Production Of Chlorides Research Articles

Effect of interaction between different plastics and polyvinyl chloride on the chlorine transformation behavior in volatiles during low-temperature pyrolysis

To reduce the pollution during the pyrolysis recovery of chlorine-containing plastic waste from different sources, effects of the interaction between different plastics and polyvinyl chloride (PVC) on the transformation of chlorine at low temperature were investigated by thermogravimetry-Fourier transform infrared (TG-FTIR) and fixed-bed pyrolysis experiments. Results showed that the proportions of chlorine in chars were all <0.04 %, indicating that almost all chlorine was released after pyrolysis. However, the chlorine forms in volatiles were significantly changed with mixing different plastics. HCl production was significantly inhibited due to the addition of other plastics, while the organic chlorinated compounds (OCCs) formation was promoted, which increased the distribution of chlorine in liquid products. During PVC pyrolysis, chlorine was mainly distributed in gas (93.09 %) in the form of HCl, only a small amount of aliphatic chlorides were generated and distributed in liquid (6.89 %). After the addition of polystyrene (PS), polyethylene (PE) and polyethylene terephthalate (PET), the chlorine distribution in liquid increased to 8.86 %, 11.98 % and 25.99 %, respectively. The formation of OCCs was significantly affected by the difference in thermochemical reaction characteristics of plastics. Specifically, the production of aromatic chlorides was promoted by PS, while the generation of aliphatic chlorides and aromatic chloroesters was significantly promoted by PE and PET, respectively. Therefore, the release form of chlorine could be significantly altered by the interaction between PVC and other waste plastics, which provides a reference for the regulation of chlorine-containing pollutants in the recovery and utilization of plastic waste.

Electrospun CuMn2O4 Spinel Nanofibers as Electrocatalysts for the Production of Chloromethane and Aromatic Chlorides

Electrospun CuMn₂O₄ Spinel Nanofibers as Electrocatalysts for the Production of Chloromethane and Aromatic Chlorides

Research on the application of microwave synthesis to obtain aluminum-containing coagulant

The extensive way of industrial development and the rate of population growth determine the increase in the amount of drinking water consumed and the requirements for water treatment. Known and applied technologies for the industrial production of aluminum oxychloride coagulant used in reagent water purifi cation are based on high-temperature processes that require complex hardware design. The paper presents the results of studies on the production of basic aluminum chlorides by the microwave method. The experiments were carried out on a designed laboratory setup based on a microwave oven; data were obtained on the yield of aluminum polyoxychloride depending on the change in process parameters, duration, coeffi cient of effi ciency, and 36% concentration of hydrochloric acid solution. Studies of the use of microwave technologies in inorganic synthesis have shown the eff ectiveness of such technologies, a decrease in the reaction time, an increase in the effi ciency of the installation, and the absence of contact between the heating elements and the reaction mixture. The infl uence of sulfuric acid as a process activator substance, which positively aff ects the productivity of aluminum polyoxychlorides, has been established. The results of physicochemical studies of the synthesized samples and their coagulation properties are presented, which indicates the possibility of using microwave technologies in the inorganic synthesis of aluminum polyoxychloride coagulants.

An Automated Continuous Synthesis and Isolation for the Scalable Production of Aryl Sulfonyl Chlorides.

In this work, a continuous system to produce multi-hundred-gram quantities of aryl sulfonyl chlorides is described. The scheme employs multiple continuous stirred-tank reactors (CSTRs) and a continuous filtration system and incorporates an automated process control scheme. The experimental process outlined is intended to safely produce the desired sulfonyl chloride at laboratory scale. Suitable reaction conditions were first determined using a batch-chemistry design of experiments (DOE) and several isolation methods. The hazards and incompatibilities of the heated chlorosulfonic acid reaction mixture were addressed by careful equipment selection, process monitoring, and automation. The approximations of the CSTR fill levels and pumping performance were measured by real-time data from gravimetric balances, ultimately leading to the incorporation of feedback controllers. The introduction of process automation demonstrated in this work resulted in significant improvements in process setpoint consistency, reliability, and spacetime yield, as demonstrated in medium- and large-scale continuous manufacturing runs.

Ultrathin Fe–N –C single-atom catalysts with bifunctional active site for simultaneous production of ethylene and aromatic chlorides

Abstract Ethylene evolution reaction (EER) by electrochemical dechlorination of 1,2-dichloroethane is a promising and an economical strategy. The process is however severely impeded by the poor reactivity of catalysts, the accumulation of HCl in the electrolyte as well as low value-added by-products at anode. Herein, a bifunctional ultrathin Fe–Nx–C single-atom catalysts (SACs) has been successfully prepared and investigated as both cathode and anode material for EER and aromatic chlorination reaction (ACR), respectively. The generated HCl was recycled as a chlorinating reagent. The Fe–Nx–C SACs exhibited an excellent electrocatalytic performance simultaneously for both EER and ACR with high ethylene and para–chloroanisole selectivity obtained. The first-principles calculations indicated that Fe–N4 was the dominating catalytic active site for the generation of ethylene as well as para–chloroanisole. The coupling strategy of ACR at anode not only can accelerate the reaction rate of EER, but also provide a highly-efficient and atom-economical approach for the production of valuable ethylene and aromatic chlorides.

An integrated chemical and ecotoxicological assessment for the photocatalytic degradation of vancomycin

The photocatalytic degradation of an antibiotic, vancomycin B hydrochloride (VAN-B), has been investigated in aqueous suspensions of titanium dioxide (TiO2) by monitoring the change in its concentration as well as the production of ammonia and chlorides as a function of irradiation time. The removal of 50 mg L−1 VAN-B solution yields maximum concentrations of 2.45 and 2.53 mg N-NH3 L−1 after 120 min of photocatalytic oxidation using 0.1 and 0.2 g TiO2 L−1, respectively. When 0.2 g TiO2 L−1 were applied up to 87% of the stoichiometric amount of chloride was reached within 120 min of irradiation, corresponding to 0.087 mmol L−1.A set of bioassays (Daphnia magna, Pseudokirchneriella subcapitata and Ceriodaphnia dubia) was performed to evaluate the potential detoxification of VAN-B and its by-products of oxidation under chronic and acute tests. The toxicity of the treated VAN-B samples varied during the oxidation, due to the formation of some intermediate products more toxic than VAN-B. Despite almost total removal of VAN-B that was achieved within 120 min of irradiation, a significant increase in toxicity was observed in chronic tests proving that the chronic assays are more appropriate than acute ones to detect the impact of by-products formed during the photocatalytic degradation of antibiotics.

ChemInform Abstract: New Synthesis of Alkane‐ and Arylsulfonyl Chlorides by Oxidation of Thiols and Disulfides with Chlorine Dioxide.

Sulfonyl chlorides are extensively used in the production of detergents, ion-exchange resins, elastomers, pharmaceuticals, dyes, herbicides, as semiproducts in the synthesis of sulfonic acids esters. Industrial and laboratory scale production of sulfonyl chlorides is based on reactions of aliphatic hydrocarbons with sulfuryl halides or with a mixture of sulfur dioxide and chlorine, on the oxidative chlorination of thiols, sulfi des, disulfi des; on the oxidation of sulfenyl chlorides; on the reaction of sulfonic acids and their derivatives with PCl5, COCl2, thionyl chloride, chlorine, and chlorosulfonic acid. Sulfonyl halides form also in reactions of organomagnesium compounds with sulfuryl halide or of diazonium salts with sulfur dioxide and CuCl 2 [1]. However all these methods have certain disadvantages due to the severe reaction conditions and side processes. The method of synthesis of sulfonyl chlorides we developed is convenient and simple for application, provides a high yield of the reaction product (45–82%), and does not require any special conditions for the process (heating or cooling, or high pressure). This new reaction of sulfonyl chlorides preparation previously was not described in the literature. It consists in the reaction of alkanethiols or arylthiols and disulfi des with chlorine dioxide. Chlorine dioxide is one among effi cient and available oxidants produced on the industrial scale applied to the bleaching of cellulose and disinfection of drinking water. It s well soluble in water and organic solvents, therefore it can be used in various media and allows variation in charging reagents. We formerly demonstrated that chlorine dioxide selectively oxidized sulfi des to sulfoxides [2–5] and tiols to disulfi des [6]. We used as initial compounds hexanethiol (Ia), hexadecanethiol (IIa), phenylmethanethiol (IIIa), 4-methylbenzenethiol (IVa), dibutyl disulfide (Va), diphenyl disulfi de (VIa).

New synthesis of alkane- and arylsulfonyl chlorides by oxidation of thiols and disulfides with chlorine dioxide

Sulfonyl chlorides are extensively used in the production of detergents, ion-exchange resins, elastomers, pharmaceuticals, dyes, herbicides, as semiproducts in the synthesis of sulfonic acids esters. Industrial and laboratory scale production of sulfonyl chlorides is based on reactions of aliphatic hydrocarbons with sulfuryl halides or with a mixture of sulfur dioxide and chlorine, on the oxidative chlorination of thiols, sulfi des, disulfi des; on the oxidation of sulfenyl chlorides; on the reaction of sulfonic acids and their derivatives with PCl5, COCl2, thionyl chloride, chlorine, and chlorosulfonic acid. Sulfonyl halides form also in reactions of organomagnesium compounds with sulfuryl halide or of diazonium salts with sulfur dioxide and CuCl 2 [1]. However all these methods have certain disadvantages due to the severe reaction conditions and side processes. The method of synthesis of sulfonyl chlorides we developed is convenient and simple for application, provides a high yield of the reaction product (45–82%), and does not require any special conditions for the process (heating or cooling, or high pressure). This new reaction of sulfonyl chlorides preparation previously was not described in the literature. It consists in the reaction of alkanethiols or arylthiols and disulfi des with chlorine dioxide. Chlorine dioxide is one among effi cient and available oxidants produced on the industrial scale applied to the bleaching of cellulose and disinfection of drinking water. It s well soluble in water and organic solvents, therefore it can be used in various media and allows variation in charging reagents. We formerly demonstrated that chlorine dioxide selectively oxidized sulfi des to sulfoxides [2–5] and tiols to disulfi des [6]. We used as initial compounds hexanethiol (Ia), hexadecanethiol (IIa), phenylmethanethiol (IIIa), 4-methylbenzenethiol (IVa), dibutyl disulfide (Va), diphenyl disulfi de (VIa).

Effect of magnetic field on the zero valent iron induced oxidation reaction

The magnetic field (MF) effect on the zero valent iron (ZVI) induced oxidative reaction was investigated for the first time. The degradation of 4-chlorophenol (4-CP) in the ZVI system was employed as the test oxidative reaction. MF markedly enhanced the degradation of 4-CP with the concurrent production of chlorides. The consumption of dissolved O 2 by ZVI reaction was also enhanced in the presence of MF whereas the competing reaction of H 2 production from proton reduction was retarded. Since the ZVI-induced oxidation is mainly driven by the in situ generated hydroxyl radicals, the production of OH radicals was monitored by the spin trap method using electron spin resonance (ESR) spectroscopy. It was confirmed that the concentration of trapped OH radicals was enhanced in the presence of MF. Since both O 2 and Fe 0 are paramagnetic, the diffusion of O 2 onto the iron surface might be accelerated under MF. The magnetized iron can attract oxygen on itself, which makes the mass transfer process faster. As a result, the surface electrochemical reaction between Fe 0 and O 2 can be accelerated with the enhanced production of OH radicals. MF might retard the recombination of OH radicals as well.

Fe–Ni Nanoparticles supported on carbon nanotube-co-cyclodextrin polyurethanes for the removal of trichloroethylene in water

Nanoscale bimetallic particles of nickel on iron were supported on carbon nanotubes and then co-polymerized with β-cyclodextrin (CNTs/CD) and the resulting polymers applied to the degradation of pollutants in water. The bimetallic nanoparticles (BMNPs) were first embedded on functionalized carbon nanotubes (f-CNTs) before being copolymerized with beta cyclodextrin (β-CD) and hexamethylene diisocyanate (HMDI) forming a water-insoluble polyurethane. The particle size and distribution of BMNPs were determined by Transmission Electron Microscopy (TEM), and the surface area was determined by using the Brunauer–Emmett–Teller (BET) method. Energy dispersive X-ray spectroscopy (EDXS) was used to confirm the formation of the BMNPs. Degradation of trichloroethylene (TCE) as a model pollutant was studied and more than 98% reduction in TCE was achieved by the polymers. Polymers with the BMNPs maintained their efficiency in degrading TCE after several cycles compared to metal-free polymers. The degradation was monitored by using gas chromatography-mass spectrometry (GC-MS), while the production of chlorides was verified by using ion chromatography (IC). Atomic absorption spectroscopy (AAS) was employed to determine the possible leaching of the BMNPs from the polymer, and confirmed to be extremely low.

A mild and general method for preparation of α-glycosyl chlorides

A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed.

Drying of Inorganic Particulate Compounds

ABSTRACT Inorganic particulates are usually dried in a fixed bed, fluidized bed, or spray dryers. These compounds are easy to dry, once their physical structure, with high porosity, allows moisture content removal with low resistances. For fluidized bed of alumina particle evaluations, a laboratory-scale drying unit was built. The drying experiments were carried out with alumina particles with different diameters to evaluate temperature and air flow rate effects on drying kinetics and bed height. In another case, the dehydration of a mixture of rare-earth chlorides in a fluidized bed was studied, aiming at the production of anhydrous rare-earth chlorides, used to obtain mischmetal by electrolytic and metallothermic processes. The spray drying experiments were carried out in a pilot plant. Spray drying is a technique largely applied in industrial processes to dry solutions or suspensions, converting their solid parts into a dried powder. A set of rare-earth drying experiments was carried out, aiming at the development of techniques to obtain a powder that could satisfy international morphological requirements. The results allowed evaluating the effects of air flow rate, feed concentration, atomizer model, rotation velocity, and atomization pressure on powder density and particle size distribution.

Recycling of galvanised steel scrap using chlorination

The chlorination of galvanised steel in air and chlorine mixtures at 800°C was investigated by means of thermogravimetric analysis. Scanning electron microscopy, atomic absorption spectroscopy and X-ray diffraction were used to examine and characterise the reaction products. The results demonstrated that it is feasible to remove zinc from iron at 800°C, using an air/chlorine flowrate of 400/40 cm3 min−1 with a ratio of 10 : 1 with respect to air and chlorine. While zinc undergoes chlorination producing a volatile zinc chloride, the oxidation of iron provides a protective oxide layer that resists the attack of chlorine and, therefore, the production of iron chlorides. This provides a novel and cheap method for the steel and related industries to recycle galvanised steel scrap.

Production of excimer molecules and the excitation of nitrogen in a steady-state low-pressure electric discharge

Conditions for the simultaneous production of argon and xenon chlorides and excited nitrogen molecules in a longitudinal dc glow discharge in Ar/Cl2/air, Xe/Cl2/air, and Ar/Xe/Cl2/air mixtures are studied. The electrical parameters of the plasma and its optical characteristics in the 130-to 350-nm wavelength range are investigated. It is shown that a small admixture of air added to argon or xenon leads to the production of excited nitrogen molecules, whose decay is accompanied by the molecular band emission in the range Δλ=176–271 nm. The conditions for simultaneous emission of the ArCl(B-X), XeCl(B-X), and nitrogen molecular bands are determined.

Electrochemical studies of copper, copper-aluminium and copper-aluminium-silver alloys: Impedance results in 0.5M NaCl

The electrochemical behaviour of Cu, Cu-Al and Cu-Al-Ag alloys in aqueous solutions of NaCl (0.5 M, pH = 3.00) was studied by means of voltammetric methods and electrochemical impedance spectroscopy. The surfaces were examined by SEM and EDX analysis. Cu-Al-Ag alloy shows a potentiodynamic behaviour similar to that of the pure copper electrode while the Cu-Al alloy presents some minor differences. In the active dissolution region the electrodes suffer pitting corrosion and in the other potential regions there are the formation of a passivant film with composition depending on the potential. The impedance responses of the electrodes are discussed. An electrodissolution mechanism is proposed and the effect of the alloying elements upon the impedance response and polarisation curves is explained. The main effects are due to the production of copper and silver chlorides and aluminium oxides/ hydroxides at the corroding interface. The addition of Al or (Al + Ag) increases the corrosion resistance of pure copper.

Electrochemical dissolution of metals of the platinum group by alternating current

The electrochemical dissolution of metals of the platinum group in acid solutions using an alternating current is investigated. It is shown that this is an efficient and promising method for the production of pure noble metal salts, and for the analysis and extraction of small amounts of noble metals from waste and poor ores. The production of pure bromides and chlorides of gold and rhodium is particularly efficient because their rates of dissolution are high. The mechanism of the influence of the alternating current on the metal/electrolyte interface is also discussed.

Multiple Reaction Channels of (N-Acyl-N-alkylcarbamoyl)oxyl Radicals from N-Acyl PTOC Carbamates

N-Acyl-N-alkyl-N'-hydroxypyridine-2-thione carbamates (N-acyl PTOC car- bamates) (1) are prepared in good to excellent yield by reactions of N-acylcarbamoyl chlorides with N-hydroxypyridine-2-thione sodium salt. Methods for production of the requisite carbamoyl chlorides by reaction of a secondary amide with trimethylsilyl triflate followed by treatment with phosgene were optimized. Precursors (1) react in radical chain re- actions to give the title radicals (2) that can further react by seve- ral pathways. Decarboxylations of radicals (2) give amidyl radicals, and this method is excellent for production of acetamidyl radicals and in particular the N-methylacetamidyl radical which is difficult to prepare by other routes. 5-Exo cyclizations of amidyl radicals produced by de- carboxylation of (2) give, ultimately, lactams and N-acylpyrrolidines. 1,5-Hydrogen transfer reactions of (2)to give α-amide radicals compete with decarboxylation; cyclization of an α-amide radicals compete with decarboxylation; cyclization of an α-amide radical thus formed also is reported. By appropriate experimental design, radicals (2) often can be directed toward one desired reaction, and several relative rate consta- nts for reactions of (2) necessary for such design were determined in this work

The functionalization of saturated hydrocarbons. Part 25. Ionic substitution reactions in GoAgg IV chemistry: the formation of carbon-halogen bonds

GoAgg IV chemistry (Fe (III) species, tert-butyl hydroperoxide in a mixture of pyridine and acetic acid) in the presence of LiCl can transform saturated hydrocarbons efficiently into the corresponding alkyl chlorides. The transformation into monosubstituted alkyl derivatives by “ionic trapping” reagents arising from the interception of the first intermediate of the system supports the presence of a high valent VFe-C species. Mechanistic studies suggest a possible pathway operating via an Fe-centered ligand coupling. In addition, the production of alkyl chlorides and alkyl bromides could also be achieved employing this system in the presence of halogenating reagents such as CCl 4 and BrCCl 3.

Direct production of butyltin chlorides from a paired electro-organic synthesis

Butyltin chlorides were produced directly from butyl chloride and a tin cathode in several undivided cell reactors with tetraethylammonium chloride and acetonitrile solvent. The complex reaction chemistry was investigated primarily in a small batch cell with a 1 cm2 planar cathode. Current densities from cathodic linear potential sweeps at 1 mV s−1 were correlated successfully with current densities and butyltin products from potentiostatic experiments. Potential windows on product formation and other major limiting reactions were thereby identified. Product yield was shown to be strongly dependent on electrolyte gas conditions, with yield decreasing as the reactor is increasingly deaerated. Use of the initial open circuit potential (i.o.c.p.) as an indicator of reaction gas conditions proved to be a convenient and reproducible technique. Under favourably oxidized conditions, current densities in the product formation potential region ranged from 66 mA cm−2 at −2.74V vs SCE to 250 mA cm−2 at −2.98 Vvs SCE which are considerably higher than previously reported current densities for this synthesis. Surprisingly, the aeration history of butyl chloride prior to synthesis may be an important factor in subsequent product yield.

Pulsed ultraviolet laser stimulated chlorination mechanisms for Si(111)

Pulsed ultraviolet laser induced surface reactions of chlorine on silicon were investigated. The predominant chlorination products were SiCl and SiCl2. Laser fluence effects could be clearly divided into three regimes: under ≊150 mJ/cm2 a nonthermal reaction occurred, from 200–400 mJ/cm2 thermal effects play a significant role, and above this vaporization and plasma formation dominate. Wavelength effects were also apparent. Fluence thresholds for the appearance of products varied with 351 nm having the lowest, 308 nm the highest, and 248 nm intermediate values. The effect of wavelength upon product ratios suggests that a competing process of chlorine photodesorption is accessed at 308 nm. Increases in dopant concentration yielded increased production of silicon chlorides. The results of combined variations in dopant concentration and wavelength indicate the presence of at least two distinct mechanisms—one involving initial photon‐substrate interactions, the other photon‐adsorbate interactions. Under all c...