Boric Acid Esters Research Articles

Polymere mit phosphor‐stickstoff‐bindungen, 5. Zu reaktion und polymerisation von (NPCI2)3 in gegenwart von elementhalogeniden und borsäureestern

AbstractHexachlorocyclotriphosphazene (1) reacts with SbCl5 or BCl3 to produce long chain polymers, whereas AlCl 3 gives phosphazenyl cations. TiCl4 does not react and boric acid esters lead to an exchange of one ester group for one chlorine. 31P NMR‐spectra were used to identify the reaction products. The molecular weights of the polymeric compounds were measured.

Organoboron compounds 346. Addition of allyl(alkyl)boranes to carbonyl compounds

1. Allyl(dialkyl)boranes and diallyl(alkyl)boranes react with carbonyl compounds by the addition of the boron-allyl fragment to the double bond of the C=O group (according to the scheme of heteroorganic synthesis). The addition proceeds with the allyl rearrangement. 2. The reaction of allylboranes with aldehydes, ketones, and esters, followed by hydrolysis or transesterification of the unsaturated esters of boric acids thus formed, is a convenient method for the synthesis of 1-substituted 3-butenols and dienic alcohols.

Über die Boronierung von Polystyrol

Boronic acid groups can be introduced in crosslinked and linear polystyrene by metalation with the complex butyllithium/N,N,N′,N′-tetramethylethylenediamine and subsequent treatment with boric acid esters. Investigations of the photochemical boronation of polystyrene by boron tribromid show that the reaction is accompanied by strong chain degradation, whereas the former method leads to an increase in molecular weight.

Über die boronierung von polystyrol

AbstractBoronic acid groups can be introduced in crosslinked and linear polystyrene by metalation with the complex butyllithium/N,N,N′,N′‐tetramethylethylenediamine and subsequent treatment with boric acid esters. Investigations of the photochemical boronation of polystyrene by boron tribromid show that the reaction is accompanied by strong chain degradation, whereas the former method leads to an increase in molecular weight.

Die Hydrolyse einiger Borsäureester unter Base-Einfluß in nichtwäßrigen Lösungsmitteln / The Hydrolysis of Some Tris(organyloxy)boranes under Alkaline Influence in Non-aqueous Solvents

The hydrolysis of tris(organyloxy)boranes (boric acid esters) in organic solvents in the presence of KOH leading to potassium polyborates (free from water of crystallization) is studied as to the influences of (a) the reaction medium (ethanol or ligroine/ethanol), (b) the concentration of water, (c) the organyl group of the boric acid ester (methyl, isopropyl, or phenyl), (d) the time of stay of the precipitated insoluble polyborates under the mother liquor (15 to 61850 s), and (e) the temperature during precipitation and the time of stay (—18 to + 60°C). In the first stage of the reaction, during precipitation time, ester hydrolysis is followed by condensation, while aggregation and desorption processes occur between the time of precipitation and filtration.

Complex formation of 1-methylcyclohexylhydroper oxide with esters of boric acid

resonance spectra (NMR spectra) of the hydroperoxidein carbontetrachlor ide were taken on an RYa-2306 instrument at a working frequency of 60 MHz. Hexamethyldisiloxane was used as the standard. The signals of boron were recorded on a spectrometer at a working frequency of 9.179 MHz. The half-width of the signal was measured by the side-line method. Measurements of the heats of combustion of the compounds studied were conducted in a "Labor" OQ-202 adiabatic calorimeter at a water temperature of 22 ~ in the outer jacket of the vessel. Benzoic acid was used as a standard in determining the water equivalent of the calorimeter. The energy of the ]3~ O donor--acceptor bond was found from the equation EB~O = (ATcatc--ATact)VM1 kcal/mole, Gin 1000 where M 1 and G1 are the molecular weight and sample weight of the hydroperoxtde; ATcalc is the calorimetric temperature difference, calculated from the heats of combustion of the individual substances; ATac t is the actual calorimetric temperature difference on combustion of mixtures of the ester and the hydroperoxide; and n is the ratio of the concentrations of ester and hydroperoxtde in the complex. Measurement of refractive indices was conducted on an Abbe'refractomet er. In the study of the IR spectra of mixtures of 1-MCHP and n-butyl borate, a shift of the characteristic absorption frequencies of the ester and hydroperoxide could not be detected. The band of most intense ]3 -- O valence bond stretching absorption, at 1340 cm -1 [7], is overlapped by the intense absorption bands of 1-MCHP and 1316 and 1359 cm -1. As is well known, the peroxide group very rarely gives a satisfactorily characteristic absorption band, because of overlap with the absorption bands of other groups [8, 9]. The strongest change in the IR spectra on increasing the concentration of the boric acid esters consisted in an intensification of the intensity of the absorption band for the stretching vibrations of bonded OH-groups and by a corresponding weakening of the intensity of the absorption band (3562 cm -1) for monomertc hydroxyls (Fig. 1). Thereupon the maximum in the absorption band of the associates was shifted from 3400 to 3367 cm -1, which corresponds to a bond energy in the associations of 3.4 kcal/mole per OH-group (the bond energy in the self-associates of 1-MCHP is 2.8 kcal/mole [10]).

Mass spectrometry in structural and stereochemical problems‐CCXXIX: Electron‐impact‐induced fragmentation of boric acid esters

AbstractThe mass spectral decompositions of cyclic and acyclic borates have been examined. Straight chain trialkyl borates fragment by CO cleavage reactions accompanied by transfer of one or two hydrogen atoms, whereas tri‐(sec‐alkyl) borates primarily undergo α‐cleavage reactions. Both types of cleavage are observed in the fragmentation of cyclic borates. BO bonds are not broken in the formation of most major fragment ions. The fragmentations of borates are compared with those of phenylboronates with special emphasis on the rearrangements leading to hydrocarbon ions in the spectra of the latter.

Boric acid esters as secondary plasticizers for poly (vinyl chloride)

AbstractIn addition to the primary plasticizers which are essential for giving the required ease of processing to and improving desirable mechanical properties of polyvinyl chloride (PVC) compounds, secondary plasticizers also play a significant role in confering specific properties to PVC. It was from this point of view that the boric acid esters were evaluated in PVC compositions. Because of the limited compatibility of boric acid esters with PVC by themselves, their use could be recommended only as secondary plasticizers. In the present paper various boric acid esters prepared in this laboratory [S. P. Potnis and A. G. Khanolkar, Popular Plastics, 15, 20 (1969)] have been evaluated for their performance in PVC compounds, and results obtained indicate that the monomeric and alicyclic esters of boric acid could be used with definite advantage and improve such properties as electrical resistance, heat stability, and in some cases even the mechanical properties.

A modified method for determination of boron with curcumin and a simplified water elimination procedure

The formation of boric acid ester with curcumin is usually performed in highly acidic solution in the absence of water. Small water contents are permissible, but the efficiency is lowered. The water content of a sample can be eliminated by a reaction with propionic anhydride catalyzed by oxalyl chloride, thus avoiding methyl borate distillation or evaporation processes. An advantage is that the reaction between boron and curcumin takes place in a completely homogeneous liquid medium. The excess of protonated curcumin is best destroyed with an ammonium acetate buffer. For trace amounts of boron, extraction of the coloured complex with a mixture of methyl isobutyl ketone, chloroform and phenol is recommended. Standard procedures for aqueous solutions with boron contents between 0.0033–40.0 μg B/l are described.

Boric acid esters. I. General survey of aromatic ligands and the kinetics and mechanism of the formation and hydrolysis of boric acid esters of salicylamide, N-phenylsalicylamide, and disalicylimide

Boric acid esters. I. General survey of aromatic ligands and the kinetics and mechanism of the formation and hydrolysis of boric acid esters of salicylamide, N-phenylsalicylamide, and disalicylimide

Mechanism of the effect of boric acid on liquid-phase oxidation of paraffin hydrocarbons

OXIDATION of paraffin hydrocarbons in the presence of boric acid forms the basis of the industrial production of higher aliphatic alcohols [1]. The use of boric acid improves process selectivity and increases alcohol yield. The alcohols obtained during oxidation are basically secondary alcohols with a statistical distribution of the functional group along the chain, retaining the structure of the initial hydrocarbon [2, 3, 4]. According to present views, dltring the reaction boric acid interacts with alcohols to form compounds, borates, which are less reactive to oxidation, thus preventing any further possible oxidation of alcohols [5, 6]. Further information has recent ly been obtained of the effect on oxidation of boric oxide [5, 7], boric acid esters [5], of the effect of certain boron ecrupounds on the accumulation and decomposition of alkylhydroperoxide [7, 8]; the inhibiting effect on oxidation of some of them was established [5, 9, 10]. The results of these investigations indieate that the effect of compounds containing boron is not restricted to protective functions in relation to alcohols. Apparently, during the oxidation of hydrocarbons in the presence of the above compounds the rates of elementary stages may vary, new directions of reaction be formed, particularly with radicals [7, 11] or intermediate compounds [7, 8] responsible for the chain process of oxidation. The s tudy of the mechanism of action of compounds containing boron, in the oxidation of hydrocarbons is of considerable interest. This paper reports the continuation of earlier investigations into oxidative conversions of aliphatic hydrocarbons and gives the results of a kinetic s tudy of the oxidation of paraffins in the presence of boric oxide.

Die darstellung von ammoniumpolyboraten durch hydrolyse von borsäureestern in organischen lösungsmitteln in gegenwart von ammoniak

The careful hydrolysis of boric acid esters with a small quantity of water in organic solvents in the presence of ammonia yields according to the proportions of the concentration of boric acid ester, ammonia and water the polyborates NH 4[B 5O 6(OH) 4], NH 4[B 4O 4(OH) 5], NH 4[B 3]O 3(OH) 4] and [NH 4B 3O 5] n. The possible structures for the complex polyborate anions have been discussed.

The possibility of producing higher glycols by liquid-phase oxidation of alkanes

IN an investigation of the composition of the products of the liquid-phase oxidation of alkanes in the presence of boric acid, it was established [1, 2] that , in addition to alcohols and ketones, some bifunctional neutral oxygencontaining compounds (glycols and ketoalcohols) are formed. In view of this, it was of considerable interest to investigate the possibility of carrying out the synthesis of neutral bifunctional compounds, in the first place glycols, by the liquid-phase oxidation of hydrocarbons. In planning the investigation, the main results of which are reported below, we were guided by the idea that the formation of the bifunctional compounds as a result of a termolecular reaction of a molecule of alkane with two molecules of oxygen is improbable. The probability of such a reaction is decreased further by the fact that this must be preceded by the formation of oxygen biradicals, since, according to the ideas most widespread in the literature [3] on the mechanism of the liquid-phase oxidation of hydrocarbons, the initial stage of the oxidation consists in a reaction between molecular oxygen and an alkyl radical of the hydrocarbon molecule, R ÷ 0 2 -~ RO.',. I t must therefore be assumed that other routes exist leading to the formation of polyfunctional compounds. One of them, apparently, can be the further oxidation of monofunctional oxygencontah~ing compounds produced in the liquid-phase oxidation of the hydrocarbons. In this case, as the concentration of monofunctional compounds in the hydrocarbons being oxidised rises, the proportion of polyfunctional compounds in the oxygen-containing reaction products must increase. This assumption was subjected to an experimental check. The laboratory apparatus and the procedure used were the same as in previous investigations [4]. The product obtained on oxidation was subjected to t reatment with hot water to decompose boric acid esters, dried over anhydrous sodium sulphate, and analysed for its content of functional groups by standard methods. As a supplement to chemical analysis, chromatographic separation o f the oxidate was carried out, which enabled the proportion of bifunctional compounds in the neutral reaction products to be evaluated. For

Exchange reactions between esters of boric and boroorganic acids and their thioanalogs

Exchange reactions between esters of boric and boroorganic acids and their thioanalogs

A New Class of the Complex Hydrides

WHILE studying the reaction of aluminium hydride with esters of boric acid, the formation of a new type of the complex hydrides was observed. Thus, aluminium hydride reacts with isopropyl borate in ethyl ether, giving rise to a typical representative of the new type of hydride compounds: The product is a colourless liquid, distillable in vacua (boiling point at about 120° C. at 0.5 mm. pressure, without decomposition). The yield is about 85 per cent. Analysis: B3Al4H75O9C27 (molecular weight, calculated 684.25). B, 4.58 per cent; Al, 15.7 per cent; H, 11.05 per cent; Hactive (assay by decomposition with diluted hydrochloric acid), 1.79 per cent. C, 45.95 per cent. Calculated values: B, 4.73 per cent; Al, 15.7 per cent; H, 11.01 per cent; Hactive, 1.76 per cent; C, 47.3 per cent. Complex formation between complex borohydrides and alcoholates is not recorded in the literature, although the possibility of the formation of mixed crystals of lithium borohydride with lithium methoxide has already been considered1.

The determination of boron in boric acid esters

Boric acid esters of high hydrolytic stability which would require prolonged periods of reflux for hydrolysis and subsequent titration of boric acid can be analyzed conveniently for boron by fusion with sodium carbonate, solution of the melt, and titration of the boric acid in the presence of mannitol. Boric acid esters of phenols or alkanolaniines which cannot be analyzed by litration of the boric acid due to the interference of the acidic phenolic or basic aminc residues can also be analyzed by the carbonate fusion method. The method has also been applied to esters of primary and tertiary alcohols as well as polyhalo, olcfinic, and carboxyl-containing borates. Further applicability to organoboron compounds containing boron-carbon and boron-nitrogen bonds is indicatcil. The PARR peroxide bomb method has also been found to be generally applicable for the determination of boron in boric acid esters.

A Method of promoting Water-forming Organic Reactions

THE great reactivity of the boric acid esters with water is well known; moreover, recently even the equilibrium constants of their hydrolysis have been measured1. So far as is known to us, hitherto the borates have not been used for promoting water-forming (condensation) reactions.

The infra-red spectra of the Borate esters

The infra-red spectra of a series of alkyl and aryl esters of boric acid have been obtained in the region from 1800 to 670 cm-1. These all show a strong characteristic absorption band at 1340 � 10 cm-1 which is assigned to the asymmetrical stretching frequency of the BO3 group. Comparison of the infra-red and Raman spectra of trimethyl borate suggests the assignment of the 728 cm-1 Raman band to the symmetrical stretching mode. The non-coincidence of infra-red and Raman bands indicates a fairly high degree of symmetry with restriction of the rotation of the methyl groups round the B-O link. This contrasts with other data on the behaviour in the vapour where such rotation may occur.

Parachors Of some esters of 5-nonanol

1. The 5-nonyl esters of carbonic, malonic, boric and orthosilicic acids, nor previously described in the literature, were synthesized. 2. The parachors that we obtained indicate the necessity for corrections for the parallelity of the main and side chains.

427. Thermochemistry of organo-boron compounds. Part I. Esters of boric acid

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