-based raw materials(original cellulose, nanocellulose and cellulose derivatives) were introduced in this review and the preparation methods and electrochemical properties of the obtained materials were also focused. The contributions of cellulose-based materials in the flexible electrode were categorized as:the backbone for supporting the flexible electrode material, the flexible substrates(or separator) and the ion channel for electrolyte. The future development and the challenges in the area of cellulose-based flexible electrode were also prospected.
In order to investigate the optimal extraction process of Cinnamomum camphora essential oil by steam distillation under laboratory conditions, several factors are investigated by single factor experiments. The results show that the extraction yield of essential oil of the C. camphora leaves is higher than that of branches. The effect of over-water distillation method is better than that of in-water distillation. The optimal distillation power is 600 W, the optimal distillation time is 40 min, and the appropriate post-harvest storage time is less than 48 h. The extraction yield of essential oil under these conditions is 1.42%. The chemical composition of C. camphora essential oil is analyzed by gas chromatograph-mass spectrometer. Six compounds are identified, which account for 94.56% of the total peak area, the main component is linalool, it accounts for 89.58% of the total peak area. The antifungal activities of C. camphora essential oil against six plant pathogenic fungi are tested through determining the growth rate of fungal hyphae. The results show that C. camphora essential oil exhibits good antifungal activity against Rhizoctonia solani, when the testing mass concentration of C. camphora essential oil are 500, 250 and 125 mg/L, the inhibition rates are 100%, 90.88% and 67.94%, respectively.
The co-pyrolysis activities of sawdust/low-density polyethylene(LDPE) were studied in fixed-bed reactor. The effect of temperature on the co-pyrolysis behavior was also investigated by comparing with sawdust and LDPE individually. The results showed that the bio-oil yield could be effectively improved by the co-pyrolysis process, the maximum bio-oil yield(56.84%) was obtained at 600℃, which was 6.44 percentage point higher than the theoretical value. The composition of biomass and LDPE co-pyrolysis liquid products was analyzed by GC-MS. It was found that the bio-oil components produced by co-pyrolysis were mainly aliphatic hydrocarbons, alcohols and phenols. Some specific components, such as undecanol, heptenal and other oxygen-containing long-chain compounds, were also produced during the co-pyrolysis process, which was the product of free radical interaction between biomass and LDPE. The synergistic effect of co-pyrolysis of sawdust and LDPE was studied by thermogravimetry-infrared spectroscopy. The results showed that the maximum reaction rate temperature during co-pyrolysis was 490℃, which was about 22℃ lower than 512℃, which was the temperature of maximum reaction rate in LDPE individual pyrolysis. The hydroxyl radical generated during the lignin cracking process combining with the small molecular produced by the cleavage of LDPE formed undecanol, octyl-phenol and the like, and the furans and aldehydes formed during the pyrolysis of cellulose were reacted with the resulting CnHm formed by cleavage of LDPE to obtain the substances such as 2-butyltetrahydrofuran, heptenal, dodecanal or the like.
The hydrophilic, ductile, thermoplastic and biodegradable properties of cellulose acetate (CA) were introduced, and the basic structure and market application of three kinds of cellulose acetate were summarized.It was pointed out that CA still had some disadvantages such as poor thermal stability at high temperature, low mechanical strength and easily being contaminated. The impacts of the physical modification and chemical modification on the properties of CA were also reassessed.It could conclude that the chemical reaction with polymer could change the structure or properties of CA.The fouling resistance, thermoplastic, selective and reuse of the CA were improved greatly, while the physical modification could improve the porosity and thermal stability of CA membrane, and the membrane mechanical strength, metal ion exclusion rate and the water flux were improved. The applications of CA in seawater desalination, adsorption of toxic substances in flue gas, preparation of biomedical membrane, drug delivery, tissue repair and regeneration, biosensor, outdoor protection and air purification were also summarized, and the market prospect and development trend of CA were prospected.
The consumption of wood adhesive in China is huge. However, the main wood adhesive based on formaldehyde is still prevalent. In recent years, environment friendly adhesives such as non-formaldehyde adhesives and biomass adhesives have developed rapidly. Herein, the recent research and application of wood adhesives including urea-formaldehyde resin adhesives, phenolic resin adhesives, melamine-formaldehyde resin adhesives, protein adhesives, lignin adhesives, starch adhesives, tannins adhesives, isocyanate adhesive, emulsion adhesives and pyrolysis biological oil adhesives were reviewed. The development trend and the research direction of wood adhesives were also prospected.
The petroleum ether part, ethyl acetate part, n-butanol part and water part of cinnamon and root bark were obtained by reflux extraction with 80% ethanol and systematic solvent method, using cinnamon and its homologous root bark as raw materials. Their antibacterial activities against three common pathogens(Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) were evaluated by the filter paper method. The results indicated that the qualities, the types and contents of components of each polar parts extracted from cinnamon and root bark of the same quality were different. The contents of the main components of the two petroleum ether parts were similar, but the contents of trans-cinnamaldehyde and o-methoxycinnamaldehyde, were quite different. Flavonoids, saponins and polysaccharide were found respectively in the two ethyl acetate parts, n-butanol parts and water parts. Moreover, o-methoxy cinnamaldehyde and cinnamyl acetate were found in ethyl acetate part, D-galactose was found in water part of root bark. The petroleum ether part of cinnamon, petroleum ether part and ethyl acetate part of root bark had a certain degree of antibacterial activity against E. coli, S. aureus and P. aeruginosa. When the mass concentrations of these three parts were 500 g/L, the diameters of bacteriostasis circles for S. aureus, E. coli and P. aeruginosa were larger than(17.62±0.22), (25.21±2.09) and(12.82±0.30) mm, respectively. Ethyl acetate part of cinnamon had weaker antibacterial activity, n-butanol part and water part of both cinnamon and root bark had no antibacterial activity.
Methane is the hydrocarbon with highest hydrogen-carbon ratio, and is a kind of clean energy with high combustion calorific value as well. During the preparation of methane from biomass, biomass fermentation and biomass syngas fermentation are limited by the temperature sensitivity of active bacteria. This paper introduces the research progress of reaction mechanism and corresponding catalyst system of biomass synthesis gas to methane by chemical catalysts. The reaction mechanism of CO methanation and CO2 methanation in syngas, as well as the effects of active ingredients, supports and promoters in catalysts on methanation are mainly discussed. At the same time, the catalytic hydrothermal method of biomass with mild reaction conditions is also introduced. The reaction route and research progress in recent years are briefly described. Finally, methanation reaction mechanism and efficient, stable catalysts are perspective remarked from the technical point of view.
The adducts MDI-RA were firstly synthesized from liquified diphenylmethane diisocyanate(MDI) and ricinoleic acid(RA). Then esterification reaction between ethylene diglycidyl ether and MDI-RA was carried out for the preparation of the castor oil based epoxy active intermediates(RAE). Finally, the chain reaction of RAE with diethylenetriamine(DETA) and glycidol was performed to obtained the waterborne epoxy curing agents based on castor oil. By this way, two kinds of target products(RAWCA-1 and RAWCA-2)were obtained from feeding ratio of the n(MDI):n(RA) of 1:3 and 1:4, respectively. The chemical structures of the intermediates and the target products were confirmed by Fourier transform infrared spectroscopy(FT-IR), proton nuclear magnetic resonance(1H NMR) and gel permeation chromatography(GPC). The results showed that the structure parameters of target products were basically agreed with the designed molecular structure and the Mn and Mw of target products were 1 832 g/mol and 1 983 g/mol. The property study showed that the target products could emulsify liquid epoxy resin E-51. The properties of the two-component film obtained from the curing reaction of RAWCA-1 and liquid epoxy resin E-51 were as follows:flexibility 1 mm, pencil hardness 3H, impact resistance 50 kg/cm, good water resistance, which could meet a requirement with commercial waterborne epoxy curing agent products.
The inherent properties of kapok fiber were summarized, such as light weight, high degree of hollowness up to 80%-90%, and super-hydrophobic surface, etc. Meanwhile, physical and chemical modification methods which could be widely used to improve the application characteristics of kapok fiber were introduced. The recent research progress focused on the application of kapok fiber and/or its modified treatment as eco-friendly oil-absorbing material, lithium-sulfur battery anode material and supercapacitor electrode material as well as the development of kapok fiber/polyester composite for sound absorbing material was presented. Based on the comprehensive research status of kapok fiber at home and abroad, the current challenges and future prospects on kapok fiber exploitation with respect to expanding new uses and high value-added utilization were highlighted.
p-Menth-3-en-1-amine was synthesized from p-menthane diacetylamide by two steps as an acid-catalyzed elimination and an alkaline-catalyzed hydrolysis. The effects of different conditions on these reactions were studied by single-factor and orthogonal tests. The optimal reaction conditions of the acid-catalyzed elimination are shown as 20 mmol p-menthane diacetylamide, 35 mL 12.5% H2SO4 solution (24 mmol) and reaction time 8 h, under which the yield is 41.6%; And the optimized technological parameters of the alkaline-catalyzed hydrolysis are shown as n(N-diacetyl-3-en-1-amine):n(NaOH) 1:7, 30 mL ethylene glycol as the solvent, reaction time 11 h and reaction temperature 170 ℃, to give N-diacetyl-3-en-1-amine in a yield of 82.2%, total yield is 34.2%, purified to 97% by vacuum rectification. The structure of the compound was determined by ESI-MS, FT-IR, 1H NMR and 13C HMR spectroscopic analyses.
The cellulose dissolution capability and dissolution mechanism of current novel solvent systems, including aqueous solvent systems (NaOH aqueous solution, alkali/urea and NaOH/thiourea aqueous solution, quaternary ammonium/phosphine aqueous solution, and molten inorganic salt hydrates) and organic solvent systems (LiCl/N, N-dimethylacetamide, ionic liquids and deep eutectic solvents) were reviewed. Sequentially, the advantages and disadvantages of various solvents were discussed, which could provided a reference for the future development and utilization of green cellulose solvents.
The fluorescence emission spectra and UV absorption spectra of three series compounds with D-A structure in five different polar solvents were studied, and the solvatochromism of compounds were also disussed. The results showed that all compounds had different fluorescence emission wavelengths in five different polar solvents, the largest was that in methanol and the smallest was that in cyclohexane, but in dioxane, tetrahydrofuran and dichloromethane, the emission wavelengths occurred red-shifted with the decrease of polarity of the solvent, and the fluorescence intensities varied in different polar solvents. The UV absorption wavelengths of compounds were affected by the polarities of solvents, they all had the minimum absorption wavelength in methanol. The absorbance of compounds in different polar solvents were also different, and those in methanol and cyclohexane were higher than others. All the properties above indicated that these three series of compounds had potential to be used as fluorescent probes to detect the polarity of the environment.
In this paper, the principle, preparation and influencing factors of bamboo-based supercapacitor materials are mainly introduced, as well as the research progress in the structural design and technical studies. Comparing to the single activated bamboo-carbon, bamboo-based carbon composites, taking bamboo-carbon as the template for the growth/fitting of pseudo-capacitance materials, are emphatically discussed. The redox reaction at the interface between the pseudo-capacitance material and the electrolyte results in the additional pseudo-capacitance, significantly improving the electrical performance of bamboo-based carbon materials and then extending the area of its applications. Finally, the perspective of the abundant bamboo resources in the field of supercapacitors is prospected, basing on the summary of current research progress and facing problems.
A cellulose-based highly conductive film (RGO/CNF/RGO(RCR)) was prepared using graphene oxide (GO) and cellulose nanofiber (CNF). Graphene oxide@polypyrrole (GO@PPy) active material was deposited on both sides of the film, then an integrated flexible film with conductive anisotropy and good flexibility was acquired. Furthermore, the liquid electrolyte was infiltrated into the composite film, and the copper foil was used as the current collector to prepare the integrated sandwich structure supercapacitor(SC). The morphology and surface elements of the film were analyzed by scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Afterwards, the electrochemical performance of integrated capacitor was compared with stacked capacitor and gel capacitor. The results showed that PPy was wrapped on the surface of GO and deposited on the surface of RCR film in the form of GO@PPy, and a pseudo-capacitive layer of about 400 nm was formed. When the scanning rate was 5 mV/s, the area specific capacitances of integrated, stacked and gel capacitor reached the maximum, which were 28.5, 28.1 and 33.8 mF/cm2, respectively. When the scanning rate increased to 200 mV/s, the area specific capacitances decreased to 4.6, 3.2 and 1.1 mF/cm2, respectively. It could be seen that the integrated capacitor has higher stability. The tight and seamless connection of the integrated capacitor could effectively avoid the relative displacement and shedding between the adjacent components, and effectively reduce the resistance of electron/ion transfer. At the same time, the integrated capacitor also showed better flexibility, and its electrical performance remained stable after bending test. When the current density was 0.2 mA/cm2, the area and volume specific capacitance of the integrated capacitor could reach 64.8 mF/cm2 and 31.0 F/cm3, respectively, showing excellent electrochemical performance. The preparation of the integrated supercapacitor provides a new method for development of wearable electronic devices.
Enzymatic hydrolysis residue of xylan was autohydrolyzed, and the autohydrolysate was then fractionated by two-step ethanol precipitation. The obtained three kinds of xylan fractions with varied degree of polymerization (Dp) were evaluated through in vitro proliferation by Bifidobacterium adolescentis. The autohydrolysis was carried out at 180℃ for 40 min to obtain autohydrolysate mainly contained xylooligosaccharides (XOS) with Dp of 2-6. The content of XOS was 57.36% of the xylan in the autohydrolysate, and the yield of XOS was 26.54% of the xylan in the feedstock. Two-step ethanol precipitation could fractionate the xylan in the autohydrolysate into sample S1, S2 and S3, with the range of Dp of 24-122, 7-19 and 1-6, respectively. Low Dp of sample S3 contained mainly XOS which was 95.91% and exhibited significant prebiotic activity. After 36 h incubation, the cell concentration was 0.25 g/L, 4.72 times of the initial, with the sugar residue of 43.48%, and with the concentration of short-chain fatty acids of 1.96 g/L.