Acid In Toluene Research Articles

Brønsted acid-catalyzed 1,4-addition of 1,3,5-trimethoxybenzene to maleimides and acrylates

Several Brønsted acids were investigated as catalysts for 1,4-additions of 1,3,5-trimethoxybenzene to maleimides. Among the acids tested, trifluoromethanesulfonic acid in low polar solvents such as toluene and 1,2-dichloroethane was found to show high reactivity, enabling preparation of 3-(2,4,6-trimethoxyphenyl)succinimides. 1,4-Additions of 1,3,5-trimethoxybenzene to acrylates were also realized by a catalytic amount of trifluoromethanesulfonic acid in toluene.

In Situ Generated Nickel Phosphide Based Catalysts for Hydroprocessing of Levulinic Acid

This article describes the production of unsupported nickel phosphide\t\t\t\t\tcatalysts generated in situ in а reaction mixture from water-soluble and\t\t\t\t\toil-soluble precursors during the hydroconversion of levulinic acid. These\t\t\t\t\tcatalysts contain crystalline phases, specifically\t\t\t\t\t\tNi12P5 and\t\t\t\t\t\tNi(PO3)2. During the\t\t\t\t\thydrogenation of levulinic acid in toluene in the presence of NiP–TOP, a lower\t\t\t\t\ttemperature and a shorter reaction time contribute to the formation of\t\t\t\t\tγ-valerolactone (100% selectivity). A higher temperature and a longer reaction\t\t\t\t\ttime favor the formation of valeric acid (94% selectivity). In the hydrogenation\t\t\t\t\tof levulinic acid in ethanol in the presence of\t\t\t\t\t\tNiP–H3PO2, the main reaction\t\t\t\t\tproduct is ethyl levulinate (95% selectivity).

Facile synthesis of spiro thiazolidinone via cyclic ketones, amines and thioglycolic acid by MCM-41-Schiff base-CuSO4·5H2O

Mesoporous MCM-41-supported Schiff base and CuSO4·5H2O (MCM-41@Schiff base-CuSO4·5H2O) catalyzed one-pot three-component condensation of cyclic ketones, amines and thioglycolic acid in toluene. And a series of corresponding spiro thiazolidinone derivatives were obtained in high yields (up to 97%). The synthesized catalyst was characterized via FT-IR, XRD, SEM, TEM and EDS and can be easily recovered by centrifugation and reused at 10 times without any change in catalytic activity. Moreover, the scale-up experiment also demonstrated the practicability of the catalytic system on the condensation. The possible mechanisms pave the way to investigation on the reactions of other cyclic ketones with thioglycolic acid.

Adsorption characteristics of aromatic pollutants and their halogenated derivatives on bio-based poly (ether-pyridine)s

In this work, innovative poly(ether pyridine) polymers obtained from bio-based monomers and pentafluoropyridine derivatives were elaborated in order to adsorb aromatic pollutants and their halogenated derivatives. These polymers were obtained with satisfactory yields by polycondensation of four pyridinium monomers (respectively based on morpholine, piperazine, dimethylamine and phenol) with isosorbide or bisphenol A. The adsorption efficiency data demonstrate that the poly(etherpyridine) based on isosorbide and morpholine-based monomer (P2) is the more efficient sorbent toward aromatic pollutants and their derivatives. Four aromatic pollutants, p-hydroxybenzoic acid, toluic acid, deisopropylatrazine, and 2,4,6-trichlorophenol, were chosen as the adsorbate to investigate the adsorption efficiency, kinetics and isotherms of the poly(ether pyridine) P2. The results demonstrate that the pseudo-second order was the best to describe the adsorption of the four target pollutants by the efficient sorbent P2 with good correlation. The experimental data of the four target pollutants adsorption were analyzed by Langmuir and Freundlich isotherms. Polymer P2 shows very high affinity (low 1/n value) for p-hydroxybenzoic acid and for 2,4,6-trichlorophenol, compared to other adsorbents. Three consecutive adsorption/desorption cycles toward eight aromatic pollutants were obtained for the efficient sorbent P2.

Preparation and properties of hydrophilic P.R. 57:1 with inorganic core/solid solution shell

A series of modified pigment red 57:1(P. R. 57:1) were prepared by forming a pigment solid solution in-situ on the surface of different inorganic cores. Influence of core type (silica gel, kaolin, sepiolite and silica micropowder) and core size (silica micropowder 850 mesh and 1250 mesh) on the properties of the modified pigments were investigated, and it was found that the pigment with silica gel as core had the best performance. The schaffer's salt, tobias acid and sulpho toluic acid were used as the second components, and DSC and XRD analysis result showed that they all formed a pigment solid solution on the surface of the inorganic cores. When the amount of sulpho tobias acid was 3% and the inorganic core was silica gel, the modified pigment had the smallest particle size, narrowest particle size distribution and showed blue-red color, which was similar to the commercial available pigment sample C. P. R. 57:1. Moreover, the contact angle, Zeta potential analysis results and water-based ink test results showed that the hydophilicity of the modified pigments was obviously improved.

An LC-MS/MS Method for a Comprehensive Determination of Metabolites of BTEX Anaerobic Degradation in Bacterial Cultures and Groundwater

BTEX (benzene, toluene, ethylbenzene, and the different xylene isomers), known for carcinogenic and neurotoxic effects, are common environmental contaminants. The first step for the development of the bioremediation technologies is the detection of intense microbial degradation in contaminated waters in the quest for the most active bacterial strains. This requires the multispecies analysis for BTEX metabolites which are considered as markers of microbial degradation. A direct (50 µL injection) HPLC–electrospray MS/MS analytical method was developed for the simultaneous analysis of 11 BTEX metabolites (o-, m-, p-toluic, salicylic, benzoate, benzyl, and phenyl succinic acids, 2-(1-phenylethyl)-, 2-(2-methylbenzyl), and 2-(3-methylbenzyl)-, 2-(4-methyl benzyl)-succinic acids) in bacterial cultures and ground waters down to 0.1 ng/mL. The optimization of the chromatographic conditions allowed for the resolution of position isomers of toluic and methylbenzyl-succinic acids. The stability of the analytes during sample storage tested in different conditions showed the instability of some of them when stored at room temperature. The feasibility of the method was demonstrated by the detection of all the investigated metabolites in a water sample of a deep aquifer hosting natural gas storage. A model laboratory study emphasized the importance of 2-(2-methylbenzyl)-succinic acid as a marker of anaerobic microbial degradation.

STUDY OF THE MECHANISM OF CATION POLYMERIZATION n-METHYLSTYROL IN THE PRESENCE OF AN INTEGRATED CATALYST ALUMINUM CHLORIDE - HYDROCHLORIC ACID IN TOLUENE BY AB INITIO METHOD

For the first time, a quantum-chemical study of the mechanism of initiation of the cationic polymerization monomer of p-methylstyrene in the presence of a complex catalyst of aluminum chloride - hydrochloric acid in toluene with a stoichiometric composition of 1:1:1 by the ab initio method with the reaction coordinate RC1-H20 was performed. The reaction is exothermic . The activation energy of the reaction is 14 kJ/mol, and the thermal effect is -110 kJ/mol.

Successive Protonation and Methylation of Bridging Imido and Nitrido Ligands at Titanium Complexes

The reactions of nitrido complexes [{Ti(η5-C5Me5)(μ-NH)}3(μ3-N)] (1) and [{Ti(η5-C5Me5)}4(μ3-N)4] (2) with electrophilic reagents ROTf (R = H, Me; OTf = OSO2CF3) in different molar ratios have allowed the structural characterization of a series of titanium intermediates en route to the formation of the ammonium salts [NR4]OTf and [NR4][Ti(η5-C5Me5)(OTf)4]. The treatment of the trinuclear imido-nitrido complex 1 with 5.5 equiv of triflic acid in toluene at room temperature led to the dinuclear complex [Ti2(η5-C5Me5)2(μ-N)(NH3)(μ-O2SOCF3)2(OTf)] (3) and [NH4]OTf. Compound 3, along with the ammonium salts [NMe4]OTf and [NMe4][Ti(η5-C5Me5)(OTf)4] (5), was also obtained in the reaction of 1 with 8 equiv of methyl triflate in toluene at 100 °C. The trinuclear complex [Ti3(η5-C5Me5)3(μ-N)(μ-NH)2(μ-O2SOCF3)(OTf)] (4), an intermediate in the formation of 3, was isolated in the treatment of 1 with 4 equiv of MeOTf, although compound 4 was prepared in better yield by treatment of 1 with Me3SiOTf (2 equiv). Addition of a large excess of MeOTf or HOTf reagents to solutions of 3 resulted in the clean formation of ammonium salts [NR4][Ti(η5-C5Me5)(OTf)4] (R = Me (5), H (6)). Treatment of the tetranuclear nitrido complex [{Ti(η5-C5Me5)}4(μ3-N)4] (2) with 1 equiv of ROTf in toluene afforded the precipitation of the ionic compounds [{Ti(η5-C5Me5)}4(μ3-N)3(μ3-NR)][OTf] (R = H (8), Me (9)), while a large excess of HOTf led to the formation of [{Ti(η5-C5Me5)}4(μ3-N)3(μ3-NH)][Ti(η5-C5Me5)(OTf)4(NH3)] (10) by rupture of a fraction of tetranuclear molecules. Complex 2 reacted with 1 equiv of [M(η5-C5H5)(CO)3H] (M = Mo, Cr) via hydrogenation of one nitrido ligand to give the molecular derivative [{Ti(η5-C5Me5)}4(μ3-N)3(μ3-NH)] (11) and [{M(η5-C5H5)(CO)3}2], while a second 1 equiv of [M(η5-C5H5)(CO)3H] produced the ionic compounds [{Ti(η5-C5Me5)}4(μ3-N)2(μ3-NH)2][M(η5-C5H5)(CO)3] (M = Mo (12), Cr (13)) by protonation of another nitrido group. The X-ray crystal structures of 3-5, 9, 10, and 13 were determined.

Generator of Actinium-228 and a Study of the Sorption of Actinium by Carbon Nanomaterials

A method has been developed for isolation of 228Ac from aged samples of natural 232Th. Macroscopic amounts of the thorium bulk (20 g) were separated by its extraction by a solution of di(2-ethylhexyl)phosphoric acid in toluene from 4 M HNO3 solutions, with microamounts of 228Ra and 228Ac remaining in the aqueous phase. 228Ac was selectively extracted from the resulting solution by the method of extraction chromatography on a column with RE resin sorbent, and 228Ra quantitatively remained in the 4 M HNO3 eluate. 228Ac was washed out of the column with 0.05 M HNO3, it could be used as a radioisotope for research purposes. After the accumulation of the daughter 228Ac the solution of 228Ra in 4 M HNO3 was repeatedly passed through an identical column. The resulting 228Ac was used in the study to examine its sorption on commercial and modified carbon nanomaterials (CNMs) instead of the difficultly accessible 225Ac. It is shown that the application of CNMs as carriers of actinium isotopes for nuclear medicine purposes is promising.

Ternary Phase Diagrams for Systems Formed by Terephthalic Acid, p-Toluic Acid, and 4-Carboxybenzaldehyde in N-Methyl-2-Pyrrolidone

The mutual solubility of terephthalic acid + p-toluic acid + N-methyl-2-pyrrolidone (NMP), terephthalic acid + 4-carboxybenzaldehyde + NMP and p-toluic acid + 4-carboxybenzaldehyde + NMP systems at...

Activation of Water at the Active‐Site Cavity of Zinc Phthalocyanine with Tris(pentafluorophenyl)borane

Activation of water bound with Zn2+ has attracted much attention as an artificial model of natural enzymes. Despite many attempts, water activation accompanied with a change in the coordination geometry of Zn2+ in complexes remains a challenge. In this study, we discover a new structure that is composed of partially protonated zinc phthalocyanine (ZnPc), hydroxide ion, and tris(pentafluorophenyl)borane (TPFB). The coordination of TPFB with water bounded with ZnPc results in the dissociation of water, and the dissociated proton from water moves to one nitrogen atom of the phthalocyanine ring through the intramolecular proton transfer. On the basis of this reaction, the coordination geometry transforms from a five‐coordinated to a distorted tetrahedral species. The Zn2+‐bound hydroxide nucleophile in the ZnPc‐TPFB complex attacks amide of ε‐caprolactam to produce hydrolyzed 6‐aminohexanoic acid in toluene.

Study of degradation of p-toluic acid by photo-oxidation, peroxidation, photo-peroxidation and photo-fenton processes

p-Toluic acid is a major content of terephthalic acid wastewater and is a cause of secondary water pollution. p-Toluic acid in aqueous solution was degraded by using photo-fenton, photo-peroxidation, photo-oxidation and peroxidation processes. A low-pressure mercury vapour lamp was taken in combination with different oxidants to degrade p- toluic acid in this study. Substrate concentration was fixed by utilizing a UV–Visible spectrophotometer. The results indicated that photo-fenton process achieved degradation rate due to synergistic effect between UV and Fe2+/H2O2. The degradation rate follow the sequence: photofenton (UV/ Fe2+/H2O2) > photo-peroxidation (UV/H2O2) > photo-oxidation (UV) > peroxidation (H2O2). The photodegradation processes were adhered to first order dynamics.

Production of 230Pa from Proton-irradiated Thorium and Developing 230Pa/230U/226Th Tandem Generator

Targeted alpha-therapy of various oncology diseases is based on the coupling of alpha-emitting radionuclides to tumour-selective carrier molecules. 230U (t1/2 = 20.8 d) is accumulated via decay of 230Pa and has strong potential for alpha-therapy due to 5 emitting alpha particles with total energy 33.5 MeV. It can be used directly or as a parent of 226Th in a generator system. A prospective way for production of 230Pa/ 230U is irradiation of natural thorium with medium-energy protons. Curie amounts of 230Pa can be generated in one irradiation run together with other useful alpha-emitters 225Ac and 223Ra. After dissolving Th-target in 6M nitric acid with the addition of catalytic amounts of hydrofluoric acid Pa was isolated by liquid extraction with octanol. The water phase may be further used for isolation of 225Ac and 223Ra according the method, proposed in [1, 2]. Namely, the most part of thorium was removed by liquid extraction with di(2-ethylhexyl)phosphoric acid in toluene. Organic phase was kept for accumulation 223Ra from parent 227Th. 225Ac and 223Ra were concentrated from aqueous phase and then separated and purified by extraction chromatography. After re-extraction 230Pa was purified on silica gel using different oxalic acid solutions. Up to 85% of 230Pa with radionuclidic purity >99% was recovered and stored for 230U accumulation. Basing on distribution coefficients 230U was separated from 230Pa in diluted nitric acid solution on DGA resin. Obtained 230U may be used for development of 230U/226Th – generator. Distribution coefficients for U and Th were obtained for a wide range of extraction chromatographic resins. TEVA (mixture of trioctyl and tridecyl methyl ammonium chloride as an extractant) and WBEC (based on a mixture of tertiary octyl and decylamines) resins are most suitable for this purpose. [1]R.A. Aliev, S.V. Ermolaev, A.N. Vasiliev, V.S. Ostapenko, E.V. Lapshina, B.L. Zhuikov, N.V. Zakharov, V.V. Pozdeev, V.M. Kokhanyuk, B.F. Myasoedov, S.N. Kalmykov. Isolation of medicine-applicable actinium-225 from thorium targets irradiated by medium-energy protons. Solvent Extraction and Ion Exchange, 2014, v. 32, p. 468-477.[2]A.N. Vasiliev, V.S. Ostapenko , E.V. Lapshina, S.V. Ermolaev, S.S. Danilov, B.L. Zhuikov and S. N. Kalmykov. Recovery of Ra-223 from natural thorium irradiated by protons. Radiochimica Acta, 2016, v. 104, N.8, p. 539-547.

An in-tube aptamer/gold nanoparticles coated capillary solid-phase microextraction for separation of adenosine in serum and urine samples

As an endogenous nucleoside, adenosine was significant for the diagnosis and treatment of some diseases, such as schizophrenia. However, due to the complicated matrix interference, it was difficult to monitor trace or ultra-trace adenosine directly in bio-samples. In this contribution, a novel in-tube SPME technique based on aptamer/Au nanoparticles coated open tubular fused-silica capillary was established to separate and enrich adenosine in bio-samples with high affinity. Therefore, a uniform and dense AuNPs layer was coated on the inner surface of the open tubular capillary, and then adenosine aptamer was immobilized on AuNPs with a high capacity of 2.44 μg per 27-cm capillary. As a result, the capillary shown high selectivity to adenosine with a selectivity factor of 14.4 when compared with the scrambled aptamer/AuNPs coated capillary. Also, the extraction amount of adenosine was 2.8–24.8 times higher than those of its structural analogs and contrast, such as guanosine, uridine, cytidine, thymidine, and toluic acid. After the optimization of extraction conditions, the aptamer/AuNPs coated in-tube SPME-HPLC method was developed for the adenosine assay with the linear range of 0.002–0.100 μg mL−1 and the detection limit of 0.45 ng mL−1. Subsequently, the approach was applied for trace adenosine monitoring in human serum and urine samples. It showed a strong performance of reducing matrix interference and improving sensitivity, and the spiking recoveries of 89.9–92.6% and 91.1–94.5% were achieved respectively.

Acid-Catalyzed Synthesis of Aryl[4,5]isothiazoles through a Sulfenic Acid Pathway

A new method to efficiently prepare 3-substituted aryl[4,5]isothiazoles by simply heating the starting materials with a catalytic amount of p-toluenesulfonic acid in toluene is reported. This simple procedure is well suitable for a variety of substrates that can tolerate substitution changes in the fusing aromatic ring, as well as at the 3-position. Substituted aryl rings of varying electronic properties and alkyl substitution eventually afford aryl[4,5]isothiazoles in high yields.

Synthesis, Photophysics and Redox Properties of Aza-BODIPY Dyes with Electron-Donating Groups.

A series of novel aza-BODIPY dyes substituted with p-(dimethylamino)phenyl groups were synthesized and their spectral and electrochemical properties were compared. In particular, the impact of p-(Me2 N)Ph- groups on these characteristics was of consideration. For two aza-BODIPYs studied, a near-IR absorption band was observed at circa λabs =796 nm. Due to the pronounced intramolecular charge transfer (ICT) exerted by the presence of strongly electron-donating p-(Me2 N)Ph- substituents, the compounds studied were weakly emissive with the singlet lifetimes (τS ) in the picosecond range. Nanosecond laser photolysis experiments of the brominated aza-BODIPYs revealed T1 →Tn absorption spanning from ca. 350 nm to ca. 550 nm with the triplet lifetimes (τT ) ranged between 6.0 μs and 8.5 μs. The optical properties of the aza-BODIPYs studied were pH-sensitive. Upon protonation of the dimethylamino groups with trifluoroacetic acid in toluene, a stepwise disappearance of the NIR absorption band at λabs =790 nm was observed with the concomitant appearance of a blue-shifted absorption band at λabs =652 nm, which was accompanied by a prominent emission band at λfl =680 nm. The transformation from a non-emissive to an emissive compound is associated with the inhibition of the ICT. As estimated by CV/DPV measurements, all aza-BODIPYs studied exhibited two irreversible oxidation and two quasi-reversible reduction processes. All compounds studied exhibit extremely high photostability and thermal stability.

Room temperature ammonia gas sensor using Meta Toluic acid functionalized graphene oxide

A gas sensor has been fabricated by depositing the thin film of Functionalized Graphene Oxide (GO) using Langmuir Blodget (LB) technique on SiO2/Si wafers. Aluminum (Al) contacts were deposited using thermal evaporation technique for measuring the resistance of fabricated thin film. Three different concentrations (15 mM, 50 mM, 75 mM) of Meta Toluic acid (MTA) have been used for functionalization of GO. X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to characterize the Graphene Oxide (GO) after functionalization. Also, Scanning Electron Microscopy (SEM) was carried out for both GO and functionalized GO to study the surface morphology. Gas sensing behavior of functionalized GO has been investigated using two probe resistance measurement method for different concentration of ammonia gas. Sensor response was studied for ammonia concentration varied from 100 to 2000 ppm. Highest response obtained at 100 ppm concentration was found to be ~12.2% for sample TG75. Higher concentration of MTA (up to a critical value) in GO leads to higher response of ammonia gas. This enhanced gas response has been due to the increased ester formation reaction at the surface of sensing film, which eventually leads to more interaction with NH3 gas molecules. In addition, defects and carbon vacancy in functionalized GO also acts as the trapping sites for gas molecules being sensed. The selectivity of the sensor has been investigated in different environment and sensor was found to be very selective towards ammonia gas. For stability investigation of the fabricated sensor, the sensor response has been recorded for 45 days.

Room temperature ammonia gas sensor using ester functionalization of graphene oxide

A room temperature ammonia gas sensor has been fabricated by depositing the thin film of Functionalized Graphene Oxide (GO) using Langmuir Blodgett (LB) technique on SiO2/Si wafers. Thermal evaporation technique was used for deposition of aluminum (Al) contacts for measuring the resistance of fabricated thin film. Different concentration of Meta Toluic acid (15 mM, 50 mM, 75 mM) has been used for functionalization of GO. X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to characterize the Graphene Oxide (GO) after functionalization. Also, Scanning Electron Microscopy (SEM) was carried out for both GO and functionalized GO. Gas sensing behavior of functionalized GO has been investigated for different concentration of ammonia gas. Sensor response was studied for low concentration (100 ppm) of ammonia gas. Highest response at 100 ppm concentration was found to be ∼12%. Higher concentration of MTA in GO leads to higher response of ammonia gas. This enhanced gas response is attributed to the enhanced ester formation reaction at the surface of sensing film, and more defects and carbon vacancy in functionalized GO, which eventually leads to more interaction with NH3 gas molecules.

Dihydroxybenzoic acids as polydentate ligands in phenylantimony (V) complexes

The compounds Ph4Sb[O(O)CC6H3(OH)2-2,5] (1), Ph4Sb[O(O)CC6H3(OH)2-2,6] (2) and [Ph4Sb]+[Ph4Sb(O2C6H3CO2H)]−(3) were obtained through the interaction of pentaphenylantimony with 2,5-; 2,6- and 2,3-dihydroxybenzoic acids in toluene. The structure of synthesized compounds and the coordination type of antimony atoms in 1, 2 and 3 depend on the location of hydroxyl groups in the benzene ring. The antimony atoms in 1 and 2 have distorted trigonal-bipyramidal coordination, through to different degrees. The antimony atom in the anion of compound 3 is hexacoordinated with [C4O2]− surroundings. The compounds 1,2 and 3 have been characterized by elemental analysis, IR- and NMR-spectroscopy, X-ray analysis.

N-(4-Chlorophenyl)-9H-fluoren-9-imine

The title compound, C19H12ClN, was synthesizedviareaction of 9-fluorenone and 4-chloroaniline usingp-toluenesulfonic acid in toluene. The dihedral angle between the fluorene moiety (r.m.s. deviation = 0.027 Å) and the chlorophenyl ring is 64.59 (6)° and a possible weak intramolecular C—H...π interaction occurs.