Boric acid phenyl borate

The general formula for boric acid esters is B(OR)2. The lower molecular weight esters such as methyl, ethyl, and phenyl are most commonly referred to as methyl borate [121 -43-7] ethyl borate [130-46-9J, and phenyl borate [1095-03-0] respectively. Some of the most common boric acid esters used in industrial appHcations are Hsted in Table 1. The nomenclature in the boric acid ester series can be confusing. The lUPAC committee on boron chemistry has suggested using trialkoxy- and triaryloxyboranes (5) for compounds usually referred to as boric acid esters, trialkyl (or aryl) borates, trialkyl (or aryl) orthoborates, alkyl (or aryl) borates, alkyl (or aryl) orthoborates, and in the older Hterature as boron alkoxides and aryloxides. CycHc boric acid esters, which are trimeric derivatives of metaboric acid (HBO2), are known as boroxines (1). 

Ebelman and Bouquet prepared the first examples of boric acid esters in 1846 from boron trichloride and alcohols. Literature reviews of this subject are available. B The general class of boric acid esters includes the more common orthoboric acid based trialkoxy- and triaryloxyboranes, B(0R)3 (1), and also the cyclic boroxins, (ROBO)3, which are based on metaboric acid (2). The boranes can be simple trialkoxyboranes, cyclic diol derivatives, or more complex trigonal and tetrahedral derivatives of polyhydric alcohols. Nomenclature is confusing in boric acid ester chemistry. Many trialkoxy- and triaryloxyboranes such as methyl, ethyl, and phenyl are commonly referred to simply as methyl, ethyl, and phenyl borates. The lUPAC boron nomenclature committee has recommended the use of trialkoxy- and triaryloxyboranes for these compounds, but they are referred to in the literature as boric acid esters, trialkoxy and triaryloxy borates, trialkyl and triaryl borates or orthoborates, and boron alkoxides and aryloxides. The lUPAC nomenclature will be used in this review except for relatively common compounds such as methyl borate. Boroxins are also referred to as metaborates and more commonly as boroxines. Boroxin is preferred by the lUPAC nomenclature committee and will be used in this review. 

A variety of chelates of B-compounds are formed by polyols. For instance, phenyl glycol may be used to extract sodium borate from dilute aqueous solutions. Recently, 2-ethyl-hexanol in kerosene was used to extract boric acid from aqueous solutions (57). 

Overbased Mo-alkylene earth metal sulfonates 2,6-Di-ferf-butyl-4-methyl phenyl-borate Borated polyhydroxy-alkyl sulfides Borated N-hydrocarbyl alkylene triamines Product of boric acid and cocosyl sarcosene Product of 1,2-hexadecanediol, C15-C19 alcohols and boric acid Zinc salts of partially borated and partially phosphosulfurized penta or dipentaerythritol N-Oleylglycolamide N-Alkoxylakylene diamine diamide N-Cocoformamide... 

Boronic acid chemistry has its roots in the work of Frankland, who in 1860 documented the preparation of ethylboronic acid, with the first synthetic publication on organoboron chemistry (The structures of boric acid and phenyl boronic acid are shown in Figure 4). " In 1880 Michaelis and Becker reacted borontrichloride and diphenyl mercury to form dichlorophenylborane. This in turn was added to water and recrystallised as white needles in the first synthesis of phenylboronic acid. The route was refined in 1909 and the classical synthesis of boronic acids from Grignard reagents and trialkyl borates was established. ... 

The presence of B(OH>3 increases the rate of hydrolysis of ionized phenyl salicylate (PS ) by nearly 10 -fold compared to the rate of hydrolysis of phenyl benzoate under essentially similar conditions (Equation 2.34). However, the hydrolysis of PS crtn also occur with measurable rate in the absence of B(OH)3. Nearly 10 -fold rate enhancement due to the presence of boric acid is attributed to the boric-acid-induced intramolecular reaction involving transition state TS,6. An alternative and kinetically indistinguishable mechanism involving transition state TSiy has been ruled out on the basis of the absence of enhanced nucleophilic reactivity of tertiary and secondary amines toward phenyl salicylate in the presence of borate buffer. 

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