Propylene glycol commercial synthesis

Moreover, flexible foams are characterized by utilization of special emulsifiers in their synthesis yielding an open-cell architecture, whereas for rigid foams emulsifiers are chosen that create more closed-cell structures. As diisocyanate for both types, the commercially available mixture of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate is especially suitable. If foam formation is to take place at room temperature, and especially when hydroxy compounds with secondary hydroxy groups are used [poly(propylene glycol)s], the presence of a catalyst is generally required (see Sect. 4.2.1). 

Prior to this time, other ventures had already been operating to produce commercial quantities of aliphatic chemicals from petroleum sources. Truly commercial production of ethylene glycol had been achieved by 1925 (10) using natural gas fractions as a starting material, and even earlier (about 1920) there had been the manufacture of isopropyl alcohol from cracking plant propylene (20), which may be termed the pioneer operation on a successful, continuing basis in the sphere of aliphatic synthesis from petroleum. 

The transformation of raw materials into products of greater value by means of chemical reaction is a major industry, and avast array of commercial products is obtained by chemical synthesis. Sulfuric acid, ammonia, ethylene, propylene, phosphoric acid, chlorine, nitric acid, urea, benzene, methanol, ethanol, and ethylene glycol are examples of chemicals produced in the United States in billions of kilograms each year. These in him are used in the large-scale manufacture of fibers, paints, detergents, plastics, rabber, paper, fertilizers, insecticides, etc. Clearly, the chemical engineer must be familiar with chemical-reactor design and operation. 

Similar to all commercial plastics, the traditional and more commonly used thermosetting resins are considered as petrochemicals, having been manufactured from petroleum. Some of the primary distillation products of crude oil, which can be classified either as olefins or aromatics, serve as precursors for the synthesis of thermosets. For example, epoxy resins are manufactured by the reaction of epichlorohydrin, a chloro-oxirane, and a derivative of propylene, with bisphenol A, which is a derivative of cumene. Another example would be the unsaturated polyesters (UPs), which are derivatives ultimately originating from ethylene (ethylene glycol) and benzene (maleic acid) [6]. Epoxies and polyesters constitute more than 95% of the thermoset composite market of the two, polyester-based systems predominate in volume by about 10-fold [6, 7]. Other thermoset resins used in reinforced form are phenolics, vinyl esters, and polyimides. Details of the properties and applications of these thermoset systems will be further discussed in the following section. 

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