Catalytic activity of PAN-based active carbon fibre (PAN-ACF) activated with sulphuric acid for reduction of nitric oxide with ammonia

Catalytic activity of PAN-ACF activated with sulphuric acid was studied in a closed circulating reactor for the reduction of nitric oxide with ammonia at 423 K. Its activity was enhanced by activation to five times that of the original ACF, being the highest of the active carbons examined in the study. Influences of activation conditions in terms of the impregnation level of sulphuric acid and the activation temperature, and the adsorption ability of the fibre against nitric oxide and ammonia revealed that ammonia, irreversibly adsorbed on the acid sites provided by sulphuric acid after its proper evacuation, is the major reactive species for the reduction. Some activation of nitric oxide is also assumed on the oxidized site of the carbon surface for easier fission of its N-O bond, since NO decomposition is enhanced by activation with sulphuric acid. Activity decreased with repeated runs and is discussed from the point of view of products as poisons.     

Physicochemical Property of Huaishan (Rhizoma Dioscorea) and Matai (Eleocharis dulcis) Starches

The physicochemical properties of starch, the main component in tuberous root of Huaishan (Rhizoma Dioscorea) and corm of Matai (Eleocharis dulcis) was investigated and compared with those of a Japanese yam, “Yamanoimo” starch, and potato starch. Mean particle sizes of Huaishan and Matai starches were 24 ± 5 μm and 12 ± 5 μm, respectively. X-Ray diffraction pattern suggests that Huaishan starch was B-type or C-type just close to B-type and Matai starch was A-type or C-type just close to A-type. Apparently, the intermediate component (IntCom) of Huaishan starch, which was obtained by fractionation of the starch into amylose and amylopectin, may still contain amylose and amylopectin. IntCom of Matai starch has an intermediate nature between amylose and amylopectin. It is concluded that the amylopectin molecules of Huaishan starch contain a larger amount of longer branch-ed chains and those of Matai starch contain a larger amount of shorter branched chains. Amylograms of Matai and Huaishan starches suggest that the gelatinized starches are difficult to retrograde. Digestibility of Huaishan starch by an α-amylase was the highest among the tested starches.     

Studies on Starch Phosphate Part 1. Estimation of glucose-6-phosphate residues in starch and the presence of other bound phosphate(s)

The phosphorus of glucose-6-phosphate residue in starch (P(G6P)) was estimated specifically by means of glucose-6-phosphate dehydrogenase (E.C.1.1.1.49) after acid hydrolysis. Sixty to 70 % of total phosphorus in potato starch was found to be P(G6P)). It was shown that the rest of phosphorus (Px) was incorporated as glucose-2-phosphate and/or glucose-3-phosphate, since it was determined as glucose by periodate oxidation, borohydride reduction, acid hydrolysis and treatment with alkaline phosphatase. The Px was more labile to acid and heat than P(G6P) and decomposed yielding inorganic phosphate. The phospholigosacharide (D. P. 3.6), which was prepared by the limit hydrolysis of potato starch with glucoamylase of Rh. delemar (α-1,4-Glucan glucohydrolase E.C.3.2.1.3) was fractionated by gel-filtration through Sephadex G-25 into fractions with D.P. 2 to 7. Each fraction contained a mole of phosphorus per mole of the saccharide. The P(G6P) and the Px were enriched in the low and the high D.P. fractions, respectively.     

[{W(O)(O2)2(H2O)}2(μ‐O)]2–‐Catalyzed Epoxidation of Allylic Alcohols in Water with High Selectivity and Utilization of Hydrogen Peroxide

A dinuclear peroxotungstate, K₂[{W(O)(O₂)₂(H₂O)}₂(μ‐O)]⋅2 H₂O, exhibits high catalytic performance for the epoxidation of various allylic alcohols with only one equivalent of hydrogen peroxide at 305 K in water solvent. The effectiveness of this system is evidenced by high chemo‐, regio‐, and diastereoselectivity, and stereospecificity for the epoxidation of allylic alcohols. Furthermore, products/catalyst separation can be easily carried out by simple extraction and the catalyst recovered can be reused with the maintenance of the catalytic performance.