ABSTRACT
Indan and tetralin are widely used as fuel additives and the intermediates in the manufacture of thermal-stable jet fuel, many chemicals, medicines, and shockproof agents for rubber industry. Herein, we disclose a two-step route to selectively produce 5-methyl-2,3-dihydro-1H-indene (abbreviated as methylindan) and tetralin with xylose or the hemicelluloses from agricultural or forestry waste. Firstly, cyclopentanone (CPO) was selectively formed with ~60% carbon yield by the direct hydrogenolysis of xylose or hemicelluloses on a non-noble bimetallic Cu-La/SBA-15 catalyst. Subsequently, methylindan and tetralin were selectively produced with CPO via a cascade self-aldol condensation/rearrangement/aromatization reaction catalyzed by a commercial H-ZSM-5 zeolite. When we used cyclohexanone (another lignocellulosic cycloketone) in the second step, the main product switched to dimethyltetralin. This work gives insights into the selective production of bicyclic aromatics with lignocellulose.
ABSTRACT
Cyclopentadiene (CPD) and methylcyclopentadiene (MCPD) are important intermediates that have been widely used in the production of high-energy-density rocket fuels, polymers and valuable chemicals. Currently, CPD and MCPD are produced from fossil energies at very low yields, which greatly limits their application. As a solution to this problem, we disclose an alternative two-step bio-route to access CPD and MCPD using xylose or extracted hemicellulose as the feedstock. In the first step, cyclopentanone (CPO) was directly produced by the selective hydrogenolysis of xylose or extracted hemicellulose over a commercial Ru/C catalyst in an acid-free toluene/NaCl aqueous solution biphasic system. In the second step, CPO was selectively converted to CPD by a cascade hydrodeoxygenation/dehydrogenation reaction over zinc molybdate catalysts. When methanol was introduced with CPO and hydrogen, MCPD was selectively obtained by a cascade dehydrogenation/aldol condensation/selective hydrodeoxygenation reaction over zinc molybdate catalysts.
ABSTRACT
A mild and efficient approach for the preparation of cellulose nanocrystals (CNCs) was developed by using mixed H2SO4/Oxalic acid hydrolysis. In this process, the mixed acid of sulfuric acid, oxalic acid and H2O in an optimal mass ratio of 1:5:4 was used to produce CNCs from bleached eucalyptus kraft pulp (BEKP) at 80 °C for 2-5â¯h. The CNCs with a diameter range of 5-20â¯nm and a length range of 150-400â¯nm were obtained at a high yield (>70%) and showed excellent dispersion stability in water and good thermal stability. Moreover, the dosage of sulfuric acid can reduce to 2.4 g/g CNCs in this mixed acid hydrolysis, which is far lower than that of the typical 64% sulfuric acid hydrolysis (55 g/g CNCs, tested in this work). In addition, 91±2% of oxalic acid could be recovered by a simple recrystallization operation.
ABSTRACT
We report a new drug-loaded film for blending poly(L-lactide) (PLLA) with lignin-based functional filler, which enhanced stability and sustained release of trans-resveratrol (trans-RSV). In addition, trans-RSV loaded PLLA/lignin films showed good antioxidant and anticancer effects. Incorporation of the optimized amount of lignin-based filler to PLLA matrix was key to achieve these desired functions. The lignin-based filler (LG-g-PDLA) was synthesized via ring-opening polymerization on alklin lignin with D-lactide. Benifiting from the stereocomplex formation (PLLA and PDLA side chains), similar polyphenolic structures between lignin and trans-RSV, and UV chromophoric groups of lignin, trans-RSV loaded PLLA/lignin-graft-PDLA films (R/P/LGPD) have good performances on mechanical property, uniformity distribution of drug, and light barrier property. The release behaviors of trans-RSV could be controlled by variation of LG-g-PDLA content. This system therefore offers great potential for the delivery of poor water soluble and light stability drugs.
