Alcohols alkyl

51V chemical shifts (ppm) observed for selected heteroligand bisperoxovanadate complexes 

The more acidic alcohols are most effective as electron-withdrawing groups. To compensate for the electron withdrawal, some electron density is pulled away from 

FIGURE 9.1 The 51V chemical shifts of monoanionic alkoxovanadates are shown as a function of their pKa values. Only a selection from all the alkoxo ligands is identified. The solid lines provide a guide for viewing the data, which was taken from the work of Tracey and coworkers [3]. 

FIGURE 9.3 The relationship between the pKa s of various ortho-( ) and meta- and para-( ) substituted phenols and the pKa s of the corresponding arylvanadates. The values are for 42% vol/vol acetone/water solutions. For the various phenolic solutions, the pKa of vanadate (V04H2 ) is about 9.5 and dependent on solution properties. A correction to a value of 9.55 was made for all solutions. Data taken from Galeffi and Tracey [4]. Not all phenols have been identified in the figure. 

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Fnedel-Crafts alkylation Alcohols in combination with acids serve as sources of carbocations Attack of a carbocation on the electron rich ring of a phe nol brings about its alkylation... 

Tertiary 3- and 4-phenylaIkanols undergo cyclo alkylation readily with H2SO4. Primary and most secondary 3-phenylaIkanols, however, do not, even at higher temperatures with H PO (64). Cyclization of phenyl alkyl alcohols to tetrahydronaphthalenes and iadanes has been extensively iavestigated (65). 

Inefficiencies ia the reaction with POCl leads to alternative production of trialkyl phosphates by employing the sodium alkoxide rather than the alkyl alcohol itself Dialkyl aryl phosphates are produced ia two steps. The low molecular weight alcohol iavolved (eg, butyl) first reacts with excess POCl. The neutral phosphate ester is then completed by the iatermediate chloridate reacting with excess sodium arylate ia water. 

Most large-scale industrial methacrylate processes are designed to produce methyl methacrylate or methacryhc acid. In some instances, simple alkyl alcohols, eg, ethanol, butanol, and isobutyl alcohol, maybe substituted for methanol to yield the higher alkyl methacrylates. In practice, these higher alkyl methacrylates are usually prepared from methacryhc acid by direct esterification or transesterification of methyl methacrylate with the desired alcohol. 

A wide selection of amino resin compositions is commercially available. They are all alkylated to some extent in order to provide compatibiUty with the other film formers, and formulation stabiUty. They vary not only in the type of amine (melamine, urea, ben2oguanamine, and glycolutil) used, but also in the concentration of combined formaldehyde, and the type and concentration of alkylation alcohol (/ -butanol, isobutyl alcohol, methanol). 

Sulfonic acids are prone to reduction with iodine [7553-56-2] in the presence of triphenylphosphine [603-35-0] to produce the corresponding iodides. This type of reduction is also facile with alkyl sulfonates (16). Aromatic sulfonic acids may also be reduced electrochemicaHy to give the parent arene. However, sulfonic acids, when reduced with iodine and phosphoms [7723-14-0] produce thiols (qv). Amination of sulfonates has also been reported, in which the carbon—sulfur bond is cleaved (17). Ortho-Hthiation of sulfonic acid lithium salts has proven to be a useful technique for organic syntheses, but has Httie commercial importance. Optically active sulfonates have been used in asymmetric syntheses to selectively O-alkylate alcohols and phenols, typically on a laboratory scale. Aromatic sulfonates are cleaved, ie, desulfonated, by uv radiation to give the parent aromatic compound and a coupling product of the aromatic compound, as shown, where Ar represents an aryl group (18). 

In another process, 50—150% excess carbon disulfide and a small excess of powdered alkah hydroxide are added, with stirring and cooling to the lower alkyl alcohol. After completion of the reaction, the excess CS2 and resulting water of reaction are removed by applyiag a vacuum to the reactor (80). 

Catalytic hydrogenolysis of an O-benzyl protective group is a mild, selective method introduced by Bergmann and Zervas to cleave a benzyl carbamate (>NC0-0CH2C6H5 —> >NH) prepared to protect an amino group during peptide syntheses. The method has also been used to cleave alkyl benzyl ethers, stable compounds prepared to protect alkyl alcohols benzyl esters are cleaved by catalytic hydrogenolysis under neutral conditions. 

The unit can perform the neutralization of most organic acids, including natural and synthetic fatty acids, specifically those resulting from the sulf-(on)ation of alkylates, alcohols, ethoxylated alcohols, and so forth, to obtain natural product at high concentration. 

The addition of linear chained alkyl alcohols shifts the percolation of AOT microemulsions to higher temperature, whereas the opposite effect is obtained by adding polyoxyethylene alkyl ethers [261]. 

In common radicofunctional nomenclature alcohols are called alkyl alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and so on. 

Secondary Alkyl Alcohols. Treatment of secondary alkyl alcohols with tri-fluoroacetic acid and organosilicon hydrides results only in the formation of the trifluoroacetate esters no reduction is reported to occur.1,2 Reduction of secondary alkyl alcohols does take place when very strong Lewis acids such as boron trifluoride126 129 or aluminum chloride136,146 are used. For example, treatment of a dichlo-romethane solution of 2-adamantanol and triethy lsilane (1.3 equivalents) with boron trifluoride gas at room temperature for 15 minutes gives upon workup a 98% yield of the hydrocarbon adamantane along with fluorotriethylsilane (Eq. 10).129... 

Aluminum chloride, used either as a stoichiometric reagent or as a catalyst with gaseous hydrogen chloride, may be used to promote silane reductions of secondary alkyl alcohols that otherwise resist reduction by the action of weaker acids.136 For example, cyclohexanol is not reduced by organosilicon hydrides in the presence of trifluoroacetic acid in dichloromethane, presumably because of the relative instability and difficult formation of the secondary cyclohexyl carbocation. By contrast, treatment of cyclohexanol with an excess of hydrogen chloride gas in the presence of a three-to-four-fold excess of triethylsilane and 1.5 equivalents of aluminum chloride in anhydrous dichloromethane produces 70% of cyclohexane and 7% of methylcyclopentane after a reaction time of 3.5 hours at... 

Tertiary Alkyl Alcohols. Tertiary alkyl alcohols generally undergo facile reduction when treated with acids in the presence of organosilicon hydrides.127,136 This comparative ease of reduction reflects the enhanced stability and ease of formation of tertiary alkyl carbenium ions compared with primary and secondary carbenium ions. Thus, treatment of 1-methylcyclohexanol with mixtures of triethylsilane and aluminum chloride in dichloromethane produces near quantitative yields of methylcyclohexane with or without added hydrogen chloride in as little as 30 minutes at room temperature, in contrast to the more vigorous conditions needed for the reduction of the secondary alcohol cyclohex-anol.136... 

Although the synthetic yields of hydrocarbon products obtained from the reduction of tertiary alkyl alcohols are frequently quite high, studies show that the reaction pathways taken by the reactants are not always as direct or straightforward as might be suggested by the structural relationships between reactants and products. For example, preparative-scale treatment of a dichloromethane solution of 3-ethylpentan-3-ol and triphenylsilane (1.2 equivalents) with excess trifluo-roacetic acid (1.5 M) at room temperature for 24 hours gives 3-ethylpentane in 78% yield (Eq. 14).127 Under these reaction conditions, the alcohol rapidly... 

Allyl halides, reduction reactions, 31 Aluminum chloride reagent/catalyst alkyl halide reduction, 30-31 secondary alkyl alcohol reduction, 14-15... 

Figure 4.28 Plot of CD intensities of poly -hexyl(j -/ -propoxyphenyl)silane (41) aggregates in toluene/series of (S)-primary chiral alkyl alcohols/methanol mixtures at 20°C. [For comparison, CD intensity with (A)-2-butanol is inserted.].

When the diazoimides 253 are subjected to Rh2(OAc)4 at 80 °C in presence of an alkyl alcohol, pcrhydropyrrolo[2,1 -b -oxazol-4-ones 254 were isolated in good yields as a diastereomeric mixture. If the alcohol is replaced by terminal alkyl diols, the corresponding bis(2,3-fused perhydropyrrolo[2,l- ]oxazol-4-one) systems 255 were obtained (Scheme 37) <2003CC440>. 

VDC polymer degradation and, 25 717 2-Alkyl-alcohols. See Guerbet alcohols Alkylalkanolamines, 2 140 Alkylaluminum compounds, 2 285 Alkylaluminum halides, 2 358 Alkylaluminum reagents, in triorganotin preparation, 24 815-816 Alkyl amino acids, protonated, 17 780 Alkylaminomethanols, 12 112 AT-Alkyl amino propionates, 24 148... 

The most representative non-ionic surfactants are the alkyl (alcohol) ethoxylates. These are adducts of a long-chain alcohol (12—18) with a variable number of EO units (3-11). Other non-ionic surfactants are derived from carbohydrates (glucoside and glucamide derivatives), organosilicones, fatty alcohols, and amides. Products in this category are as follows (compare also Table 1.2) ... 

In 1899 R. C. Guerbet discovered the self-condensation reaction of alcohols, which, via the aldehyde as an intermediate, lead to branched structures (2-alkyl alcohols) (Fig. 4.21) - the Guerbet alcohols. Starting with fatty alcohols from vegetable sources, such as octanol and decanol, the corresponding C1(, and C2o alcohols are produced (2-hexyldecanol and 2-octyldecanol, respectively). The reaction is carried out under alkali catalysis and high temperatures (>200 °C). Over the years, both products have proven to be efficient emollients, but are also used for other applications, such as plasticizers or components for lubricants (Fig. 4.21). 

Alkyl alcohols (15) triphenyl phosphate cresyl diphenyl phosphate... 

Stereoselective oxidation of alkyl-silanes into the corresponding alkyl-alcohols using peracids. 

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