Carbon solid

Katz A I, Schiferl D and Mills R L 1981 New phases and chemical reactions in solid carbon monoxide under pressure J. Phys. Chem. 88 3176... 

Carbon dioxide is used in the manufacture of sodium carbonate by the ammonia-soda process, urea, salicyclic acid (for aspirin), fire extinguishers and aerated water. Lesser amounts are used to transfer heat generated by an atomic reactor to water and so produce steam and electric power, whilst solid carbon dioxide is used as a refrigerant, a mixture of solid carbon dioxide and alcohol providing a good low-temperature bath (195 K) in which reactions can be carried out in the laboratory. 

Solid carbon dioxide (Dry Ice, Drikold) is employed when very low temperatures are required. If it is suspended in solvents, such as alcohol or a mixture of equal volumes of chloroform and carbon tetrachloride, temperatures down to — 50° can be easily attained. Lower temperatures still are reached if intimate mixtures of solid carbon dioxide and organic solvents are employed with ethyl alcohol, — 72° with... 

By cooling the solution in a freezing mixture (ice and salt, ice and calcium chloride, or solid carbon dioxide and ether). It must be borne in mind that the rate of crystal formation is inversely proportional to the temperature cooling to very low temperatures may render the mass... 

By adding a few lumps of solid carbon dioxide this produces a number of cold spots here and there, and assists the formation of crystals. 

For some purposes in the Grignard reaction) solid carbon dioxide, narketed as Dry Ice or Drikold, may be employed. 

The gas is dried by passage through wash bottles containing concentrated sulphuric acid. Alternatively and more simply, the technique (described below for n.valeric acid) utilising solid carbon dioxide (Dry Ice or Drikold) may be employed. 

Alternatively, the solution of the Grignard reagent may be poured on to solid carbon dioxide (Dry Ice)—for experimental details, see under n-Valeric Acid, Section 111,84. 

It is better not to remove the lower bromoform layer in a separatory funnel, but to do so entirely by steam distillation complete oxidation of the ketone id thus ensured. The weight of recovered bromoform may be somewhat smaller (100-105 g.), but the yield of pure acid is increased to 36 g. The steam distillation must be carefully watched as a solid (carbon tetrabromide) may crystallise in the condenser this can easily be removed by turning ofi the water supply when the solid will soon melt and pass on into the distillate. 

Sodamide. Assemble the apparatus shown in Fig. VI, 16, 1, a. Fill the bath to a point about half-way up the side of the flask with methyl alcohol (or methylated spirit) and add solid carbon dioxide (Dry Ice or Drikold) in lump form until a white frost commences to form on the outside of the bath (2) the bath temperature should be about — 35 . 

It is advisable to filter the a-picolyl-lithium solution rapidly through a thin layer of glass wool (to remove any unreacted lithium) on to the solid carbon dioxide. 

The formation of an organosodium compound (p-tolyl-sodium) is well illustrated by the interaction of sodium sand or wire with p-chlorotoluene in light petroleum (b.p. 40-60°) at about 25°, for when the reaction mixture is added to excess of solid carbon dioxide pure/ -toluic acid is obtained directly in a yield exceeding 70 per cent. ... 

It is usually better to use a fire extinguisher charged with carbon dioxide under pressure this produces a spray of solid carbon dioxide upon releasing the pressure intermittently and is effective for extinguishing most fires in the laboratory. 

Solid acid catalyst Solid bridges Solid carbon dioxide... 

Fig. 2. Overall schematic of solid fuel combustion (1). Reaction sequence is A, heating and drying B, solid particle pyrolysis C, oxidation and D, post-combustion. In the oxidation sequence, left and center comprise the gas-phase region, tight is the gas—solids region. Noncondensible volatiles include CO, CO2, CH4, NH, H2O condensible volatiles are C-6—C-20 compounds oxidation products are CO2, H2O, O2, N2, NO, gaseous organic compounds are CO, hydrocarbons, and polyaromatic hydrocarbons (PAHs) and particulates are inerts, condensation products, and solid carbon products.

At reduction temperatures below about 1000°C, the reducing agents usually ate restricted to CO and Above about 1000°C, solid carbon can... 

Table 2. Vapor Pressure of Solid Carbon Dioxide ...

Solid carbon monoxide exists in one of two aUotropes, a body-centered cubic or a hexagonal stmcture. The body-centered stmcture converts into the hexagonal stmcture at 62 K with a heat of transition of 0.632 kj/mol (0.151 kcal/mol) (5). The melting point at atmospheric pressure is 68.1 K and... 

The recorded use of metallo derivatives in the pyrimidine and quinazoline series is minimal. The best described pyrimidinyllithium compounds are those derived from 5-bromopyrimidines. Their reactions are illustrated in the following examples. Pyrimidin-5-yllithium (474 R = H) reacts with solid carbon dioxide under ether to give pyrimidine-5-carboxylic acid (475 R = H) in good yield (65ACS1741) 4,6-dimethoxy- (474 R = OMe),... 

If the pump is a filter pump off a high-pressure water supply, its performance will be limited by the temperature of the water because the vapour pressure of water at 10°, 15°, 20° and 25° is 9.2, 12.8, 17.5 and 23.8 mm Hg respectively. The pressure can be measured with an ordinary manometer. For vacuums in the range lO" mm Hg to 10 mm Hg, rotary mechanical pumps (oil pumps) are used and the pressure can be measured with a Vacustat McLeod type gauge. If still higher vacuums are required, for example for high vacuum sublimations, a mercury diffusion pump is suitable. Such a pump can provide a vacuum up to 10" mm Hg. For better efficiencies, the pump can be backed up by a mechanical pump. In all cases, the mercury pump is connected to the distillation apparatus through several traps to remove mercury vapours. These traps may operate by chemical action, for example the use of sodium hydroxide pellets to react with acids, or by condensation, in which case empty tubes cooled in solid carbon dioxide-ethanol or liquid nitrogen (contained in wide-mouthed Dewar flasks) are used. 

Incorporation of powdered solid carbon dioxide which volatilises at elevated temperatures. This process has been used in conjunction with PVC pastes. 

Essentially, carbonization entails the heating of organic precursors in the absence of air. In so doing, a solid carbon residue along with gaseous and volatile hydrocarbons is created. Bituminous coals are used to make metallurgical-grade coke while wood and other similar substances make charcoal. The condensed volatile material can be further refined to yield chermcals, pitches, or other useful commodities. 

On a number of occasions people have received a mild electric shock while using a carbon dioxide fire extinguisher. The gas jets from the extinguishers contain small particles of solid carbon dioxide, so a charge will collect on the horn of the extinguisher and may pass to earth via the hand of the person who is holding the horn. 

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