Conversion incomplete

These ideas have been extended by Green, Harbottle, and Maddock (IS) to cases where oxide ions are lost. They supposed that the important reaction of the recoil species at the end of its track was the loss of one or more oxide ions, or conversely, incomplete readdition of oxide ions to the recoil atom. Then each partially-reconstituted species (for example, MnOr, MnOs+, Mn02+ +, etc.) will suffer either hydration (which will reconstitute the parent) or reduction on dissolution in water. The argument runs that the greater the oxidation potential of the parent anion, the sooner will a species be reached (through successive loss of oxide ions) which will inevitably oxidize water on dissolution, and consequently the lower the retention. This rough relationship is indicated by Fig. 1 in... 

Incomplete conversion in the reactor requires a recycle for unreacted feed... 

An alternative method of working up the distillate, which has its advantages when dealing with volatile ketones or when it is suspected that conversion into the ketone is incomplete, is to treat the combined ketones with sodium hydroxide pellets until the mixture is alkaline. Should solids separate, these may be dissolved by the addition of a little water. The ketone is then separated, dried over anhydrous potassium carbonate, and fractionated. 

Synthetic oil is feasible and can be produced from coal or natural gas via synthesis gas (a mixture of carbon monoxide and hydrogen obtained from incomplete combustion of coal or natural gas). However, these are themselves nonrenewable resources. Coal conversion was used in Germany during World War II by hydrogenation or. 

Note 1. If the addition is carried out too slowly and/or the reaction mixture is allowed to stand for too long, part of the allenic anion may be converted into CcC-CHj-SPh, which gives HC C-CH2-SPh upon hydrolysis. If shorter reaction times are applied, the conversion of the CHjCEC-SPh appears to be incomplete. 

Olefin—Paraffin Separation. The catalytic dehydrogenation of / -paraffins offers a route to the commercial production of linear olefins. Because of limitations imposed by equiUbrium and side reactions, conversion is incomplete. Therefore, to obtain a concentrated olefin product, the olefins must be separated from the reactor effluent (81—85), and the unreacted / -paraffins must be recycled to the catalytic reactor for further conversion. 

Recycle and Polymer Collection. Due to the incomplete conversion of monomer to polymer, it is necessary to incorporate a system for the recovery and recycling of the unreacted monomer. Both tubular and autoclave reactors have similar recycle systems (Fig. 1). The high pressure separator partitions most of the polymers from the unreacted monomer. The separator overhead stream, composed of monomer and a trace of low molecular weight polymer, enters a series of coolers and separators where both the reaction heat and waxy polymers are removed. Subsequendy, this stream is combined with fresh as well as recycled monomers from the low pressure separator together they supply feed to the secondary compressor. 

Reagent grade potassium cyanide was purchased from Matheson, Coleman and Bell, and dried at IIB C (0.5 itm) for 24 hr. The checkers found it necessary to use newly purchased potassium cyanide. The use of potassium cyanide which was several years old gave incomplete reaction even at extended reaction times. The large excess of potassium cyanide is used simply to obtain convenient reaction times. For comparison, use of 1.5 equiv of KCN gave 38% conversion under conditions where 3 equiv produced 100% conversion. 

Atoms and free radicals are highly reactive intermediates in the reaction mechanism and therefore play active roles. They are highly reactive because of their incomplete electron shells and are often able to react with stable molecules at ordinary temperatures. They produce new atoms and radicals that result in other reactions. As a consequence of their high reactivity, atoms and free radicals are present in reaction systems only at very low concentrations. They are often involved in reactions known as chain reactions. The reaction mechanisms involving the conversion of reactants to products can be a sequence of elementary steps. The intermediate steps disappear and only stable product molecules remain once these sequences are completed. These types of reactions are refeiTcd to as open sequence reactions because an active center is not reproduced in any other step of the sequence. There are no closed reaction cycles where a product of one elementary reaction is fed back to react with another species. Reversible reactions of the type A -i- B C -i- D are known as open sequence mechanisms. The chain reactions are classified as a closed sequence in which an active center is reproduced so that a cyclic reaction pattern is set up. In chain reaction mechanisms, one of the reaction intermediates is regenerated during one step of the reaction. This is then fed back to an earlier stage to react with other species so that a closed loop or... 

An isolated acetoxyl function would be expected to be converted into the alkoxide of the corresponding steroidal alcohol in the course of a metal-ammonia reduction. Curiously, this conversion is not complete, even in the presence of excess metal. When a completely deacetylated product is desired, the crude reduction product is commonly hydrolyzed with alkali. This incomplete reduction of an acetoxyl function does not appear to interfere with a desired reduction elsewhere in a molecule, but the amount of metal to be consumed by the ester must be known in order to calculate the quantity of reducing agent to be used. In several cases, an isolated acetoxyl group appears to consume approximately 2 g-atoms of lithium, even though a portion of the acetate remains unreduced. Presumably, the unchanged acetate escapes reduction because of precipitation of the steroid from solution or because of conversion of the acetate function to its lithium enolate by lithium amide. 

It should be noted that the data collection and conversion effort is not trivial, it is company and plant-specific and requires substantial effort and coordination between intracompany groups. No statistical treatment can make up for inaccurate or incomplete raw data. The keys to valid, high-quality data are thoroughness and quality of personnel training comprehensive procedures for data collection, reduction, handling and protection (from raw records to final failure rates) and the ability to audit and trace the origins of finished data. Finally, the system must be structured and the data must be coded so that they can be located within a well-designed failure rate taxonomy. When done properly, valuable and uniquely applicable failure rate data and equipment reliability information can be obtained. 

In contrast to carbon monoxide, small hydrocarbon molecules and soot that result from incomplete conversion of the hydrocarbon fuels, nitric oxide and nitrogen dioxide, are noxious emissions that result from the oxidizer—air. However, fuel components that contain nitrogen may also contribute, in a lesser way, to the formation of the oxides of nitrogen. 

Adiabatic Reaction Temperature (T ). The concept of adiabatic or theoretical reaction temperature (T j) plays an important role in the design of chemical reactors, gas furnaces, and other process equipment to handle highly exothermic reactions such as combustion. T is defined as the final temperature attained by the reaction mixture at the completion of a chemical reaction carried out under adiabatic conditions in a closed system at constant pressure. Theoretically, this is the maximum temperature achieved by the products when stoichiometric quantities of reactants are completely converted into products in an adiabatic reactor. In general, T is a function of the initial temperature (T) of the reactants and their relative amounts as well as the presence of any nonreactive (inert) materials. T is also dependent on the extent of completion of the reaction. In actual experiments, it is very unlikely that the theoretical maximum values of T can be realized, but the calculated results do provide an idealized basis for comparison of the thermal effects resulting from exothermic reactions. Lower feed temperatures (T), presence of inerts and excess reactants, and incomplete conversion tend to reduce the value of T. The term theoretical or adiabatic flame temperature (T,, ) is preferred over T in dealing exclusively with the combustion of fuels. 

Other poly(2,5-dialkoxy-1,4-phenylene vinylene)s have been prepared in a similar fashion [34, 35, 40, 41]. Alternatively, a soluble a-halo precursor polymer 17 may be obtained by using less than one equivalent of base (Scheme 1-6). This may then be converted into fully conjugated material 16 by thermal treatment. This halo-precursor route may be preferred if the fully conjugated material has limited solubility or if incomplete conversion is desired. 

In practice, production processes are usually rather more complex. Raw materials are usually impure and thus some pre-purification steps may be required. Obviously impurities in the raw materials will incresae the probability of impurities and byproducts occuring in the output stream from the chemical conversion step. Even using pure raw materials, most chemical conversion are incomplete and often lead to the formation of undesirable byproducts. Furthermore often additional (auxiliary) materials are used (for example catalysts, specific solvents), which have to be separated from the desired product. Thus, in typical production processes a large number of separation steps are required. 

Conversely, at strains above the first damage limit recovery will be incomplete and permanent deformation should be expected and accounted for in the evaluation. This is true not only for plastics in general but also of reinforced plastics. When RPs are stressed... 

These equations suggest that a plot of M vs conversion should be linear. A positive deviation from the line predicted by eq. 16 indicates incomplete usage of transfer agent (T) while a negative deviation indicates that other sources of polymer chains are significant (e.g. the initiator). 

The variation in the second-order rate coefficients with time and with change in initial concentration of mercuric salt can also be explained on the basis of equilibria (213) and (214). At low acidities, conversion of mercuric acetate to acetoxymercury perchlorate is incomplete, and, therefore, decreasing the concentration of the acetate increases the concentration of free perchloric acid which thus increases the conversion of the acetate into the more reactive perchlorate, hence the second-order rate coefficients increase. Decreasing the concentration of mercuric perchlorate will, however, decrease the concentration of free perchloric acid and this effect will be particularly marked since solvation of the perchlorate produces two equivalents of perchloric acid the second-order rate coefficients will, therefore, decrease. In both cases, substitution changes the concentration... 

Many ester-forming reactions reported in the literature cannot be applied to the synthesis of polyesters due to side reactions, incomplete conversions, or non-quantitative yields. Some examples of nonconventional polyester syntheses are listed below. Most of them lead to oligomers rather titan polymers and require expensive reactants or special reaction conditions, which make them of little practical interest. 

According to [4], the optimum conditions of the sulfonation stage are a reactor temperature of 15°C, an S03/I0 ratio of 1.08, and 2.8 vol % S03 in the gas stream. Such mild conditions lead to sulfonation mixtures consisting of 85% P-sultones (1) 10% alkenesulfonic acids (2) 5% y-sultones (3) and less than 5% unreacted olefins. The authors observe that the reaction has been completed to more than 95% at the outlet of the reactor. This means that the incomplete conversions found by earlier authors [15] must have been due to phenomena occurring after the sulfonation. Of equal importance is the observation that the reactivity of 10 toward gaseous S03 seems similar to that of AO. 

---