Comparative Study Of Methyl-Tert-Butyl Ether Extractives From RYE And Rice Straw

The chemical composition of lipophilic extractives from rye and rice straws has been comparatively examined. Free fatty acids (19.04-22.95%), sterols (12.54-14.60%), waxes (9.53-27.14%), steryl esters (16.02-18.19%), and triglycerides (5.72-11.38%) were identified as the five major classes of lipids in the two straw extractives. Minor components of diglycerides (0.23-0.42%) and resin acids (0.05-0.12%) were also verified from the two straw lipophilic extracts. Of the individual compounds in each group, fifteen free fatty acids, four sterols, three waxes, five steryl esters, and three triglycerides were quantitatively determined. The most abundant saturated free fatty acids were palmitic acid (C16:0, 3.96-4.24%) and tetradecanoic acid (C14:0, 2.95-3.62%), whereas linoleic (C18:2) and/or oleic (C18: 1) acids (1.87-2.09%) were the most dominant unsaturated free fatty acids. β-Sitosterol was identified as a predominant component, accounting for 83.89% of the total sterols in rye straw extract and 94.45% in rice straw extractives. Palmitic acid palmityl ester was verified as a dominant component in a group of waxes, accounting for approximately 70% of the waxes analyzed in the two extracts. The steryl esters analyzed were composed mainly of steryl laurate (0.29-0.95%), steryl myristate (3.20-3.56%), steryl palmitate (1.86-2.28%), steryl margarate (2.20-2.93%), and steryl oleate (2.13%). Of the triglycerides verified, glyceryl tripalmitate (0.23-1.64%), 1,2-dipalmitoyl-3-oleoylrac-glycerol (1.06-2.08%), and triolein (cis-9) (0.77-1.61%) were identified in this group

Isolation and Characterization of Hot Water-Soluble Lipophilic Extractives From Wheat Straw. Part II. Spectroscopic and Thermal Characterization

The chemical composition of the six extractives, isolated with hot water at 80-95°C for 0.5 h at pH 6.0-8.0 from wheat straw, consists mainly of free fatty acids, waxes, sterols, triglycerides, and sterol esters, together with minor amounts of diglycerides, resin acid, and phenolic compounds. In this continuing study, the six lipophilic extractives were further investigated by Fourier transform infrared, and 1H and 13C nuclear magnetic resonance as well as thermal analysis, and the results are reported

Value-added uses for crude glycerol--a byproduct of biodiesel production

Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds

Technical Note: Melt Dispersion Technique for Preparing Paraffin Wax Microspheres for Cellulose Encapsulation

A practical and convenient approach for making paraffin wax microspheres with a melt dispersion technique was reported in this study. Surfactants were melted in water by water bath and then added to a flask after the wax was completely melted with stirring. Paraffin wax microspheres were generated by cooling. The obtained microspheres exhibited uniform diameters in the range of 10-60 μm observed with a scanning electrical microscope and were mainly dependent on the surfactant ratio. Encapsulated microcrystalline cellulose particles with the previously mentioned conditions were also generated and demonstrated the possibility of encapsulating microcrystalline cellulose with some acceptable agglomeration, although some encapsulated individually. Encapsulation of cellulose could be beneficial if agglomeration could be minimized and the encapsulated microcapsules could be dispersed during blending for wood composites manufacture

Au@h-Al2O3 Analogic Yolk–Shell Nanocatalyst for Highly Selective Synthesis of Biomass-Derived D-xylonic Acid via Regulation of Structure Effects

Selective oxidation of biomass-based monosaccharides into value-added sugar acids is highly desired, but limited success of producing D-xylonic acid has been achieved. Herein, we report an efficient catalyst system, viz., Au nanoparticles anchored on the inner walls of hollow Al2O3 nanospheres (Au@h- Al2O3), which could catalyze the selective oxidation of D-xylose into D-xylonic acid under base-free conditions. The mesoporous Al2O3 shell as the adsorbent first adsorbed D-xylose. Then, the interface of Au nanoparticles and Al2O3 as active sites spontaneously dissociated O2, and the exposed Au nanoparticle surface as the catalytic site drove the transformation. With this catalyst system, the valuable D-xylonic acid was produced with excellent yields in the aerobic oxidation of D-xylose. Extensive investigation showed that Au@h- Al2O3 is an efficient catalyst with high stability and recyclability

Molecular Characteristics of Kraft-AQ Pulping Lignin Fractionated by Sequential Organic Solvent Extraction

Kraft-AQ pulping lignin was sequentially fractionated by organic solvent extractions and the molecular properties of each fraction were characterized by chemical degradation, GPC, UV, FT-IR, 13C-NMR and thermal analysis. The average molecular weight and polydispersity of each lignin fraction increased with its hydrogen-bonding capacity (Hildebrand solubility parameter). In addition, the ratio of the non-condensed guaiacyl/syringyl units and the content of β-O-4 linkages increased with the increment of the lignin fractions extracted successively with hexane, diethylether, methylene chloride, methanol, and dioxane. Furthermore, the presence of the condensation reaction products was contributed to the higher thermal stability of the larger molecules

Comparative Study of Acetylation of Rice Straw Fiber With or Without Catalysts

The reaction of acetic anhydride with rice straw fiber without solvent was investigated, and the extent of acetylation was measured by weight percent gain, which increased with an increment of reaction time or temperature. Meanwhile, the potential of four tertiary amine catalysts (pyridine, 4-dimethylamino pyridine, N-methyl pyrrolidine, and N-methyl pyrrolidinone) for the acetylation at 100°C for 0.5 h was also studied. The hypernucleophile 4-dimethylamino pyridine was found to be the most effective catalyst of those studied. The characterization of acetylated fibers was performed by FT-IR, CP MAS 13C-NMR, and thermal studies. Thermal stability of acetylated rice straw fiber was found to be higher than the unreacted fiber and increased with weight percent gain due to the acetylation