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1.
Fully bio‐based polyesters derived from 2,5‐furandicarboxylic acid (2,5‐FDCA) and dodecanedioic acid (DDCA): From semicrystalline thermoplastic to amorphous elastomer
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A serials of fully bio‐based poly(ethylene dodecanedioate‐2,5‐furandicarboxylate) (PEDF) were synthesized from Dodecanedioic acid (DDCA), 2,5‐Furandicarboxylic acid (2,5‐FDCA), and ethylene glycol through a two‐step procedure consisted of transesterification and polycondensation. After their chemical structures were confirmed by Nuclear Magnetic Resonance and Fourier Transform Infrared Spectroscopy, their thermal, mechanical, and biodegradation properties were investigated in detail. Results showed that the chemical composition of PEDFs could be easily controlled by the feeding mole ratio of DDCA to FDCA and they possessed the characteristic of random copolyester with the intrinsic viscosity ranged from 0.82 to 1.2 dL/g. With the varied mole ratio of DDCA to FDCA, PEDFs could be changed from semicrystalline thermoplastic to the completely amorphous elastomer, indicated by the elongation at break ranged from 4 for poly(ethylene 2,5‐furandicarboxylate) to 1500% for amorphous PEDF‐40. The amorphous PEDF‐30 and PEDF‐40 showed satisfactory shape recovery after cyclic tensile test, which was the typical behavior for elastomer. Enzymatic degradation test indicated that all the PEDFs were biodegradable and the degradation rate was heavily affected by their chemical compositions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46076. 相似文献
2.
Ashot Khrimian Matthew S. Siderhurst Grant T. Mcquate Nicanor J. Liquido Janice Nagata Lori Carvalho Filadelfo Guzman Eric B. Jang 《Journal of chemical ecology》2009,35(2):209-218
Oriental fruit fly, Bactrocera dorsalis (Hendel), males are highly attracted to the natural phenylpropanoid methyl eugenol (ME). They compulsively feed on ME and
metabolize it to ring and side-chain hydroxylated compounds that have both pheromonal and allomonal functions. Side-chain
metabolic activation of ME leading to (E)-coniferyl alcohol has long been recognized as a primary reason for hepatocarcinogenicity of this compound in rodents. Earlier,
we demonstrated that introduction of a fluorine atom at the terminal carbon of the ME side chain significantly depressed metabolism
and specifically reduced formation of coniferyl alcohol but had little effect on field attractiveness to B. dorsalis. In the current paper, we demonstrate that fluorination of ME at the 4 position of the aromatic ring blocks metabolic ring-hydroxylation
but overall enhances side-chain metabolism by increasing production of fluorinated (E)-coniferyl alcohol. In laboratory experiments, oriental fruit fly males were attracted to and readily consumed 1,2-dimethoxy-4-fluoro-5-(2-propenyl)benzene
(I) at rates similar to ME but metabolized it faster. Flies that consumed the fluorine analog were as healthy post feeding
as ones fed on methyl eugenol. In field trials, the fluorine analog I was ∼50% less attractive to male B. dorsalis than ME.
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Ashot KhrimianEmail: |
3.
Refugio Bernardo Garcia‐Reyes Jose Rene Rangel‐Mendez 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(10):1533-1538
BACKGROUND: Agro‐waste materials can be used as biosorbents of heavy metals in aqueous solution. However, it is necessary to further study the contribution of agro‐waste materials components (i.e. hemicelluloses, cellulose, and lignin) to the heavy metal ions removal from aqueous solution to better understand the biosorption mechanism, and also based on the biosorbents main components, to predict their potential to remove heavy metals. RESULTS: Cellulose is contained in major proportion (greater than 46%) in the agro‐waste materials reported herein compared with hemicelluloses (from 12% to 26%), lignin (varying from 3% to 10%), and other compounds (22% to 30%) that were removed after the neutral detergent fiber procedure. The identified functional groups in agro‐waste materials and their fractions included hydroxyl, carboxyl, and nitrogen‐containing compounds. Lignin contributed in higher proportion than hemicelluloses to Cr (III) adsorption capacity in both sorghum straw and oats straw. On the other hand lignin was the main fraction responsible for Cr (III) adsorption in agave bagasse. CONCLUSION: Hemicelluloses and lignin were the main contributors to Cr (III) removal from aqueous solution, and cellulose contained in the agro‐waste adsorbents studied did not seem to participate. Copyright © 2009 Society of Chemical Industry 相似文献
4.
Victorio Cadierno Josefina Díez SergioE. García‐Garrido Jos Gimeno Noel Nebra 《Advanced Synthesis \u0026amp; Catalysis》2006,348(15):2125-2132
A large variety of conjugated dienones R1R2CCHCHC(R3)C(O)R4 and diene‐diones R1R2CCHCHC{C(O)R3}C(O)R4 have been synthesized in high yields by reacting terminal propargylic alcohols HCCCR1R2(OH) with enolizable ketones R3CH2C(O)R4 and β‐dicarbonyl compounds R3C(O)CH2C(O)R4, respectively. The process, which is catalyzed by the 16e‐ (η3‐allyl)‐ruthenium(II ) complex [Ru(η3‐2‐C3H4Me)(CO)(dppf)] [SbF6] associated with CF3CO2H, involves the initial isomerization of the propargylic alcohol into the corresponding α,β‐unsaturated aldehyde R1R2CCHCHO (Meyer–Schuster rearrangement) and subsequent aldol‐type condensation. 相似文献