Tetrabutylammonium Hydroxide Research Articles

Effect of surfactant type on oxygen barrier behavior of polyvinyl alcohol/α‐zirconium phosphate nanocomposites

AbstractSurfactants used to exfoliate and disperse nanoparticles are expected to have an impact on polymer nanocomposite properties. In this work, both ionic tetrabutylammonium hydroxide (TBA) and amphiphilic polyoxyalkyleneamine (M1000) surfactants were used to exfoliate α‐zirconium phosphate (ZrP) in polyvinyl alcohol (PVA) matrix through simple solution blending. The oxygen barrier properties of the nanocomposites were investigated as a function of ZrP content based on the above two surfactant types. At a low ZrP loading level (≤2.4 vol%), regardless of the surfactant type, the ZrP nanoplatelets in PVA matrix do indeed create a “torturous pathway” to improve barrier properties even though the crystallinity in PVA/ZrP‐M1000 system is decreased. In addition, the PVA/ZrP‐TBA films exhibit excellent transparency as good as the neat PVA films. Furthermore, it is found that the high molecular weight amphiphilic M1000 surfactant is less effective than the low molecular weight ionic TBA surfactant in dispersion and exfoliation of ZrP in PVA. This relative incompatibility of ZrP‐M1000 compared to ZrP‐TBA in PVA leads to its dramatic drop in oxygen barrier properties. This facile aqueous solution blending technique is eco‐sustainable and expected to facilitate the preparation of effective polymer nanocomposites for barrier properties applications.

Process Optimization for Ionic Liquid Tetrabutylammonium Hydroxide Pretreatment of Waste Particleboard to Heighten Enzymatic Hydrolysis Saccharification

Process Optimization for Ionic Liquid Tetrabutylammonium Hydroxide Pretreatment of Waste Particleboard to Heighten Enzymatic Hydrolysis Saccharification

Reacting Mn3O4 powders with quaternary ammonium hydroxides to form two-dimensional birnessite flakes

There is a current interest in synthesis of two-dimensional (2D) materials that would be cost-efficient to scale to industry production. In this study, we report on a bottom-up approach to convert a manganese oxide (Mn3O4) powder into crystalline, 2D layered birnessite flakes. The Mn3O4 precursor powder, is reacted with aqueous solutions of, tetramethyl-, tetraethyl- or tetrabutylammonium hydroxide in a shaker oven at 80 °C for 4 days. X-ray diffraction confirmed that in all cases, upon filtration of colloidal suspensions, well-stacked, crystalline, 2D MnO2 birnessite layers formed, that upon characterization were found to be quite similar. The major differences were the spacings between the flakes that depended on cation size. Selected area diffraction patterns in a transmission electron microscope confirmed both the structure and the polycrystallinity of the flakes. Raman spectroscopy confirmed the structure. The zeta-potentials of the 2D flakes were measured to be ≈−35 ± 2 mV. When UV–Vis spectra were converted to Tauc plots, direct and indirect band gap energies of ≈2.15 and ≈2.60 eV were obtained, respectively. Additionally, the oxygen evolution reactivity of our birnessite flakes significantly are better than those found for Pt/C, demonstrating a high degree of catalytic reversibility. The facile conversion of a relatively inexpensive, earth-abundant oxide, Mn3O4, into a highly value-added 2D birnessite using a one-pot, simple hugely scalable, protocol at near ambient temperatures and pressures with various quats can be considered a breakthrough in the production of these nanomaterials.

New Chemical Dopant and Counterion Mechanism for Organic Electrochemical Transistors and Organic Mixed Ionic-Electronic Conductors.

Organic mixed ionic-electronic conductors (OMIECs) have varied performance requirements across a diverse application space. Chemically doping the OMIEC can be a simple, low-cost approach for adapting performance metrics. However, complex challenges, such as identifying new dopant materials and elucidating design rules, inhibit its realization. Here, these challenges are approached by introducing a new n-dopant, tetrabutylammonium hydroxide (TBA-OH), and identifying a new design consideration underpinning its success. TBA-OH behaves as both a chemical n-dopant and morphology additive in donor acceptor co-polymer naphthodithiophene diimide-based polymer, which serves as an electron transporting material in organic electrochemical transistors (OECTs). The combined effects enhance OECT transconductance, charge carrier mobility, and volumetric capacitance, representative of the key metrics underpinning all OMIEC applications. Additionally, when the TBA+ counterion adopts an "edge-on" location relative to the polymer backbone, Coulombic interaction between the counterion and polaron is reduced, and polaron delocalization increases. This is the first time such mechanisms are identified in doped-OECTs and doped-OMIECs. The work herein therefore takes the first steps toward developing the design guidelines needed to realize chemical doping as a generic strategy for tailoring performance metrics in OECTs and OMIECs.

Structural, optical, and electrical properties of cellulose/titanate nanosheets composite with enhanced protection against gamma irradiation

Two-dimensional (2D) materials have emerged as a promising functional filler in nanocomposites due to their unique anisotropy and resilience to harsh conditions. We report herein the use of Ti0.91O2 nanosheets as a protective component against γ-irradiation to cellulose paper. The titanate nanosheets were prepared via a sequence of solid-state synthesis of lepidocrocite-type Cs0.7Ti1.825O4, proton exchange to H0.7Ti1.825O4·H2O, and exfoliation with tetrabutylammonium hydroxide. The nanosheets were incorporated into the commercial cellulose filter paper by a simple dip coating up to 0.6 mg cm−2, equivalent to 10 wt% TiO2. The nanosheets distribution was demonstrated by energy dispersive X-ray (EDX) mapping, synchrotron radiation X-ray tomographic microscopy (SRXTM), and atomic force microscopy (AFM). It is found that γ-irradiation (up to 50 kGy) destroyed the cellulose Iβ crystallinity of uncoated paper, but this is less pronounced in the cellulose/titanate nanosheets composite. This was also confirmed by the lack of a 235 nm-absorption characteristics of irradiation-induced decomposition product(s) in nanosheets-containing papers, which also exhibit UVA shielding property. The coated samples remained white while the uncoated ones were darkened with γ-irradiation. In addition, the nanosheets-coated papers showed dielectric permittivity, loss tangent, and AC conductivity which were invariant of the γ-dose, unlike those from the uncoated ones. Our work demonstrates the use of lead-free Ti0.91O2 nanosheets as a γ-shielding component to slow down/prevent structural, optical, and electrical properties damages in cellulose paper, which could extend to other nature-derived materials.

AIE interfacial supramolecular polymers

High monomer concentration is a requisite for engendering the aggregation-induced emssion (AIE) phenomenon as well as the formation of supramolecular polymers. Therefore, this is supposed to ensure the generation of AIE supramolecular polymers, wherein the monomer soluability takes effect. Nevertheless, parts of supramolecular monomers are considered as poessessing different soluability towards the same sovlent, through which the polymerzation process is thus hard to proceed. Interfacial polymerzation gets over the soluabilty restriction, providing a facile method for propelling the reaction of thesemonomers. Herein, we had prepared M1 containing tetraphenylethene (TPE) functionalized with two terpyridine derivatives, then making M1 dissolving in CHCl3 to give solutions. Cu2+ solutions were fabricated through dissolving CuCl2 into H2O. Towards mixing those solutions, AIE interfacial supramolecular polymers (AIEISPs) displaying green fluorescence were generated at the interface of two phases on the basis of metal-coordination between terpyridine and Cu2+. These AIEISPs were certificated to possess the stimuli-responsiveness, for which the excessive addition of tetrabutylammonium hydroxide would cause the structure destruction owing to the stronger bonding ability with Cu2+ than that of terpyridine. These fabricated AIEISPs had provided a new avenue to prepare AIE supramolecular polymers.

Alkylthialactonization: A novel protocol for access to either diastereoisomer of α-(thiomethyl)-γ-butyrolactones

Presented herein are the first highly diastereoselective, controlled alkylthia-Michael reactions of mercaptans onto α-methylene butanoates. This addition occurs with concomitant lactonization and provides ready access to either the kinetic cis,cis- or thermodynamic cis,trans-butyrolactones under catalytic promotion by tetrabutylammonium hydroxide in methanol.

Construction of ionic liquid-Pd/C based bifunction catalysts for the synthesis of UV-P

Adding light stabilizers to polymeric materials can inhibit or delay the light aging effect and improve the light resistance of materials. 2-(2′-Hydroxy-5′-methylphenyl) benzotriazole (UV-P), as a typical benzotriazole ultraviolet absorber, is widely used in various polymer synthetic materials and products owning to its outstanding oil resistance, color change resistance and low volatility. Currently, it is of great theoretical and practical significance to develop an environmentally friendly method to produce UV-P. Here, we introduce ionic liquids, tetra-butyl ammonium hydroxide, into the palladium-based catalyst, design a “transfer hydrogenation site - alkaline site” duel active center system, and investigate the physical and chemical properties and possible mechanism of this bifunction catalyst system. Such heterogeneous catalytic transfer hydrogenation method can remain 100% conversion and 93.86% selectivity. This bifunction catalyst also shows an outstanding stability when it was used for ten times, proving a green and efficient transfer hydrogenation method for the synthesis of UV-P.

Delamination of MXene Flakes Using Simple Inorganic Bases

Since the discovery of the first MXene, Ti3C2Tz, in 2011, more than 30 new MXene chemistries have been reported. A universal method via which all MXenes can be synthesized is by etching the “A” layer from the MAX phase using hydrofluoric acid, HF. After etching, to delaminate the resulting MXene multilayers, MLs, they are typically treated with a surfactant like tetrabutylammonium hydroxide, TBAOH, tetramethylammonium hydroxide, TMAOH, dimethyl sulfoxide, DMSO, etc. In our earlier work, we found that treating HF-etched Ti3C2Tz MLs with a base like NaOH renders them ion-exchangeable, similar to the earlier reported treatments using expensive and more toxic bases like TMAOH or TBAOH. In this work, we study the effects of sodium hydroxide, NaOH, treatment on Nb2CTz and Mo2Ti2C3Tz MXene MLs. We show that, similar to Ti3C2Tz, Na ions also intercalate in these two MXenes. This was clearly confirmed by X-ray diffraction analysis, which showed an increase in the interlayer spacing post treatment of HF-etched MXenes with NaOH. This increase in the interlayer space reduces the van der Waals interaction between the flakes, allowing for their facile delamination to single or few layers. It was also observed that NaOH treatment reduces the flakes’ surface oxidation during processing, compared to when TBAOH is used. The surface chemistry and morphology of the MXenes post NaOH and TBAOH treatments were also analyzed using X-ray photoelectron spectroscopy and scanning electron microscopy, respectively, and compared. Finally, we conclude that inexpensive NaOH can be used to substitute for TBAOH or TMAOH, conventionally used for MXene delamination.

Schottky contact of nano-BiOx thin film synthesized galvanostatically on stainless steel in acetonitrile

In this study, the nanosized-BiOx thin film (mostly Bi2O3 with a trace amount of Bi2O5) is electrochemically synthesized on stainless steel (SS) surface at room temperature. The coating process is carried out using the galvanostatic pulse deposition method in an acetonitrile solution containing bismuth tetrafluoroborate, tartaric acid, tetrabutylammonium hydroxide, and tetrabutylammonium tetrafluoroborate. The structural and morphological characterizations of thin film are performed by XRD, XPS, SEM-EDX, and AFM techniques. Accordingly, α- and δ-Bi2O3-based coating with oxygen vacancies contains a small amount of Bi2O5 on the SS surface. The BiOx thin film exhibits a rough surface with many nano-sized hills homogeneously distributed. Electrical characterization is conducted with electrochemical impedance spectroscopy, current-voltage, and Hall effect measurements. The pseudoresistance with the most drastic change increases with rising potential and decreases again after reaching its maximum value at the open circuit potential. It could be inferred that the composition (oxidation states or oxygen deficiency) of the Bi2O3-based film varies according to the applied potential. The n-type Schottky behavior is observed at the SS/BiOx interface. Furthermore, the n-type SS/BiOx-based Schottky diode tested for endurance shows significant stability over 200 cycles.

Photoresist stochastic defect generation depending on alkyl chain length and concentration of tetraalkylammonium hydroxide in alkali aqueous developer

The effects of photoresist dissolution on randomly occurring (“stochastic”) pattern defects in extreme ultraviolet (EUV) lithography were investigated. Specifically, the effects of the alkali concentration of two developers of different alkyl chain lengths; tetramethylammonium hydroxide and tetrabutylammonium hydroxide (TBAH) on stochastic defect generation were investigated for two typical EUV photoresists. In the case of the PHS-type photoresist, results show that stochastic defect generation was almost the same regardless of developer type, given the same developer concentration. For the hybrid-type photoresist, a decrease in stochastic defects was found with the application of the longer alkyl chain length TBAH developer. Results also suggest the existence of an optimum developer concentration. Such optimum developer concentration is considered to be affected by the balance between polarity and non-polarity of the photoresist and developer components.

Fine‐Tuning Texture of Highly Acidic HZSM‐5 Zeolite for Efficient Ethanol Dehydration

AbstractAchieving high and stable ethylene yield from (bio)ethanol dehydration over highly active acidic zeolite remains challenging due to undesired side‐reactions. To overcome this issue, the fine‐tuned textural property of the HZSM‐5 catalyst with a hierarchical structure is crucial to overcome diffusion restrictions and limit undesired side‐reactions. Herein, the texture of high acid catalysts obtained via hydrothermal synthesis was simply tuned in the presence of tetrabutylammonium hydroxide as a meso‐ and micropore directing agent and the controlled molar ratio of NaF‐to‐Al2O3. The hierarchically designed HZSM‐5 with the small nanosheet size of 6.5 nm exhibits a high external surface area and mesopores, largely enhancing the catalytic performance of ethanol dehydration up to 95 % ethylene yield as well as preventing the formation of heavy hydrocarbons. To gain insights into the mechanistic points of view, the in situ DRIFTS study revealed that ethylene could form through ethoxy‐mediated mechanism or decomposition of diethyl ether (DEE). The catalyst deactivation caused by polyaromatics obtained from side‐reactions is the reason for low ethanol conversion and high DEE selectivity. Reducing the crystal size of highly acidic zeolite to ultra‐thin nanosheet can shorten the residence time of ethanol, intermediates, and products in porous structures, substantially suppressing the transformation of coke precursors into heavy hydrocarbons to achieve high and stable ethylene yield.

Effects of photoacid generator decomposition on dissolution kinetics of poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

For the advancement of lithography, the resist materials and processes are the most critical factors. In particular, the process of developing resist materials is important in reducing the line width roughness and stochastic defects. In this study, a quartz crystal microbalance method was used to investigate the dissolution dynamics of poly(4-hydroxystyrene) (PHS) films containing triphenylsulfonium nonaflate (TPS-nf) in tetraalkylammonium hydroxide (TAAH) aqueous solutions. The time required for dissolution increased with the alkyl chain length of TAAH. The dissolution rate of PHS films increased with UV irradiation dose for tetramethylammonium hydroxide and tetraethylammonium hydroxide developers, whereas the dissolution time increased for the tetrabutylammonium hydroxide developer. For the tetrapropylammonium hydroxide developer, the dissolution time of PHS films without postexposure baking (PEB) slightly decreased with UV irradiation, whereas that with PEB increased. Both the surface free energy of PHS films and the molecular size of TAAH are considered to affect dissolution kinetics.

Quantitative Methylation of Lignin Monomers Using Tetrabutylammonium Hydroxide and MeI and Applications in Organic Synthesis.

Efficient O-alkylation of phenols and carboxylic acids has essential applications in organic synthesis. A mild alkylation method for phenolic and carboxylic OH groups is developed using alkyl halides as alkylation reagents and tetrabutylammonium hydroxide as a base, and lignin monomers can be fully methylated in quantitative yields. Additionally, phenolic and carboxylic OH groups can be alkylated by different alkyl halides in one pot in different solvent systems.

Multistep sequence-controlled supramolecular polymerization by the combination of multiple self-assembly motifs

The precise sequence control of polymer chain is an important research topic of polymer chemistry. Although some methods such as iterative synthesis and supramolecular polymerization have been developed to fabricate sequence-controllable polymer, it is still a great challenge to consecutively prepare multiple supramolecular polymers with different sequence structures. In this work, through the reasonable utilization of assembly motifs, we integrated multiple host-guest recognitions and metal coordination interactions to prepare different sequence-controlled supramolecular polymers by a multistep assembly strategy. This research provides inspiration for the design and preparation of supramolecular polymers with different sequence structures.

Effects of surface compositions and interlayer distance on electrochemical performance of Mo2CTx MXene as anode of Li-ion batteries

In this study, highly pure Mo2CTx MXene was made from Mo2Ga2C by hydrothermal method in five different etching solutions (LiF, NaF, KF, NH4F or HF). The as-prepared multi-layer MXene samples were furthered delaminated by tetrabutyl-ammonium hydroxide (TBAOH) to increase the interlayer distance. The c-lattice parameter (c-LP) was increased from 20.3 Å to 23.87 Å. Thereafter, the electrochemical properties of Mo2CTx MXene samples as anode of Li-ion batteries (LIBs) were investigated. The multilayer Mo2CTx MXene made by KF + HCl etching had some residual K+ on the surface and had higher discharge specific capacity (32.7 mA h/g at the current density of 800 mA/g) than the samples made by other etchants. This is because that the residual K+ on MXene surface pillar the multi-layer structure, which provides larger room for Li+ storage and immigration. The Mo2CTx MXene after delamination with the c-LP of 23.87 Å presented a high discharge specific capacity of 239 mA h/g at the current density of 800 mA/g, which was 7.3 times higher than the discharge specific capacity of Mo2CTx MXene before delamination. The final discharge specific capacity was 118.83 mA h/g at 2000 mA/g after 100 cycles. The superior electrochemical performance of delaminated Mo2CTx MXene was attributed to the more easily accessible ion active sites between layers and the lower resistance. Therefore, the increasing of interlayer distance is the main direction to improve the performance of Mo2CTx as anode of LIBs.

Measurements of the Dissociation Heats of Tetrabutylammonium Acetate and Tetrabutylammonium Hydroxide Ionic Semiclathrate Hydrates

Measurements of the Dissociation Heats of Tetrabutylammonium Acetate and Tetrabutylammonium Hydroxide Ionic Semiclathrate Hydrates

Anion-exchange facilitated selective extraction of sulfate and phosphate by overcoming the Hofmeister bias.

Selective recognition and removal of sulfate and phosphates from aqueous media in the presence of highly competing anions is very demanding because of their biological and environmental implications. In this paper, we present the anion recognition approach for the selective and efficient extraction of sulfate by nitrophenyl-functionalized tris-urea receptors (L1-L2) from highly competitive aqueous media with an equivalent concentration of nitrate and other anions. Tetrabutylammonium hydroxide has been used for the first time as a phase transfer anionic extractant for sulfate-exchange from the aqueous phase to the organic phase (dichloromethane) containing a tris-urea receptor (L1-L3). The sulfate extraction efficacy of L2 (≈84-90%) was observed to be higher than those of L1 (≈76-82%) and L3 (≈68-75%) in competitive extraction experiments. In contrast, an analogous nitrophenyl-functionalized tris-thiourea receptor (L4) has been recognized for the selective and efficient extraction of phosphates from aqueous media in the presence of several competing anions including sulfate and nitrate, with ≈85-92% extraction efficiency. In this case, tetrabutylammonium acetate has been used as a phase transfer anionic extractant for phosphate exchange between the two immiscible phases. Due to the higher acidity of tris-thiourea -NH groups in comparison to the analogous tris-urea, tetrabutylammonium hydroxide could deprotonate a hydrogen bond donating -NH group of the thiourea receptor and phosphate extraction was observed to be inefficient in such a case. Several liquid-liquid extraction (LLE) experiments have been carried out to establish the selective removal of sulfate and phosphates by the tripodal receptors from competitive aqueous media having different combinations of two or more anions. The LLE products obtained from organic phases were characterized by NMR (1H, 13C, 31P, and 19F) spectroscopy to affirm the oxoanion selectivity of the receptors and purity of the complexes. The tripodal receptors can easily be recycled for successive extraction cycles by simply washing the LLE products (oxoanion complexes) with a methanol-water (1 : 1, v/v) solvent system followed by filtration.

Controlled synthesis of polycarbonate diols and their polylactide block copolymers using amino-bis(phenolate) chromium hydroxide complexes.

A diamine-bis(phenolate) chromium(III) complex, CrOH[L] ([L] = dimethylaminoethylamino-N,N-bis(2-methylene-4,6-tert-butylphenolate)), 2, in the presence of tetrabutylammonium hydroxide effectively copolymerizes CO2 and cyclohexene oxide (CHO) into a polycarbonate diol. The resultant low molar mass (6.3 kg mol-1) diol is used to initiate ring-opening polymerization of rac-lactide with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) giving ABA-type block copolymers with good molar mass control through varying rac-LA-to-diol loadings and with narrow dispersities. As the degree of rac-LA incorporation increases, the glass transition temperatures (Tg) are found to decrease, whereas decomposition temperatures (Td) increase. (Diphenylphosphonimido)triphenylphosphorane (Ph2P(O)NPPh3) was used as a neutral nucleophilic cocatalyst with 2, giving phosphorus-containing polycarbonates with an Mn value of 28.5 kg mol-1, a dispersity of 1.13, a Tg value of 110 °C and a Td value of over 300 °C. A related Cr(III) complex (4) having a methoxyethyl pendent group rather than a dimethylaminoethyl group was structurally characterized as a hydroxide-bridged dimer.

Determination of HNP and pKa Values of Some 3-Alkyl(Aryl)-4-phthalimido-4,5-dihydro-1H-1,2,4-triazol-5-one Compounds by Semi-Neutralization Method

In this study, the effects of solvents and molecular structure upon acidity, five 3-alkyl(aryl)-4-phthalimido-4,5-dihydro-1H-1,2,4-triazol-5-ones (3-7) were potentiometrically titrated with tetrabutylammonium hydroxide (TBAH) in four different anhydrous solvents (isopropyl alcohol, acetonitrile, tert-butyl alcohol and N,N-dimethylformamide) and HNP and corresponding pKa values were determined by half-neutralization method for all cases.