Temperature control during

In practice, such a fractionation experiment could be carried out by either lowering the temperature or adding a poor solvent. In either case good temperature control during the experiment is important. Note that the addition of a poor solvent converts the system to one containing three components, so it is apparent that the two-component Flory-Huggins model is at best only qualitatively descriptive of the situation. A more accurate description would require a... 

The average value of the rephcates is reported along with the standard deviation, which reflects the variabihty in the measurement. Large standard deviations relative to the average measurement indicate the need for an action plan to improve measurement precision. This can be accomphshed through more rephcate measurements or the elimination of the source of variation, such as the imprecision of an instmment or poor temperature control during the measurement. 

The purity of the product was determined by the checkers by GLC analysis using the following column and conditions 3-nm by 1.8-m column, 5% free fatty acid phase (FFAP) on acid-washed chromosorb W (60-80 mesh) treated with dimethyldichlorosilane, 90 C (1 min) then 90 to 200 C (15°C per rain). The chromatogram showed a major peak for methyl 2-methyl-l-cyclohexene-l-carboxylate preceded by two minor peaks for methyl 1-cyclohexene-l-carboxylate and l-acetyl-2-methylcyclohexene. The areas of the two impurity peaks were 5-6% and 0.5-2% that of the major peak. The purity of the product seems to depend upon careful temperature control during the reaction. The total amount of the two impurities was 14-21% in runs conducted at about -15 to -20°C or at temperatures below -23°C. 

As with the 1,2,4-triazines,83 temperature control during these cycloadditions is important, since additions at 0-25 C result in the formation of 2 1 cyclopropene-azepine cycloaddition products.113... 

Temperature control during pressure hydrogenation of cis- or tram-isomers is essential, since at 155°C violent decomposition to carbon, hydrogen and carbon monoxide with development of over 1 kbar pressure will occur. The material should not be heated above 100°C, particularly if acid or base is present, to avoid exothermic polymerisation [1], The m-isomer is readily cyclised to 2,3-dimethylfuran, which promotes lire and explosion hazards. These were measured for the cis- and tram-isomers, and for fram-3-methyl-l-penten-4-yn-3-ol [2],... 

It has been reported1 that, during the preparation of f-butyl hypochlorite according to the directions published in this series,2 an explosion occurred and caused moderate physical damage and minor injury to the operator. The cause of the accident has been attributed to lack of proper temperature control during addition of chlorine. It is strongly recommended that the reaction vessel be fitted with a thermometer that dips into the reaction mixture and that the rate of flow of chlorine be regulated so that the temperature of the reaction mixture never exceeds 20°. 

The catalyst life would probably be longer, because of better temperature control during regeneration. 

Proper, timely addition of SO 2 Temperature control during fermentation Pure yeast cultures... 

As was mentioned above, every efficient application of microwave energy to perform chemical syntheses requires reliable temperature measurement as well as continuous power feedback control, which enable heating of reaction mixtures to a desired temperature without thermal runaways. Moreover, power feedback control systems that are operated in the most microwave reactors enable a synthesis to be carried out without knowing the dielectric properties or/and conductive properties of all the components of the reaction mixture in detail. On the other hand, temperature control during microwave irradiation is a major problem that one faces during microwave-assisted chemical reactions. In general, temperature in microwave field can be measured by means of ... 

In the extensive review of diazotisation, frequent reference is made to the need for close temperature control during processing operations, and to the explosive nature of isolated diazonium salts [1]. Inclusion of methanol in the reaction mixture used to diazotise 2-toluidine, and use of sulfuric acid rather than acetic acid in the ensuing... 

Fermentation generates heat, and red wines must have some type of temperature control during their fermentation. They must not be allowed to get too hot or to become too cold. Ough and Amerine (18) recommended temperatures of 18°-29° C and found that cap temperatures can exceed liquid temperatures by over 6° C. In large stainless steel fermentors, the author has noted cap-liquid temperature differences of 11°. 

Temperature control during irradiation was effected by placing the tubes in holes in a thermostatted aluminum block. 

Temperature control during the sodium nitrite addition is essential to the success of the preparation. The temperature can go as low as -15°C but must not exceed — 5°C. The addition takes ca. 1 hr. At temperatures greater than -5°C, dark red by-products form which lower the yield. 

The major issues to be solved for nickel-metal hydride batteries are the temperature control during charge (damage occurs if the cell operates at T > 65°C), the high self-discharge (15 % in two days at 38 °C), and cell cost. Nevertheless, efforts to develop nickel-metal hydride batteries for use in electric vehicles have even led several automotive companies to offer models powered by this type of battery [14]. 

The worker unit is normally mounted with a heating jacket for tempered water on the cylinder and often also equipped with its own built-in water heater and circulation pump for the tempered water. This is advantageous in preventing product buildup on the cylinder wall and allows better product temperature control during the passage through the worker unit. Product temperature increases of 2°C or more due to release of latent heat of crystallization and mechanical work can be observed in the worker imit (3). 

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