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In the present work, dispersive micro-solid phase extraction (D-μ-SPE) method using magnetic graphene oxide tert-butylamine (GO/Fe3O4/TBA) nanocomposite, as an efficient sorbent, was applie...

The current work reports ionic liquid (IL) facilitated dehydrogenation of tert-butylamine borane (TBAB) at 90 and 105 °C. For the screening of potential IL solvent, solubility predictions of TBAB in ILs were performed by the conductor-like screening model segment activity coefficient (COSMO-SAC) model. The COSMO-SAC model predicted a logarithmic infinite dilution activity coefficient of −6.66 and −7.31 for TBAB in 1-butyl-3-methylimidazolium acetate [BMIM][OAc] and trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate [TDTHP][Phosph], respectively. Hydrogen (1.95 equiv) was seen to release from TBAB/[BMIM][OAc] at 105 °C, whereas TBAB/[TDTHP][Phosph] produced 1.63 equiv of hydrogen after 360 min of dehydrogenation. The proton nuclear magnetic resonance (1H NMR) characterization of TBAB/IL systems revealed the structural integrity of ILs during dehydrogenation. Further characterization through the boron NMR (11B NMR) technique disclosed the time-resolved formation and stability of the start...

The atomically economic and green chemical reaction of direct amination of isobutylene to tert-butylamine, particularly under the relative mild reaction conditions available for future industrial use, was carried out over zeolite catalysts possessing different topological structures, from one dimensional to three dimensional pore system, and from small 8-member ring pore (MRP) to medium 10 MRP and further to large 12 MRP zeolites, to disclose the relationship between the zeolite properties/topologies and their amination performance systematically under the mild reaction conditions. It was discovered that the pore structure and the acidities of zeolite catalysts played crucial roles in the isobutylene amination process, and suitable pore diameter (larger than 0.5 nm or with large side pockets/cups in the outside surface) and a certain number of mid-strong acid sites are indispensable to catalyze the amination reaction, while too strong acid strength was not conducive to the process of isobutylene amination. Among them, zeolites with topologies of BEA, MFI, MEL, MWW and EUO exhibited good amination performance, with which the isobutylene conversion was higher than 12.61% (>46.42% of the equilibrium conversion) under the studied mild reaction conditions. Due to the good amination performance and the large adjustable Si/Al2 ratio range, ZSM-5 was selected to further study the effect of acidity on the amination performance systematically under the mild reaction conditions, and the activity-acidity relationship in the amination process was disclosed: the amination activity (isobutylene conversion) had a linear correlation with the amount of mid-strong B acidity under the studied conditions over ZSM-5 catalyst, which can provide guidance for further developing high-efficient amination catalyst under mild reaction conditions available for future industrial use.

On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct amination of isobutylene to tert-butylamine, an atomically economic and green chemical reaction, were calculated. In particular, the equilibrium conversion of isobutylene under various reaction conditions close to those used in industry was calculated and discussed. Isobutylene amination is a temperature sensitive reaction due to its exothermic nature and isobutylene equilibrium conver-sion decreases with temperature. However, kinetically, the amination reaction will be faster at a higher temperature. Thus, there must be an optimum temperature for the reaction. A high pressure and n (NH 3 )/ n (i-C 4 H 8 ) molar ratio promote the transformation of isobutylene to tert-butylamine. Developing a highly efficient catalyst under mild reaction conditions is preferred for the amination process. The reaction was investigated over a series of acidic zeolites. ZSM-11 zeolite exhibited the best performance with 14.2% isobutylene conversion (52.2% of the equilibrium conversion) and > 99.0% tert-butylamine selectivity. The effect of reaction conditions on the performance of the ZSM-11 catalyst agreed with the thermodynamic results, which provides guidance for further cata-lyst development and reaction condition optimization.

A shaped binderless and two binder-containing ZSM-11 zeolite catalysts were prepared and char-acterized by powder X-ray diffraction, N 2 adsorption-desorption, and pyridine adsorption-infrared measurements. The binderless catalyst was synthesized using a dry-gel conversion technique, in which 1,6-hexanediamine and tetrabutylammonium bromide were used as structure-directing agents and no other alkaline materials were added. The catalytic performance of the zeolites in the direct amination of isobutene to tert -butylamine was evaluated in a fixed-bed reactor. By virtue of its high crystallinity as well as its good mechanical strength, the shaped binderless ZSM-11 catalyst showed a higher rate of formation of tert -butylamine than did the binder-containing catalysts.

Several errors in the published paper by Wongkaew and coworkers [Fluid Phase Equilibria 434 (2017) 141–151] are identified. The errors noted include the failure of the calculated curve-fit parameters for the Modified Apelblat model, the van't Hoff model and the empirical polynomial equation in temperature to correctly back-calculate the measured solubility data for the salts of 2-mercaptobenzothiazole with cyclohexylamine (2-MBT-CHA) and tert-butylamine (2-MBT-TBA) dissolved in methyl isobutyl ketone (MIBK), 1,4-dioxane, toluene and water in the temperature range from 303.15 K to 348.15 K. Internal inconsistencies were noted in the reported thermodynamic properties of dissolution, and several errors were noted in the experimental mole fraction solubilities versus temperature graphs.

Herein we report the morphology tailoring of hierarchical Bi4Ti3O12 architectures by using tert-butylamine (TB) and oleic acid (OA). It is demonstrated that the content of TB and OA has an important effect on the morphologies of as-derived Bi4Ti3O12 samples. When adding 12 mmol TB and 6 mmol OA (with respect to 1 mmol Bi4Ti3O12) to the precursor solution, rod-like hierarchical architectures (length 2–15 μm, diameter 0.5–1.7 μm) are obtained. The hierarchical microrods are composed of nanosheets of 20–50 nm in thickness and 300–1700 nm in diameter. The addition of other amounts of TB and OA results in the formation of nanoflake-assembled hierarchical hollow microspheres with size of several micrometres; however the sizes of the microspheres and their sub-nanoflakes depend on the TB/OA amounts. Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) aqueous solutions, as well as RhB/MO/MB mixture solution (simulated dye wastewater), were used to evaluate the photodegradation performances of the as-prepared Bi4Ti3O12 samples under simulated sunlight irradiation. It is demonstrated that the nanosheet-assembled hierarchical microrods possess a photodegradation activity preponderating over the other morphologies. Moreover, the photocatalytic experiments reveal an interesting photodegradation process of RhB/MO/MB in the mixture solution, which is different from the photodegradation of single dye solution. The photodegradation mechanism of the Bi4Ti3O12 photocatalysts was investigated and discussed.

The shape and surface morphology of mono-dispersed barium titanate (BaTiO 3 ) nanocrystals were controlled by tuning the composition of hydrothermal reaction system. High quality BaTiO 3 nanocubes with the smooth surface and 90° standard corner angle were synthesized by the hydrothermal method using a relatively low concentration of oleic acid and tert-butylamine, which were used as surfactant and additive, respectively. The average size of BaTiO 3 nanocubes was ∼25 nm and the size distribution was relatively narrow. As a large amount of surfactant and additive was employed, BaTiO 3 nanocrystals with convex structure were synthesized. The terrace structure were developed at the {100} surface of the nanocrystals. Here, we analyzed systematically the role of oleic acid and tert-butylamine on the surface morphology of BaTiO 3 nanocrystals. Our study demonstrates the possibility of synthesizing high quality BaTiO 3 nanocubes for commercial application. These findings can be applied on other perovoskite nanomaterials.

The atmospheric chemistry of (CH3)3CNH2 (tert-butylamine, tBA) and (CH3)2(CH2OH)CNH2 (2-amino-2-methyl-1-propanol, AMP) has been studied by quantum chemistry methods and in photo-oxidation experiments in the EUPHORE chamber in Valencia (Spain). Aerosol formation and composition has been quantified. Yields of nitramines and other products in the photo-oxidations have been determined and complete photo-oxidation schemes including branching between the major reaction routes have been obtained. Published by Elsevier Ltd.

In this work, experimental hydrate dissociation pressures of the (tert-butylamine + CO2) and (tert-butylamine + N2) systems were reported at (0.005, 0.015, 0.03, 0.056 and 0.093) mole fraction of tert-butylamine with measurements made in the temperature range of (273.5 to 283.3) K and in the pressure range of (2.27 to 13.79) MPa. The equilibrium data were generated using an isochoric pressure-search method. The hydrate dissociation data for the (CO2 + water) system were obtained in advance and compared with experimental data reported in the literature, and the acceptable agreements demonstrate the reliability of the experimental method and apparatus employed in this work. Dissociation experimental results indicated that tert-butylamine had an inhibition effect on the dissociation conditions of carbon dioxide, shifting the dissociation conditions of CO2 hydrate to lower temperatures/higher pressures, while for the (tert-butylamine + N2 + water) system, tert-butylamine showed a hydrate promotion effect, whi...

In situ high-pressure crystallization and diffraction techniques have been applied to obtain two very structurally distinct semi-clathrates of the tert-butylamine-water system with hydration numbers 5.65 and 5.8, respectively, thereby considerably reducing a notable hydration gap between the monohydrate and the 71/4 -hydrate that results when crystallization space is explored by temperature alone. Both structures can be considered as an intriguing solid-state example of hydrophobic hydration, in which the water network creates wide tert-butylamine-filled channels stabilized by cross-linking hydrogen bonds. The existence of interconnected channels might also add low hydration structures to a list of potential targets for hydrogen storage. A detailed analysis of the topology of host water and host-guest interactions is reported and extended to those of other hydrates of the compound. This analysis offers new insight into properties of the tert-butylamine-water system and provides some clues as to the occurrence of the sizable number of hydrates of this compound.

Copper(II) carboxylate compounds with tert-butylamine of the general formula [Cu2(tBuNH2)2(μ-O2CR)4], where R = CnF2n+1, n = 1–6, were synthesized in the reaction of copper(II) perfluorinated carboxylates with tert-butylamine generated in situ from tert-butyl isocyanate. The obtained complexes were characterized in the solid state and in the gaseous phase by electron impact mass spectrometry (EI MS), IR spectroscopy, and thermal analysis with the detection of evolved gases. In addition, during the recrystallization of the [Cu2(tBuNH2)2(μ-O2CC3F7)4] complex the (tBuNH3)+(C3F7CO2)− ion pair was isolated, and its X-ray structure was determined. As a result of a mass spectra analysis, the presence of metallated species in the gaseous phase was revealed. Among the species detected, the pseudomolecular ions [Cu2(tBuNH2)2(μ-O2CR)3]+ were found. The fact confirmed the dimeric structure of the studied complexes with bridging carboxylates and axially N-coordinated amines. TGA studies demonstrated that copper transfer to the gaseous phase occurs at atmospheric pressure, which suggests that the obtained compounds can be promising precursors for chemical vapor deposition. The selected Cu(II) compounds were used in the preliminary CVD experiments, and the conformal copper layers were formed with no additional reducing agents.

L-α-glycerophosphocholine, transesterification, tert-butylamine, natural lecithin Abstract. Tert-butylamine was confirmed as effective catayst for preparing L-α-glycerophospho -choline at mild conditions. The process using this catalyst would be much simpler, since the recovery of the catalyst can be combined with the recovery of methanol by distillation. The conversion of phosphatidylcholine could reach over 98% after 4 h, with a catalyst content of 2.4% under 60 °C. The mechanism of the methanolysis reaction was proposed and the experimental data fit the equation model well. GC was used to analyze the product, it was indicated that the product had high purity, and the catalyst could get similar effect to the fresh after repeatedly used.

The possibility of mild SO2 oxidation in sulfur(IV) oxide-alkylamine-water-oxygen systems is demonstrated to yield onium sulfates.

Salts between N-trityl amino acids (Ala, Val, Leu, Ile, Phe, and phenylglycine) and tert-butylamine are examined in terms of inclusion ability for alcohols. An X-ray crystallographic study elucidated the column structures, hydrogen-bond network, and phenyl–phenyl interactions. It also found that tert-butylammonium N-trityl phenylalanate was superior to other salts of amino acids at including several alkyl alcohols. When the salt included 1-chloro-2-propanol as a guest alcohol, the enatioselectivity of inclusion reached up to 69% ee (S-form).

A systematic study on methane hydrate formation and dissociation was carried out in presence of liquid hydrocarbon promoters namely tetrahydrofuran (THF) and tert-butylamine (t-BuNH2). Mixed hydrates with THF/t-BuNH2 (mole fraction x = 0.05) were of sII symmetry. The hydrate formation/dissociation of mixed hydrates with x = 0.033 and 0.0056 were complex with co-existence of sII and sI structures. We observed the hydrate formation in two steps, hydrates in the first stage (∼T = 295 K) were mostly with sII and in the second stage (∼T = 275 K) were with sI structure, corroborating the literature. However, dissociation pattern of the hydrates formed in second stage significantly differ from pure methane hydrates and the above two liquid hydrocarbons show considerable promoter effect for sI hydrates. © 2011 Elsevier B.V. All rights reserved.

Novel catalytic systems were proposed for controlled radical polymerization of vinyl monomers. These systems are based on the paramagnetic (17-electron) closo-complex, namely, 3,3-(dppb)-3-Cl-closo-3,1,2-RuC2B9H11 (1, dppb is 1,4-bis(diphenylphosphino)butane) and its mono(P-phenylene)- and di(P,P-ortho-phenylene)cycloboronated derivatives, namely, (R = H, n = 10 (2); R = Me, n = 8 (3)) and (4). With the polymerization of methyl methacrylate as an example, the effect of the steric hindrances in complexes 1–4 on the synthesis and molecular-weight characteristics of the resulting polymers was analyzed. In the presence of aliphatic amines, the polymerization rate increases substantially and the catalyst concentration can be lowered without losing control of the process. The structure of 17-electron complex 3 in the solid state and its paramagnetic nature were confirmed by X-ray diffraction and ESR spectroscopy.

The three-phase equilibrium conditions of ternary (hydrogen + tert-butylamine + water) system were first measured under high-pressure in a “full view” sapphire cell. The tert-butylamine–hydrogen binary hydrate phase transition points were obtained through determining the points of intersection of three phases (H–L w –V) to two phases (L w –V) experimentally. Measurements were made using an isochoric method. Firstly, (tetrahydrofuran + hydrogen) binary hydrate phase equilibrium data were determined with this method and compared with the corresponding experimental data reported in the literatures and the acceptable agreements demonstrated the reliability of the experimental method used in this work. The experimental investigation on (tert-butylamine + hydrogen) binary hydrate phase equilibrium was then carried out within the temperature range of (268.4 to 274.7) K and in the pressure range of (9.54 to 29.95) MPa at (0.0556, 0.0886, 0.0975, and 0.13) mole fraction of tert-butylamine. The three-phase equilibrium curve (H + L w + V) was found to be dependent on the concentration of tert-butylamine solution. Dissociation experimental results showed that tert-butylamine as a hydrate former shifted hydrate stability region to lower pressure and higher temperature.

The condensation reactions of partly substituted spiro and ansa phenoxycyclotriphosphazenes, N3P3[2,2'-methylenebis(4-chlorophenoxide)]Cl4 (1 and 2) with tert-butylamine produce disubstituted geminal-bis(tert-butylamino)phenoxyphosphazene derivatives (3 and 4). The structures of these compounds were characterized by elemental analysis, and IR, 1H-, 13C-, 31P-NMR and mass spectroscopic techniques. Compound 3 was also examined by X-ray crystallography and found to be crystallized in the monoclinic space group P21/n with the unit cell parameters: a = 10.842(4), b = 9.375(5), c = 29.104(11) ?, ? = 99.25(3)?, V = 2920(2) ?3, Dx = 1.404 g cm-3.

Photochemistry of all-trans tert -butylamine retinal protonated Schiff-base (TB-RPSB) is investigated by femtosecond pump–hyperspectral probe spectroscopy. Unlike the n -butyl analogue (NB-RPSB) no shifting of the transient spectral bands is observed upon tuning the excitation pulses from 395 to 475 nm. The 15 nm shift observed for NB-RPSB in similar experiments was assigned to unspecified ground state structural inhomogeneity. Present results indicate that is most likely due to the coexistence of C 15 N double bond isomers in NB-RPSB. Elimination of this inhomogeneity in TB-RPSB makes it a more appropriate model for appreciating protein effects on RPSB photochemistry in retinal proteins.

Thermal and microwave initiated cyclization of 2,4-disubstituted 6-arylethynylpyrimidine-5-carbaldehydes with tert -butylamine has been studied. A novel high-yielding preparation of 2,4-disubstituted 7-arylpyrido[4,3- d ]pyrimidines has been developed. The intermediate compounds were isolated and possible mechanism of the reactions is discussed.

Unexpected thermal cyclization of 2,4-disubstituted 6-(arylethynyl)pyrimidine-5-carbaldehydes with tert-butylamine proceeded to give 2,4-disubstituted 7-arylpyrido[4,3-d]pyrimidines in good yields in the absence of any catalysts. The intermediate compounds were isolated and possible mechanism of the reactions is discussed.

A mild protocol for transesterification of simple esters is described. The method is based on the use of t -BuNH 2 /ROH (R = Me, Et, i -Pr, t -Bu) with or without LiBr. The scope of the procedure was explored for aliphatic and aromatic esters. The protocol is particularly useful when going from higher to lower hindered esters and harsh reaction conditions are needed for the reversal process. A rationalization of the mechanism is presented. The scope and limitation of this transformation are also described.

The structure of 1,8-bis(fluoroboro)-2,7,9,14,15,20-hexaoxa-3,6,10,13,16,19-hexaaza-4,5,11,12-tetraphenyl-17,18-bisc(tert-butylamino)-bicyclo[6.6.6]eicosa-3,5,10,12,16,18-hexaene(2−)iron(2+) tris-dioximate clathrochelate was determined by X-ray diffraction (XRD) analysis. The compound has a molecular structure and crystallizes as triclinic crystals: a = 10.7673(2) A, b = 11.9520(4) A, c = 22.5473(7) A, α = 75.729(1)°, β = 89.161(1)°, γ = 65.334(1)°, V = 2542.64(13) A3, Z = 2, space group 1. P1¯.

An efficient, simple protocol for the selective cleavage of a variety of N-alkoxycarbonyl protecting groups by t-BuNH2/MeOH is described. The scope of the procedure was explored for a series of indole, aniline and pyrrolidine carbamate derivatives containing other potentially reactive functional groups affording a clean cleavage of the carbamate group.

The dilution of tert-butylamine (tBA) with water and subsequent cooling leads to a large series of different crystalline hydrates by an in situ IR laser melting-zone procedure. The crystal structures were determined for tBA⋅n H2 O, with n=0, 1/4, 1, 7 1/4, 7 3/4, 9 3/4, 11, and 17. For the two lower hydrates (n= 1/4, 1), one- and two-dimensional hydrogen-bonded networks are formed, respectively. The higher hydrates (n1) exhibit a clathrate-like three-dimensional water framework with the tBA molecules as part of, or sitting inside, the cages. In all cases, tBA is hydrogen-bonded to the H2 O framework. In the intermediate range (1n7 1/4), crystallization is hindered, and no crystalline phases could be observed. The crystal structures that are achieved from the dilution of tBA with water are considered to be frozen stages of hydration, describing the genesis of such clathrate-like structures, finally ending at ice as an example of an infinitely diluted hydrate.

The primary amine-borane t-BuNH2·BH3 reacts with a β-diketiminate-supported silylamido calcium complex with elimination of HN(SiMe3)2 and formation of the corresponding primary amidoborane complex, in which the deprotonated amine-borane is attached to the alkaline-earth center via its nitrogen atom and anagostic interactions with the boron-bound hydrides. Catalytic dehydrocoupling reactions employed with this β-diketiminate precatalyst are found to be slow and complicated by protonation of the supporting ligand and the formation of a number of boron-containing products, all of which have been positively identified. In common with previous studies of group 2 catalyzed secondary amine-borane dehydrogenation, the first formed major product of the catalysis is identified by solution NMR and solid-state single-crystal X-ray studies to be a cyclic diborazane, [HtBuN-BH2]2, the formation of which is accompanied by variable proportions of diamidoborane and aminoborane products. The active calcium species is also observed to be depleted during the catalysis due to the formation of hydrocarbon-insoluble [Ca(BH4)2·THF]∞, which has also been structurally characterized. Continued heating of these reaction mixtures results in the formation of cyclic trimeric 1,3,5-tri-tert-butylborazine, which is proposed to form through the intermediacy of [HtBuN-BH2]2 by an, as yet, undefined sequence of borazane dehydrogenation and ring expansion reactions.

Relative permittivities of numerous binary mixtures of 2-methoxyethanol (1) + isobutylamine (2), 2-methoxyethanol (1) + sec-butylamine (2), and 2-methoxyethanol (1) + tert-butylamine (2), between 291.15 and 313.15 K, are reported. These results are used to calculate deviations in the relative permittivities. The results are fitted to the Redlich–Kister polynomial equation to estimate the binary coefficients and standard errors. Furthermore, the experimental results are used to expose the nature of binary interactions in the bulk of the binary mixtures studied.

Densities of binary mixtures containing 2-methoxyethanol with n-butylamine, sec-butylamine and tert-butylamine have been determined at different temperatures, between 291.15 and 313.15 K, over the complete concentration range. Excess molar volumes were calculated and the departure from ideal behaviour is explained on the basis of specific interactions between the components in these mixtures.

Refractive index (n) and related properties such as molar refraction (R) have been investigated for 2-methoxyethanol (ME) + n-butylamine (n-BA) and 2-methoxyethanol (ME) + isobutylamine (iso-BA), 2-methoxyethanol (ME) + sec-butylamine (sec-BA) and 2-methoxyethanol (ME) + tert-butylamine (tert-BA) binary mixtures over the entire composition range, at different temperatures in the range 291.15 ≤ T/K ≤ 313.15. Furthermore, the excess molar refraction (RE ) and deviation from ideality refractive index (Δn) have been examined, in order to identify the presence of intermolecular complexes in these binary liquid mixtures. The results obtained have been interpreted on the basis of specific intermolecular interactions between species.