Codeinone (3) was efficiently and directly converted to 14-hydroxycodeinone (1) by catalytic air oxidation in aqueous solution. A number of simple manganese and copper salts were identified to be effective catalysts, including MnSO4, KMnO4, and CuSO4. An appropriate reducing agent, such as sodium thiosulfate, is required in the reaction mixture presumably for the reduction of a detrimental pero...

As an important precursor and derivate of graphene, graphene oxide (GO) has received wide attention in recent years. However, the synthesis of GO in an economical and efficient way remains a great challenge. Here we reported an improved NaNO3-free Hummers method by partly replacing KMnO4 with K2FeO4 and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO3-free...

A simple, rapid and reliable method was developed for the determination of total mercury in biological samples. Samples were solubilized using tetramethylammonium hydroxide (TMAH). The organically bound mercury was cleaved and converted to inorganic mercury by on-line addition of KMnO4. The decomposed mercury together with inorganic mercury originally present in samples was determined by flow i...

In an attempt to produce effective and lower price gaseous Hg(0) adsorbents, two methods of HCl and KMnO4/heat treatment were used respectively for the surface modification of liginite semicoke from inner Mongolia. The different effects of modification process on the surface physical and chemical properties were analyzed. The characteristics and stability of mercury vapor adsorption over two ki...

Human XPG nuclease makes the 3' incision during nucleotide excision repair of DNA. The enzyme cleaves model DNA bubble structures specifically near the junction of unpaired DNA with a duplex region. It is not yet known, however, whether an unpaired structure is an intermediate during actual DNA repair. We find here that XPG requires opening of >5 bp for efficient cleavage. To seek direct eviden...

The effect of temperature and air humidity on the stability of 7 derivatives of 1,4-dihydropyridine (nifedipine, nisoldipine, nitrendipine, nimodipine, nicardipine, felodipine and amlodipine) in solid state has been studied by accelerated testing. Quantitative analysis of the compounds studied was made by UV spectrophotometry, identification of the thermodegradation products and reference to th...

Graphene oxide (GO) is widely recognized as a promising material in a variety of fields, but its structure and composition has yet to be fully controlled. We have developed general strategies to control the oxidation degree of graphene-like materials via two methods: oxidation of graphite by KMnO4 in H2SO4 (oGO), and reduction of highly oxidized GO by hydrazine (rGO). Even though the oxygen con...

Metallic monoliths were prepared by anodized aluminum-scale pilot plant, using sulfuric acid as electrolyte. Anodisation tests were conducted at different times and different temperatures of the electrolytic bath. Aluminum monolith anodized at 40oC for 30 min was selected for catalysts support. The monoliths were impregnated by two methods: i) impregnation in two stages using two Mn salts in an...