Methanol boiling

Figure 2.35 Effect of agitation in methanol boiling at 1 atm. (From Pramuk and Westwater, 1956. Copyright 1956 by American Institute of Chemical Engineers, New York. Reprinted with permission.)... 

Subsequent evidence proved that Nukiyama was right. At least three types of boiling exist. In Fig. 3, which shows some recent data (W3) for methanol boiling on a horizontal copper tube, the portion of the curve... 

The sound emitted from methanol boiling on a copper tube at 1 atm. has been measured (W2). No forced convection was used. Figure 10 shows how the sound, in total decibels for the frequency range of 25 to 7500 cycles/sec., varies with the temperature difference. Nucleate boiling... 

At the other end of the liquid scale, methanol boils at one temperature (65°C [149°F]) unlike gasoline which boils over a very wide temperature range. This characteristic of methanol, along with its low vapor pressure (32 kPa 38°C... 

A mixture of 312 g. (3 moles) of acetone dimethyl acetal (Note 1), 489 g. (6.6 moles) of butanol, 1.0 1. of benzene, and 0.2 g. of / -toluenesulfonic acid is placed in a 3-1. flask. The flask is connected to a packed fractionating column and the solution distilled until the azeotrope of benzene and methanol, boiling at 58°, is completely removed (Note 2). The contents of the boiler are then cooled below the boiling point and a solution of 0.5 g. of sodium methoxide in 20 ml. of methanol (Note 3) is added all at once with stirring. The flask is replaced for further distillation, and most of the remaining benzene is distilled at atmospheric pressure. The pressure is then reduced, and the remaining benzene and imreacted butanol are removed (Note 4). Finally, the pressure is reduced to 20 mm., the last traces of low-boiling materials are taken to the cold trap, and the product is distilled. After a small fore-run, acetone dibutyl acetal is collected at 88-90°/20 mm. The yield is 421-453 g. (74.6-80.3%), 1.4105, df 0.8315. 

For analytical purposes, e.g., for thin-layer chromatography, the O-silyl groups are most rapidly removed by addition of TBAF (72JA6I90). For preparative workup, the crude reaction mixture is transsilylated by boiling with excess methanol for several hours. These transsilylations are accelerated by continuous removal of the trimethylsilylated methanol (boiling point = 55°C) formed using a distillation column. 

Fig. 6. Effect of surface-active agent on transition boiling. Rohm and Haas Hyamine 1622 (benzyldimethyl 2-[2(p-l,l,3,3-tetramethylbutylphenoxy)ethoxy]-ethyl ammonium chloride mol. wgt. = 466) was added to methanol boiling on a Ji-inch, horizontal steam-heated, copper tube at one atmosphere (LI).

In general, the heat of adsorption increases as the boiling point of the liquid becomes higher, but exceptions are found. Thus, when adsorbed on carbon, methanol (boiling point 64° C) liberates 2400 less calories per mole than does diethyl ether (boiling point 34° C). 

Standard plastic soft drink bottles are made of poly(ethylene terephthalate), or PET. In the industrial-scale synthesis of PET, the usual starting materials are dimethyl terephthalate and ethylene glycol (Eigure 10.1). These compounds react to form bis-(2-hydroxyethyl) terephthalate (BHET) and methanol. The methanol boils off at the reaction temperature (typically around 210°C), leaving fairly pure BHET. Then, the BHET is heated further to around 270°C, where it undergoes a condensation reaction to form PET polymer. Ethylene glycol is a byproduct in this second step and can thus be reused within the plant to produce more BHET. 

With regard to the physics, BHR believe that a large scale adiabatic reactor could be used with high mass transfer and near plug flow. Temperature is around 100°C and the residence time can be seconds to a few minutes. The reactor pressure should be sufficient to suppress methanol boiling at the desired temperature. Challenges are associated with the mixing duty and the fact that operation is currently mainly batch mode. 

Methanol - Boiling Boiling — — — N2 atmosphere, methanol recovery column stoch solutions sent to lab for test... 

Dissolve from 2 to 5 g of the mixture of fatty and resin acids in 10 to 20 ml of dry methanol and add 5 to 10 ml of a solution of 1 part of concentrated sulphuric acid in 4 parts of methanol. Boil the mixture for two minutes under a reflux condenser. To the liquid add 5 to 10 times its volume of 7 to 10 per cent sodium chloride solution and extract the fatty esters and resin acids with ether. Wash the combined extracts with dilute sodium chloride solution, add ethanol and titrate the mixture with 0-5N ethanolic potash. With a mean acid value of 160 taken for the resin acids, and a correction of 1 5 per cent allowed for fatty acids that have escaped esterification, the percentage of resin acids is obtained by the formula... 

Select the answer that explains why methanol boils so much higher than ethane or fluoromethane, even though they all have nearly equal molecular weights. 

Solubility Insoluble in water soluble in N,N-dimethylformamide, dimethyl sulfoxide, methanol Boiling Point (Calcd.) 845.9 65.0 °C, pressure 760Torr... 

Foimaldehyde is readily soluble in the lower alcohols, giving solutions which do not readily give up formaldehyde on heating. Del pine observed that a concentrated solution of formaldehyde gas in methanol boiled at 92°C, 26°C higher than the normal boiling point of the pure solvent. 

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