Time-temperature conversion

Z 2. =L ft P lys 3 1 r ft -s 0 i l RUN NO. Monarch (Lower Bench, 74-53) Effect of Reaction Time on Conversion and Oil Yield with CONTACT TIME, TEMPERATURE, CONVERSION, MINUTES °C PRESSURE, osle PERCENT Synthesis Gas OIL YIELD, PERCENT VISCOSITY AT 60°C CD... 

This provides time-temperature-conversion-viscoslty correlations which can be directly utilized in computer studies designed to minimize actual molding times while avoiding a damaging exotherm during cure. The particular system studied is a low viscosity liquid epoxy cured with aminoethylpiperazine and was found to be moldable over specific temperature ranges. 

A numerical analysis of cavity filling was developed to evaluate and optimize the use of reactive fluids in RIM. This method, which has been previously described in detail O), employs the marker and cell method for treating transient fluid flows in conjunction with finite difference solutions of the conversion and temperature fields in the pre-polymer and the mold wall. The time-temperature-conversion-vlscoslty correlations shown earlier for epoxy + AEP were then used in the mold filling simulation. 

Conversion at Equilibrium. The maximum urea conversion at equilibrium attainable at 185°C is ca 53% at infinite heating time. The conversion at equiUbtium can be increased either by raising the reactor temperature or by dehydrating ammonium carbamate in the presence of excess ammonia. Excess ammonia shifts the reaction to the right side of the overall equation ... 

Oxidation of cumene to cumene hydroperoxide is usually achieved in three to four oxidizers in series, where the fractional conversion is about the same for each reactor. Fresh cumene and recycled cumene are fed to the first reactor. Air is bubbled in at the bottom of the reactor and leaves at the top of each reactor. The oxidizers are operated at low to moderate pressure. Due to the exothermic nature of the oxidation reaction, heat is generated and must be removed by external cooling. A portion of cumene reacts to form dimethylbenzyl alcohol and acetophenone. Methanol is formed in the acetophenone reaction and is further oxidized to formaldehyde and formic acid. A small amount of water is also formed by the various reactions. The selectivity of the oxidation reaction is a function of oxidation conditions temperature, conversion level, residence time, and oxygen partial pressure. Typical commercial yield of cumene hydroperoxide is about 95 mol % in the oxidizers. The reaction effluent is stripped off unreacted cumene which is then recycled as feedstock. Spent air from the oxidizers is treated to recover 99.99% of the cumene and other volatile organic compounds. 

Conditions for hydrolysis (82) of the intermediate sultone mixture also help modify the ratio of alkenesulfonate to -hydroxyalkanesulfonate, distribution of alkenesulfonate positional isomers, and completeness of conversion. Caustic hydrolysis using a slight stoichiometric excess of base is employed to ensure alkaline conditions throughout the hydrolysis phase of AOS production. The rate of hydrolysis depends a great deal on temperature. The 5-sultone requires the most time for conversion to 4-hydroxyalkanesulfonate. P-Sultones and y-sultones hydrolyze so rapidly to 2-hydroxyalkanesulfonate and 3-hydroxyalkanesulfonate that temperatures below 100°C can be used. 5-Sultone completely hydrolyzes between 120 and 175°C in 1—30 minutes. The quaUty of the final product mixture is ultimately determined by the choice of conditions. 

Catalyst system Molar ratio of the components Reactant Alkene catalyst mol/mol Temperature (K) Reaction time Solvent Conversion (%) Reference... 

Me-ester sulfonation has to be carried out at relatively high temperatures as the initial reactions and the decomposition of intermediate products is relatively slow compared with sulfonation reaction rates for alkylbenzenes, primary alcohols, ethoxylated alcohols, and a-olefins. The required aging time for conversion of the intermediates to FAME sulfonation acid is long (about 45 min at 85°C). It is not possible to sulfonate Me-esters without an excess of S03. 

Conversion of units from one system to another is simply carried out if the quantities are expressed in terms of the fundamental units of mass, length, time, temperature. Typical conversion factors for the British and metric systems are ... 

Temperature ( C) Residence time (min) Conversion (%) Seledivity (%) Yield (%)... 

Table V. Conversion of Utah Resinite Concentrate Temperature (°C) Time (min) Conversion (% daf ...

Andrianov et al. (52) studied the rate of disappearance of Si—H as a function of time, temperature, and concentration of chloroplatinic acid in an equimolar solution of isoprene and dodecamethylhexasiloxane, H(Me2SiO)5SiMe2H. With a constant concentration of catalyst a plot of % conversion of SiH up to at least 60% vs. time at 20°, 50°, 70° and 110°C gave a family of straight lines. The slopes of the lines increased by a factor of 2.5-3 between 50° and 110°C. 

For an isothermal spherical particle (at the surrounding bulk-gas temperature) of species B reacting with gaseous species A as in Example 9-1, derive the time (f)-conversion (/B) relation from the SCM for each of the following three cases individually, and show that additivity of the three results for t agrees with the overall result reached in Example 9- 1 ... 

Substrate Temperature rq Time [h] Conversion [%] Yield of y-butyro-lactone [%]b)... 

The temperature and the rate of heat input Q are tabulated as functions of the residence time for conversions of 90 and 95%... 

Kinetic simulation methods are used as advisory controls in potentially thermally hazardous batch amination reactions of nitroaromatic compounds. Time-temperature process data are fed as input to a kinetic simulation computer program which calculates conversions, heat release and pressure profiles. Results... 

Fig. 8. Effect of reduction time on conversion and hydrogenolytic behaviors. Catalyst, 10 wt % M0O3/AI2O3 calcined at 650°C for 3 hr and reduced at 450°C reaction temperature, 350°C WjF, 7.9 g catal hr/mole total pressure, 1 atm, H2/(2,5,3 -TrMeDPM + benzene) molar ratio, 2.0. [Data from Massoth (5S).]...

Conditions a-pinene 15.9 mL (100 mmol) reaction temperature 60°C oxidant air (15 mL/mrn) reaction time = 24h. Conversion and product composition were determined by GC Turnover number (TON), mole of a-pinene converted per mole of cobalt. "Rearranged products of a-pinene oxide were the main products. 

The importance of time, temperature and acid concentration in the hydrolysis of cellulose with dilute acid was recognized by early investigators and applied in the investigations of Simonsen in 1898. Further study was made by Kressman and reported in U. S. Department of Agriculture Bulletin No. 983. Reviews of the quantitative aspects have been made by Doree. Liiers pointed out that the conversion of cellulose dextrin to D-glucose by dilute sulfuric acid was a monomolecular reaction. The constants of the hydrolysis of wood cellulose have been determined by Saeman. The reaction rate (A ) was found to be expressed by the following equation ... 

The complete analytical system is under the control of a Motorola 6802 microprocessor. All switching of gas flows, timing, temperature control, error detection, analog to digital conversion, FID current measurement, signal Integration and manipulation, and data storage and transfer are controlled by this system. 

Run nr. Catalyst mass Temperature Residence time Initial conversion Selectivity (mol%) ... 

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