Halogen-alcohols

The usual containers for shipping are glass for small quantities, and steel cans, dmms, or tank cars for bulk items. Over a period of time, moisture passes through the walls of some plastic containers. If this occurs, the more hydrolytically unstable borate esters may hydroly2e. Thus caution should be used when storing borate esters in plastic. In addition, shipping in metal cans or dmms is not acceptable where hydrolysis can lead to a corrosive product, such as a halogenated alcohol. 

Activated esters of halogenated alcohols, such as 2-chloroethanol, 2,2,2-trifluoroethanol, and 2,2,2-trichloroethanol, have been often used as substrate for enzymatic synthesis of esters, owing to an increase in the electrophilicity (reactivity) of the acyl carbonyl and avoid significant alcoholysis of the products by decreasing the nucleophilicity of the leaving alcohols. ... 

Electronegative substituents, such as halogens, alcohol, and ether functions, deshield the fluorine nuclei of CF2 groups when they are attached directly to the carbon bearing the two fluorine substituents, whereas electronegative substituents at the (3-position always have a shielding influence. 

Produced by action of carbon monoxide on potassium in liquid ammonia at —50°C, the yellow powder bums explosively in contact with air, halocarbons, halogens, alcohols, water and any material with acidic hydrogen. Analogous metal derivatives are reviewed. 

Chau and Terry [146] reported the formation of penta-fluorobenzyl derivatives of ten herbicidal acids including 4-chloro-2-methyl-phenoxy acetic acid [145]. They found that 5h was an optimum reaction time at room temperature with pentafluorobenzyl bromide in the presence of potassium carbonate solution. Agemian and Chau [147] studied the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxy butyric acid from water samples by making the pentafluorobenzyl derivatives. Bromination [148], nitrification [149] and esterification with halogenated alcohol [145] have also been used to study the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxybutyric acid. Recently pentafluorobenzyl derivatives of phenols and carboxylic acids were prepared for detection by electron capture at very low levels [150, 151]. Pentafluorobenzyl bromide has also been used for the analytical determination of organophosphorus pesticides [152],... 

M. Jackson and H. H. Mantsch, Halogenated alcohols as solvents for proteins FTIR spectro scopic studies. Biochim. Biophys. Acta 1118, 139 143 (1992). 

Carboxylic acids containing halogens are easily reduced to halogenated alcohols... 

Catalytic hydrogenation is hardly ever used for this purpose since the reaction by-product - hydrogen chloride - poses some inconveniences in the experimental procedures. Most transformations of acyl chlorides to alcohols are effected by hydrides or complex hydrides. Addition of acyl chlorides to ethereal solutions of lithium aluminum hydride under gentle refluxing produced alcohols from aliphatic, aromatic and unsaturated acyl chlorides in 72-99% yields [5i]. The reaction is suitable even for the preparation of halogenated alcohols. Dichloroacetyl chloride was converted to dichloro-... 

The possibility of hydrogenating halogenated aldehydes and ketones by means of phytochemical reduction was tested as early as 1913 the successful results in this field clearly demonstrate the importance of this method. Lintner and Ltters found that chloral hydrate can be converted to trichloroethyl alcohol. This transformation takes place so easily that, according to Willstatter and Duisberg, it can be used under favorable experimental conditions as a convenient method for the preparation of the halogenated alcohol. The tribromoethyl alcohol may be prepared in an analogous manner. 

Similarly, methyl a-chloroethyl ketone, a, -dichloroacetone and a,a,/3-trichlorobutyraldehyde have been converted phytochemically and in good yield to the corresponding primary or secondary halogenated alcohols. Since all these alcohols show optical rotation, it seems established that the phytochemical reduction generally takes an asymmetric course. (See pp. 80, 81, 88 and 92.)... 

Brand Name(s) Aquachloral Supprettes, Somnote Chemical Class Halogenated alcohol... 

Thomas, R.M. Levek, R.P. (1972) Process for die production of halogenated alcohols. US Patent US-3,681,468, Patent Assignee Great Lakes Chemical Corp. [Abstract CA76-013805]... 

In the condensation of diols, halogenated alcohols, amino alcohols, cyclic hydroxy ethers, or other bifunctional hydroxy compounds with carbodiimides, 5-, 6-, and 7-membered 1,3-O-N- or l,3-7V,7V-heterocyclics are obtained [14]. 

In the substrates, special attention has been devoted to zeolites and fullerenes [34, 38, 39, 44], in the reactions to acid-base equilibria and the influence of hardness and softness on both sides of the equilibrium (acidity of carboxylic acids [45], alkyl [46] and halogenated alcohols [47], hydrides [48] and recently hydrofullerenes [49], basicity of amines [50, 51] and proton affinities of amino acids [52]). For reviews of these studies, see [18, 53, 54],... 

Halohydrins are /J-halogenated alcohols. They can be obtained in H20-containing solvents from alkenes and reagents, which transfer Hal ions. N-Broniosuccinnuide (transfers Br Figures 3.43 and 3.44 as well as 3.47), chloramine-T (transfers Cl Figure 3.46), and elemental iodine (transfers I Figure 3.47) have this ability. Bromonium and chloronium ions react with H20 via an SN2 mechanism. This furnishes the protonated bromo- or chlorohydrins, which are subsequently deprotonated. 

TABLE 7. Ionization energies of halogenated alcohols ROH1851... 

The most important derivatives of this mixed type are those obtained by substituting, in alcohols, aldehydes, or acids, some other element or group. This gives us compounds known, in general, as substituted alcoholsj substituted aldehydes, and substituted acids. These three classes of mixed compounds will now be considered. The simplest group of substituted alcohols are the halogen alcohols. Of the halogen alcohols the simplest would be derived from methyl alcohol, e.g.,... 

Halogen Hydrines.— Another type of halogen-alcohol is possible in the case of alcohols containing two or more carbon groups. The halogen may enter the other carbon group than the one in which the hydroxyl is already present, e.g.,... 

In such cases, with the halogen and hydroxyl linked to different carbon atoms, stable compounds result. As direct action of halogens oxidizes the alcohol to aldehyde or ketone, this new kind of halogen-alcohol must be prepared by a different reaction. When poly-hydroxy alcohols react with halogen acids, e.g.j hydrochloric acid, HCI, or with phos-... 

From the higher poly-hydroxy alcohols similar halogen-alcohols are obtained, which are known, also, as halogen-hydrines, e.g. ... 

The halogen acids, of course, bear the same relation to the halogen aldehydes and the halogen alcohols (halogen hydrines) that unsubstituted acids do to the unsubstituled aldehydes and alcohols. That is, they are the direct oxidation products. 

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