Propylene oxide, treatments

For food and pharmaceutical applications, the microbial count must be reduced to less than 10,000 viable cells per g exopolysaccharide. Treatment with propylene oxide gas has been used for reducing the number of viable cells in xanthan powders. The patented process involves propylene oxide treatment for 3 h in a tumbling reactor. There is an initial evacuation step before propylene oxide exposure. After treatment, evacuation and tumbling are alternated and if necessary the reactor is flushed with sterile nitrogen gas to reduce the residual propylene oxide level below the Food and Drug Administration permitted maximum (300 mg kg 1). The treated polysaccharide is then packaged aseptically. 

Cool dry storage Propylene oxide treatment Sterile nitrogen gas treatment Aseptic packaging... 

Synthesis of racemic naproxene Friedel-Crafts acylation (aluminum chloride - nitrobenzene) of p-naphthol methyl ether affords 2-acetyl-6-methoxy naphthalene, which, when treated with either dimethyl sulfonium or dimethylsulfoxonium methylide, gives 2-(6-methoxynaphthalen-2-yl)propylene oxide. Treatment of the latter with boron trifluoride etherate in tetrahydrofuran gives 2-(6-methoxynaphthalen-2-yl)propionaldehyde, which is oxidized using Jones reagent (4 M chromic acid) to yield the racemic 2-(6-methoxynaphthalen-2-yl)propionic acid. 

However, the uncovered silica surface consisting in residual silanols could induce indesirable competitive reaction from propylene oxide treatment such as epoxide opening and alkoxylation of the surface. In order to overcome these drawbacks, the uncovered surface of the Cl-MTS 3 was previously passivate with hexamethyldisilazane treatment before the ligand 1 was anchored according to scheme 3. 

FTIR spectra of the sample 5 and of the resulting sample 6 (Fig 2) show the disappearance of the characteristic N-H vibration band at 3276 cm assigned to the secondary amine functions upon alkylation step. This result ensures the efficiency of propylene oxide treatment. 

A sample referred to as CPS was prepared by Grace-Davison. The modification of the base catalyst was done by incipient wetness impregnation with nickel and vanadium napthenates plus 30 cycles of reduction (propylene)-oxidation treatment. 

OTHER COMMENTS used as a chemical intermediate in the preparation of polyethers to form polyurethanes used in the preparation of lubricants, surfactants, oil demulsifiers, urethane polyols, and propylene and dipropylene glycols propylene oxide treatment is a practical method of control for salmonella in meat scraps also used in the manufacture of detergents and as a component in brake fluids. 

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