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• 75-50-3 trimethylamine 

Relevant academic research and scientific papers

Highly efficient and recyclable alkylammonium hydrosulfate catalyst for formation of bisphenol F by condensation of phenol with formaldehyde

Several C1-C4 alkylammonium hydrosulfates [R3NH][HSO4] have been conveniently prepared from the cheap raw materials sulfuric acid and alkylamines. Their acidities were measured by chemical titration and determined using UV-vis spectroscopy with a basic indicator 4-nitroaniline. The catalytic performance of these hydrosulfates for the condensation of phenol with formaldehyde to bisphenol F (BPF) was evaluated in detail on a batch reactor. The results indicated that the proposed catalysts are very active for such condensation due to its homogeneous catalysis characteristics in reaction conditions. Among the catalysts examined, [H3NCH2CH2NH3][HSO4]2 shows the best catalytic performance and it can achieve a complete conversion of formaldehyde, providing a higher than 90% selectivity for BPF under the optimal conditions. Furthermore, the catalyst can be recovered from the reaction mixture via an azeotropic distillation with cyclohexane to remove water and then filtration and used repeatedly six times almost without loss of activity, showing an excellent reusability. It is suggested that the present catalytic process combines the characteristics of a homogenized reaction and heterogenized recovery so might provide a highly-efficient, environmentally-friendly and low-cost route for synthesis of bisphenol F.

[HSO4]-catalyzed eco-friendly and expeditious synthesis of thiazolidine and oxazolidine derivatives

The present study reports a facile and green approach for the synthesis of thiazolidine/oxazolidine derivatives 4(a-u) in excellent yields (92-98%) with high purity. The protocol involves a one-pot three-component reaction of substituted 1,3-diketones 1(a-g), cyanates 2(a-c) and ethylchloroacetate (3) in ionic liquid [Et3NH][HSO4] under solvent-free conditions. The notable feature of this pathway is that the ionic liquid possesses both catalytic as well as medium engineering capability in this protocol. Use of [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminates the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present synthetic route is a green protocol offering several advantages, such as excellent yield of products, mild reaction conditions, minimizing chemical waste, shorter reaction time, simple operational procedure, easy preparation of the catalyst and its recyclability up to five cycles without any noticeable loss in catalytic activity. The protocol is applicable to a broad substrate scope. The optimization of conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free conditions at 120 °C are the best reaction parameters for the synthesis of thiazolidine/oxazolidine derivatives in excellent yields. This journal is

Temperature dependence measurements and structural characterization of trimethyl ammonium ionic liquids with a highly polar solvent

We report the synthesis and characterization of a series of an ammonium ionic liquids (ILs) containing acetate, dihydrogen phosphate, and hydrogen sulfate anions with a common cation. To characterize the thermophysical properties of these newly synthesized ILs with the highly polar solvent N,N-dimethylformamide (DMF), precise measurements such as densities (ρ) and ultrasonic sound velocities (u) over the whole composition range have been performed at atmospheric pressure and over wide temperature ranges (25 - 50 °C). The excess molar volume (VE) and the deviation in isentropic compressibilities (ΔKs) were predicted using these temperature dependence properties as a function of the concentration of ILs. The Redlich - Kister polynomial was used to correlate the results. The ILs investigated in the present study included trimethylammonium acetate [(CH3) 3NH][CH3COO] (TMAA), trimethylammonium dihydrogen phosphate [(CH3)3NH][H2PO4] (TMAP), and trimethylammonium hydrogen sulfate [(CH3)3NH][HSO 4] (TMAS). The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. In addition, the hydrogen bonding between ILs and DMF has been demonstrated using semiempirical calculations with help of Hyperchem 7. A qualitative analysis of the results is discussed in terms of the ion - dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. The influence of the anion of the protic IL, namely, acetate (CH 3COO), dihydrogen phosphate (H2PO4), and hydrogen sulfate (HSO4), on the thermophysical properties is also provided.