Propanol 2-methyl-, dehydration

Membranes and Osmosis. Membranes based on PEI can be used for the dehydration of organic solvents such as 2-propanol, methyl ethyl ketone, and toluene (451), and for concentrating seawater (452—454). On exposure to ultrasound waves, aqueous PEI salt solutions and brominated poly(2,6-dimethylphenylene oxide) form stable emulsions from which it is possible to cast membranes in which submicrometer capsules of the salt solution ate embedded (455). The rate of release of the salt solution can be altered by surface—active substances. In membranes, PEI can act as a proton source in the generation of a photocurrent (456). The formation of a PEI coating on ion-exchange membranes modifies the transport properties and results in permanent selectivity of the membrane (457). The electrochemical testing of salts (458) is another possible appHcation of PEI. 

Isobutyl alcohol, isobutanol, 2-methyl-propanol, isopropyl carbinol, Me2CHCH20H. B.p. 108°C. Occurs in fusel-oil. Oxidized by potassium permanganate to 2-methyl-propanoic acid dehydrated by strong sulphuric acid to 2-methylpropene. 

In the acid catalyzed dehydration of 2 methyl 1 propanol what carbocation would be formed if a hydride shift accompanied cleavage of the carbon-oxygen bond in the alkyloxonium lon" What ion would be formed as a result of a methyl shift" Which pathway do you think will predominate a hydnde shift or a methyl shift" ... 

Melhyl-l-propanol Isobutyl Alcohol) and 2-Phenyl-1-propanol Herling and Pines (SO) studied the dehydration of 2-methyl-l-propanol and 2-phenyl-1-propanol. The two alcohols were passed over alumina under nonacidic conditions at temperatures of 350° and 270°, respectively (Tables III and IV). The 2-methyl-l-propanol underwent, in part, skeletal isomerization forming butenes, whereby the ratio of cisjtrans 2-butene produced was four to six times greater than the equilibrium ratio. The extent of skeletal isomerization depended to some extent on the method of preparation of the alumina. 

Dehydration of 2-Methyl-1-propanol over Alumina Catalysts at 350°... 

Contrary to the statements of Schulman etal. (81) and Taft et al. (77), there is very little similarity between thermal decomposition of aluminum alkoxides and dehydration of alcohols over aluminas. The thermal decomposition mechanism would not explain the skeletal isomerization occurring during the dehydration of 2-methyl-1-propanol (82). 

The required alkene is available by dehydration of 2-methyl-2-propanol. 

Dimethylethylenimine has been prepared by the dehydration of 2-amino-2-methyl-l-propanol.8 The method described here is essentially that of Cairns.8... 

MeS02-PCBs are initially co-extracted from tissue with other OHS and lipids. Lipid-rich tissues such as adipose, liver and lung have been homogenized with dichloromethane (DCM) and n-hexane/2-propanol (3 2) to co-extract lipid and OHS [95,117, 118]. Tissues have also been homogenized with acetone/n-hexane and extracted with n-hexane/diethyl ether or methyl tert-butyl ether (MTBE) [119]. Mammalian adipose and liver and whole fish have been dehydrated with sodium sulfate prior to extraction with n-hexane/DCM (1 1) [11, 96]. Human liver and feces have been extracted with benzene and refluxing by Soxhlet [120], Formic acid has been added to milk samples in preparation for further cleanup [16], After extraction, OHS and aryl methyl sulfones have been separated from lipids by various techniques. Lipid destructive strategies include saponifi-... 

Dehydration of alcohols proceeds by heterolytic cleavage of the C-O bond, yielding carbocation and hydroxide anion, and the dehydration rate is determined by the stability of the thus-formed carbocation. Therefore tertiary alcohols such as tcrt-butyl alcohol (2-methyl-2-propanol) are more easily dehydrated. When these solvents are used for the solvothermal reaction, the essential nature of the reaction may be identical to that of the hydrothermal reaction. 

Phthalic anhydride has also been used for dehydration of terpene alcohols.21 However, Waldmann and Petru22 found that the dehydrating action of phthalic anhydride is appreciably increased by addition of a little benzenesulfonic acid 2-propanol, 2-methyl-l-propanol, and cyclohexanol, inter alia are readily dehydrated by boiling phthalic anhydride containing a little benzenesulfonic acid. 

Dehydration of either erythro- or f reo-l,2-diphenyl-l-propanol, (1) and (2), with triphenylphosphite methiodide in HMPT gives a mixture of a-methyl-stilbenes in which the less stable Z-olefin predominates. Dehydration of (1) and... 

H NMR spectrum, 817 in mixed Claisen condensation, 836 2-Methyl-2-propanol, 138. See also tert-Butyl alcohol acid-catalyzed dehydration, 182 2-Methylpropene. See also Isobutene Isobutylene... 

Oxazolines are formed directly from the reaction of carboxylic acids with 2-ami-no-2-methyl-l-propanol in refluxing toluene but a two-step procedure involving reaction of 2-amino-2-methyl-l-propanol with an acid chloride followed by treatment of the resultant amide with excess thionyl chloride as a dehydrating agent is generally preferred (Scheme 2.128].2 o 26i Alternatives include reaction of dimethylaziridine with a carboxylic acid in the presence of dicyclohexylcarbo-diimide to form the N-acylaziridine followed by acid-catalysed rearrange-ment or reaction of an orthoester, or an imidate ester, with an amino alcohol as illustrated by the conversion of 129.1 to 1293 [Scheme 2.129). ... 

The usage of metal sulfates as catalysts is not new. In 1901, aluminum sulfate was used as the dehydration catalyst for the formation of 2-methylpropene from 2-methyl-2-propanol (29) and, in 1923, as the hydration catalyst for the formation of ethanol from ethylene 30). 

Steric interactions between the alkyl substituents and the catalyst surface cause trans-o tfin formation to be less favourable than cis. Dehydration of 2-methyl-1-propanol over a variety of alumina catalysts gives isobutylene (77-88%), similar amounts of 1-butene and r/i-2-butene (4-10%) and smaller yields of tra 5-2-butene (2-4%). Non-classical rather than classical intermediates were suggested, as the least acidic alumina, which possessed the lowest dehydration activity, caused the greatest skeletal isomerisation (173). 

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