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Step-wise and one-step vacuum pyrolysis of birch-derived biomass to monitor the evolution of phenols 总被引:6,自引:0,他引:6
Jean Npo Murwanashyaka Hooshang Pakdel Christian Roy 《Journal of Analytical and Applied Pyrolysis》2001,60(2):1339-231
One-step and stepwise laboratory batch vacuum pyrolysis of a mixture of birch bark (ca. 46%) and birch sapwood (ca. 54%) was carried out in the temperature range 25–550°C. The pyrolysis oil (defined as the total condensates, including water and organics) was analyzed by GC–MSD and the quantity of phenols (referred to monolignols in this paper) was determined as a function of temperature. The active zone of decomposition and the maximum recovery of phenols were found to be in the temperature range 275–350°C. Distribution of phenols, charcoal and water as a function of temperature was investigated. Stepwise and one-step pyrolysis yielded total phenols of 4.43 and 2.51 wt.% (anhydrous feed basis), respectively. The yields of pyrolysis oil (62.39 wt.%), wood charcoal (23.25 wt.%) and gas ( 14.36 wt.%) produced by both methods were approximately similar, on an anhydrous feed basis. 相似文献
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The rates of rearrangement in 1-phenyl-2,4,6-tris(p-methoxyphenyl)thiabenzene (4) and 1-(p-tri-fluoromethylphenyl)-2,4,6-triphenylthiabenzene (5) were determined and a crossover experiment was carried out with a mixture of these thiabenzenes. The possibility of 2,4-migrations in the thiopyran system under the reaction conditions was also studied by examining two samples of thiopyrans. The results indicate an intramolecular rearrangement which involves a 1,2- and 1,4-migration of 5-aryl groups in thiabenzenes. 相似文献
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Ahmad Momeni Tikdari Ali Shokrani Hooshang Hamidian Hojatollah Khabazzadeh 《中国化学会会志》2005,52(6):1153-1156
Nitro‐aromatic compounds are used in many human enteropathogenic bacterial infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram‐negative intestial Enterobacteriaceae. The interesting properties of these compounds encourage us to synthesis some new of these compounds by a simple route, starting from (Chlorocarbonyl) phenyl ketene. 相似文献
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Hooshang Pirelahi Yahya Abdoh Faezeh Hadjmirsadeghi Hasan Sagherichi 《Journal of heterocyclic chemistry》1976,13(2):237-239
1-(p-Methoxyphenyl)-2,4,6-triphenylthiabenzene (X) has been synthesized and shown to be more stable than the 1-phenyl analog. 1-Phenyl-2,4,6-tri(p-methoxyphenyl)thiabenzene (XVI) was not stable enough to be isolated in pure form and rearranged readily to the isomeric 2-and 4-thiopyrans. Only the pure 4-phenyl-2,4,6-tri(p-methoxyphenyl)thiopyran (XVIII) could be isolated. 相似文献
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Some 2‐alkyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyrans were synthesized, and the crystal structure of 2‐tert‐butyl‐4‐methyl‐2,6‐diphenyl‐2H‐thiopyran 1 was determined by single‐crystal X‐ray diffraction. X‐ray crystallographic analysis and ab initio HF/6‐31G(d) and B3LYP/6‐31G(d) calculations revealed a favorable nonplanar half‐chair conformation for these compounds in which two ethylene units were rotated relative to each other around the single bond. The most conspicuous feature was the orientation of alkyl and phenyl groups with respect to the S atom. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:142–147, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20192 相似文献
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Mohammad Reza Ganjali Ali Sepehri Azadeh Daftari Parviz Norouzi Hooshang Pirelahi Arash Moradzadegan 《Mikrochimica acta》2005,149(3-4):245-249
A novel sulfate polymeric membrane sensor based on 2,6-diphenyl 4-(4-methoxyphenyl) pyrylium perchlorate (DMPP) as a sensing material is presented. The electrode displays a very low detection limit (4.0×10–7M) and wide working concentration range (8.0×10–7–1.0×10–1M). The sensor shows remarkable selectivity toward sulfate over most common organic and inorganic anions, including chloride, acetate, nitrate, nitrite, bromide, iodide, thiocyanate, phosphate, fluoride, sulfite, hydrogen sulfite, hydrogen carbonate, citrate, tartarate and oxalate. The sensor reveals a Nernstian behavior (slope of –29.7±0.5mV per decade) in a wide pH range (3.0–9.5). The proposed sensor shows a short response time over the entire working range (15s) and was successfully applied to the direct determination of salbutamol, amikacin and paromomycin sulfate. 相似文献