Hydroxyl-containing compounds

Chromic acid, nitric acid, hydroxyl-containing compounds, ethylene glycol, perchloric acid, peroxides, or permanganates Concentrated nitric and sulphuric acid mixtures Chlorine, bromine, copper, silver, fluorine or mercury Carbon dioxide, carbon tetrachloride, or other chlorinated... 

Chromic acid, nitric acid, hydroxyl-containing compounds, ethylene glycol, perchloric acid, peroxides, and permanganates. 

Reactive halogen crosslinkers are mainly specific for sulfhydryl groups at physiological pH, however at more alkaline pH values they can readily cross-react with amines and the imidazole nitrogens of histidine residues. Some reactivity with hydroxyl-containing compounds also may be realized, particularly with dichloro-s-triazine derivatives under alkaline conditions. 

Generally, hydroxyl-containing compounds form with peroxyl radical an equilibrium system... 

Two different mechanisms have been proposed for the ROP of (di)lactones depending on the nature of the organometalhc derivatives. Metal halides, oxides, and carboxylates would act as Lewis acid catalysts in an ROP actually initiated with a hydroxyl-containing compound, such as water, alcohol, or co-hydroxy acid the later would result more hkely from the in-situ hydrolysis of the (di)lac-tone [11]. Polymerization is assumed to proceed through an insertion mechanism, the details of which depends on the metal compound (Scheme la). The most frequently encountered Lewis acid catalyst is undoubtedly the stannous 2-ethylhexanoate, currently referred to as stannous octoate (Sn(Oct)2). On the other hand, when metal alkoxides containing free p-, d-, or f- orbitals of a favo-... 

In contrast to isocyanates, isothiocyanates are relatively unreactive toward hydroxyl-containing compounds thus they are not even affected by aqueous media [31]. Their reaction with hydroxyalkyl thioureas has been reported [32]. With free 2-mercaptoethylamine, 1 mole of phenyl isothiocyanate gave the N-substituted product, l-(2-mercaptoethyl)-3-phenyl-2-thiourea, and 2 moles gave the N,S-disubstituted product. Isocyanates, regardless of the relative amounts, reacted with 2-mercaptoethylamine to give the N,S-disubsti-tuted products. Cleavage with silver nitrate affords the l-(2-mercaptoethyl)-3-alkylureas [33]. 

Acetic acid is an important industrial chemical. The reaction of acetic acid with hydroxyl-containing compounds, especially alcohols, results in the formation of acetate esters. The largest use of acetic acid is in the production ofvinyl acetate (Figure 1.1). Vinyl acetate can be produced through the reaction of acetylene and acetic acid. It is also produced from ethylene and acetic acid. Vinyl acetate is polymerized into polyvinyl acetate (PVA), which is used in the production of fibers, films, adhesives, and latex paints. 

It is well known 113,14 20 25> that the addition of hydroxyl-containing compounds (water, alcohols, phenols, acids) considerably promotes the interaction of epoxy compounds with amines and other nucleophilic reagents. In this case, the epoxy ring carbon atom becomes more sensitive to nucleophilic attack. The reaction proceeds through a trimolecular transition state initially suggested by Smith26 27) for the reactions of epoxy compounds with amines2... 

This equation is in agreement with the experimentally found dependence of the reaction rate on amine concentration. The decrease of the order of the reaction kinetics with respect to amine concentration in the presence of hydroxyl-containing impurities is partially due to the catalytic mechanism when a hydroxyl-containing compound, whose acidity is far higher than that of amine, acts as a proton donor. It should be stressed that, with the usual technique of reagent purification and cleaning of the reaction vessels, the moisture content in the reaction mixture is still rather high, and the order of the reaction kinetics with respect to aniline concentration considerably differs from two. 

Therefore, the reaction of an epoxy compound with amine can proceed in the absence of hydroxyl-containing compounds specially added or occurring as impurity, the amine acting both as a nucleophilic and an electrophilic reagent. 

Scheme (8) does not include additives of hydroxyl-containing reagents, and H denotes the hydroxyl groups formed as a result of the reaction. If a hydroxyl-containing compound is added to the system, the kinetic Scheme (8) should be supplemented. Finally, in the formation of autocomplexes it is necessary to distinguish linear and cyclic forms whose reactivities are rather different. The cyclic forms are completely deactivated, i.e. they do not take part either in reaction 2 or in reactions 3-5 in Scheme (8). 

Let us consider this problem in more detail. In fact, the autoassociates of the hydroxyl-containing compounds and amines can be composed of molecules, having different reactivities in the interaction with amine. Therefore, the actually observed reaction rate constant is complex in its composition. Thus, even the simplest noncatalytic (in the absence of proton donors) reactions of the epoxy compound with amine, considering all the donor-acceptor interactions, is generally described by the following kinetic scheme ... 

Hydroxyl-containing compounds are very suitable for transformation into esters, enabling detection improvement when proper labels are introduced. Most commonly, benzoyl chlorides with various spectroscopic properties are used, but phenyldimethylsilylchloride or phenylisocyanates are also applied. 

The active species in the accelerating effect of hydrogen chloride is presumed (25) to be the chloride ion which acts as a strong base. In a protic environment—e.g., in the presence of water or a hydroxyl-containing compound—the hydrogen chloride becomes a strong acid and the auto-catalyzed decomposition is prevented. 

For the sensitive and selective detection of trace amounts of low-molecular-weight alcohols and other hydroxyl-containing compounds by means of the alkali FID, Vilceanu and Schulz [43] prepared phosphorus-containing derivatives. Derivatives 5.1 and 5.2 were prepared by the reaction with 2-chloro-l, 3,2-dioxaphosphorinane (5.3) and 2-chloro-1,3,2-dioxaphospholane (5.4), respectively, in the presence of triethylamine in benzene, which proceeds very quickly, and were particularly suitable for the determination of trace amounts of alcohols in non-alcoholic and anhydrous media. Retention indices of these derivatives of alcohols up to C5 are listed in Table 5.4. 

In general, primary hydroxyl groups are faster to react than secondary hydroxyls, which are in turn faster than tertiary hydroxyls, absent catalysts. When reacted with hydroxyl-containing compounds, aliphatic isocyanates tend to be more sluggish than their aromatic counterparts. Urethane linkages made with tertiary hydroxyls tend to be less stable and at... 

TFA-water at rt or by PPTS (pyridinium p-toluensulfonate) in DCE (dichlo-roethane)-n-BuOH 1/1 at 60 °C for 16 h to release hydroxyl-containing compounds. 

A different approach to the synthesis of aldosyl phosphates involves the intermediacy of aldosyl phosphites [470], The reaction of the anomeric hydroxyl group, with a trivalent phophitylating reagent, furnished an anomeric phosphorochloridite, which is able to react with a hydroxyl-containing compound, to generate a phosphorous triester which, upon oxidation gives the corresponding aldosyl phosphoric triester (O Scheme 83). 

Polymerisation occurs by addition of a hydroxyl-containing compound to an isocyanate group as follows ... 

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