Factors affecting yields

J. W. Hall, F.A. De Thomas. Near-infrared spectroscopic analysis of bovine milk for fat, protein and lactose. In Proceedings of Cheese Yield Factors Affecting its Control, IDF Seminar, Cork, Ireland - April 1993, International Dairy Federation Publishing, Bruxelles, Belgium. 1993, p. 222-229. 

Carbon is alkylated ia the form of enolates or as carbanions. The enolates are ambident ia activity and can react at an oxygen or a carbon. For example, refluxing equimolar amounts of dimethyl sulfate and ethyl acetoacetate with potassium carbonate gives a 36% yield of the 0-methylation product, ie, ethyl 3-methoxy-2-butenoate, and 30% of the C-methylation product, ie, ethyl 2-methyl-3-oxobutanoate (26). Generally, only one alkyl group of the sulfate reacts with beta-diketones, beta-ketoesters, or malonates (27). Factors affecting the 0 C alkylation ratio have been extensively studied (28). Reaction ia the presence of soHd Al O results mosdy ia C-alkylation of ethyl acetoacetate (29). 

This chapter discusses the factors affecting yields and qualities of FCC product streams. The section on FCC economics describes several options that can be used to maximize FCC performance and the refinery s profit margin. 

The factors affecting the preparation of the cyclic chlorophosphazenes from phosphorus pentachloride and ammonium chloride continue to receive attention. For example, the yields and reaction times for the preparation of the series, (NPCla) ( — 3—7), varied with the fineness of the ammonium chloride, the nature and volume of the solvent, and added catalysts such as phosphoryl chloride. A procedure, giving due consideration to these factors, was described for the preparation of N3P3CI6 in good yield (88% of cyclic products) and in a relatively short time (2J h). The cyclic chlorophosphazenes can be obtained in even shorter times ca. 10 min) by addition of four moles of pyridine to remove the hydrogen chloride formed ... 

Hardiman R.T., Jacoby B., Banin A. Factors affecting the distribution of cadmium, copper and lead and their effect upon yield and zinc content in bush beans (Phaseolus vulgaris L.). Plant Soil 1984a 81 17-27. 

Several factors affect the overall economics of PHA production. These include PHA productivity, PHA content, yield of PHA on carbon source, carbon substrate cost, and recovery method employed. Figure 1 shows the production costs of P(3HB) by various P(3HB) contents and P(3HB) productivities [29]. The effect of P(3HB) productivity on the production cost is only related to the cost of the fermentation equipment [18]. However, the P(3HB) content has multiple effects on the volume of the fermentation equipment and the recovery process [17,18]. The increase of P(3HB) yield on carbon source and the use of less expensive carbon substrates reduce the cost of carbon substrate [17, 29]. Development of an efficient recovery method, which will be different for each bacterium employed, is also important to overall economics of PHA production. When the actual fermentation processes employing many different re-... 

The development of microwave heterogeneous catalysis is, however, impeded because most synthetic chemists are not well acquainted with factors affecting both heterogeneous catalysis and microwaves. Although attempts have been made to accelerate reaction rate or to improve yield and selectivity, they have been based on the rule let s try microwaves and see what happens . 

Factors Affecting Extraction Yield in SC-CO2 Extraction Sample Preparation... 

To achieve highly sensitive detection, optimization of various factors affecting the CL reaction is required. Reaction temperature, pH, solvent, nature of CL compounds, and coexisting compounds such as a catalyst and an enhancer affect the CL reaction yield. 

Product distributions obtained on esterification of nucleosides and nucleotides under basic conditions throw further light on factors affecting selective reactivity. p-Toluenesulfonylation of adenosine 5 -monophosphate in aqueous alkali yielded exclusively (in 54-61% yield) the 2 -p-toluenesulfonate.107 Lack of reaction at HO-3 was attributed either to formation of a phosphoric p-toluenesulfonic anhydride, which sterically protected this hydroxyl group, or to the higher acidity of HO-2. It has been shown that the acidic site (with pKa 12.5) in adenosine is associated with the presence of both HO-2 and HO-3, as replacement of either of these by hydrogen, or of HO-2 by methoxyl, results in loss of this acidity.108 Inductive effects, or the sta-... 

In one experiment the checkers used 3-butyn-l-ol available from Aldrich Chemical Company, Inc., and found that it was of satisfactory purity. In other experiments, both the submitters and the checkers prepared the hydroxy compound from sodium acetylide and ethylene oxide in liquid ammonia according to the procedure described by Schulte and Reiss3 and further attempted to maximize the yield by varying the ratio of sodium ethylene oxide liquid ammonia used ip the reaction. Unfortunately, the checkers failed to obtain consistent results in repeated experiments and consequently could not define the optimum conditions for the reaction. Thus, the yield of 3-butyn-l-ol varied from 15 to 45% and 15 to 31% on the basis of sodium and ethylene oxide, respectively. Unknown and apparently subtle experimental factors affect the yield significantly. 

CO adsorption, 28 8 metal-alkene surfaces, 29 85-86 metal oxide surfaces, 29 55-92 oxide surface, 28 26 solid surfaces, 29 55-92 surface chemistry, 29 55-92 yield, chemisorbed layer, 29 59-62 factors affecting yield, 29 61 Photoemission... 

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