A review of the direct oxidation of methane to methanol

This article briefly reviewed the advances in the process of the direct oxidation of methane to methanol （DMTM） with both heterogeneous and homogeneous oxidation. Attention was paid to the conversion of methane by the heterogeneous oxidation process with various transition metal ox‐ides. The most widely studied catalysts are based on molybdenum and iron. For the homogeneous gas phase oxidation, several process control parameters were discussed. Reactor design has the most crucial role in determining its commercialization. Compared to the above two systems, aque‐ous homogenous oxidation is an efficient route to get a higher yield of methanol. However, the cor‐rosive medium in this method and its serious environmental pollution hinder its widespread use. The key challenge to the industrial application is to find a green medium and highly efficient cata‐lysts.

Catalytic oxidation of calcium sulfite in solution/aqueous slurry

Forced oxidation of calcium sulfite aqueous slurry is a key step for the calcium-based flue gas desulfurization(FGD) residue. Experiments were conducted in a semi-batch system and a continuous flow system on lab scales. The main reactor in semi-batch system is a 1000 ml volume flask. It has five necks for continuous feeding of gas and a batch of calcium sulfite solution/aqueous slurry. In continuous flow system, the main part is a jacketed Pyrex glass reactor in which gas and solution/aqueous slurry are fed continuously. Calcium sulfite oxidation is a series of complex free-radical reactions. According to experimental results and literature data, the reactions are influenced significantly by manganese as catalyst. At low concentration of manganese and calcium sulfite, the reaction rate is dependent on 1.5 order of sulfite concentration, 0.5 order of manganese concentration, and zero order of oxygen concentration in which the oxidation is controlled by chemical kinetics. With concentrations of calcium sulfite and manganese increasing, the reactions are independent gradually on the constituents in solution but are impacted by oxygen concentration. Manganese can accelerate the free-radical reactions, and then enhances the mass transfer of oxygen from gas to liquid. The critical concentration of calcium sulfite is 0.007 mol/L, manganese is 10 -4 mol/L, and oxygen is of 0.2—0.4 atm.

Structural Description of Polyaromatic Nucleus in Residue

The proton nuclear magnetic resonance spectroscopy （1H-NMR）, the synchronous fluorescence spectrometry （SFS） and the ruthenium ions catalyzed oxidation （RICO） method were used to determine the chemical structure of polyaromatic nucleus in Oman residue fractions. The results of 1H-NMR analyses showed that the average numbers of aromatic rings in the aromatics, resins and asphaltenes units were 3.2, 5.6 and 8.2, respectively. SFS was used to investigate the distribution of aromatic rings in residue fractions, the main distribution range of aromatic rings in aromatics, resins and asphaltenes were 3 4 rings, 3--5 rings and more than 5 rings, respectively. The aromatic network in residue fractions was oxidized to produce numerous carboxylic acids. The types and content of benzenepolycarboxylic acids, such as phthalic acid, benzenetricarboxylic acids, benzenetetracarboxylic acids, benzenepentacarboxylic acid and benzenehexacarboxylic acid disclosed the condensed types of aromatic nuclei in the core. The biphenyl fraction （BIPH）, the cata-condensed fraction （CATA）, the peri-condensed fraction （PERI） and the condensed index （BCI） were calculated based on the benzenepolycarboxylic acids formed. The results implied that there was less biphenyl type structures in all residue fractions. The aromatics fraction was almost composed of the cata-condensed type system, and the asphaltenes fraction was wholly composed of the peri-condensed type system, while in the resins fraction co-existed the two types, herein the peri-con- densed type was predominant over the cata-condensed type. Based on the analytical results obtained in the study, the components --aromatics, resins and asphaltenes -- were given the likely structural models.

Washing-off of Unfixed Reactive Dyes on Cotton Fabrics Using Fe-TAML/H_2O_2 Catalyzed Oxidation System

Unfixed reactive dyes stained on cotton fabric could be removed using Fe-tetra-amido macro-cyclic ligands( TAML) / H_2O_2 catalyzed oxidation system( COS). The colored washing-off wastewater also could be decolorized simultaneously in the same system. The decolourization kinetics showed that the decolourization ratio of reactive dyes in water could reach at least 80% at room temperature in 10 min,which followed the law of pseudo-first order reaction kinetics. The effects of the COS washing-off process parameters on the decolourization ratio,chemical oxygen demand( COD) of wastewater,K/S value,color fastness,color difference,and bursting strength were investigated in detail. The results showed that color fastness properties and final shade of fabric treated by COS were very similar to conventional soaping. The reactive dye molecules in wash-off bath were destroyed using the COS,potentially reduced COD which generated during conventional washing-off procedure.

OXIDATION OF ALKYLBENZENES CATALYZED BY IRON( Ⅱ,Ⅲ)-1,10-PHENANTHROLINE AND 2, 2'-BIPYRIDINE COMPLEXES

Oxidation of alkybenzenes PhCH_2R(R=H, CH_3, C_2H_5 and n-C_3H_7) under 1 atm. of O_2 or air catalyzed by iron(Ⅱ, Ⅲ)-2,2'-bipyridine and 1,10-phenanthroline complexes, affords the aryl-substituted ketones and alcohols with the conversion of 15.00％～34.58％ containing of 97.60％～99.80％ ketones and alcohols. The turnover numbers of these catalysts are over 3500 mol-cat. ^(-1)for 3.5 h.

Nonheme Oxovanadium(V,IV) Complexes Catalyze the Oxidative Cleavage of Catechols

It was found that the oxovanadium(V) complex of triethanolamine (TEA) exhibits catalytic activity to the oxidative cleavage of catechols. On the other hand. the vanadyl nitrilotriacetic acid (NTA) complex is inactive. but leads to the formation of stable ternary complex. The main products of the catalytic oxidative cleavage of 3.5-di-tert-butylcatechol were separated and characterized. Based on the results. a reaction mechanism was discussed

New Integrated Processes for Treating Cold-Rolling Mill Emulsion Wastewater

Two new integrated processes, gas-energy-management （GEM）—electrochemical catalytic oxidation （ECO）—membrane bioreactor （MBR） and ultrafiltration （UF）—ECO—MBR, in industrial-scale test for treating cold-rolling mill emulsion wastewater with water quantity of 200 L/h to 3000 L/h were studied. The former was put forward firstly and the latter was applied initially in this field. The operation conditions and mechanisms of each module in the integrated processes were analyzed and the influences of operational parameters of two processes on chemical oxygen demand （CODCr） removal efficiency were comparatively investigated. The test results showed that the ultimate water quality from the two processes after treatment could meet the requirement for reuse.However, the quality of effluent treated by GEM—ECO—MBR was more stable than that of UF—ECO—MBR.

A deep insight into the structural characteristics of Yilan oil shale kerogen through selective oxidation

The structural characteristics of oil shale are important to its application.In this work,a deep insight into the structural characteristics of Yilan oil shale kerogen(YLK)was studied using alkali-oxygen oxidation at different times and ruthenium ion catalyzed oxidation(RICO).The results indicate that YLK is gradually converted to humic acids(HAs),water-soluble acids(WSAs),carboxylic acids(CAs),CO_(2)and H_(2)O.^(13)C NMR analyses of YLK,residues and HAs indicate that C-O bonds,especially C_(ar)-O bonds of YLK,are easily cleaved.The condensed aromatic rings and long alkyl chains are difficult to be oxidized during the oxidation process.With increasing oxidation time,the molar fraction of aromatic bridgehead carbon(Xb)of YLK and the residues increases from 0.174 to 0.201,and that of HAs increases from 0.225 to 0.267.The result indicates that the aromatic structures of YLK are composed of 1-ring aromatic clusters(26.5%),2-ring aromatic clusters(67.1%)and 3 or more-ring aromatic clusters(6.4%).Also,the average methylene chain(Cn)of YLK and the residues increases from 2.0 to 5.1,and that of HAs increases from 1.3 to 2.7,indicating that the alkyl chain length is not average but has a distribution.2.5%methylene carbons exist as long n-alkyl chains in the alkyl side chains groups(SCGs)on the aromatic rings in YLK.The carbon number of SCGs ranges from 5 to 22,and C_(15)and C_(17)are predominant.3.8%methylene carbons exist as alkyl bridges linkages(BLs)connecting aromatic rings in YLK.The carbon number of BLs connecting aromatic rings ranges from 6 to 19,and C_(8)is predominant.Because of the existence of above long n-alkyl chains,93.7%methylene carbons in YLK exist as alkyl chains with an average length of 1.84.