Butanol decomposition

In 1938 Stankiewicz reproduced the asymmetric 2-butanol decomposition experiments of Schwab (1932) at a higher temperature and atmospheric pressure and extended studies to the asymmetric decomposition of racemic menthol and 3-methylheptan-3-ol. Over a Cu-r/-quartz catalyst the latter substrate produced a maximal optical rotation of -0.26° and the decomposition of 2-butanol gave a reaction mixture with a rotation of +0.25°. 

In [138] a number of siliea- and alumina-supported Ln203 samples are investigated by means of TPD of ehemisorbed CO2 and pyridine, FTIR of adsorbed pyridine, as well as eatalytie assays of a-pinene isomerization and 2-butanol decomposition. Particular attention is paid to the supported ytterbia systems. In good agreement with the results commented on above, supported rare earth oxide systems... 

This study describes two methods to prepare well-ordered adipate-pillared hydrotalcite-like LDHs. One is the ion-exchange method, the other is the coprecipitation method. The former has not been reported before. As to the latter, products with diffuse or amorphous X-ray patterns were previously observed (Drezdzon 1988 Reichle 1985). These organic-pillared LDHs served as precursors and were ion-exchanged with tetraborate ions. The resultant pillared hydrotalcite-like LDHs had fairly good crystallinity. This is ascribed to tetraborate anions being stable under mildly basic conditions. The variables in preparation conditions which might influence the pillared products were examined. The catalytic activity of the pillared material in 2-butanol decomposition reaction was also discussed. 

Table 8-1 The catalytic activities of hydrotalcite-like materials in 2-butanol decomposition. 

When the borate-pillared hydrotalcite-like compound was used as a catalyst in the 2-butanol decomposition reaction, butene was obtained as the major product... 

Solutions of NaBH in methanol, and to a lesser degree ethanol, are subject to a similar decomposition reaction that evolves hydrogen these solutions can be stabilized by alkaU. The solubiUty of NaBH in lower aUphatic alcohols decreases as the carbon chain length increases, but the stabiUty increases. Solutions in 2-propanol and /-butanol are stable without alkaU (22,24). 

The purification of Hquid nitro alcohols by distillation should be avoided because violent decompositions and detonation have occurred when distillation was attempted. However, if the distillation of a nitro alcohol cannot be avoided, the utmost caution should be exercised. Reduced pressure should be utilised, ie, ca 0.1 kPa (<1 mm Hg). The temperature of the Hquid should not exceed 100°C hot water should be used as the heating bath. A suitable explosion-proof shield should be placed in front of the apparatus. At any rise in pressure, the distillation should be stopped immediately. The only commercially produced Hquid nitro alcohol, 2-nitro-1-butanol, is not distilled because of the danger of decomposition. Instead, it is isolated as a residue after the low boiling impurities have been removed by vacuum treatment at a relatively low temperature. 

Stabilizers. Nitro alcohols can be used to prevent the decomposition of phenylenediarnine color-developing agents (27). 2-Hydroxymethyl-2-nitro-l,3-propanediol and 2-nitro-1-butanol have been used as additives for the stabilization of 1,1,1-trichloroethane. 

Other by-products include acetone, carbonaceous material, and polymers of propylene. Minor contaminants arise from impurities in the feed. Ethylene and butylenes can form traces of ethyl alcohol and 2-butanol. Small amounts of / -propyl alcohol carried through into the refined isopropyl alcohol can originate from cyclopropane [75-19-4] in the propylene feed. Acetone, an oxidation product, also forms from thermal decomposition of the intermediate sulfate esters, eg. 

To this acid was then added 1 g of 4-ethyl-2,3-dioxo-1-piperazinocarbonyl chloride (from the reaction of N-ethylethylenediamine and diethyl oxalate to give 2,3-dioxo-4-ethyl-piperazine which Is then reacted with phosgene) and the resulting mixture was reacted at 15°C to 20°C for 2 hours. After the reaction, a deposited triethylamine hydrochloride was separated by filtration, and the filtrate was incorporated with 0.4 g of n-butanol to deposit crystals. The deposited crystals were collected by filtration to obtain 1.25 g of white crystals of 6-[ D(—l-Ct-(4-ethyl-2,3-dioxo-1 -piperazinocarbonylaminolphenylacetamido] penicillanic acid. Into a solution of these crystals in 30 ml of tetrahydrofuran was dropped a solution of 0.38 g of a sodium salt of 2-ethyl-hexanoic acid in 10 ml of tetrahydrofuran, upon which white crystals were deposited. The deposited crystals were collected by filtration, sufficiently washed with tetrahydrofuran and then dried to obtain 1.25 g of sodium salt of 6-[D(—)-a-(4-ethyl-2,3-di-0X0-1-piperazinocarbonylaminolphenylacetamido] penicillanic acid, melting point 183°C to 185°C (decomposition), yield 90%. 

The second major discovery regarding the use of MTO as an epoxidation catalyst came in 1996, when Sharpless and coworkers reported on the use of substoichio-metric amounts of pyridine as a co-catalyst in the system [103]. A change of solvent from tert-butanol to dichloromethane and the introduction of 12 mol% of pyridine even allowed the synthesis of very sensitive epoxides with aqueous hydrogen peroxide as the terminal oxidant. A significant rate acceleration was also observed for the epoxidation reaction performed in the presence of pyridine. This discovery was the first example of an efficient MTO-based system for epoxidation under neutral to basic conditions. Under these conditions the detrimental acid-induced decomposition of the epoxide is effectively avoided. With this novel system, a variety of... 

A dry solution of the sodium salt in n-butanol was usually prepared by azeotropic drying. Use of excessively wet recovered butanol led to complete removal of the butanol with the water and heating of the dry salt at 200°C, when rapid decomposition occurred, leaving a glowing carbonised residue. 

CuS04-catalyzed decomposition of the (l-sila-cyclopentadienyl)diazomethane 398 did not furnish defined products. The desired rearrangement reactions to a silabenzene and a l-ethylidene-l-sila-2,4-cyclopentadiene, both trapped by /-butanol, were brought about by irradiation of 398, however 388... 

An example of an alcohol that can undergo rapid skeletal rearrangement is 3,3-dimethyl-2-phenyl-2-butanol (Eq. 29). Attempts to reduce this alcohol in dichloromethane solution with l-naphthyl(phenyl)methylsilane yield only a mixture of the rearranged elimination products 3,3-dimethyl-2-phenyl-l-butene and 2,3-dimethy 1-3-phenyl-1 -butene when trifluoroacetic acid or methanesulfonic acid is used. Use of a 1 1 triflic acid/triflic anhydride mixture with a 50 mol% excess of the silane gives good yields of the unrearranged reduction product 3,3-dimethyl-2-phenylbutane, but also causes extensive decomposition of the silane.126 In contrast, introduction of boron trifluoride gas into a dichloromethane solution of the alcohol and a 10 mol% excess of the silane... 

As the chain length of the primary alcohols increases, thermal decomposition through fracture of C—C bonds becomes more prevalent. In the pyrolysis of n-butanol, following the rupture of the C3Ht—CH2OH bond, the species found are primarily formaldehyde and small hydrocarbons. However, because of the relative weakness of the C—OH bond at a tertiary site, f-butyl alcohol loses its OH group quite readily. In fact, the reaction... 

Fig. 20 MIKE/CID spectra of the substituted m/z228 ions from the enantiomers of menthol ((7/ ,25,5R)-(— )-14 (A) and (75,27 ,55)-(+)-14 (B)) formed under CE(5)-2-amino-l-butanol (As) conditions (the m/z2 0 and mlz90 daugther ions are also produced during unimolecular decomposition of the m/z228 ions) (reprinted from ref. 472, with permission from Elsevier).

Figure 3. Scheme of ozone decomposition mechanism in water. P = promoter (e.g. ozone, methanol), S = scavenger or inhibitor (e.g. /-butanol, carbonate ion), I = initiator (e.g. hydroxyl ion, perhydroxyl ion) (adapted by Beltran [35]). 

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