Yield increase

Calcium hydride has also been used as the base[2,3]. A comparison of the effect of metal cations indicated that yields increase in the order < Na < Li and a procedure in which -BuLi serves as the base has been developed [4]. 

To determine the feasibiUty of, or need for, fertilization requires knowing (/) which of the required elements, if any, are deficient in the soil (2) what chemical forms of the deficient elements are assimilable by the plants and thus suitable as fertilizers (5) what quantity of fertilizer material is required to meet the needs of the crop and (4) whether the crop yield increase resulting from fertilizer appHcation would warrant the cost of the fertilizer production and appHcation. 

In general terms, as the molecular weight of the feedstock is increased, similar operating conditions of hydrogasification lead to decreasing hydrocarbon gas yields, increasing yields of aromatic Hquids, with carbon also appearing as a product. 

Properties. Results for the operation using subbituminous coal from the Wyodad mine near Gillette, Wyoming, are shown in Table 13. Char yields decreased with increasing temperature, and oil yields increased. The Fischer assay laboratory method closely approximated the yields and product assays that were obtained with the TOSCOAL process. 

This confinement yields a higher carrier density of elections and holes in the active layer and fast ladiative lecombination. Thus LEDs used in switching apphcations tend to possess thin DH active layers. The increased carrier density also may result in more efficient recombination because many nonradiative processes tend to saturate. The increased carrier confinement and injection efficiency faciUtated by heterojunctions yields increasing internal quantum efficiencies for SH and DH active layers. Similar to a SH, the DH also faciUtates the employment of a window layer to minimise absorption. In a stmcture grown on an absorbing substrate, the lower transparent window layer may be made thick (>100 /tm), and the absorbing substrate subsequendy removed to yield a transparent substrate device. 

The production of elfamycins is described in the references cited in Table 1. Fermentation yield improvements with aurodox (1, R = CH ) proved difficult because of feedback inhibition (48). Aurodox-resistant strains (49), however, responded positively to conventional mutagenic methods leading to yield increases from 0.4 to 2.5 g/L (50). Scale-up of efrotomycin (7, R = CH ) fermentations were found to be particularly sensitive to small changes in sterilization conditions of the oil-containing medium used (51). 

By-products include propylene dibromide, bis-(bromopropyl) ether, propylene glycol, and propionic acid. Bromide losses are to the brominated organics and bromate formation. Current efficiency is a function of ceU design and losses to bromate. Energy consumption decreases with an increase in electrolyte concentration and a decrease in current density. Space—time yield increases with current density. See Table 5 for performance data (see... 

Plant and Animal Nutrient. Copper is one of seven micronutrients that has been identified as essential to the proper growth of plants (87). Cereal crops are by far the most affected by copper deficiency (see Wheat and other cereal grains). Greenhouse studies have shown yield increases from 38% to over 500% for wheat, barley, and oats (88) using copper supplementation. A tenfold increase in the yield of oats was reported in France (89). Symptoms of copper deficiency vary depending on species, but often it is accompanied by withering or chlorosis in the leaves that is not ammenable to iron supplementation. In high concentrations, particularly in low pH sods, copper can be toxic to plants. 

Some investigators have proposed, mostly on the basis of mathematical modeling, to optimize the design of scrubbers to obtain a given efficiency with a minimum power consumption (e.g., Goel and Hollands, op. cit.). In fact, no optimum in performance appears to exist apart from some avoidable regions of unfavorable operation, increased contacting power yields increased efficiency. 

When larger runs are made the yields increase thus 2000 cc. of ethyl acetate and 200 g. of sodium give 515-568 g. of ethyl acetoacetate. From a run of this size it is possible to recover about 700 cc. of ethyl acetate. Approximately a proportionate recovery is obtained in smaller runs. 

While high defect generation rates in the shock can qualitatively be applied to explain the approximately sevenfold yield increase in copper to 210 MPa following loading to a 10 GPa shock [13], significant shock har-... 

As severity is increased, C5+ gasoline yields decrease, with a corresponding increase in C, to C4 products. Hydrogen yields increase with severity until the level at which no further aromatics are produced as severity is increased even further, hydrogen yields then decrease. 

Hydrogenation of 19-hydroxy-3a- and 3j5-substituted-A -steroids over platinum or rhodium yields increased amounts of 5j9-products as compared to the corresponding 19-desoxy series (hydroxyl group effect). In contrast, the A -19-carboxaldehyde (27) gives only the 5a-product when hydrogenated over either palladium or platinum. ... 

The most satisfactory method of dehydrating 12a-alcohols appears to be through the sulfonate esters Engel and coworkers have shown (ref. 236 and ref. cited therein) that treatment of such sulfonates with alumina gives A -compounds. The reaction appears to be subject to steric acceleration in that bulky IToc-substituents and cw-fused A-rings aid elimination, and that yields increase with increasing size of the sulfonate employed. 

The lrialkyl(trifluorovmyl)slannanes were used in the Pd(0)-catalyzed coupling reaction of aryl halides [77] (equation 12). The product yield increased with the solvent type in the order hexamethylphosphorus triamide (HMPT) DMF > dimethyl sulfoxide (DMSO) > tetrahydrofuran (THF) > CgHg > C2H4CI2. 

Dehydrochlorination of bis(tnfluoromethylthio)acetyl chloride with calcium oxide gives bis(trifluoromethylthio)ketene [5] (equation 6) Elimination of hydrogen chloride or hydrogen bromide by means of tetrabutylammonium or potassium fluoride from vinylic chlorides or bromides leads to acetylenes or allenes [6 (equation 7) Addition of dicyclohexyl-18-crown-6 ether raises the yields of potassium fluoride-promoted elimination of hydrogen bromide from (Z)-P-bromo-p-ni-trostyrene in acetonitrile from 0 to 53-71 % In dimethyl formamide, yields increase from 28-35% to 58-68%... 

HF, CH3CN. In certain sensitive substrates it may be advisable to run this reaction in a polypropylene vessel, as was the case in Schreiber s synthesis of FK-506, where the yield increased from 35% to 73% after switching from the standard glass vessel. This is presumably because of the products formed when HF reacts with glass. 

The addition followed a radical chain mechanism initiated by photoinitiated electron transfer from the tertiary amine to the excited aromatic ketone and occurred with complete facial selectivity on the furanone ring (99TL3169). The yields increased and best results were obtained with sensitizers (4-methoxyacetophenone,... 

When methylene chloride was used as a solvent, it was found that 28 are obtained in minor amounts, while the dominating product is the -coordinated chloro-carbyne species [(> -Tp )Mo(CO)2(=CCl)], whose yield increases abruptly with substitution in the pyrazol-l-yl fragments (3-methyl-, 3,4,5-trimethyl-, and 3,5-dimethyl-4-chloro derivatives) [90AX(C)59,95JCS(D) 1709]. The tungsten analog can be prepared similarly. The chlorocarbyne molybdenum complex follows also from the reaction of the parent anion with triphenylsulfonium cation but conducted in dichloromethane. The bromo- and iodocarbyne derivatives are made similarly. 

A more detailed study of the reaction with malonitrile revealed that the yields are dependent of the molar ratio malonitrile/quinazoline. The yield increases from 29 (ratio 1.0) to 81% (ratio 2.0), suggesting that the mechanism of the ring transformation involves the contribution of 2 mol of malonitrile. Reaction of quinazoline 3-oxide with the above-mentioned active methylene compounds gives about the same results, although the yields are poor (Scheme 12) (73CPB1943, 75CPB746). 

The relative ratios of the ethanolamines produced depend principally on the ethylene oxide/ammonia ratio. A low EO/NH3 ratio increases monoethanolamine yield. Increasing this ratio increases the yield of di-and triethanolamines. Table 7-1 shows the weight ratios of ethanolamines as a function of the mole ratios of the reactants. ... 

A small amount of nickel in the FCC feed has a significant influence on the unit operation. In a clean gas oil operation, the hydrogen yield is about 40 standard cubic feet (scf) per barrel of feed (0.07 wi /r ). This is a manageable rate that most units can handle. If the nickel level increases to 1.5 ppm, the hydrogen yield increases up to 100 scf per barrel (0.17 wt%). Note that in a 50,000 barrel/day unit, this corresponds to a mere 16 pounds per day of nickel. Unless the catalyst addition rate is increased or the nickel in the feed is passivated (see Chapter 3), the feed rate or conversion may need to be reduced. The wet gas will become lean and may limit the pumping capacity of the wet gas compressor. 

Thermal reactions are a function of time and temperature yields are proportional to (time) (exp " ). Figure 9-1 shows the typical elfects of vapor residence time and temperature on dilute phase cracking. For example, at 5 seconds residence time, the dry-gas yield increases 8% when the reactor temperature increases from 960°F to 9S0 "F. increasing the residence time to 10 seconds increases the dry gas yield another 8%. 

If the fusion temperature is about 300°, the yield of platinum oxide is very low, at higher temperatures the yield increases, and at temperatures of 450° and higher it is practically quantitative. With a proper fusion a slightly lower yield than quantitative is generally not due to non-precipitation of the platinum but to loss by spattering and to deposition of a small amount on the casserole. 

Hydrogen bromide is eliminated from 10,11-dibromo-l 0,1 l-dihydrodibenz[7>,/]oxepin with potassium tert-butoxide at room temperature to give 10-bromodibenz[i,/]oxepin (17a).160161 When the elimination reaction was performed in boiling toy-butanol the yield increased from 58 to 92%.261 Dehydrohalogenation of 10-chloro-2,3-dimethoxy-10,ll-dihydrodi-benz[/),/]oxepin afforded 2,3-dimethoxydibenz[6,/]oxepin (17b) in 52% yield.162... 

Reaction of the secondary silylnitronate 4 with acetaldehyde, catalyzed by anhydrous tetra-butylammonium fluoride, furnished only 20% of the desired product 5 as a 56 44 (R, S )j (R, R ) mixture. With tetrabutylammonium fluoride trihydrate as base the yield increased to 89% while the diastereoselectivity remained low16. 

Results of these orienting experiments compiled in Table 3 in regard to the effect of temperature, medium polarity, initiator concentration, monomer concentration, and coinitiator concentration are similar to those reported by others36"39 for cationic polymerization of a-methylstyrene. For example, decreasing temperature, the molecular weight increases and increasing medium polarity, the yield increases. 

As discussed in Section 10.3, the system consisting of a diazonium ion and cuprous ions can be used for hydroxy-de-diazoniation at room temperature in the presence of large concentrations of hydrated cupric ions (Cohen et al., 1977 see Schemes 10-7 to 10-9). With (Z)-stilbene-2-diazonium tetrafluoroborate under these conditions, however, the major product of ring closure of the initially formed radical was phenanthrene (64%). When the cupric nitrate was supplemented by silver nitrate the yield increased to 86% phenanthrene. Apparently, the radical undergoes such rapid ring closure that no electron transfer to the cupric ion takes place. 

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