Dioxide early work

Phase Behavior. One of the pioneering works detailing the phase behavior of ternary systems of carbon dioxide was presented ia the early 1950s (12) and consists of a compendium of the solubiHties of over 260 compounds ia Hquid (21—26°C) carbon dioxide. This work contains 268 phase diagrams for ternary systems. Although the data reported are for Hquid CO2 at its vapor pressure, they yield a first approximation to solubiHties that may be encountered ia the supercritical region. Various additional sources of data are also available (1,4,7,13). 

Early work was based on concentrating the radium from the seawater sample by adding barium and coprecipitating with barium sulfate. This concentration procedure has been replaced by one involving the extraction of radium from seawater on acrylic fibre coated with manganese dioxide [19,20] (Mn fibres). By use of this technique, volumes of 200-2000 litres may be sampled routinely. 

Early work with sulfur dioxide showed a linear relationship between visible injury and reduction in yield for many crop species. The assessment was made that no reduction in yield would be found unless visible injury were noted. Definitive research with ozone, other oxidants, or mixtures of these pollutants with other gases has not been done. Thus, we do not know whether such relationships between visible injury and yield hold for the oxidants, but data in Table 11-3 suggest that for acute exposures there may be good correlations between injury and yield reductions. Many researchers have hypothesized that the oxidants may have an effect on plants that will produce a yield reduction with little or no visible injury. Such studies need to be designed in a more defmitive manner before it is concluded that yield reductions without visible symptoms are clearly acceptable. Projections of yield losses have made use of some of the data reported earlier. ... 

In early work, />-chloranil was used to prepare the oxazines 106-108 from the corresponding 5,6-dihydro derivatives (Equation 10) < 1962CB1460>. The reaction proceeded in a very low yield for 106 and yields of 55% for 107 and 15% for 108. Mercurous oxide, chromium trioxide, and selenium dioxide were also tried unsuccessfully as oxidants for this process. 

In early work, iodine was electrochemically generated from an iodide salt in anhydrous methanol containing sulfur dioxide and pyridine. The titration reaction is... 

Fortunately, the absence of such irreversible attachment to E-glass did not extend to other important substrates. Early work conducted with ATH (alumina trihydrate), calcium carbonate, and titanium dioxide demonstrated irreversible attachment to such substrates [2, 3], thereby laying the foundation for use in a diverse array of non-fiberglass applications. 

As summarized by Cassell et al. (ref. 36), the early work on microflotation described the removal of bacteria and algae from water (ref. 61, 62) thereafter, further studies demonstrated that B. cereus (ref. 63), colloidal constituents of tea (ref. 64), humic acid (ref. 65), colloidal silica (ref. 66), illite (ref. 67), titanium dioxide (ref. 68), and polystyrene latex (ref. 69) could be rapidly and efficiently removed from water by microflotation. The general variety of dispersed materials which have been separated successfully... 

The most common methods for the preparation of 1-benzoselenophene and its analogs involve the annulation of the selenophene ring onto a benzene substrate. Early works, such as reaction of selenium with phenylacetylene or the reaction of selenium dioxide with styrene, gave low yields but more recently elaborated procedures, e.g., gas-phase reaction of cinnamaldehyde with dimethyl diselenide at 630 °C, give 1-benzoselenophene in high yield [131, 132],... 

Whilst early work indicated that for carbon dioxide absorption heat release could not be expected to be significant (2), Van de Vusse had already remarked in 1966 (2) that the absorption of chlorine into a hydrocarbon could produce flames at the interface. Around that time the heat effects accompanying ammonia absorption were estimated to give increases of around 15°C across the mass transfer film (3), and subsequently further treatments quantified temperatures up to U0°C (4,5,6). 

Cupric oxide reacts with CO at temperatures which are substantially higher than those at which manganese dioxide is effective. The use of copper oxide in the combustion of CO in gas analysis is well known. By itself, it is not an effective catalyst for the oxidation of CO at ordinary temperatures. It may, however, greatly increase the activity of other oxides when used in mixtures of the proper proportion. The early work of Hofmann (23) indicated that a previously prepared surface of CuO will oxidize a mixture of CO and air, but that the rate can be increased by a factor of 3 if the copper is moistened with a little alkali. The catalytic activity is further increased if a little iridium is incorporated in the oxide. It was thought that the oxidation of CO depended upon the formation of an unstable copper peroxide of the composition, Cu203 or Cu02, which reacted with CO to form C02 and CuO. The principle was proposed for a gas generator cell of the type O/Cu/alkali/Cu/CO. The reaction was, however, too slow to be of practical importance. 

With an increased interest and awareness of the impact of society and industry on the environment, there has been a significant attempt in recent years to reduce or replace the usage of organic solvents. Much early work in this area concentrated on the application of supercritical and subcritical carbon dioxide, but in recent years superheated (or subcritical/pressurized hot) water (SHW) has become of interest for both chromatography and extraction [43,54], The earliest work was reported by GuUlemin et al. [55], who used the term thermal aqueous liquid chromatography. As well as using SHW for the separation of... 

C = 0) appears to be variable. It comes to 149 kcal, in formaldehyde, 159 kcal in acetaldehyde, and 162 kcal in ketones. The heats of formation are mainly due to early work. (C= 0) in carbon dioxide is a good deal higher, 175 kcal. This is in accord with the fact that the CO distance is less than in carbonyl compounds and has been attributed to resonance 2, xhe interpre cation in terms of resonance has, however, been severely... 

Much of the early work done on the biochemistry of methane formation supported the position that methane is formed almost exclusively by reduction of carbon dioxide. However, it was shown with methanol and a species of Methanosarcina that less than 1% of the methane is derived from carbon dioxide (Schnellen, 1947 Stadtman and Barker, 1949). According to the mechanism proposed by van Neil for catabolism of acetic acid, all of the acid should be... 

Many investigators have attempted to isolate mercury derivatives from aceto-acetie ester, but the results have been so varied that no reliance can be placed on any of the early work on this compound. Kharasch and Staveley, however, have obtained definite results by heating mercury salts of substituted acetic acids in vacuo, e.g, di-method and diethyl aceto-acetic acids when dried and heated in vacuo at 90 C. evolve carbon dioxide, and the mercury becomes bound to the carbon atoms which were formerly attached to the carboxyl groups —... 

S. A. Fuqua, W. G. Duncan, and R. M. Silverstein, Org. Syn., 47,49 (1967) definitive paper F. E. Elerkes and D. J. Burton, J. Org., 32, 1311 (1967). In the early work it was assumed that the reaction of sodium chlorodifluoroacetate in the presence of triphenyl-phosphinc involved formation of difluorocarbene, which then reacts with triphenylphosphine to form difluoromethylenetriphenylphosphorane, (C2H,i.,P—CF,. However, addition of tetra-methylethylene to the reaction in the presence of a ketone failed to yield any cyclopropane derivative. Herkes and Burton (loc. cit.) suggest that a phosphobetaine salt (a) is the intermediate which loses carbon dioxide to form the active reagent (b). 

Most of the early work on the catalytic oxidation of acetylene resulted in the fonnation of complete combustion products. Thus, in the presence of palladianized asbestos at temperatures above 339° C. carbon dioxide and water were formed if sufficient oxygen was present and carbon monoxide and water if the oxygen was not sufficient for the complete combustion. The hydrogen and carbon were oxidized simultaneously.10" When pure acetylene was passed over palladianized copper oxide, however, water began to form at temperatures as low as 225° to 230° C. but no carbon dioxide. Even at temperatures as high as 400° C. carbon was deposited and the amount of water formed was always in excess of the carbon dioxide.101... 

Prochiral carbon radicals have enantiotopic faces reaction with chiral nitroxides can result in two possible diastereomeric products (Scheme 9). Our laboratory has been investigating the ability of chiral nitroxides to differentiate between the two enantiotopic faces of a transient prochiral carbon radical. In many of the examples, the prochiral radical is generated by the lead dioxide oxidation of a secondary benzylic hydrazine. Early work utilized a camphor-derived nitroxide 27, which was coupled to a secondary benzylic prochiral carbon radical with low but reproducible stereoselectivity (Scheme 10) [26]. The stereoselectivity jumped dramatically upon moving to a conformationally rigid nitroxide in the form of the steroid doxyl radical... 

As in the case of <%-amino carboxylic acids, the zwitterions of N- and O-heterocyclic a-carboxylic acids can be decarboxylated thus <%-picolinic, thiazole-2-carboxylic, quinaldic, and chelidonic acid afford, respectively, pyridine, thiazole, quinoline, and 4-pyrone. Furan is best prepared by removal of carbon dioxide from pyromucic acid (2-furoic acid) by heat in early work this was effected by heating the acid in a sealed tube or with soda-lime, but Wilson19 has described a convenient method that involves only simple apparatus and affords the very good yields of 72-78% ... 

The solvent and raw materials were dissolved completely with vigorous stirring before the hydrolysis reaction at a certain temperature. The solution was refluxed for many hours. Generally this temperature is near the boiling point of the solvent. The solvent must be dried before use to prevent partial hydrolysis. Because the alkoxide and salts are extremely moisture and carbon dioxide sensitive [7], they may be handled under an N2 atmosphere. The early work of... 

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