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This paper aims to contribute to the search for sustainable solutions for CO2 capture from industrial processes such as steelmaking. This is realized by exploring possibilities of a CO2 capture from blast furnace gas using clathrates and comparing this technique to conventional absorption with monoethanolamine (MEA). First a design with pure clathrate hydrates was made to act as a reference and aid to construct a more detailed model for the semiclathrate tetra-n-butyl ammonium bromide (TBAB). Herein the capture process was modeled as a crystallization process in a bubble column like crystallization vessel. It was found that the TBAB process suffers mostly from the low capacity which requires high volume flows. Because of the low temperature, large amounts of expensive refrigerants are required (>300 MW). Because of the high pressure, a large amount of electrical power is required as well (>80 MW). Overall, the process as designed here cannot compete with the conventional MEA process. However, several options were identified that could improve the process in such a way that it could become more feasible. These include an apparently higher capacity than estimated and the use of more stable semiclathrates, hence reducing the need for expensive refrigerants.

Hydrate-based gas separation (HBGS) technology can effectively separate CH4 and CO2 in multicomponent gases. To provide the necessary basic data for the HBGS technology, the hydrate phase equilibri...

Multidentate acylhydrazone ligand dinuclear and pentanuclear complexes were constructed with the lighter lanthanide ions (La3+, Pr3+, and Eu3+) and the heavier lanthanide ions (Tb3+ and Er3+), respectively, which indicated the structural change of polynuclear lanthanide complexes is controlled by the ionic radii of Ln3+ ions. In addition, these polynuclear lanthanide complexes as catalysts in combination with tetrabutylammonium bromide (TBAB) as a co-catalyst displayed excellent catalytic performance for CO2 conversion to obtain cyclic carbonates with a wide scope of substrates and high selectivity under solvent-free conditions.

A vital issue for the fixation and conversion of CO2 into useful chemical products is to find effective catalysts. In this work, in order to develop more effective and diverse catalysts, we implemented the first computational screening study (at M06-2X//B3LYP level) on the cycloaddition of CO2 with aziridines under eighteen metal-substituted HKUST-1 MOFs and tetrabutylammonium bromide (TBAB) as a co-catalyst. For all considered catalytic systems, the ring-opening of aziridine is calculated to be the rate-determining step. Up to 11 M-HKUST-1 systems, i.e., Rh (31.87 kcal mol−1), Y (31.02), Sc (30.50), V (30.02), Tc (29.90), Cd (29.80), Ti (29.32), Mn (29.05), Zn (28.29), Fe (27.85) and Zr (25.09), possess lower ring-opening barrier heights than the original Cu-HKUST-1 (32.90), indicative of their superior catalytic ability to the original Cu-HKUST-1 in theory. With the lowest ring-opening barrier, Zr-HKUST-1 is strongly advocated for future synthetic and catalytic studies.

The solubility of carbon dioxide (CO2) in three carboxylic acid-based deep eutectic solvents (DESs) constituted by tetrabutylammonium bromide (TBABr)/octanoic acid (1:2) or TBABr/decanoic acid (1:2...

Ionic clathrate hydrates formed from aqueous solutions of tetra-n-butylammonium bromide in the course of rapid cooling (30 K min−1) to −35 °C have been examined. An earlier unknown metastable hydrate of cubic structure I was obtained from the solutions with concentrations from 3.2 to 4.8 mol%.

A stereoselective method has been developed for the synthesis of (1E)-chloroalk-1-en-4-ynes, promising precursors to 1,4-enynes, on the basis of alkynylation of (E)-1,3-dichloropropene in the presence of copper(I) iodide and tetrabutylammonium bromide.

Biogas is one of the green energy resources. To enhance usage of biogas (64.0 mol % CH4/CO2) and reduce the greenhouse effect, CH4 purification by the hydrate-based gas separation (HBGS) technology...

CH4 purification and CO2 removal by hydrate-based separation method from the simulated biogas (64 mol % CH4/CO2) were investigated in tetrabutylammonium bromide (TBAB) solution. Three different hyd...

Critical micelle concentrations (CMC) of cetylpyridinium chloride (CPC) in aqueous sodium bromide and tetrabutylammonium bromide (TBAB) solutions were determined at 30 °C by conductivity and surface tension measurements. Bromide counterions reduce CMC of CPC more than the chloride. The modified form of the Corrin-Harkins (CH) equation describes the variation of CMC of CPC with the concentration of added electrolyte containing different counterions. It is demonstrated that the mixed-electrolyte-model (MEM) of Shanks and Franses can be applied to analyze the conductivity data of the surfactant solution containing mixed counterions, which was otherwise used for a surfactant solution containing single counterion only. The value of the total counterion binding constant (β) obtained from the MEM was then used to separate from the slope of the modified CH equation the counterion binding constants for chloride (β1) and bromide (β2) ions. This data analysis showed that binding of bromide counterion to cetylpyridinium ionic micelle is stronger than that of the chloride counterion, which is in accordance with the positions of chloride and bromide ions in the Hoffmeister series and the results reported from other studies.

An efficient Cu(II)-catalyzed and tetrabutylammonium bromide (TBAB)-promoted strategy for highly regioselective and chemoselective C(sp3)–H acyloxylation of aliphatic amides is described. Acyloxylation occurs selectively at the β position with a broad substrate scope of carboxylic acids and aliphatic amides and good functional group compatibility. Notably, the competing reaction of intramolecular dehydrogenative amidation and intermolecular acyloxylation could be efficiently controlled by the amount of copper salt and the addition of TBAB. The intramolecular dehydrogenative amidation product was obtained in high yield when the amount of copper salts was increased. However, when TBAB was used as an additive, a preference for acyloxylation over intramolecular amidation was observed and the acyloxylated products were obtained in good yield. Preliminary studies were carried out to gain insights into the mechanism.

A new additive method for inorganic perovskite solar cells (PSCs) was developed by adding tetrabutylammonium bromide (TBAB) additive into the CsPbI2.4Br0.6 precursor solution. The CsPbI2.4Br0.6-TBAB film shows high crystallinity, large grain size, low trap density, and excellent charge transport properties. Finally, the CsPbI2.4Br0.6-TBAB based PSC exhibits an impressive PCE of 15.21%, which outperforms many reported inorganic PSCs. Meanwhile, the CsPbI2.4Br0.6-TBAB based PSC could retain over 93% of the initial PCE after being stored in a N2 glovebox for 1600 hours.

A rapid, transition metal-free, high-yielding, tetrabutylammonium bromide-promoted method of N-arylation is reported within. The optimized conditions tolerated a wide range of secondary amines and was equally effective with bromo- and chlorobenzene-including substituted aryl halides. The developed method is found to be effective for N-arylation when compared to earlier methods which involve harsh conditions, transition metals, lack of scalability, and long reaction times. Our method utilizes conventional heating only; it is readily scalable; and the products are facile to purify.

Carbonated methyl soyates have been successfully prepared by cycloaddition of carbon dioxide (CO2) to epoxidized methyl soyates in tetrabutylammonium bromide (TBAB)-based deep eutectic solvents (DES). Experimental parameters, i.e., reaction temperature, reaction time, CO2 pressure and TBAB concentration were evaluated. The different reaction conditions have a significant influence on the yields of carbonated methyl soyates. The use of TBAB-based DES (tetrabutylammonium bromide/triethylene glycol) significantly shortened the reaction time of the cycloaddition of CO2 to epoxidized methyl soyates. FT-IR and NMR analysis indicated that 95% of the yield of the five-membered cyclic carbonated methyl soyates were obtained at 120°C with 1.0 MPa pressure of CO2.

The title compounds both comprise a tetra­butyl­ammonium cation, a halide anion and an ortho-phenyl­ene bis-urea mol­ecule. Each halide ion shows four N—H⋯X (X = Cl or Br) inter­actions with two urea receptor sites of different bis-urea moieties. A crystallographic inversion centre leads to the formation of a 2:2 arrangement of two halide anions and two bis-urea mol­ecules., The title compounds, tetra­butyl­ammonium chloride–1,1′-(1,2-phenyl­ene)bis­(3-m-tolyl­urea) (1/1), C16H36N+·Cl−·C22H22N4O2 or [(n-Bu4N+·Cl−)(C22H22N4O2)] (I) and tetra­butyl­ammonium bromide–1,1′-(1,2-phenyl­ene)bis­(3-m-tolyl­urea) (1/1), C16H36N+·Br−·C22H22N4O2 or [(n-Bu4N+·Br−)(C22H22N4O2)] (II), both comprise a tetra­butyl­ammonium cation, a halide anion and an ortho-phenyl­ene bis-urea mol­ecule. Each halide ion shows four N—H⋯X (X = Cl or Br) inter­actions with two urea receptor sites of different bis-urea moieties. A crystallographic inversion centre leads to the formation of a 2:2 arrangement of two halide anions and two bis-urea mol­ecules. In the crystals, the dihedral angle between the two urea groups of the bis-urea mol­ecule in (I) [defined by the four N atoms, 165.4 (2)°] is slightly smaller than that in (II) [167.4 (2)°], which is probably due to the smaller ionic radius of chloride compared to bromide.

In this paper, we offered a green, environment-friendly, novel and inexpensive method for the synthesis of a series of pyrazole derivatives. The reaction took place in the presence of tetrabutylammonium bromide, a commercially available organic ionic salt, at room temperature under solvent-free conditions. All products were confirmed by infrared radiation, nuclear magnetic resonance and elemental analysis. Yields of products were 75–86%.

In this paper, C–N bond formation between 2,3-dihydrophthalazine-1(4H),4-dione (phthalhydrazide) and α,β-unsaturated esters was investigated and a new series of phthalazine derivatives was synthesized using an efficient and simple method under solvent-free conditions. An aza-Michael addition of phthalhydrazide to both acrylic and fumaric esters led to N-mono-substituted phthalhydrazides (as mono-Michael adduct) in the presence of tetrabutylammonium bromide as a high polar media, and 1,4-diaza-bicyclo[2,2,2]octane as an available organic base. In this reaction, the N1,N2-bis-Michael adduct was not observed at all. Also, reactions were performed at 90°C and yields of products were good to excellent.

In this paper, we describe a new, simple and efficient strategy for the formation of novel and valuable acyl hydrazide derivatives from reaction between diverse acyl hydrazides and α,β-unsaturated esters in the presence of 1,4-diaza-bicyclo[2,2,2]octane (DABCO) – an inexpensive base – and tetrabutylammonium bromide (TBAB) – an ionic organic salt – under solvent-free conditions. In the reaction, double Michael adducts were produced in good yields in 7 h when acrylic esters were used as Michael acceptors. Surprisingly, no double Michael adducts were produced with fumaric esters, and single Michael adducts were the only products of these reactions in 10 h.

A g-C3N4 and n-Bu4N+Br− combination was found to be an efficient catalyst for the conversion of epoxides to cyclic carbonates under CO2 filled balloon conditions.

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.

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.

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.

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.

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.

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.

This paper reports the vapor–liquid–hydrate three phase equilibrium conditions of ionic semiclathrate hydrates formed in the system of water + tetra-n-butylammonium bromide pressurized with carbon dioxide. The three phase equilibrium temperatures were measured in the ranges from 278.8 to 287.4 K of temperature and from 0.05 to 0.45 of mass fraction of tetra-n-butylammonium bromide (wTBAB). Measurements were performed at the system pressures of 0.3 MPa, 0.6 MPa, and 1 MPa. For the three system pressures, the equilibrium temperatures increased with the increase in wTBAB for wTBAB 0.40. The highest equilibrium temperatures were obtained at wTBAB = 0.35 and 0.40. The equilibrium temperatures of the tetra-n-butylammonium bromide + carbon dioxide hydrates were higher than those of the simple tetra-n-butylammonium bromide hydrates formed under atmospheric pressure. The improvement of the thermodynamic stability of the tetra-n-butylammonium bromide + carbon dioxide hydrates is asc...

An efficient one-pot method for the selective benzylation of diols and polyols using 0.1 equiv. of organotin reagents and tetrabutylammonium bromide as catalyst has been developed. The diols and polyols containing a cis-vicinal diol were regioselectively benzylated in 70–94% isolated yields. A catalytic reaction mechanism was also proposed.

The combination of a vanadiumV(salen) complex V+O(salen) EtOSO3− and tetrabutylammonium bromide forms a highly active catalyst system for the reaction between epoxides and isocyanates leading to oxazolidinones. The reaction conditions were optimized and the optimal conditions (80 °C in toluene for 5 hours with 2 mol% of vanadium catalyst and 2 mol% of tetrabutylammonium bromide cocatalyst) applied to eight epoxides and six aromatic isocyanates, giving 18 oxazolidinones with conversions of 34–98% and isolated chemical yields of the major regioisomer of 23–89%.

A heterogeneous reaction with the ammonium salt of 12-tungstophosphoric acid as catalyst has been designed for synthesis of 1,4-dihydropyridine and polyhydroquinoline via the Hantzsch condensation. Molten tetrabutylammonium bromide ionic liquid was used as reaction medium.

2-Iodoxybenzoic acid (IBX) has been shown to react with alkyl halides in the presence of tetraethyl ammonium bromide to give 2-iodobenzoate esters. Most of the monohalides and dihalides reacted easily with moderate to good yields. The 2-iodobenzoate esters containing other functional groups can offer further synthetic uses. The 2-iodobenzoic acid can be recycled easily and oxidised to IBX again.

The regioselective and efficient bromination of primary hydroxyl groups in unprotected carbohydrates or glycosides is successfully achieved by using (chloro-phenylthio-methylene)dimethylammoniumchloride (CPMA) in the presence of tetrabutylammonium bromide (TBAB) in dry DMF.

The complexes [Bu4N]2+[PtBr6]2− (I), [Ph4P]2+[PtBr6]2− (II), and [Ph3(n-Am)P]2+ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu4N]+[PtBr5(DMSO)]− (IV), [Ph4P]+[PtBr5(DMSO)]− (V), and [Ph3(n-Am)P]+[PtBr5(DMSO)]− (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) A, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) A). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) A.

A reusable CuSO4 · 5H2O/cationic 2,2′-bipyridyl system catalyzed the homocoupling reaction of terminal alkynes in water using I2 as the additive in the presence or absence of tetrabutylammonium bromide, giving the 1,3-diynes in good to high yields. After reaction, the residual aqueous solution could be reused several times. Copyright © 2011 John Wiley & Sons, Ltd.

We review the state of the art in microfluidic separation technique based two-phase laminar flow with an application focus on chemical and biological sample. As we describe herein, two-phase laminar flow in the microfluidic extraction has several biological and engineering advantages over other methods including high reproducibility, biocompatibility, and selectivity. We review advances in applications of two-phase laminar flow and examine key parameters such as flow rate, phase composition, and surface charge property, how these can affect extract performance with the technology including microfluidic separation system. A special technology focus is given to emerging novel integrative microfluidic extraction, which aims to merge aqueous phase laminar flow and electric field technologies into simple packages. We conclude with a brief discussion of some of the emerging challenges in the field and some of the approaches that are likely to enhance their application.

The hydrogen bonded complexes formed between tetrabutylammonium bromide and phenol derivatives are studied by infrared spectrometry in CCl4. The logarithm of the stability constants of complexes of 1:1 and 2:1 stoechiometry, and the frequency shifts of the stretching vibration IVOH are linearly related to the sum of the Hammett substitution constants. The influence of the proton donor concentration on the infrared spectrum and the structure of the complexes are discussed.

Hydrogen has only been recently recognized as a hydrate former, forming structure II hydrate (sII). In this communication, we report new experimental hydrate stability data for the binary hydrogen + water system at pressures ranging from (111.4 to 178.4) MPa and temperature down to 264.45 K. In addition, the formation and dissociation of so-called semiclathrates of hydrogen in the presence of tetrabutylammonium bromide (TBAB) were evaluated. The clathrate and semiclathrate dissociation measurements were conducted using a standard constant volume (isochoric) technique together with step-heating for achieving equilibrium conditions.

The oxidation of toluene was carried out at room temperature with a Fenton reactant FeII-H2O2 in a diphase medium and a modified Udenfriend FeII-O2 system electrochemically regenerated We remarked that the Udenfriend system is much more selective for oxidation products of the methyl group (benzaldehyde, benzyl alcohol) than for the hydroxylation products of the aromatic cycle (ortho- and para-cresols, methyl-p-quinone). This tendency is the opposite with a Fenton reactant. Furthermore, it is to be noted that the regeneration of the catalyst results in a significant increase in the activity of the two catalytic systems. As for as the Fenton reactant is concerned, the use of a phase transfering agent (tetrabutylammonium bromide) made the reaction possible and improved the activity of the system.

Several polyfluoroalkoxyl benzaldehydes were synthesized from the nucleophilic reaction between polyfluoroalkanesulfonate and various sodium phenolates with cetyltrimethylammonium bromide or tetrabutylammonium bromide as PTC. The yields were in the range of 55%–70%. Using a modified procedure Cl(CF2)2SO2Cl was prepared from ClCF2CF2I with an improved yield of 91% and was used to synthesize the polyfluoroalkanesulfonate 2'.

Photochemical oxidative desulfurization of thiophene with tetrabutylammonium bromide (TBAB) as phase transfer catalyst was studied. The effects of the TBAB addition and pH on the desulfurization yield of thiophene were investigated. The cycle model of desulfurization of thiophene with TBAB was proposed. The results show that the desulfurization yield of thiophene in n-octane is 80.6% for a 2-hr photoirradiation under the conditions of air flow at 150 mL/min, V (n-octane):V (water) = 1:1, pH = 12, and 0.1 g of TBAB as catalyst. The photooxidation kinetics of thiophene is first-order with rate constant of 0.5702 hr−1 and half-life of 1.22 hr.

A simple and efficient procedure for the synthesis of 2-arylquinazolin-4(3H)-ones has been developed through cyclocondensation of 2-aminobenzamide with aromatic aldehydes using tetrabutylammonium bromide (TBAB) as novel neutral ionic liquid catalyst in the presence of copper (II) chloride (CuCl2) as oxidizing agent under solvent-free conditions at 100 °C. In the absence of CuCl2 and under a nitrogen atmosphere, the unoxidized intermediates, 2-aryl-2,3-dihydroquinazolin-4(1H)-ones, were isolated. Treatment of these intermediates with CuCl2 in TBAB media gave the oxidized products 2-arylquinazolin-4(3H)-ones. On the other hand, cyclocondensation of 2-aminobenzamide with aromatic aldehydes in TBAB under microwave irradiation directly gave 2-arylquinazolin-4(3H)-ones.

[Fe(III)(salophen)]Cl in molten tetrabutylammonium bromide was used as a cost effective and efficient catalytic system for the electrophilic reaction of indole with carbonyl compounds. The remarkable features of this new procedure are high conversions, short reaction time, clean reaction profiles and simple experimental and work-up procedures.

A highly efficient procedure for glucosylation of flavonoids by acetobromoglucose is described. Glucosylation is carried out in a two-phase system CHCl3/H2O over 96 h using tetrabutylammonium bromide as phase-transfer catalyst. A purification procedure can be performed without column chromatography, and the yields of the glucosylated flavonoids are mostly quantitative. Acetylated glucosides were deprotected with sodium methanolate to afford the desired glucosides of flavonoids.

Precise conductance measurements of solutions of tetrabutylammonium bromide (Bu4NBr), sodium tetraphenylborate (NaBPh4), and sodium bromide (NaBr) in N,N-dimethylformamide have been reported at (30...