Carbonation indirect

The partially halogenated hydrocarbons, such as poly(vinylidene fluoride) (PVDF) and polyvinylchloride (PVC) are not carbonizable by direct reductive dehalogenation [59]. Nevertheless, PVDF carbonizes indirectly by... 

Wrackmeyer, B., Carbon Carbon and Metal Carbon Indirect Nuclear Spin-Spin Coupling Constants J( C C) and J(M C) in Organometallic Compounds, Spectrosc. Intern. J. 1 [1982] 201/8. 

Carbon dioxide in the atmosphere is the principal source of carbon in plants, which obtain carbon through photosynthesis. Animals obtain that carbon indirectly by eating plants or by eating other animals that have eaten plants. Animals, and plants, return carbon dioxide to the atmosphere through respiration. 

Using the isotopic composition of meteoric waters to infer climatic conditions is a less direct means to get at paleotemperatures. This is particularly so when the composition of the fluid represents either an average of many events (ice cores) or an average value of some fluid in equilibrium with a solid phase such as a soil carbonate, a concretion, or tooth enamel from a terrestrial herbivore. Because of the imcertainties in the correlation between surface temperature and isotopic composition of precipitation and in the formation conditions of the proxy phase (e.g., carbonate), indirect estimates of paleotemperatures have an uncertainty somewhat greater ( 5°C). 

The asphaltene content is found either directly by precipitation using n-heptane (NF T 60-115 or ASTM D 32), or indirectly by correlation with the Conradson Carbon. It can vary from 4 or 5% to as much as 15 or 20% in extreme cases. 

In situations where conserved internal markers caimot be used, such as in spills of essentially pure compounds, the evidence for enhanced biodegradation may have to be more indirect. Oxygen consumption, increases in microbial activity or population, and carbon dioxide evolution have all been used with success. 

Recovery of Ammonia. The filter Hquor contains unreacted sodium chloride and substantially all the ammonia with which the brine was originally saturated. The ammonia may be fixed or free. Fixed ammonia (ammonium chloride [12125-02-97]) corresponds stoichiometrically to the precipitated sodium bicarbonate. Free ammonia includes salts such as ammonium hydroxide, bicarbonate, and carbonate, and the several possible carbon—ammonia compounds that decompose at moderate temperatures. A sulfide solution may be added to the filter Hquor for corrosion protection. The sulfide is distilled for eventual absorption by the brine in the absorber. As the filter Hquor enters the distiller, it is preheated by indirect contact with departing gases. The warmed Hquor enters the main coke, tile, or bubble cap-fiUed sections of the distiller where heat decomposes the free ammonium compounds and steam strips the ammonia and carbon dioxide from the solution. 

Rayon is unique among the mass produced man-made fibers because it is the only one to use a natural polymer (cellulose) directly. Polyesters, nylons, polyolefins, and acryflcs all come indirectly from vegetation they come from the polymerization of monomers obtained from reserves of fossil fuels, which in turn were formed by the incomplete biodegradation of vegetation that grew millions of years ago. The extraction of these nonrenewable reserves and the resulting return to the atmosphere of the carbon dioxide from which they were made is one of the most important environmental issues of current times. CeUulosic fibers therefore have much to recommend them provided that the processes used to make them have minimal environmental impact. 

Iodine forms compounds with all the elements except sulfur, selenium, and the noble gases. It reacts only indirectly with carbon, nitrogen, oxygen, and some noble metals such as platinum. 

SL/RN Process. In the SL/RN process (Fig. 4), sized iron ore, coal, and dolomite are fed to the rotary kiln wherein the coal is gasified and the iron ore is reduced. The endothermic heat of reduction and the sensible energy that is required to heat the reactants is provided by combustion of volatiles and carbon monoxide leaving the bed with air introduced into the free space above the bed. The temperature profile in the kiln is controlled by radial air ports in the preheat zone and axial air ports in the reduction zone. Part of the coal is injected through the centerline of the kiln at the discharge end. The hot reduced iron and char is discharged into an indirect rotary dmm cooler. The cooled product is screened and magnetically separated to remove char and ash. 

The double titration method, which involves the use of ben2ylchloride, 1,2-dibromoethane, or aUyl bromide, determines carbon-bound lithium indirectly (101,102). One sample of the //-butyUithium is hydroly2ed directly, and the resulting alkalinity is determined. A second sample is treated with ben2ylchloride and is then hydroly2ed and titrated with acid. The second value (free base) is subtracted from the first (total base) to give a measure of the actual carbon-bound lithium present (active base). 

Carboxylate soaps are most commonly formed through either direct or indirect reaction of aqueous caustic soda, ie, alkaH earth metal hydroxides such as NaOH, with fats and oils from natural sources, ie, triglycerides. Fats and oils are typically composed of both saturated and unsaturated fatty acid molecules containing between 8 and 20 carbons randomly linked through ester bonds to a glycerol [56-81-5] backbone. Overall, the reaction of caustic with triglyceride yields glycerol (qv) and soap in a reaction known as saponification. The reaction is shown in equation 1. 

Indirect methods of estimating sorption have been used when actual measurement of sorption isotherm is impossible (44). For instance, sorption coefficients have been estimated from soil organic carbon and a specific surface of soil, and from semiempidcal equations using pesticide properties. 

Electric-Arc Furnace. The electric-arc furnace is by far the most popular electric steelmaking furnace. The carbon arc was discovered by Sir Humphry Davy in 1800, but it had no practical appHcation in steelmaking until Sir William Siemens of open-hearth fame constmcted, operated, and patented furnaces operating on both direct- and indirect-arc principles in 1878. At that early date, the avadabiHty of electric power was limited and very expensive. Furthermore, carbon electrodes of the quaHty to carry sufficient current for steel melting had not been developed (see Furnaces, electric). 

The effect of the ahoying elements on AISI steels is indirect because ahoying elements control microstmcture through their effect on hardenabhity. These elements permit the attainment of desirable microstmctures and properties over a much wider range of sizes and sections than is possible with carbon steels. 

Bromine is used as an analytical reagent to determine the amount of unsaturation in organic compounds because carbon—carbon double bonds add bromine quantitatively, and for phenols which add bromine in the ortho and para positions. Standard bromine is added in excess and the amount unreacted is deterrnined by an indirect iodine titration. Bromine is also used to oxidize several elements, such as T1(I) to T1(III). Excess bromine is removed by adding phenol. Bromine plus an acid, such as nitric and/or hydrochloric, provides an oxidizing acid mixture usefiil in dissolving metal or mineral samples prior to analysis for sulfur. 

The best indirect, but seldom used, method is to determine the total moisture separately in a Penfteld tube, determine the loss on ignition in air at 825—875°C, and report graphitic carbon as percent loss on ignition (100 — %moisture — %ash). It is desirable to use a platinum dish for ignition loss and it... 

Other carbon electrophiles which are frequently employed include aldehydes, ketones, esters, nitriles and amides of the type RCONMei. An indirect method of acylation involves the initial reaction of a lithio compound with an aldehyde followed by oxidation of the resulting secondary alcohol to the corresponding acyl derivative. 

Indirect rotary calciner. This is a bare metal cyhnder surrounded on the outside by a fired or elec trally heated furnace. It is suitable for operation at medium temperatures up to the maximum which can be tolerated by the metal w of the cylinder, usuaUy 6.50 to 700 K for carbon steel and 800 to 1025 K for stainless steel. 

Performance and Cost Data for Indirect-Heat Rotary Steam-Tube Dryers Table 12-22 contains data for a number of standard sizes of steam-tube diyers. Prices tabulated are for ordinaiy carbon steel construction. Installed costs will run from 150 to 300 percent of purchase cost. 

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