February, 1943
INDUSTRIAL
AND
ENGINEERING
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Summary and Conclusions The types of wheat best suited for alcohol production are White or Soft Red Winter, Red Winter subclass. Durum and Hard Red Spring wheats are generally not suitable for alcohol production, owing to the lower starch content and resultant low yield of alcohol. Hard Red Winter wheat falls between the above two groups. The location of the White wheat and the limited supply of the Soft Red Winter wheat make it imperative that the Hard Red Winter be used. The starch content of wheat is a reliable index of the anticipated yield of alcohol. Alcohol yields from wheat are generally lower than yields from corn; the difference is about 0.2 proof gallon per bushel. Higher yields of alcohol can be obtained from wheat, either by pressure cooking (batch or continuous processes) or by atmospheric mashing at 155° F. Mixed grain bills comprised of over 50 per cent corn, 35-40 per cent wheat, and the remainder distiller’s barley malt can be successfully handled in a grain distillery and produce yields only slightly lower than those obtained from corn. The most suitable method of processing for any given plant necessarily depends on the existing equipment. The minimum concentration of barley malt required for corn mashing may be reduced by 50 per cent through the
CHEMISTRY
137
utilization of wheat-barley malt mixtures as the conversion agent. This is successful if the mash is allowed to ferment for 72 hours. The dried grain yield is 2-3 pounds per bushel lower when recovering spent wheat grains from high percentage (80-90 per cent) wheat mashes.
This and other problems incidental to the utilization of wheat in alcohol production are discussed. These problems vary with the equipment of each individual plant. Further research must be done to utilize wheat efficiently as a raw material for alcohol production and to minimize the operating problems.
Acknowledgment The authors gratefully acknowledge the technical assistance of the following members of the Research and Development Department: R. S. Mather, G. A. Snyder, J. S. Hudson, and Fuella Shehan.
Literature (1) Gallagher, F. H.,
Cited
Bilford, H. R., Stark, W. H., and Kolachov,
Paul, Ind. Eng. Chem., 34, 1395 (1942). D., Thesis, Case School of Applied Science.
(2) Unger, E.
Presented before the Division of Agricultural and Food Chemistry at the 104th Meeting of the American Chemical Society, Buffalo, N. Y.
Solubility of Melamine in Water R. P. CHAPMAN, P. R. AVERELL, AND R. R. HARRIS Stamford Research Laboratories, American Cyanamid Company, Stamford, Conn.
The solubility of melamine has been determined at several temperatures over the range 20-100° C. starting from unIndependent determinations saturated and supersaturated solutions yielded values which were in satisfactory agreement. The points thus obtained, when plotted on semilogarithmic paper, coincided closely with a straight line
purpose of this paper is to present data on the solubility· of melamine in water over the range 0-100° C. In his review of the chemistry of melamine, McClellan (S) showed that there was a discrepancy between the solubility found by Christmann and Foster (1) in this laboratory and that reported by Lemoult (2) many years earlier. The Christmann and Foster data were the result of a few rough determinations made for immediate practical use in the crystallization of melamine-dicyandiamide mixtures. Present day interest in melamine and its rapidly growing commercial importance, particularly in the field of amino plastics, made it seem desirable to redetermine in an exact way the solubility-temperature relation of the melamine-water system.
THE
Experimental Material. Several pounds of the purest melamine available were recrystallized four times from water, air-dried, and micropulverized. Apparatus. The Walton-Judd apparatus, diagrammed and described in Scott’s book (4) was adopted with a few additions and modifications; Figure 1 shows the modified apparatus. The outer vessel is a 1000-ml. tail-form beaker
representing the Clausius-Clapeyron relationship. The equation of this line is as follows: log (solubility)
=
-1642 X
1/ +
5.101
By means of the equation reasonably reliable extrapolated values can be obtained down to 0° C.
without a spout, the inner sampling vessel an ordinary 25 ml. weighing bottle. The small thistle at the lower end of the filter tube is covered with No. 44 Whatman filter paper, reinforced by a piece of strong, white, soluble-free cotton cloth; the filter paper and cloth are tied tightly over the flange of the thistle with thread. The outer vessel, held in a specially designed clamp, is immersed as deeply as possible in an electrically controlled constant-temperature oil bath maintained within 0.1° C. of the equilibrium temperature. Procedure. Two separate sets of apparatus were used to run simultaneous determinations starting from unsaturation and supersaturation, respectively. Each beaker contained 750 ml. of water and enough melamine to provide a 3-5 gram excess over the necessary amount. Before being placed in position in the bath, one beaker was raised to about 5° C. below the bath temperature, the other 5-10° above the bath temperature, and held there until supersaturated with respect to bath temperature. The two vessels were then lowered into position in the bath and allowed to reach equilibrium. When the time for sampling arrived, the sampling device (previously raised to bath temperature) was inserted, and the necessary amount of sample allowed to siphon into the sample
INDUSTRIAL
138
AND
ENGINEERING
bottle.
A
simple peri-
device and a tubular electric light bulb immersed scope
were remarkably close, thus boxing in the true equilibrium value within a satisfactory range. The values obtained are plotted in the usual manner in Figure 2 and given in the following table:
---Soly., np„
0
0.324 0.321 0.590 0.590 1.040 1.040 1.69 1.69 2.34 2.35 3.15 3.14 4.55 4.58 4.53 5.03 5,07
34.9 49.8 64.1 74.5 83.5
94.8 99.0
rinsed off and
Figure
From supersatn. 0.324 0.326 0.591 0.590 1.048 1.051 1.75 1.69
2.43 2.35 3.17 3.15
Mean 0.324 0.590
1.045
1.70 2.37 3.15
4.63 4.64 4.60
4.59 5.05
The
stopper carrying the thistle was replaced by the ground glass stopper, and the sample weighed. The melamine content of the solution was then determined by suitable means.
Modified Walton-Judd 1. Solubility Apparatus
G. Melamine/100 G. H$0--
