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The ultrasonic velocity and density for ternary liquid mixtures containing tetrabutylammonium bromide and some inorganic salts in water as a function of electrolyte concentration were measured in the temperature range 293–318 K. These data have been used to estimate the acoustical parameters. The observed variation of these parameters helps in understanding the nature of ion-solvent and ion-ion interactions in the liquid mixtures. The results are discussed in terms of structure-making tendency of additive inorganic salts in the mixtures.

A new series of spiro[[1,3]dithiolane-2,3′-indolines]-2′-one derivatives was synthesized using Michael addition reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one to various α,β-unsaturated esters as well as direct alkylation of this compound with alkyl dihalides. Michael reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one and α,β-unsaturated esters produced related Michael adduct in the presence of tetrabutylammonium bromide and base 1,4-diazabicyclo[2.2.2]octane in good to excellent yields at 80°C under solvent-free conditions. Also, direct alkylation of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one by dihaloalkanes in the presence of base K2CO3 afforded the corresponding products in good yields under the same conditions.

The chlorofullerene C60Cl6 was demonstrated as a versatile precursor for the synthesis of two isomerically pure fullerenols via tetrabutylammonium bromide promoted reactions with water. Performing the synthesis in wet chlorobenzene produced 1,4-C60(OH)2 as the only isolable product along with substantial amounts of non-functionalized C60. However, the addition of DMSO as a co-solvent altered the reaction pathway, leading to the formation of C60(OH)5Br as the main product. Both isolated compounds were novel and their molecular compositions and structures were confirmed by mass spectrometry and NMR spectroscopy. The fullerenol C60(OH)5Br, which was formed in a moderate yield, represents the first isomerically pure polyhydroxylated fullerene available on a large scale.

Metal-free oxidative bromination reactions in aqueous media were performed using tetrabutylammonium bromide, trifluoroacetic acid, and hydrogen peroxide under mild conditions. Oxidative bromination reaction of alkenes was found to afford the corresponding vic-bromides. Furthermore, this oxidative bromination system is applicable to the oxidative bromination of alkynes, arenes, and 3,4-dihydronaphthalen-1(2H)-one. A gram-scale bromination reaction was also performed successfully.

This report describes the α-stereoselective addition of alcohols to glycals promoted by a cooperative Lewis acid/base pair catalytic system composed of B(C6F5)3 and tetrabutylammonium bromide (TBAB), which provides access to 2-deoxylglycosides in high yields. A mechanistic investigation supported by NMR analysis highlights the possible involvement of nucleophilic addition through boron-induced activation of alcohols under the assistance of TBAB. The protocol discussed here features the high stereoselectivity, mild reaction conditions, inexpensive and stable catalysts, and a broad substrate scopes.

An efficient and broadly applicable protocol for the aerobic coupling of styrenes with sulfonylhydrazides has been developed that affords β-ketosulfones bearing various functional groups in moderate to excellent yields. The preliminary experimental results support the involvement of active benzyl radical species, and a radical pathway was therefore proposed for the reaction.

A convenient and efficient method was developed for the synthesis of arylacetones from (E)-3-aryl-2-methylacrylic acids through a Curtius rearrangement. The Curtius rearrangement of (E)-3-aryl-2-methylacryloyl azides and subsequent hydrolysis proceeded at mild temperatures in a two-phase medium of carbon tetrachloride and water containing a catalytic amount of tetrabutylammonium bromide to give the corresponding derivatives in 82–93% yield.

A bimetallic aluminium(salphen) complex is reported as a sustainable, efficient and inexpensive catalyst for the synthesis of cyclic carbonates from epoxides and carbon dioxide. In the presence of this complex and tetrabutylammonium bromide, terminal and internal epoxides reacted at 50 °C and 10 bar carbon dioxide pressure to afford their corresponding cyclic carbonates in yields of 50-94 % and 30-71 % for terminal and internal cyclic carbonates, respectively. Mechanistic studies using deuterated epoxides and an analogous monometallic aluminium(salphen) chloride complex support a mechanism for catalysis by the bimetallic complex, which involves intramolecular cooperative catalysis between the two aluminium centres.

In this study, CO2 capture from (67.00 mol %) CH4/CO2 mixed gas with tetra-n-butylammonium bromide (TBAB) solution at 281.3 K through a pressure recovery of hydrate separation method were studied. During the experiment, pressure was recovered by TBAB solution injected into the cell to improve the separation efficiencies of CO2, and the effects of the concentration of TBAB solution and the operating conditions was investigated. The results showed that the CH4 concentration in the gas phase could achieve 93.52 mol % with a pressure recovery method at 1.14 MPa and 0.293 mol % TBAB. Under the pressure of 1.14 MPa and 0.1 mol % TBAB, the maximum CO2 separation factor was 52.87 and the CH4 separation and recovery factor was 2.050. The results demonstrated that the pressure recovery method can significant enhance the separation efficiency of hydrate separation. It is an effective method to cut down energy consumption of hydrate-based gas separation.

The direct conversion of simple and sterically hindered Nα-protected amino/peptide hydroxamic acids to O-benzyl hydroxamates employing K2CO3, tetrabutylammonium bromide and benzyl bromide is described. In addition, Cbz-Ala-CONHOH and Cbz-Phe-CONHOH derived acylaminoxy peptides 3j and 3k have also been prepared. The method is of importance in the view of easy availability of precursors, catalyst and reaction conditions. All the products are obtained in moderate to good yields.

Size exclusion chromatography (SEC) columns pre-treated with a tetrabutylammonium bromide (TBABr) solution were used to develop a new method for extracting the microgel of Natural Rubber (NR). A solution of microaggregates smaller than 1 μm (Microgel

This paper reports experimental values of the interfacial tension between (CO2 + N2) gas and tetrabutylammonium bromide aqueous solution (TBABaq). The experiments were performed by the pendant drop method in conditions from P = (1.00 to 4.00) MPa, from T = (288.15 to 303.15) K and from wTBAB = (0.10 to 0.40), where wTBAB denotes the mass fraction of TBAB in the aqueous solution. The interfacial tension decreased with increasing wTBAB and pressure. The depletion of the interfacial tension with increasing wTBAB in the (CO2 + N2 + TBABaq) system was consistent with that in (CO2 + TBABaq) system. The depletion ratio of the pressure gradient of the interfacial tension caused by the addition of TBAB in (CO2 + N2 + water) system was almost the same as that in (CO2 + water) system. There might be little effect on the interfacial tension caused by the interaction between gases and tetrabutylammonium ions. The temperature dependence of γ was not observed as well as in the (CO2 + TBABaq) system.

A series of Al(III) unsymmetrical β-aminoalcohol based complexes 1–6 were synthesized via metalation of the corresponding ligands 1′–6′ those were prepared by the reaction of benzylamine with readily available epoxides viz., styrene oxide, 1,2-epoxy-3-phenoxypropane, 4-tertbutylphenyl glycidyl ether, 4-chlorophenyl glycidyl ether, glycidyl 2-methylphenyl ether and 1,2-epoxyhexane. Among these complexes, the complex 2 was found to be most effective in the cycloaddition of aryloxy/aliphatic terminal epoxides with CO 2 under atmospheric pressure to get corresponding cyclic carbonates with high conversion and selectivity (up to >99%) in the presence of tetrabutylammonium bromide as a co-catalyst. The DFT calculations revealed the important role played by counter-ion in the co-catalyst during cycloaddition reaction of CO 2 with the substituted epoxides.

Despite significant progress, copper-catalyzed/mediated C-H amination reactions with electron-rich anilines remain an unsolved problem due to catalyst deactivation and deleterious side reactions. Herein, we report a copper(II)-mediated C(sp(2))-H amination of benzamides with electronically neutral or electron-rich anilines. A dramatic influence of silver(I) and tetrabutylammonium bromide was observed on the reaction outcome. The present protocol also demonstrates the synthesis of a number of nonsteroidal anti-inflammatory drugs.

Dissociation temperatures of mixed tetrabutylammonium bromide (TBAB) + tetrabutylammonium chloride (TBAC) semiclathrate hydrates were determined by using the DSC technique. The system was measured in five groups with a fixed total mole fraction (x = 0.0100, 0.0200, and 0.0337), TBAB mole fraction (xTBAB = 0.0370) or TBAC mole fraction (xTBAC = 0.0337). The obtained results demonstrated that at a given x, the dissociation temperatures of mixed (TBAB + TBAC) semiclathrate hydrates were all higher than that of pure TBAB hydrate, and the maximum dissociation temperature appeared at xTBAB/x = 0.25 instead of xTBAB/x = 0 or 1 (corresponding to pure TBAC or TBAB hydrate). In addition, for systems with fixed xTBAB or xTBAC, TBAC gained the control of forming TBAC semiclathrate hydrate preferentially.

An unexpected reaction between 4-phenylurazole and fumaric esters which led to the formation of 5-alkylidene derivatives of hydantoin is described in this paper. The reaction takes place in the presence of tetrabutylammonium bromide (TBAB), and 1,4-diaza-bicyclo[2,2,2]octane (DABCO) at 70 °C under solvent-free conditions.

A novel metal-free approach to directly synthesize α-acyloxy sulfides from readily available alkyl sulfides utilizing the hypervalent (diacyloxyiodo)benzene and TBAB reagent combination is reported. This transformation is characterized by its broad substrate scope in moderate to excellent yields, convenient operating conditions and outstanding functional group tolerance.

This paper reports experimental values of the surface tension between CO2 gas and tetra-n-butylammonium bromide (TBAB) aqueous solution measured by the pendant drop method. The experimental conditions were pressures from 1.00 MPa to 4.00 MPa, temperatures from 288.15 K to 303.15 K and wTBAB from 0.10 to 0.40, where wTBAB denotes the mass fraction of TBAB in the aqueous solution. These pressure–temperature-composition conditions partially fall into the stability zone of (CO2 + TBAB) semiclathrate hydrate but all data were obtained without any hydrate in the system. Surface tension decreased with increasing wTBAB and pressure but temperature dependency was not observed. Compared to the air–TBAB aqueous solution system and CO2–water system, the values of the surface tension were smaller.

To better assess the stabilization effects of chemical treatments on Cu(II)-catalyzed cellulose degradation, we developed Cu(II)-containing model rag paper with typical copper corrosion characteristics using e-beam radiation. The paper can be prepared homogeneously and quickly compared to tedious pre-aging methods. Using the Cu(II)-containing model rag paper, the stabilization effects of various chemicals on Cu(II)-catalyzed degradation of cellulose were tested. Benzotriazol was highly effective in retarding the degradation of the Cu(II)-containing model rag paper under hot and humid aging condition, as well as under photo-oxidative stress. Tetrabutylammonium bromide reduced Cu(II)-catalyzed degradation of cellulose, but its efficacy was dependent on the accelerated aging conditions. The results with the alkaline treatments and gelatin treatment suggested that their roles in the degradation mechanisms of cellulose in the presence of Cu(II) differ from those of benzotriazol and tetrabutylammonium bromide.

A transition-metal-free difluoromethylenation of diazo compounds that proceeds under mild conditions has been developed and is based on the use of TMSCF2 Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the promoter. The chemoselective formal carbene dimerization reaction is achieved owing to the electronic properties and the relative stability of the difluorocarbene intermediate.

Aurones, a sub-class of the flavonoids with proven therapeutic importance, also exist in variously glycosylated forms. Although a large number of glycosylated aurone derivatives have been isolated from plant sources, no syntheses have been reported yet. Inspired from this gap, here we report the first synthesis of peracetylated glycosyl derivatives of synthetic aurones. The direct O-glycosylation was achieved by reacting 6-hydroxy aurones with 2, 3, 4, 6-tetra-O-acetyl-α-D glucopyranosyl bromide in the presence of a phase transfer catalyst tetrabutylammonium bromide (TBAB). The successful synthesis of aurone glycosides (33 examples) in 60–92% yield will benefit the synthesis of combinatorial libraries of glycosylated aurones for their biological study and comparison with non-glycosylated aurones.

2-Bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone are highly reactive species known to dimerize in various ways. The product obtained in the dimerization of each compound is primarily dependent upon the solvent used. Ionic liquids represent a new class of solvents having non-molecular (ionic) character. Replacement of a conventional organic solvent with an ionic solvent frequently changes the mechanism of a reaction. In this study, reactions of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in ionic liquids were examined. Dimerization of 2-bromo-3-methyl-1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone with N-methylcyclohexylamine in tetra-n-butylammonium bromide (TBAB), an ionic liquid, under an aerobic atmosphere afforded 5,7,12,14-pentacenetetrone and 1-methylKuQuinone, respectively. The use of TBAB as a solvent improved the yields of the products as compared with previously reported methods. The mechanism of each dimerization was also investigated.

Copper-catalyzed fragmentation-rearrangement sequence of cycloketoxime esters is reported. This strategy provides direct access to diverse ring-opening acyloxylation nitriles avoiding the use of toxic cyanic reagents with good atom economy and well functional group tolerance. Experimental exploration showed that tetrabutylammonium bromide (TBAB) played an irreplaceable role in this transformation. Based on the primary mechanistic experiments, a plausible mechanism was also proposed.

In the framework of the lattice dynamics method, the densities of the phonon states of tetrabutylammonium bromide ionic clathrate hydrate have been found. The dynamic stability of the hydrate is shown for a number of temperatures. Using the developed statistical-thermodynamic theory, the free energy curves have been constructed for a wide range of temperatures at different unit cell volumes and, based on the calculated data, the lines of thermal expansion of the hydrate have been constructed.

Магістерська дисертація на тему: «Гідрофобні добавки на основі амінів для полідисперсних в’яжучих матеріалів» містить 94 с., 20 рис., 13 табл., 45 джерел, 3 додатки. Хімічні добавки широко використовуються у виробництві цементів та бетонів. Основною причиною їх використання є зниження економічних та енергетичних затрат (саме на помел клінкеру), а також покращення властивостей цементів і бетонів та надання їм спеціальних властивостей. Наразі важливою проблемою є зберігання цементу. Під час транспортування та зберігання цемент поглинає вологу з навколишнього середовища, в результаті чого втрачає свою активність. Також при помелі клінкеру адсорбована волога сприяє налипанню частинок цементу на стінки млина, що погіршує процес помелу. З метою подовження терміну зберігання цементу та уникнення негативного впливу води до його складу вводять спеціальний вид добавок – гідрофобізуючі. Добавки на основі амінів широко використовуються у виробництві цементу, насамперед, як інтенсифікатори помелу та прискорювачі тужавлення та тверднення. Метою науково-дослідної роботи є дослідження впливу добавок на основі амінів різної будови та складу на процес помелу клінкеру, гідратацію цементного каменю, а також встановлення можливості їх використання в якості гідрофобізуючих добавок. Об’єкт дослідження – цемент, модифікований добавками на основі амінів. Предмет дослідження – оцінка впливу вибраних добавок на основі амінів на фізико-механічні та гідрофобні властивості отриманих цементів. Методи дослідження: визначення залишку на ситі та питомої поверхні матеріалів; визначення фізико-механічних властивостей: нормальної густини, термінів тужавлення та міцності; проба на гідрофобність; визначення крайового кута змочування; дослідження сипучості та гігроскопічності матеріалів. Публікації: наукові результати магістерської дисертації опубліковано у збірнику матеріалів XVIII Всеукраїнської студентської науково-практичної конференції «Science and Technology of the XXI Century» та у збірнику тез доповідей І Міжнародної наукової конференції студентів, аспірантів та молодих учених «Хімічні проблеми сьогодення». Також була взята участь в очній VII Міжнародній конференції студентів, аспірантів та молодих учених «Неорганічне матеріалознавство». Master's dissertation on the subject: "The amines-based hydrophobic admixtures for poly-dispersive binders" contains 94 pages., 20 fig, 13 tabl., 45 sources, 3 appendixes. Chemical admixtures are widely used in the manufacture of cements and concretes. The main reason for their use is the reduction of economic and energy costs (namely clinker milling), as well as the improvement of the properties of cements and concrete and giving them special properties. Nowadays, cement storage is an important issue. Cement absorbs the humidity of the environment, which is leading to, activity loss during transportation and storage. Also, the adsorbed moisture contributes to sticking particles of cement to the walls of the mill, during milling process, which worsens the grinding process. In order to extend the storage of cement and to avoid the negative influence of water on its composition, a special type of admixtures is added. Amine-based admixtures are widely used in the production of cement, primarily as grinding intensifiers and boosters and curing agents. The purpose of the research work is the influence of amines-based admixtures of different structure and composition in the process of milling of clinker, hydration of cement stone investigation, and the research of possibility of their use as hydrophobic admixtures. The object of the study is cement modified with amine-based admixtures. The subject of the study is the evaluation of the influence of selected additives amines-based on the physical, mechanical and hydrophobic properties of the cements obtained. Research methods are determination dispersity of the materials; determination of physical and mechanical properties: normal density, setting time; hydrophobic test; definition of the contact angle; study of the flowability and hygroscopicity of materials. Publications: scientific results of the master's dissertation are published in the collection of materials of the XVIII All-Ukrainian Student Scientific and Practical Conference "Science and Technology of the XXI Century" and in the collection of abstracts of the I International Scientific Conference for students and young researchers "Current Chemical Problems". Participation in the VII International Conference of Students and Young Scientists "Inorganic Materials Science" was also attended.

Thermal conductivities of structure H (sH) methane–methylcyclohexane hydrate and type A tetrabutylammonium bromide (TBAB) clathrate hydrate were measured using a single-sided transient plane source technique. The thermal conductivity of sH hydrate exhibited a positive trend with temperature and the average thermal conductivity was found to be 0.44 W m−1 K−1 at a compaction pressure of 12 MPa. The thermal conductivity of sH hydrate was lower than those of structure I and structure II hydrates at the same temperature and was found to depend not only on guest–host interactions but also on the rigidity of the framework. Unlike sH hydrates, the thermal conductivity of type A TBAB hydrates exhibited a negative trend with temperature. One possible reason for this strange phenomenon could be that the TBAB hydrate has a semi-clathrate structure, which retains the crystal heat transmission characteristics. The structures of the hydrates studied were different from those of normal gas hydrates. In addition, the thermal conductivity values for TBAB hydrates were also affected by interactions between the cations and anions.

New derivatives of 2,5-bis(4-heteroarylphenyl)-1,3,4-thiadiazole were synthesized under Suzuki cross-coupling reactions from 2,5-bis(4-bromophenyl)-1,3,4-thiadiazole and commercially available boronic acids. Reactions were conducted in a two-phase solvent system in the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium(0), cesium carbonate as a base, and tetrabutylammonium bromide playing a role of a phase-transfer catalyst.

In this paper, we report the absolute measurements of CO2 solubility in aqueous tetra-n-butylammonium bromide (TBAB) solution. The measurement range was 0.2 MPa 3 MPa and T > 292 K with wTBAB ⩾ 0.4 mass fraction of TBAB.

Treatment of [Ru2(CO)4(CH3CN)6](BF4)2 with 3-methyl-1-(pyridin-2-yl)-imidazolium bromide in the presence of tetrabutylammonium bromide at room temperature in dichloromethane affords a RuII–N-heterocyclic carbene–carbonyl complex [Ru(py-NHC)(CO)2Br2] (1). Catalyst 1 displays diverse substrate scope for phosphine-free acceptorless coupling between alcohols and amines to amides at low catalyst loading. A RuII-dihydride/Ru0 sequence is proposed in the catalytic cycle.

A reusable ligand-free palladium catalyzed phosphorylation of aryl iodides using PdCl2/tetrabutylammonium bromide is described. Functionalized triarylphosphines were obtained in good to excellent yields in the absence of external reductants and supporting ligands.