September, 1943
INDUSTRIAL AND ENGINEERING CHEMISTRY
b A U T ~ ~ L Afor ~ Ecarrying S out reactions under controlled pressure and temperature are practically universal tools in chemical industry. That lends special interest and importance to an exhaustive discussion of the many factors involved in their design and use provided by Gooch (page 927). Characteristics of the vessel itself, heating methods, agitation, drives, instrumentation, and safety precautions are all treated in some detail. b SYNTHETIC ELASTOMERS continue as high priority problems as the huge program for their production approaches completion. Nine papers in this issue present as many aspects of this general subject and provide new data of great value.
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b SWELLING EFFECT of gasolines on neoprene vulcanizates has been found by Fraser (page 947) t o be indicated by the aniline point or the Diesel index of the fuel. Tests have been made with a variety of motor fuels and blends. b MOLECULAR WEIGHTSOF POLYMERS of large molecular size
are difficult t o determine accurately, yet this value is often irnportant in gaging their properties. Huggins (page 980) critically examines methods used for this purpose and makes specific recommendations for improvement applicable t o both resins and synthetic elastomers.
thetics is a vital factor in designing tires. Gehman, Jones, and Woodford (page 964) describe a simple, convenient flexometer for measuring this value and give comparable results obtained with it for rubber and GR-S. Effects of several important variables are shown.
b MATURINGOF WHISKYhas been studied by Liebmann and Rosenblatt (page 994) using a large sampling (108 barrels) and analyzing each barrel annually over a period of five years. Thc large number of analyses provides a basis for statistical study of the changes occurring during aging. Both Bourbon and rye whiskies were included in the sample. The data presented are suggested as a basis for whisky specifications.
b BLENDSof the several available synthetic elastomers possess important characteristics which indicate their widening use. Martin and Laurence (page 986) have made blends of Thiokol FA with synthetics of three other types and report the properties of the blends in some detail. They find variations from the expected linear relation with composition.
b COPPERAS can be crystallized from spent pickle liquor, and the acid content of the liquor recovered for re-use, by the addition of large volumes of acetone, according to Gehm (page 1003). Acetone, he found, is superior to methanol for this purpose. Application of the method depends upon the efficiency of recovering acetone.
b HEATRESISTANCE of neoprene vulcanizates is improved by a high state of cure, according to Forman (page 952). Data on Neoprene GN are given and principles applicable to heat resistance of all types of neoprene are developed.
b CYCLOPENTANE has been isolated by Tooke (page 992) from the pentane-hexane fraction of natural gasoline from the Burbank field. His results indicate the presence of 2.4 per cent cyclopentane in the original natural gasoline.
b BUNAS VULCANIZATES with sulfur in varying percentages have been prepared by Cheyney and Robinson (page 976), and their chemical and physical properties determined. The rmge covered extends from soft rubbers to compounds resembling ebonites. Compositions of intermediate sulfur content, unlike rubber, possess intermediate properties.
b COMMERCIAL SOAPSowe their properties to the proportions in which three separate crystalline phases of sodium soap are present in the product, according to Ferguson, Rosevear, and Stillman (page 1005). These phases, together with a fourth of less importance in commercial products, are identified by their x-ray patterns, and their properties are described. The balance between them is determined by the conditions of soap boiling and establishes the characteristics of the product.
b HEAT GENERATED during flexing of both rubber and syn-
b CARBON REINFORCEMENT, vital in the use of rubber, is also important in compounding synthetics. Turner and his coworkers (page 958) have determined the effects of different types of carbon on Butyl rubber and find important differences between its behavior and that of rubber.
STRUCTURE OF CARBONS of several types has been investigated by Rossman and Smith (page 972) in an effort to relate this property t o reinforcing effect in rubber. Density determined by helium displacement is compared with x-ray data. b
b COLD’SEFFECT on the rubberlike properties of synthetic elas-
tomers is noted by King (page 949) t o be determined by bendbrittle and shatter points. These two points are measured for a variety of synthetics in a number of different compositions.
b HIGHLYPURIFIEDLIQUIDShave been found by Foulk and Barkley (page 1013) not to form films as do those containing minute amounts of impurities. Experimental results with seven t,ypical liquids reprrsenting as many classes are presented.
