Acetone from propane

Oxidation of hydrocarbons in zeolites with blue light gives improved selectivity.442 Isobutane can be converted to tert-butylhydroperoxide with 98% selectivity. Benzalde-hyde is produced from toluene, acrolein from propylene, and acetone from propane. 

Two papers have been presented on the photochemistry of 5-methylphena-zinium salts in aqueous solution. Fluorescence, optical flash photolysis, and electron paramagnetic resonance (e.p.r.) techniques have been used to elucidate various aspects of product formation and quantum yield. Two products have been identified, namely the 5-methyl-10-hydrophenazinium cation radical (MPH ) and the pyocyanine (l-hydroxy-5-methyl-phenozinium) cation (PyH ) in a stoicheiometric ratio of 2 1. The quantum yield of formation of (MPH ) was found to be 0.29 0.03 at pH 7.0 and 1.1 0.1 at pH 3.0. The triplet state of MP (Ti) has also been detected by triplet-triplet absorption and is found to have a lifetime of 0.5 ns. Flash photolysis and e.p.r. have also been used to study a geminate triplet radical pair obtained from hydrogen abstraction by excited triplet acetone from propan-2-ol. The authors demonstrate that the geminate pairs contribute most of the polarization in photochemically-induced dynamic electron polarization (CIDEP) as compared with free random-phase pairs. 

Acetone is obtained by fermentation as a by-product of -butyl alcohol manufacture, or by chemical synthesis from isopropyl alcohol from cumene as a by-product in phenol manufacture or from propane as a by-product of oxidation-cracking. 

The solute molecules were chosen as water, methanol (MeOH), dimethyl ether, acetone and propane. Because the transformation from a hydroxyl group to an O-methyl group does not behave smoothly, extra care had to be taken. Lynden-Bell et al. introduced an additional site in order to stabilize the transformation [9], For water and methanol large negative values of the excess chemical potential (-29 kJ... 

Further chemically induced dynamic nuclear polarization (CIDNP) studies have appeared concerning the photoreduction of acetone by propan-2-ol, including the use of a variety of deuteriated components.19 The enol of acetone has been detected by such methods,20 and Bargon and Seifert21 have now observed by CIDNP spectroscopy the ends from acetaldehyde (giving vinyl alcohol) and several aliphatic aldehydes. Vinyl alcohol, for example, is generated in a spin-polarized state by photoreduction of [2He]acetone with ethanol in DaO (Scheme 3). 

Vapor-phase reaction between ozone and olefins is quite rapid, the overall reactions become complicated, and stoichiometry varies with the reaction pressures. A 3 mole per cent mixture of OTOne in oxygen reacts with methane, propane, i -butane, and isobutane at 25-50 C. The reaction of ozone with isobutane resulted in formation of ferf-butanol plus one-third to one-half as much acetone, the combined yield being about equivalent to ozone reacted. Acetone was formed from propane oxidation. 

A heterogeneous hydrogenation catalyst enabling the reduction of acetone to propane was prepared from the cluster [Os3Ni(//-H)3Cp(CO)9] supported on Chro-mosorb-P and thermally treated under A multi-step reaction pattern was... 

Methylhydrazones act just like protic H—trapping reagentsJ i For example, the methylhydrazone of acetaldehyde 202 undergoes Pd-catalyzed reaction with butadiene to afford linear dimer 203 (1 mol % (Ph3P)4Pd, THF, 110 °C, 24 h, 89%) (Scheme 64). Methylhydrazones derived from propanal, acetone, and methyl ethyl ketone behave similarly (80-86% yield). 

Phenylhydrazones exhibit another mode of reaction (Scheme 65). The reaction of butadiene with the phenylhydrazone of acetaldehyde 204 (1 mol % (Ph3P)4Pd, THF, 110 °C, 24 h) affords a 2 1 mixture of 205 and 206 (86%). A small amount of the protic (H—Y) trapping prodnct was also observed. The formation of 205 can be rationalized by addition of the phenylhydrazone in the fashion of a R (R )C=Y-type electrophile to a palladacycle in an Sgs fashion to 208 followed by hydride transfer to 209. Rednctive elimination conld acconnt for the formation of 205. Thns, 206 could be formed via a similar pathway, by addition of the phenylhydrazone in an rather than fashion. The proposed hydride transfer invoked to rationalize the formation of the observed products offers interesting possibilities and appears worthy of further investigation. Phenylhydrazones derived from propanal, acetone, and methyl ethyl ketone behave similarly (60-95% yield), although the ratio of 205/206 and the proportion of the protic (H—Y-type) trapping product vary. 

Scheme 23 also outlines a potential problem with the syjnthesis. The initial attack can occur at either end of the double bond of the 7r-complex, 28, to give the two isomers 29 and 30 in a ratio of 4 1. These two isomers are expected from Wacker chemistry since propene produces both acetone and propanal in about the same ratio from the two modes of addition. However, as shall be discussed below, this is not a serious problem with most a-olefins. The same catalyst oxidizes methyl vinylketone only to 4-chloro-3-hydroxy-2-butanone (29 R = C(=0)CH3). The optical purity was still only about 12%. 

From propan-2-ol, propene is formed with zeohtes of predominantly acid character, while it is converted to acetone over predominantly basic materials. Hathaway and Davis [223] used it to explore alkah metal-exchanged X and Y zeohtes. The study shows imequivocally that propene is formed with Bronsted and Lewis acid sites. It is also formed via alkoxide intermediates... 

Commercial VPO of propane—butane mixtures was in operation at Celanese Chemical Co. plants in Texas and/or Canada from the 1940s to the 1970s. The principal primary products were acetaldehyde, formaldehyde, methanol, and acetone. The process was mn at low hydrocarbon conversion (3—10%) and a pressure in excess of 790 kPa (7.8 atm). These operations were discontinued because of various economic factors, mainly the energy-intensive purification system required to separate the complex product streams. 

Other Processes. Isopropyl alcohol can be prepared by the Hquid-phase oxidation of propane (118). It is produced iacidentaHy by the reductive condensation of acetone, and is pardy recovered from fermentation (119). Large-scale commercial biological production of isopropyl alcohol from carbohydrate raw materials has also been studied (120—123). 

To a cold solution of 29 g of atropine in 250 ml of acetone a solution of 1 3 g of propane-1,3-sultone in 100 ml of acetone is generally added. The combined solution is left for 48 hours. The white precipitate of fine crystalline needles is separated, washed several times with acetone, and then recrystallized from ethanol. It melts at 220°C. 

The solubility of most inorganic compounds is reduced by the addition of organic solvents, such as methanol, ethanol, propan-l-ol, acetone, etc. For example, the addition of about 20 per cent by volume of ethanol renders the solubility of lead sulphate practically negligible, thus permitting quantitative separation. Similarly calcium sulphate separates quantitatively from 50percent ethanol. Other examples of the influence of solvents will be found in Chapter 11. 

Run infrared spectra of pure acetone and of pure propan-2-ol. From them select an absorption band for acetone which does not overlap significantly with any of those for the propan-2-ol. The best band is most probably that at 1718 cm-1, the carbonyl stretching frequency. 

Take 10 mL of commercial propan-2-ol and dilute to 100 mL with carbon tetrachloride in a graduated flask. Record the infrared spectrum and calculate the absorbance for the peak at 1718 cm-1. Obtain a value for the acetone concentration from the calibration graph. The true value for the acetone in the propan-2-ol will be 10 times the figure obtained from the graph (this allows for the dilution) and the percentage v/v value can be converted to a molar concentration (mol L-1) by dividing the percentage v/v by 7.326 e.g. 1.25 per cent v/v = 1.25/7.326 = 0.171 molL-1. 

Polar organic solvents readily precipitate exopolysaccharides from solution. The solvents commonly used are acetone, methanol, ethanol and propan-2-ol. Cation concentration of the fermentation liquor influences the amount of solvent required for efficient product recovery. In the case of propan-2-ol, increasing the cation concentration can lead to a four-fold reduction in die volume of solvent required to precipitate xanthan gum. Salts such as calcium nitrate and potassium chloride are added to fermentation broths for this purpose. 

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