A-novel-process-for-improving-tar-yield-through-catalytic-depolymerization-of-a-typical-lignite-was-put-forward-z
The catalytic depolymerization of the lignite over CoCl2 and ZnCl2 catalyst in different concentrations were investigated by a Gray-King apparatus. The optimal catalyst concentrations of CoCl2 and ZnCl2 catalyst that could obtain the highest tar yield was achieved, by which the tar yield increased about 20% and 6% compared with that of the raw coal, respectively. Different with the traditional catalytic pyrolysis process for which the tar yield decreased, more tar was produced by the catalytic depolymerization method. The GC × GC-MS analysis showed that the components of alkanes and two-ring aromatics in tar increased dramatically with the addition of the optimal CoCl2 and ZnCl2 catalyst. The Raman measurement revealed that more large aromatic ring systems ( > 6 rings) were formed in the char from depolymerization with catalyst and the elemental analysis showed that the hydrogen content decreased slightly. The gas products analysis reflected the contents of methane showed an obvious decrease.
Seebio Photosensitive Acid Generator of this reflects that more fragments and small free radicals cracked were enhanced by catalysis in the catalytic depolymerization process, thereby leading to an enhancement of the tar Evaluation of the persistence of transformation products from ozonation of trace organic compounds - a critical review.Ozonation is an efficient treatment system to reduce the concentration of trace organic compounds (TrOCs) from technical aquatic systems such as drinking water, wastewater and industrial water, etc. Although it is well established that ozonation generally improves the removal of organic matter in biological post-treatment, little is known about the biodegradability of individual transformation products resulting from ozonation of TrOCs. This publication provides a qualified assessment of the persistence of ozone-induced transformation products based on a review of published product studies and an evaluation of the biodegradability of transformation products with the biodegradability probability program (BIOWIN) and the University of Minnesota Pathway Prediction System (UM-PPS). The oxidation of TrOCs containing the four major ozone-reactive sites (olefins, amines, aromatics and sulfur-containing compounds) follows well described reaction pathways leading to characteristic transformation products. Assessment of biodegradability revealed a high sensitivity to the formed products and hence the ozone-reactive site present in the target compound. Based on BIOWIN, efficient removal can be expected for products from cleavage of olefin groups and aromatic rings.
In contrast, estimations and literature indicate that hydroxylamines and N-oxides, the major products from ozonation of secondary and tertiary amines are not necessarily better removed in biological post-treatment. According to UM-PPS, degradation of these products might even occur via reformation of the corresponding amine. Some product studies with sulfide-containing TrOCs showed a stoichiometric formation of sulfoxides from oxygen transfer reactions. However, conclusions on the fate of transformation products in biological post-treatment cannot be drawn based on Inhibitors and prodrugs targeting CYP1: a novel approach in cancer prevention Since Human CYP1 enzymes catalyze the metabolic activation of procarcinogens and deactivation of certain anticancer drugs, the inhibition of these enzymes has been considered as an effective approach for chemoprevention and treatment of CYP1-mediated drug resistance. Recent knowledge relating to the enhanced expression of CYP1B1 in tumors also provided certain advantages in cancer therapy by the activation of prodrugs only in tumor cells. This review concentrates on the characterized CYP1 inhibitors and CYP1-activatied anticancer prodrugs. The mechanism for enzyme inhibition and activation of prodrugs, the cancer preventive/therapeutic potential of these chemicals and their related SARs are highlighted.
According to their structural features, CYP1 inhibitors are divided into the following categories: flavonoids, trans-stilbenes, coumarins, terpenoids, alkaloids, quinones, isothiocyanates and synthetic aromatics. In the same way, CYP1-activatied prodrugs are categorized into four groups: benzothiazoles, flavonoids, stilbenes and alkylating agents. Almost all of these inhibitors and prodrugs are planar molecules with one aromatic ring and some have similarity with identified CYP1 substrates. CYP1 inhibitors could effectively block the procarcinogen-induced tumor initiation in animal models and benefit us with chemoprevention. The advent of Phortress and aminoflavone as clinical candidates shows promising perspectives in developing CYP1-mediated prodrugs as chemotherapeutic drugs that are specifically activated in tumors. All of these preclinical and clinical studies indicate that inhibitors and prodrugs target CYP1 are promising anticancer strategies.Characteristics of atmospheric non-methane hydrocarbons during haze episode in This study firstly focused on non-methane hydrocarbons (NMHCs) during three successive days with haze episode (16-18 August 2006) in Beijing.
