High vacuum autoclaves

Rubber gloves Autoclave Gamma-radiation Ethylene oxide Sterilization Gamma-radiation If autoclave used, care with drying at end of process. Little oxidative degradation when high-vacuum autoclave used... 

This compound is prepared by the reaction of tetrasulfur tetranitride with sulfur. An autoclave, fitted with a magnetic stirrer and capable of being heated to 100°, is used as the reaction vessel. A mixture of 24 g. of tetrasulfur tetranitride and 50 g. of sulfur is suspended or, respectively, dissolved in 380 ml. of pure carbon disulfide. The mixture is heated in the autoclave for 2 hours at 110° and then cooled rapidly. It is then filtered from the polythiocyanogen which is formed under these conditions, and the residue washed well with carbon disulfide. These washings are added to the original filtrate, and this is then evaporated in vacuum. The red residue after removal of carbon disulfide is distilled in high vacuum with a bath temperature of 60 to 65°, whereupon dark red crystals separate in the receiver (f.p. 23°). It is found that the best yields are obtained when the walls of the autoclave are soiled from a previous preparation, in which case about 4 g. of tetrasulfur dinitride is usual. 

The basic liposome composition used in this protocol consists of SPC/Chol 7 3 (molar ratio). Lipids are dissolved in dichlo-romethane in an autoclaved round bottom flask and the solvent is dried by rotary evaporation followed by high vacuum for 1 h. This lipid film can be stored at -20 °C for several weeks. 

A solution of pentacarbonyl[phenyl(methoxy)carbene]chromium(0) (3.12 g, 10 mmol) in ethoxyethene (9.66 mL, 100 mmol) was placed in a rotary autoclave (250 mL volume) and heated at 100 atm pressure of carbon monoxide at 50 "C for 65 h. Hexacarbonylchromium formed was filtered and the residue, after the evaporation of excess of vinyl ether, was distilled at 50 °C under high vacuum yield 1.18 g (61%) (mixture of isomers). The isomers were separated by preparative GC the tranj-isomer has mp 29.5 °C, the cii-isomer is a colorless liquid. 

The hydrotreating catalyst (Haldor Topsoe tk-551) consisted of 2.8% Ni, 10.1% Mo and 7.2% P supported on alumina. The 1/16 inch extrudates were crushed and sieved to 40-60 mesh size particles and calcined at 500° C for 16 hours- Catalyst samples were sulfided at 400c 0 in a separate flow reactor with 10% HjS in H for two hours and rapidly transferred to a high pressure, stirred autoclave containing vacuum gas oil (VGO) or a mixture of VGO in mineral oil. The VGO had a corrected boiling range of 265-515° C and a density (15° C) of 0.924 g/cm3, and contained 2.86% S, 740 ppm N, and 200 ppm asphaltenes. Catalysts were coked for 2-3 days at 375 cC in the different concentrations of VGo with added CS, in order to obtain different amounts of coke. Two additional run were made in which the sulfided catalyst was treated with a mixture of n-butylamine or N-phenylcarbazole in hexadecane at 300° C, Coked catalysts were Soxhlet extracted with xylene, followed by an acetone wash, dried at 110° C, and subsequently resulfided in order to assure removal of oil and weakly adsorbed species. Coronene uptakes and diffusivities of... 

After this has been achieved the sample is flame sealed at position 1. All the glass parts and the high vacuum seal are removed under continuous cooling from the high-pressure capillary, and the filling capillary is resealed at position 2. The capillary glass sample cell is then screwed into the copper-beryllium autoclave, which is precooled, while the assembly remains in the cold bath until the assembly is complete. 

The main factor accounting for lack of reliable attainment of sterility in autoclaves has been entrapped air acting as a barrier to direct contact between stetun and product. Thus the main thrust for technological advances in steam sterilization has been concerned with improved effectiveness of removal of air from the chamber and its contents. Advanced high vacuum autoclaves have evolved from downward-di lacetnent types by the addition of condensors, vacuum pumps, and ejector systems to assist in air removal. 

Detailed investigation of the reaction mechanism was performed using a TAP reactor (Autoclave Engineers). Both the TAP apparatus and technique have been described in detail by the inventors [7,8], and otdy those aspects most relevant to this study will be included here. The system comprises four main features (i) a valve assembly which permits the introduction of either a very narrow gas pulse or a continuous flow, (ii) a catalytic microreactor, (iii) a high vacuum system, (iv) a quadrupole mass spectrometer. 

A mixture of 24 g. of and 50 g. of S is dissolved or suspended in 380 ml. of pure CS3 and heated in the autoclave for two hours at 110°C. The mixture is then cooled as rapidly as possible. If a great deal of thiocyanogen polymer forms during the reaction, it is filtered off. The residue is thoroughly washed with CS3 and the wash liquor is combined with the filtrate. The carbon disulfide is then evaporated in vacuum. The red evaporation residue is distilled in high vacuum at a bath temperature of 60-65°C. Dark-red crystals separate in a trap cooled with Dry Ice-methanol mixture. 

A cyanate ester resin for prepreg manufacture, autoclave and vacuum bag processing, offering high temperature wet condition performance. Cure temperature 175 C and an equivalent hot-wet service temperature. 

PhenoHc and furfuryl alcohol resins have a high char strength and penetrate into the fibrous core of the fiber stmcture. The phenoHc resins are low viscosity resoles some have been neutralized and have the salt removed. An autoclave is used to apply the vacuum and pressure required for good impregnation and sufficient heat for a resin cure, eg, at 180°C. The slow pyrolysis of the part foUows temperatures of 730—1000°C are recommended for the best properties. On occasion, temperatures up to 1260°C are used and constant weight is possible even up to 2760°C (93). 

The cmde oxide is pressure-leached in a steam-heated autoclave using water or circulating mother hquor. The arsenic trioxide dissolves, leaving behind a residue containing a high concentration of heavy metal impurities and sihca. The solution is vacuum-cooled and the crystallisation is controUed so that a coarse oxide is obtained which is removed by centrifuging. The mother hquor is recycled. The oxide (at least 99% purity) is dried and packaged in a closed system. 

---