Reactions of the Hydroxyl Group

Reactions of the Hydroxyl Group. The hydroxyl proton of hydroxybenzaldehydes is acidic and reacts with alkahes to form salts. The lithium, sodium, potassium, and copper salts of sahcylaldehyde exist as chelates. The cobalt salt is the most simple oxygen-carrying synthetic chelate compound (33). The stabiUty constants of numerous sahcylaldehyde—metal ion coordination compounds have been measured (34). Both sahcylaldehyde and 4-hydroxybenzaldehyde are readily converted to the corresponding anisaldehyde by reaction with a methyl hahde, methyl sulfate (35—37), or methyl carbonate (38). The reaction shown produces -anisaldehyde [123-11-5] in 93.3% yield. Other ethers can also be made by the use of the appropriate reagent. 

A. 6 Intramolecular nucleophilic catalysis of the hydrolysis of sulphonamides 238 B Reactions of the hydroxyl group 239... 

Chemical reactions of the hydroxyl groups were reported by Stober eJ, al. (225). y-AlaOj of high surface area (80 m /gm) was esterified with alcohols using the autoclave technique. About 7.7 OCH3 groups per 100 A were formed with methanol. The surface alcoholates are very sensitive to hydrolysis, however. Therefore, the reaction products were... 

Cellulosic fibers (cotton, rayon) are crosslinked by reaction of the hydroxyl groups of cellulose with formaldehyde, diepoxides, diisocyanates, and various methylol compounds such as urea-formaldehyde prepolymers, /V, /V -di tnethylol-A(A -dimethy lene urea, and trimethyl-olmelamine [Marsh, 1966]. Crosslinking imparts crease and wrinkle resistance and results in iron-free fabrics. 

IR spectra for the pillared bentonites in the OH-stretching region show an intense and broad OH-band centered near 3640 cm this band is shifted to near 3600 cm for the ACH-nontronite sample under study, Fig. 1. After pyridine sorption, only minor changes were observed in these spectra, indicating little reaction of the hydroxyl groups present with pyridine. As the degassing temperature is increased from 200 C to 500 C, OH bands decrease in intensity due to dehydroxylation reactions of the clay lattice. Fig. 1. Dehydroxylation is more facile in the iron-containing ACH-nontronite sample. Fig. IF. 

In chemical modifications of inorganic particles, the adsorbed water sometimes affects the reaction of the hydroxyl group with the modifier. According to Fripiat et al. (6), evacuation at 200°C and 10-7 mmHg for 24 h still leaves about 0.2 mmol/ g adsorbed water on silica (Aerosil 200). 

One conventional procedure for organic modification of inorganic particles is to utilize the reaction of the hydroxyl group with silane coupling agents. Many kinds... 

The reactions of the hydroxyl groups of phenols, wherein the O-H bonds are broken, are similar to those of alcohols. Thus phenols are weak acids (Ka = 10-10 to 10 s Table 26-1), intermediate in strength between carboxylic acids and alcohols. 

Functionalisation of the polymer backbone through reaction of the hydroxyl groups (esterification and etherification), nucleophilic displacement reactions, oxidation and selective reactions at the terminal reducing ends... 

Other Cig-fatty acids have also a high potential in hydroformylation, such as ricinoleic acid, which contains an additional hydroxy group at position 12 of the fatty carbon chain and which is not food relevant [26], The hydroformylation of ethyl ricinoleate, derived from castor oil, shows selectivity for cyclization of the carbon chain because of the reaction of the hydroxyl group with the formyl group (Scheme 8). 

All acrylate- and methacrylate-based membranes were synthesized by photopolymerization on top of the polyHEMA interlayer. The resulting FETs showed in the absence of an ionophore a cation response of 36-54 mV/decade and therefore we concluded that residual anionic groups must be present. Titration of the ACE monomer with KOH solution indicated the presence of 7.5 x Id5 eq. acid.g"1 ACE monomer. As shown in Table 2 the ACE was chemically modified by reaction of the hydroxyl group. In this way acetyl, pentanoyl, and hydroxy... 

The dependence of the rate upon the inverse of the hydrogen ion concentration (base-catalysis) is reasonably attributed to the necessity for the coordinated water molecule to lose a proton. The resulting ethyl-ene-hydroxypalladium species (the cis isomer), I, is then believed to undergo an internal addition reaction of the hydroxyl group to the coordinated ethylene to form the dichloro-2-hydroxyethylpalladium anion, II. The final step is a decomposition of the last compound into acetaldehyde, palladium metal, hydrogen ion and chloride anions. 

Alcoholysis. The reaction of the hydroxyl group of an alcohol with a substance a reaction on the part of an alcohol analogous to that of water. 

Scheme 4.351665 illustrates the most common method for synthesising carbonates — reaction of the hydroxyl group with a chloroformate in the presence of base - and a particularly mild method of deprotection, hydrogenolysis, giving toluene and a carbonic acid monoester that decarboxylates to liberate the free hydroxyl.666 Alkoxycarbonyl groups can be easily installed on carbohydrates by reaction with the appropriate chloroformate in the presence of TMEDA at low... 

Several strategies have been employed in supporting metal complexes on oxide surfaces. For example, surface 0x0 and hydroxyl groups may be used as ligands the surface may be modified by reaction of the hydroxyl groups to introduce ligands to the surface, and more recently amorphous metal oxides, such as silica, have been imprinted via sol-gel techniques to generate shape selective cavities. ... 

Alkoxy acids" and esters" have been prepared from the corresponding chloro derivatives. Reaction of the hydroxyl group of methyl lactate with methyl iodide is brought about by silver oxide (65%). Alkylation of the isomeric hydroxy benzoic acids is readily accomplished. ... 

Studies of the synthesis of phosphorus-containing derivatives of cellulose fall into two groups phosphorylation of cellulose with derivatives of phosphoric acids and phosphorous acids, respectively. Until recently, most studies have been of derivatives of cellulose and phosphoric compounds. There are a few publications reporting the synthesis of esters of phosphorous acids and cellulose, but the properties of these compounds have not been studied at all. However, esters ctf phosphorous adds and cellulose can be used for the preparation ctf ters of phosphoric adds and cellulose, which cannot be obtained by direct synttesis (or only with difficulty) by the reaction of the hydroxyl groups of the cellulose macromolecule with phosphorus-containing reagents. 

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