OXYGEN lime-soda

It decomposes exothermically to oxygen, a reaction which can be explosive. Even dilute ozone decomposes slowly at room temperature the decomposition is catalysed by various substances (for example manganese(IV) oxide and soda-lime) and occurs more rapidly on heating. 

The purity of oxygen from chlorate candles before and after gas filtration is indicated in Table 2. A particulate filter is always used. Filter chemicals are HopcaUte, which oxidizes CO to CO2 molecular sieves (qv), which remove chlorine compounds and basic materials, eg, soda lime, which removes CO2 and chlorine compounds. Other than H2O and N2, impurity levels of <1 ppm can be attained. Moisture can be reduced by using a desiccant (see Desiccants). Gas purity is a function of candle packaging as well as composition. A hotter burning unit, eg, one in which steel wool is the binder, generates more impurities. 

Sevoflurane. Sevoflurane, l,l,l,3,3,3-hexafluoro-2-propyl fluromethyl ether [28523-86-6] is nonpungent, suggesting use in induction of anesthesia. The blood/gas partition coefficient is less than other marketed products (Table 1) yet similar to nitrous oxide, suggesting fast onset and recovery. In animal studies, recovery was faster for sevoflurane than for isoflurane, enflurane, or halothane (76). Sevoflurane is stable to light, oxygen, and metals (28). However, the agent does degrade in soda lime (77). 

Hydrogen sulphide combusts spontaneously in the presence of oxygen when the mixture is at a temperature of 280-360 . Under controlled conditions this reaction is used to make suiphur from hydrogen sulphide. When soda lime is present, the interaction with pure oxygen is explosive whereas air simply causes soda lime to glow. 

Interaction is exothermic, and if air is present, incandescence may occur with freshly prepared granular material. Admixture with oxygen causes a violent explosion [1], Soda-lime, used to absorb hydrogen sulfide, will subsequently react with atmospheric oxygen and especially carbon dioxide (from the solid coolant) with a sufficient exotherm in contact with moist paper wipes (in a laboratory waste bin) to cause ignition [2], Spent material should be saturated with water before separate disposal. Mixture analogous to soda-lime, such as barium hydroxide with potassium or sodium hydroxides, also behave similarly [1],... 

Structure of soda-lime glass. Four oxygen atoms surround each silicon atom in randomly arranged tetrahedrons. 

Hydrogen sulfide forms explosive mixtures with air the LEL and UEL are 4.3 and 45.0% by volume in air, respectively. Its autoignition temperature is 260°C. Its reaction with soda-lime in oxygen can be explosive. Reactions with strong oxidizing agents can progress to incandescence. 

High vacuum technique (h.v.t.) is one of several types of experimental technique which can be employed to obtain a controlled experimental environment. The most usual reason for wanting this is the necessity to exclude oxygen and/or water and, less commonly, carbon dioxide from the reaction being studied. Perhaps the most primitive example of creating a controlled environment is the use of a soda-lime tube to protect a store of sodium hydroxide from the ingress of carbon dioxide. 

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