Ethers diisopropyl

In general this method is limited to the preparation of symmetrical ethers m which both alkyl groups are primary Isopropyl alcohol however is readily available at low cost and gives high enough yields of diisopropyl ether to justify making (CH3)2CHOCH(CH3)2 by this method on an industrial scale... 

The hazards of working with diisopropyl ether are de scribed in the Journal of Chemical Education p 469 (1963)... 

A second dangerous property of ethers is the ease with which they undergo oxi dation in air to form explosive peroxides Air oxidation of diisopropyl ether proceeds according to the equation... 

Although the selectivity of isopropyl alcohol to acetone via vapor-phase dehydrogenation is high, there are a number of by-products that must be removed from the acetone. The hot reactor effluent contains acetone, unconverted isopropyl alcohol, and hydrogen, and may also contain propylene, polypropylene, mesityl oxide, diisopropyl ether, acetaldehyde, propionaldehyde, and many other hydrocarbons and carbon oxides (25,28). 

AlkoxyaLkyl hydroperoxides are more commonly called ether hydroperoxides. They form readily by the autoxidation of most ethers containing a-hydrogens, eg, dioxane, tetrahydrofuran, diethyl ether, diisopropyl ether, di- -butyl ether, and diisoamyl ether (10,44). From certain ethers, eg, diethyl ether (in the following, R = H R = 35 — CH2CH2), the initially formed ether hydroperoxide can yield alcohol on standing, or with acid treatment... 

Although the selectivity is high, minor amounts of by-products can form by dehydration, condensation, and oxidation, eg, propylene [115-07-17, diisopropyl ether, mesityl oxide [141-79-7] acetaldehyde [75-07-0], and propionaldehyde [123-38-6]. Hydrotalcites having different Al/(A1 + Mg) ratios have been used to describe a complete reaction network for dehydrogenation (17). This reaction can also be carried out in the Hquid phase. 

Etherification. Isopropyl alcohol can be dehydrated ia either the Hquid phase over acidic catalysts, eg, sulfuric acid, or ia the vapor phase over acidic aluminas to give diisopropyl ether (DIPE) and propylene (qv). 

The sulfate ester hydrolysate is stripped to give a mixture of isopropyl alcohol, isopropyl ether, and water overhead, and dilute sulfuric acid bottoms. The overhead is neutralized using sodium hydroxide and refined in a two-column distillation system. Diisopropyl ether is taken overhead in the first, ie, ether, column. This stream is generally recycled to the reactors to produce additional isopropyl alcohol by the following equiUbrium reaction ... 

After flashing the propylene, the aqueous solution from the separator is sent to the purification section where the catalyst is separated by a2eotropic distillation 88 wt % isopropyl alcohol is obtained overhead. The bottoms containing aqueous catalyst solution are recycled to the reactor, and the light ends are stripped of low boiling impurities, eg, diisopropyl ether and acetone. A2eotropic distillation yields dry isopropyl alcohol, and the final distillation column yields a product of more than 99.99% purity. 

Fig. 3. Direct hydration process where the product is isolated as diisopropyl ether.

The effects of pressure and temperature on the equihbrium concentration of alcohol ia both phases of hydration of propylene when both Hquid and vapor phases are present have been calculated and are presented ia Table 3. Low temperature reduces by-product diisopropyl ether. 

Chemical. The use of isopropyl alcohol as a feedstock for the production of acetone is expected to remain stable, as the dominant process for acetone is cumene oxidation. Isopropyl alcohol is also consumed in the production of other chemicals such as methyl isobutyl ketone, methyl isobutyl carbinol [108-11-2] isopropjlamine, and isopropyl acetate. The use of diisopropyl ether as a fuel ether may become a significant oudet for isopropyl alcohol. 

Regioselective hydrolysis of diesters is a challenging problem ia synthetic chemistry because the side reactions always reduce the yield of desired product. Some Upases are well suited to perform this task. Lipase OF-360 (Meito Sangyo) hydrolyzes diester (55) ia 74% theoretical yield and 93% ee (70). Lipase from Pseudomonas cepacia suspended ia diisopropyl ether saturated with water hydrolyzes triester (56) with a remarkable efficiency and regio- and stereoselectivity (71). 

Type 4A sieves. A crystalline sodium aluminosilicate with a pore size of about 4 Angstroms, so that, besides water, ethane molecules (but not butane) can be adsorbed. This type of molecular sieves is suitable for drying chloroform, dichloromethane, diethyl ether, dimethylformamide, ethyl acetate, cyclohexane, benzene, toluene, xylene, pyridine and diisopropyl ether. It is also useful for low pressure air drying. The material is supplied as beads, pellets or powder. 

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