Industrial applications alcohol dehydration

Membranes becoming more widely available for aqueous—organic separations some successful industrial applications reported for dehydrations and removal of alcohols (ethanol and above) from water. 

R. L. Banks takes up the subject of olefin metathesis previously discussed by J. J. Rooney and A. Stewart in Volume 1 and gives an authorative review of the very substantial literature which has appeared in the last four years. Naturally his account covers both heterogeneous and homogeneous catalysis and he summarizes as well the industrial applications which have been made to date of metathesis reactions. S. Malinowski and J. Kijeriski review the specialist field of very highly basic catalysts largely developed by the work of the Polish school. In their chapter they discuss the evidence for the nature of catalysts such as alkali-treated magnesium and other oxides and the kind of reactions that take place thereon. J. M. Winterbottom in a chapter with emphasis on the literature since 1973 concentrates mainly on the dehydration of alcohols as the fundamental studies on dehydration far exceed those on hydration, which features mainly in the patent literature. His chapter dis-... 

Ion-exchange resins can also be used for dehydration [8]. The superacidic Na-fion-H catalyzes selective alkene formation from 1-propanol, 2-propanol, and tert-butyl alcohol at 433 K [45]. Ion-exchange resins have found industrial application in the production of isobutylene from ieri-butyl alcohol [46]. 

Specific modification of hydrophilic membranes can be used to remove the light alcohols methanol and ethanol from their mixtures with other organics. The selectivity of these membranes is not as high as in dehydration processes, but sufficient for effective and economical large-scale industrial applications. One such plant for the removal of methanol from an organic azeotrope has been described [16]. 

Shape selective catalysis as typically demonstrated by zeolites is of great interest from scientific as well as industrial viewpoint [17], However, the application of zeolites to organic reactions in a liquid-solid system is very limited, because of insufficient acid strength and slow diffusion of reactant molecules in small pores. We reported preliminarily that the microporous Cs salts of H3PW12O40 exhibit shape selectivity in a liquid-solid system [18]. Here we studied in more detail the acidity, micropore structure and catal3rtic activity of the Cs salts and wish to report that the acidic Cs salts exhibit efficient shape selective catalysis toward decomposition of esters, dehydration of alcohol, and alkylation of aromatic compound in liquid-solid system. The results were discussed in relation to the shape selective adsorption and the acidic properties. 

They are a small class of surfactants with applications in the industrial sector rather than the detergent industry. They are produced using the same equipment as for alcohol ethoxylates but the first step is uncatalysed. Primary amine is dehydrated as normal under vacuum and the reactor nitrogen padded and the required ethylene oxide to produce diethanolamine is added. The addition of the second mole is more rapid than the first but then, even in the presence of excess ethylene oxide, there is little or no ethoxylation of the diethanolamine [32, 33]. This reaction is carried out at about 120°C ... 

A zeotropic and extractive distillations have been used through the years in the chemical industry to separate mixtures where the relative volatility of the key components is very close, or equal, to unity. Applications from the classical dehydration of alcohol with benzene (1) to more recent ones such as the propylene-propane separation (2) and aromatics recovery from hydrocarbon mixtures with N-methylpyrrolidone (3), indicate a continuous interest through the years in this area. 

The phenomenon of PV was described for the first time by Kober in 1917 (Kober, 1919). The real breakthrough of this membrane process started in the 1980s with the development of a series of industrial appUcations and the use of poly(vinyl alcohol)-poly(acryl nitrile) (PVA-PAN) composite membranes for the dehydration of alcohol/water azeotropic mixtures (Thsel and Bruschke, 1985). The other main PV commerdal application was developed by Membrane Technology Research (MTR) and is based on the removal of VOCs from contaminated water (Cox and Baker, 1998). 

Rare earth oxides have been studied to a lesser extent than alkaline earth oxides. However, they show characteristic selectivity in the dehydration of alcohols. Secondary alcohols form 1-olefins, whereas the same reaction over an acid catalyst produces the thermodynamically more stable 2-olefin (312). An example of an industrially important rare earth oxide catalyst is Zr02. It has several applications, including the reduction of aromatic carboxylic acids with hydrogen to aldehydes (314), the dehydration of 1-cyclohexyl ethanol to vinyl cyclohexane (315), and the production of diisobutyl ketone from isobutyraldehyde (316). The extensive use of Zr02 is mainly due to its resistance to poisoning by H2O and CO2, and its inherent catalytic activity is a result of its bifunctional acid-base properties. It contains both weakly acidic and basic sites, neither of which is susceptible to poisoning. The acid-base functionality of Zr02 is displayed in the reaction of alkylamine to nitrile (278) (Fig. 33). To form nitriles from both secondary and tertiary amines, both acid and base sites are required. 

Packaging Rectified spirit (96% ethanol by volume) is marketed directly for the manufacture of chemicals such as acetic acid, acetone, oxalic acid and absolute alcohol. Denatured ethanol for industrial and laboratory use typically contains 60-95% ethanol as well as between 1% and 5% each of methanol, isopropanol, methyl isobutyl ketone (MIBK), ethyl acetate and so forth. For beverages, the alcohol is matured and blended with malt alcohol (for manufacture of whisky) and diluted to requisite strength to obtain the desired type of liquor. This is bottled appropriately in a bottling plant. Anhydrous ethanol for fuelblending applications (power alcohol) requires concentration of the ethanol to 99.5 wt% purity. The ethanol dehydration is typically done using molecular sieves. 

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