Benzyl alcohol effect

P. Haider, B. Kimmerle, F. Krumeich, W. Kleist, J.-D. Grunwaldt and A. Baiker, Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol Effect of Gold Particle Size on Activity and Selectivity in Different Solvents, Catal Lett, 2008, 125, 169-176. 

The alternative synthetic route using the sodium salt of benzyl alcohol and an isopropyl halide would be much less effective because of increased competition from elimination as the alkyl halide becomes more sterically hindered... 

However, a second mole of alcohol or hemiformal caimot be added at the ordinary pH of such solutions. The equiUbrium constant for hemiformal formation depends on the nature of the R group of the alcohol. Using nmr spectroscopy, a group of alcohols including phenol has been examined in solution with formaldehyde (15,16). The spectra indicated the degree of hemiformal formation in the order of >methanol > benzyl alcohol >phenol. Hemiformal formation provides the mechanism of stabilization methanol is much more effective than phenol in this regard. 

Coordination numbers ranging from five to seven were observed, and they appeared to be controlled by the steric bulk of the supporting amidinate and coligands. Complexes 2-5 and 7 were found to be active catalysts for the pol3uneiization of D,L-lactide (e.g., with 2 and added benzyl alcohol, 1000 equiv of D,L-lactide were polymerized at room temperature in <1 h). The neutral complexes 2, 5, and 7 were more effective than the anionic complexes 3 and 4. ... 

By small-angle neutron scattering experiments on water/AOT/hydrocarbon microemulsions containing various additives, the change of the radius of the miceUar core with the addition of small quantities of additives has been investigated. The results are consistent with a model in which amphiphilic molecules such as benzyl alcohol and octanol are preferentially adsorbed into the water/surfactant interfacial region, decreasing the micellar radius, whereas toluene remains predominantly in the bulk hydrocarbon phase. The effect of n-alcohols on the stability of microemulsions has also been reported [119],... 

Kunz and Sager also demonstrated the effectiveness of this procedure. Under BFj catalysis, reactions (in CH2CI2) of 18,20a, and 45a with alcohols [including benzyl alcohol, cholesterol, their silyl ethers, and A-(benzyloxy-... 

The oxidation of benzyl alcohol to benzaldehyde is carried out for elucidating mass transfer effects in a mini trickle-bed reactor [58]. 

John Ward has functionalized an indane using method D in route to tetra-petalone A (46) (Fig. 4.24).25 The o-OBoc benzyl alcohol 44 undergoes addition with two equivalents of Grignard and affords after acidic workup the phenolic indane 45 in 73% yield. Because of steric effects, only one diastereomer is observed after hydrolysis of the enol ether and thermodynamic equilibration of the... 

Many of these reactions are related to the quantity of excipient found in a dosage form. Benzyl alcohol benzalkonium chloride, propylene glycol, lactose, and polysorbates are all associated with dose-related toxic reactions [52-54], Large-volume parenterals containing 1.5% benzyl alcohol as a preservative have caused metabolic acidosis, cardiovascular collapse, and death in low birth weight premature neonates and infants. The cumulative dose of benzyl alcohol ranged from 99 to 234 mg/kg per day in these patients [55,56], Dose-related adverse effects to excipients are of particular concern in the preterm, low birth weight infant because... 

A polyacrylamide with a molecular mass of 1.87 x 105 was prepared by polymerising a 5% w/v aqueous solution of acrylamide monomer in the presence of 0.15% w/w benzyl alcohol and 0.025% w/w potassium persulphate for 45 minutes at 80 °C. This product was effective in preventing the bleeding of direct dyes and hydrolysed reactive dyes from dyed cotton, which was simply dipped in a 1% solution of the polyacrylamide and dried in air [450]. 

Zr compounds are also useful as Lewis acids for oxidation and reduction reactions. Cp2ZrH2 or Cp2Zr(0 Pr)2 catalyze the Meerwein-Ponndorf-Verley-type reduction and Oppenauer-type oxidation simultaneously in the presence of an allylic alcohol and benzaldehyde (Scheme 40).170 Zr(C)1 Bu)4 in the presence of excess l-(4-dimethylaminophenyl) ethanol is also an effective catalyst for the Meerwein-Ponndorf-Verley-type reduction.1 1 Similarly, Zr(0R)4 catalyze Oppenauer-type oxidation from benzylic alcohols to aldehydes or ketones in the presence of hydroperoxide.172,173... 

Table 4 The effects of a-carbonyl and a-thiocarbonyl substituents on the relative stabilities of a-methyl benzyl alcohols R-[16]-OH and the corresponding styrenes R-[17] (Scheme 13)"...

Ring-substituted benzyl alcohols sometimes undergo such reduction more effectively than unsubstituted alcohols. For example, treatment of a dichloromethane solution of 2,4,6-trimethylbenzyl alcohol with trifluoroacetic acid and triphenylsilane produces a 41% isolated (89% by GLC) yield of isodurene.26 Treatment of 2-me(hyl-4,6-di-/m-buty I benzyl alcohol with a three-fold excess of triethylsilane and trifluoroacetic acid in dichloromethane at room temperature gives an 85% yield of 2-mclhyl-4,6-di-/m-butyltoluene together with 15% of 3,5-di-ferf-butyltoluene. The latter is presumably formed by loss of protonated formaldehyde from the Cl ring-protonated substrate.128 Similar treatment of 2,4,6-tri-ferf-butylbenzyl alcohol produces a 90% yield of 2,4,6-tri-tert-butyltoluene within one hour (Eq. 21).128... 

The secondary benzylic alcohol l-phenylethan-l,2-diol requires 20 hours of treatment at room temperature to produce a 64% yield of 2-phenylethanol (Eq. 43).137 Under the same conditions, methyl mandelate fails to undergo reduction, presumably because of the greater carbocation-destabilizing effect of a neighboring carboalkoxy compared to a hydroxymethyl group (Eq. 43).137... 

Triethylsilane reduces benzaldehyde to benzyl alcohol in 98% yield after 32 hours in a reaction medium containing sulfuric acid, water, and sulfolane (1 2 5) (Eq. 157). Neither benzene nor dimethylformamide is effective as an interfacing solvent for producing alcohol products under these conditions.313... 

Polar solvents have no effect on the rate constant of the reaction R02 + RH [56], This means that the solvation energies of the peroxyl radical R02 and TS R02 HR are very close. A different situation was observed for the reaction of cumylperoxyl radical with benzyl alcohol (see Table 7.10). The rate constant of this reaction is twice in polar dimethylsulfoxide (s = 33.6) than that in cumene (a 2.25). It was observed that the very important property of the solvent is basicity (B), that is, affinity to proton. A linear correlation... 

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