P-chlorotoluene Research Articles

Evaluation of the bioluminescence activity, biokinetics, and the effects of binary mixtures of inducers on the Pm-lux recombinant strain

The bioluminescence activity and biokinetics of a recombinant Pseudomonas putida mt-2 were investigated in the presence of various inducers: three chlorotoluenes (CTs) and two nitrotoluenes (NTs). The effects of binary mixtures (40 combinations) of eleven inducers on the bioluminescence activity were also studied. Different responses and toxicities were observed depending on the type of inducers and concentrations. The intensity of the bioluminescent response at 1 mM of individual inducers was in the following order: o-CT > p-CT > m-CT > o-NT and p-NT. The biokinetics calculated based on the bioluminescence activity was in the range of 0.109–8.417 mM for the half-saturation constant (Ks) and 6.083–19.880 h−1 for the maximum SBR (µmax). In the case of binary mixtures, the observed bioluminescence was 4–810% (avg. 80.4%) of the expected bioluminescence intensity depending on the combinations (0.0001 < p < 0.5226). Among these binary mixture combinations, 27 out of 40 combinations indicated antagonistic effects (3–83% of expected activity; p < 0.0391) under the exposure of inducer mixtures. Overall, this study demonstrated that the proper biomonitoring for specific chemicals could be established by considering the characteristics of mixture pollutants for their possible usages as a preliminary rapid and field analytical bio-tool.

Molecular oxygen-promoted reconstruction of molybdenum phosphide enables selective electrochemical oxidation of p-chlorotoluene

It is highly challenging to develop efficient catalysts for selective oxidation of p-chlorotoluene (PCT) into p-chlorobenzaldehyde (PCB) as PCB easily undergoes over-oxidation. Herein, a new electrochemical strategy was developed for selective oxidation of PCT with high selectivity toward PCB. A self-standing molybdenum phosphide (MoP) anode was directly synthesized on carbon cloth with the assistance of polyvinyl pyrrolidone. The as-synthesized MoP anode with 3D network structure, exhibits the selectivity of 91.4% toward PCB at the conversion of 75.6% in acetonitrile solution containing 0.1 M Bu4NClO4. During electrochemical oxidation, molecular oxygen-induced transformation of MoP into MoO2 initiates the activation of PCT into ClC6H5CH2+. The ClC6H5CH2+reacts with molecular O2 over electrode surface, producing the product of PCB. This work offers a promising strategy to achieve selective oxidation of CH bond based on electrochemical environment.

Catalytic Oxidation of o-Chlorotoluene with Oxygen to o-Chlorobenzaldehyde in a Microchannel Reactor

Liquid-phase selective oxidation of o-chlorotoluene (OCT) to o-chlorobenzaldehyde (OCBD) with oxygen as the oxidant catalyzed by a cobalt acetate/manganese acetate/potassium bromide (Co(OAc)2/Mn(OA...

Hydrogen Bonding Interactions of m-Chlorotoluene with 1-Alkanol Analyzed by Thermodynamic, Fourier Transform Infrared Spectroscopy, Density Functional Theory, and Natural Bond Orbital.

Fourier transform infrared spectroscopy (FT-IR) has been employed to obtain information about the nature of interactions in the liquid solutions of pure solvents and their mixtures of m-chlorotoluene (MCT) with 1-alkanol systems at different mole fractions. Furthermore, densities (ρ) and speeds of sound (u) of binary mixtures of MCT with a set of five 1-alkanols, namely, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol, were measured as a function of composition at 298.15 K. From the experimental quantities, the excess volumes (VE), isentropic compressibility (ks), and excess isentropic compressibility (ksE) were calculated for the binary mixtures over the entire composition range and under the atmospheric pressure. These excess properties (VE) and (ksE) were correlated with the Redlich–Kister polynomial equation. Additionally, theoretical density functional theory calculations and natural bond orbital analyses were carried out to further discern the nature and strength of interactions between MCT and 1-alkanols. Moreover, the recorded FT-IR spectra-derived excess properties and quantum chemically derived data revealed the presence of interactions between component molecules in binary liquid solutions.

Molecular interactions of p-chlorotoluene and 1-alkanols at different temperatures: Volumetric, ultrasonic and FT-IR spectroscopic studies

To understand the nature and type of intra- and inter molecular interactions between p-chlorotoluene (PCT) and 1-alkanols, measurements such as density and speed of sound at T = (298.15 K - 318.15) K and at 0.1 MPa have been carried out. These experimental quantities were used to calculate excess properties, i.e. excess volume (VE) and excess isentropic compressibility (ksE) for all the binary mixtures. The calculated excess properties were satisfactorily fitted to the Redlich–Kister polynomial equation. Furthermore, FT-IR spectra of pure liquids with their mixtures at various mole fractions (≈0.2, ≈0.5, ≈0.8) of PCT for all binary systems were recorded. Moreover, it is required to analyze the ??OH, ??CH and ??CCl stretching vibrational frequencies from the recorded FT-IR spectrum to predict the hydrogen bond formation, dipole interactions, Vander Waals interactions and structural effects between component molecules in liquid mixtures.

Influence of chlorine atom on interactions between halo-hydrocarbons and 1-nonanol: Density and speed of sound measurements

Abstract Herein we have investigated densities and speed of sound for the binary mixtures of o -chlorotoluene (OCT), m -chlorotoluene (MCT), p -chlorotoluene (PCT) and 1,2-dichloroethane with 1-nonanol at temperature range from (293.15 to 308.15) K and at a pressure p = 0.1 MPa. In addition, the experimental data have been used to calculate excess volumes ( V E ), isentropic compressibilities ( k s ) and excess isentropic compressibilities ( k s E ) over the entire composition range. The measured excess properties were correlated with the Redlich–Kister Polynomial equation to confirm the accuracy of experimental results. As well, the calculated excess properties were discussed in terms of influence of chlorine atom on interactions between halo hydrocarbons and 1-nonanol.

Experimental study of non-uniform bubble growth in deep fluidized beds

Non-uniform bubble growth occurs in deep fluidized beds, resulting in generation of large bubbles or even slugs. Gas tracer method, in combination with analysis of pressure fluctuations, is employed to quantify the time-averaged and transient characteristics of bubble growth with respect to the bed depth in a 300-mm ID cold flow unit. The bubble distribution, growth and its residence time in the transition from uniform to non-uniform bubble growth and finally to slugging are investigated. In addition, appreciably better conversion and selectivity in a 1200-mm ID industrial fluidized bed reactor with ammoxidation of p-chlorotoluene (PCT) is obtained by eliminating non-uniform bubble growth.

Energy Transfer and Bond Dissociation in the o‐chlorotoluene + H2/Cl2/HCl Collisions

Energy flow and C–H and C–Cl bond dissociations in o‐chlorotoluene (OCT) in collisions with H2, Cl2, and HCl are studied using classical trajectory methods. The energy loss by the excited OCT is small, but it increases with increasing total vibrational energy content ET of OCT between 5000 cm−1 and 30000 cm−1. The energy loss is larger in OCT + HCl collision than in OCT + H2 or OCT + Cl2. The difference is mainly due the near‐resonant conditions between the vibration of the incident molecule and the C–H or C–Cl vibrations. Intermolecular energy transfer occurs through vibration–translation (V–T) and vibration–vibration (V–V) pathways. The intramolecular energy flow between C–H and C–Cl in highly excited OCT (60000–60300 cm−1) leads to bond dissociation. The probabilities of C–H and C–Cl dissociation are 10−5–10−1 and increase exponentially with increasing vibrational excitation of OCT. The probabilities are found to increase when the incident molecule becomes heavier.

Efficacy of zero-valent copper (Cu0) nanoparticles and reducing agents for dechlorination of mono chloroaromatics

The zero-valent copper (Cu0) nanoparticles were prepared by chemical reduction method. The morphology of nanoparticles was investigated by using X ray diffraction, scanning electron microscopy-energy dispersive X ray, UV–visible spectrophotometer and Brunauer-Emmett-Teller surface area analyser. The Cu0 nanoparticles along with reducing agents, NaBH4/5% acidified alcohol were used for the dechlorination of chloroaromatics at room temperature. Chlorobenzene (Cl-B), chlorotoluene (Cl-T), chloropyridine (Cl-Py) and chlorobiphenyl (Cl-BPh) were selected as the contaminants. The effect of various operating parameters such as pH, concentration of the catalyst and reducing agent (NaBH4), and recycling of the catalyst on dechlorination were studied. Nearly complete dechlorination of all the chloroaromatics were achieved in the presence of Cu0 nanoparticles (2.5 g L−1) and NaBH4 (1.0 g L−1) within 12 h. On the contrary, approximately 70% of dechlorination was observed in the presence of 5% acidified alcohol at similar experimental conditions. The dechlorination mechanism highlighted the importance of Cu0 nanoparticles as a surface mediator. The kinetics of the dechlorination of chloroaromatics was investigated and compared with chloroaliphatics. The dechlorination rate differed from 0.23 h−1 (Cl-B) to 0.15 h−1 (Cl-BPh) in the presence of Cu0 nanoparticles and NaBH4. The effectiveness of Cu0 nanoparticles with NaBH4 (1 g L−1) and 5% acidified alcohol as electron donors were studied by oxidation-reduction potential and observed to be −1016 mV and −670 mV, respectively. Final products of the dechlorination were benzene, toluene, pyridine and biphenyl, as identified by gas chromatograph mass spectrometer and nuclear magnetic resonance spectroscopy.

Catalytic Oxidation of o-chlorotoluene to o-chlorobenzaldehyde by Vanadium Doped Anatase Mesoporous TiO<sub>2</sub>

A novel method for the catalytic oxidation of o-chlorotoluene (OCT) to o-chlorobenzaldehyde (CBD) was proposed using vanadium doped anatase mesoporous TiO2 (V/MTiO2), the catalytic reaction conditions were investigated. Under the optimum catalytic reaction conditions: 10 mL of acetic acid 100 °C of reaction temperature, 10 h of reaction time and 100 mg of catalyst, the conversion rate of OCT could reach to 95.3%, with a selectivity of 63.5%.

Determination of chlorinated toluenes in soils using gas chromatography tandem mass spectrometry

A method for the analysis of chlorotoluenes (CTs) in soil has been developed based on ultrasonic assisted extraction with a low volume of organic solvent and determination by gas chromatography-tandem mass spectrometry (GC–MS/MS). A simultaneous clean-up on an alumina–anhydrous sodium sulphate mixture was carried out to remove soil interferences. However, an additional clean-up with graphitised carbon was needed for some very dirty samples. Several solvents were assayed and a mixture of ethyl acetate:hexane (80 : 20, v/v) was selected to carry out soil extractions. Recovery studies were performed at 0.2, 0.1, 0.05 and 0.02 ng g−1 fortification levels, and recoveries obtained for all the compounds and concentrations were higher than 81% with standard deviations fulfilling the requirements of the IUPAC. LODs from 0.7 to 5.2 ng kg−1 and LOQs from 2.2 to 17.5 ng kg−1 were achieved for the analysed compounds, being pentachlorotoluene the compound with the highest limits, followed by the monochlorinated toluenes. The proposed analytical method was applied to determine CT levels in agricultural and industrial soils. These compounds were found in all the industrial soils analysed and some CTs were present in agricultural soils at lower levels.

Phosphino imidazoles and imidazolium salts for Suzuki C–C coupling reactions

The consecutive syntheses of imidazoles 1-(4-X-C(6)H(4))-4,5-R(2)-(c)C(3)HN(2) (3a, X = Br, R = H; 3b, X = I, R = Me; 3c, X = H, R = Me; 5, X = Fc, R = H; 7, X = C≡CFc, R = H; 9, X = C(6)H(5), R = Me; Fc = Fe(η(5)-C(5)H(4))(η(5)-C(5)H(5))), phosphino imidazoles 1-(4-X-C(6)H(4))-2-PR'(2)-4,5-R(2)-(c)C(3)N(2) (11a-k; X = Br, I, Fc, FcC≡C, Ph; R = H, Me; R' = Ph, (c)C(6)H(11), (c)C(4)H(3)O), imidazolium salts [1-(4-X-C(6)H(4))-3-R''-4,5-R(2)-(c)C(3)HN(2)]I (16a; X = Br, R = H, R'' = n-Bu; 16b, X = Br, R = H, R'' = n-C(8)H(17); 16c, X = I, R = Me, R'' = n-C(8)H(17), 16d, X = H, R = Me, R'' = n-C(8)H(17)) and phosphino imidazolium salts [1-C(6)H(5)-2-PR'(2)-3-n-C(8)H(17)-4,5-Me(2)-(c)C(3)N(2)]PF(6) (17a, R' = C(6)H(5); 17b, R' = (c)C(6)H(11)) or [1-(4-P(C(6)H(5))(2)-C(6)H(4))-3-n-C(8)H(17)-4,5-Me(2)-(c)C(3)HN(2)]PF(6), (20) and their selenium derivatives 1-(4-X-C(6)H(4))-2-P([double bond, length as m-dash]Se)R'(2)-4,5-R(2)-(c)C(3)N(2) (11a-Se-f-Se; X = Br, I; R = H, Me; R' = C(6)H(5), (c)C(6)H(11), (c)C(4)H(3)O) are reported. The structures of 11a-Se and [(1-(4-Br-C(6)H(4))-(c)C(3)H(2)N(2)-3-n-Bu)(2)PdI(2)] (19) in the solid state were determined. Cyclovoltammetric measurements were performed with the ferrocenyl-containing molecules 5 and 7 showing reversible redox events at E(0) = 0.108 V (ΔE(p) = 0.114 V) (5) and E(0) = 0.183 V (ΔE(p) = 0.102 V) (7) indicating that 7 is more difficult to oxidise. Imidazole oxidation does not occur up to 1.3 V in dichloromethane using [(n-Bu)(4)N][B(C(6)F(5))(4)] as supporting electrolyte, whereas an irreversible reduction is observed between -1.2 - -1.5 V. The phosphino imidazoles 11a-k and the imidazolium salts 17a,b and 20, respectively, were applied in the Suzuki C-C cross-coupling of 2-bromo toluene with phenylboronic acid applying [Pd(OAc)(2)] as palladium source. Depending on the electronic character of 11a-k, 17a,b and 20 the catalytic performance of the in situ generated catalytic active species can be predicted. As assumed, more electron-rich phosphines with their higher donor capability show higher activity and productivity. Additionally, 11e was applied in the coupling of 4-chloro toluene with phenylboronic acid showing an excellent catalytic performance when compared to catalysts used by Fu, Beller and Buchwald. Furthermore, 11e is eligible for the synthesis of sterically hindered biaryls under mild reaction conditions. C-C Coupling reactions with the phosphino imidazolium salts 17b and 20 in ionic liquids [BMIM][PF(6)] and [BDMIM][BF(4)] were performed, showing less activity than in common organic solvents.

Theoretical Study on σ-Complexes in Ring-Chlorination of Toluene

Theoretical studies on mechanism of mutual conversion between σ-complexes and the solvent effect in ring-chlorination of toluene were performed with density functional theory (DFT). All geometry optimizations, intrinsic reaction coordinate calculations and frequency analyses were carried out at B3LYP/6-311G** level. Calculation results indicate that ortho-, meta- and para-complexes can convert mutually by overcoming a π-complex structured transition state. It was also confirmed that the mutual conversion between ortho- and para- complexes can occur directly which give answer to the experimental result that ortho-chlorotoluene (OCT) and para- chlorotoluene (PCT) are predominant products while meta-chlorotoluene (MCT) shares less than one percent in total products. In addition, a theoretical investigation of solvent effect was carried out at the same level via Onsager model, where all stagnation points were optimized completely using toluene as solvent. The free energies and activating free energies were also calculated at the same level, which decrease due to solvent effect, suggesting that it is better for toluene to be ring-chlorinated in liquid phase than in gas phase, which is in agreement with experimental results.

Molecular structure and vibrational spectra of o-chlorotoluene, m-chlorotoluene, and p-chlorotoluene by ab initio HF and DFT calculations

In this work, experimental and theoretical study on the molecular structure and the vibrational spectra of o-chlorotoluene (OCT), m-chlorotoluene (MCT) and p-chlorotoluene (PCT) are presented. The vibrational frequencies of these compounds were obtained theoretically by ab initio HF and DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set for optimized geometries and were compared with Fourier transform infrared (FTIR) in the region of 400–4000 cm −1 and with Raman spectra in the region of 100–4000 cm −1. Complete vibrational assignment, analysis and correlation of the fundamental modes for these compounds have been carried out. The vibrational harmonic frequencies were scaled using scale factors, yielding a good agreement between the experimentally recorded and the theoretically calculated values.

Dual phosphorescence and excited state dynamics of p-bromotoluene

Excited state dynamics of dual phosphorescent p-bromotoluene (PBT) was investigated in low temperature matrix between 77 K and 91 K. Dual phosphorescence was ascribed to two low-lying triplet states, 3ππ * and 3πσ *. The phosphorescence decay rate constants were divided into temperature dependent and independent terms. The temperature independent decay rate constants of 3ππ * state was 180 times larger than that of p-chlorotoluene (PCT). The decay rate constant of chlorobenzene (CB) and bromobenzene (BB) were determined in our previous study, and the ratio of the decay rate constants were 13, which has been successfully explained by increase of spin–orbit interaction due to internal heavy atom effect. In the case of p-bromotoluene, the large decay rate constant is partly explained by taking into account of non-radiative decay process due to spin–vibronic interaction through promoting vibrational modes possible even at 77 K. Moreover, homolysis reaction to produce bromine atom was also suggested to induce non-radiative process within triplet manifold.

Calix[4]arene‐Supported N‐Heterocyclic Carbene Ligands as Catalysts for Suzuki Cross‐Coupling Reactions of Chlorotoluene.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Selective oxidation of p-substituted toluenes to the corresponding benzaldehydes over (VO) 2P 2O 7: an in situ FTIR and EPR study

The adsorption and oxidation of p-chlorotoluene (PCT), p-methoxytoluene (PMT), and toluene on vanadyl pyrophosphate catalyst (VPP) were studied by in situ FTIR and EPR spectroscopy. Various amounts of strongly adsorbed benzaldehydes and cyclic anhydride species were observed by FTIR in dependence on the different educts after oxidation experiments. The extent of spin–spin exchange pertubation and, thus, the loss of the EPR signal intensity caused by substrate adsorption and interaction is influenced by the nature of the aromatic compound. The strength of reactant and product adsorption on the catalyst surface was found to be an important selectivity-limiting factor in the aldehyde formation. The benzaldehyde adsorption is enhanced by additional interaction of the carbonyl group with Brønsted acid hydroxyl groups generated during oxidation reaction, which facilitates deeper oxidation. The co-adsorption of pyridine is one possibility to suppress the strong aldehyde adsorption and to improve the selectivities. Yields of benzaldehydes and selectivities at constant conversion increase in the order PMT<toluene<PCT. Strong product adsorption favoured by electron donating p-substituents causes total oxidation leading to lower aldehyde selectivities. Both, the acid/basic characters of the reactants and products and their steric properties play an important role for adsorption/desorption processes.

Selective up-hill transport of gold to iodide stripping solution through a solvent modified liquid membrane containing a polysulphide podand as carrier

The polydentate neutral sulphide podand 1,12-di-2-thienyl-2,5,8,11-tetrathiadodecane, (TTD), C 4H 3S-(CH 2-S-CH 2) 4-C 4H 3S, which shows high affinity towards “soft metal ions” has been used as a carrier for gold transport through a supported liquid membrane (SLM). Transport of gold (5 × 10 −5M) from hydrochloric acid solution to the stripping solution was facilitated by TTD in m-chlorotoluene(MCT)/kerosene solution immobilized in the pores of a polyvinylidene fluoride Millipore membrane. A study of the influence of different chemical and physical parameters on Au transport has been carried out. This includes the presence of kerosene in TTD-MCT solutions, the concentration of the carrier in the liquid membrane, the concentration of the stripping agent NaI (or NaSCN) and the stirring rate of both aqueous solutions. The highest value obtained for the permeability coefficient P was 0.34 cm min −1, and for the Au flux 1.5 × 10 −6 mol m −2 s −1. A high selectivity in the separation of Au from its bi-cation mixtures with an excess of Zn, Cu(II), Fe(III), or Cd was achieved.

On the role of partition and surface reactions in the adsorption of binary liquid mixtures on silica gel

The adsorption behaviour of benzene (A), toluene (A), p-xylene (A), and o-xylene (A) in their binary mixtures with o-chlorotoluene (B) on silica gel has been studied at 308.15 K. The data have been analysed in terms of a model that assumes that partition and surface reactions play an important role in the adsorption process, and have revealed that while both partition and surface reactions dictate the adsorption (U-shaped isotherms) of o-chlorotoluene (OCTE) (B) from benzene (A) or toluene (A) + OCTE (B) mixtures, the adsorption of A and B entities of p-xylene (A) or o-xylene (A) + OCTE (B) mixtures (S-shaped isotherms) onto the silica gel surface is governed primarily by the distribution process and secondarily by the surface reaction.

The Photoelectron Spectra the Chloro Toluenes

The HeI and HeII photoelectron spectra of the chloro toluenes have been measured. The spectra are assigned using HeI/HeII cross-section ratios and a composite-molecule model within an ab initio valence-electron-only model potential (VEOMP) framework. The order of the first two ionization potentials for the chloro toluenes is assigned as πS &lt; πA which is contrary to the VEOMP assignment for benzal chloride and benzotrichloride , but is consistent with linear correlations using group electronegativities and σI scales. Furthermore, linear correlations using the first two ionization potentials of fluoro and chloro toluenes with group electronegativities are shown to be a useful aid in spectral assignment and, moreover, suggest that for benzyl fluoride and benzal chloride the most appropriate σI values are 0.20 and 0.31 respectively.