Acetone generation

As it pertains to the solid state photodecarbonylation reaction, the model assumes that most aliphatic ketones have similar excitation energies, that reactions are more likely along the longer-lived triplet excited state, and that each reaction step must be thermoneutral or exothermic to be viable in the solid state. " Using acetone and its decarbonylation intermediates as a reference reaction (dashed lines in Fig. 7.24), we can analyze the energetic requirements to predict the effects of substituents on the stability of the radical intermediates. The a-cleavage reaction of triplet acetone generates an acetyl-methyl radical pair in a process that is 3.5 kcal/mol endothermic and the further loss of CO from acetyl radical is endothermic by 11.0... 

Hoffmann has shown that diastereoselective bromine-lithium exchange may be achieved even in acyclic systems.118 Treatment of 138 with BuLi in the Trapp solvent mixture at -120 °C in the presence of acetone generates the epoxides 139 and 140 in a 94 6 ratio of diastereoisomers.119 120 The selectivity was found to depend on the organolithium used for the bromine-lithium exchange, and it must therefore be under kinetic control. 

Acetic acid decomposed on the (114[-faceted of the TiOi (001) surface to produce ketene as well as acetone [44]. The acetone generated arose from bimolecular coupling of pairs of surface acetates at four-fold coordinate cations this is analogous to the production of formaldehyde from surface formate on identically prepared surfaces. The reaction of propionic acid corresponded directly to the reaction of acetic acid, producing methyl ketene and 3-pentanone [46]. 

Contact with many organic compounds can lead to immediate fires or violent explosions (consult Bretherick for references and examples). Hydrogen peroxide reacts with certain organic functional groups (ethers, acetals, etc.) to form peroxides, which may explode upon concentration. Reaction with acetone generates explosive cyclic dimeric and trimeric peroxides. Explosions may also occur on exposure of hydrogen peroxide to metals such as sodium, potassium, magnesium, copper, iron, and nickel. 

Hydrogen peroxide/acetone Generation of alkyl radicals from iodides... 

Assume that ionization to a primary carbocation or a methyl carbocation is simply too slow to be relevant. This is a very important concept. If 72 is dissolved in aqueous acetone, generation of the unstable cation 73 will be very slow because the energy required to form it is quite high. This does not mean that it is impossible to form 73. It simply means that the rate is very slow. This is indicated with an X for the conversion of 72 to 73, which signifies that the conversion does not occur at a significant and competitive rate. This point is worth repeating. In this book, assume that primary alkyl halides do not form primary carbocations by ionization in aqueous solvents. 

You learned in Section 17 8 of the relationship among hemiacetals ketones and alcohols the for mation of phenol and acetone is simply an example of hemiacetal hydrolysis The formation of the hemiacetal intermediate is a key step in the synthetic procedure it is the step in which the aryl—oxygen bond is generated Can you suggest a reasonable mechanism for this step" ... 

Gestodene Gestodene (54), along with norgestimate and desogestrel, are the progestin components of the third-generation oral contraceptives (see Contraceptives). It may be crystallised from hexane/acetone (81) or ethyl acetate (82), and its crystal stmcture (83) and other spectral data have been reported (84). 

Butane. The VPO of butane (148—152) is, in most respects, quite similar to the VPO of propane. However, at this carbon chain length an important reaction known as back-biting first becomes significant. There is evidence that a P-dicarbonyl intermediate is generated, probably by intramolecular hydrogen abstraction (eq. 32). A postulated subsequent difunctional peroxide may very well be the precursor of the acetone formed. 

In addition to generating malodorous sulfur dioxide [7446-09-5], the acetone formed can undergo further condensation in the acidic medium to generate mesityl oxide [141-79-7], (CH2)2C=CHCOCH2, and higher products. 

Single-pass conversions of acetone cyanohydrin are 90—95% depending on the residence times and temperatures in the generator and hold tank. Overall yields of product from acetone and hydrogen cyanide can be >97%. There are no significant by-products of the reaction other than the sodium salts produced by neutralization of the catalyst. 

Toluene is a notoriously poor electrical conductor even in grounded equipment it has caused several fires and explosions from static electricity. Near normal room temperature it has a concentration that is one of the easiest to ignite and, as previously discussed, that generates maximum explosion effects when ignited (Bodurtha, 1980, p. 39). Methyl alcohol has similar characteristics, but it is less prone to ignition by static electricity because it is a good conductor. Acetone is also a good conductor, but it has an equihbrium vapor pressure near normal room temperature, well above UFL. Thus, acetone is not flammable in these circumstances. 

The ketimine is an acetone-blocked diamine. The synthesis and applications of ketimines will be discussed later. The curing concept for the adhesive is shown in Fig. 7. Phenol-blocked prepolymers would normally unblock at approximately 150°C. However, an aliphatic diamine, generated by the hydrolysis of the ketimine to an aliphatic diamine and ketone as a result of exposure to the moisture in the air, is sufficient to cure the windshield adhesive at room temperature. 

The immediate outcome of the Hantzsch synthesis is the dihydropyridine which requires a subsequent oxidation step to generate the pyridine core. Classically, this has been accomplished with nitric acid. Alternative reagents include oxygen, sodium nitrite, ferric nitrate/cupric nitrate, bromine/sodium acetate, chromium trioxide, sulfur, potassium permanganate, chloranil, DDQ, Pd/C and DBU. More recently, ceric ammonium nitrate (CAN) has been found to be an efficient reagent to carry out this transformation. When 100 was treated with 2 equivalents of CAN in aqueous acetone, the reaction to 101 was complete in 10 minutes at room temperature and in excellent yield. 

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