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The current work focuses on the comparison of renewable choline cation-based ionic liquids (ILs) with imidazolium cation-based ILs for their delignification performance. Choline cation-based ILs removed a higher percentage of lignin (78.1–83.7% vs. 51.4–64.5%) and hemicellulose (64.7–72.8% vs. 7.1–29.9%) from sugarcane straw pre-treatment compared to imidazolium cation-based ILs. This was mainly attributed to the presence of fewer alkyl group and extra –OH group in choline cation. In general, ILs pre-treatment significantly increased the volatile matter and reduced fixed carbon in regenerated cellulose-rich material. Higher content of cellulose and higher crystallinity in the case of choline-based ILs enhanced the production of furfural and levoglucosenone from the pyrolysis of regenerated cellulose rich material. On the contrary, the presence of higher content of amorphous cellulose from imidazolium-based ILs, particularly 1-ethyl-3-methylimidazolium acetate produced γ-butyrolactone. Therefore, ILs pre-treatment can be favourable for the selective production of platform chemicals via pyrolysis route.

Catalytic methane decomposition (CMD) was studied by employing biochar and activated char of biosolids’ origin under different reaction temperatures and methane concentrations. Higher reaction temperatures and lower inlet methane concentrations were found to be favourable for achieving higher methane conversion. A maximum initial methane conversion of 71.0 ± 2.5 and 65.2 ± 2.3% was observed for activated char and biochar, respectively at 900 °C and for 10% CH4 in N2 within the first 0.5 h of experiment. Active sites from oxygen containing carboxylic acid functional groups and smaller pore volume and pore diameter were attributed to assist in higher initial methane conversion for biochar and activated char respectively. However, rapid blockages of active sites and surfaces of biochar and activated char due to carbon formation have caused a rapid decline in methane conversion values in the first 0.5 h. Later on, crystalline nature of the newly formed carbon deposits due to their higher catalytic activity have stabilised methane conversion values for an extended experimental period of 6 h for both biochar and activated char. The final conversion values at the end of 6 h experiment with biochar and activated char at 900 °C and for 10% CH4 in N2, were found to be 40 ± 1.9 and 35 ± 1.6% respectively. Analysing carbon deposits in detail revealed that carbon nanofiber type structures were observed at 700 °C while nanospheres of carbon were found at 900 °C.

The delignification of sugarcane straw (SCS) was investigated using 1-ethyl-3-methylimidazolium acetate, [Emim][OAc], varying three process parameters such as temperature, residence time, and stirring rate. The maximum degree of delignification was around 63.9% at 90 °C for a stirring rate of 1400 rpm and a residence time of 5 h. The 23 full factorial statistical model was well-fitted with the experimental results. Among the 26 solid-liquid reaction mechanisms studied in this study, Zhuravlev, Lesokhin, and Templeman diffusion (i.e., shrinking core/product layer) model was found to be the most suitable model for describing the delignification mechanism of SCS using [Emim][OAc]. When compared with other process parameters, higher temperatures produced low crystalline and low thermally stable recovered cellulose-rich material with high porosity and BET surface area due to higher degree of crystalline cellulose I to amorphous cellulose II transformation. The recovered lignin was of low molecular structure with high content of phenolic OH− groups and syringyl units. The recovery of [Emim][OAc] was > 85% with no structural changes.

Biosolids, the treated and stabilised sewage sludge, was pyrolysed in the presence of naturally occurring minerals in a Thermogravimetric Analyser (TGA). The results were then compared with a synthetic catalyst (i.e., 5% Co/Al2O3). Higher mass loss was observed in TGA in the presence of both minerals and the metal oxide based catalyst when compared to biosolids' alone pyrolysis. The scanning electron microscope (SEM) images confirmed significant morphological changes in the produced biochars while Fourier Transform Infrared (FTIR) spectra corroborated noticeable chemical changes in their structure. The kinetic analyses conducted using a hybrid approach consisting of model-fitting and model-free methods, suggested that there was a reduction in activation energy in the presence of minerals and the catalyst. Overall, it is concluded that minerals despite their low catalytic activity, offer various process and morphological advantages.

The effective pre-treatment methods are required for the destruction of the complex biomass structure to economically produce high grade fuels and valuable platform chemicals. Ionic liquids have high potential for energy efficient biomass pre-treatment due to their low vapour pressure, emission profile, recyclability and tuneable properties; some ionic liquids can even be prepared from renewable biomass feedstocks. However, a number of issues currently impede the large scale uptake of ionic liquids including their cost of production, detailed understanding the macro, micro and molecular level deconstruction mechanisms which inhibits process optimisation and modelling, and the need for techno-economic astable sessment on large scale trials. So far, laboratory to bench scale IL pre-treatments of various lignocellulosic biomasses were studied by changing various process parameters where the aims were to investigate the biomass dissolution mechanism and understand the pre-treatment performance of ILs. This review outlines current research gaps and potential applications for ionic liquids in the destruction of biomass into its components followed by separation of lignin, hemicellulose and cellulose rich fractions.

With the aim of separating cellulose-rich material from river red gum, it was pre-treated with three ionic liquids (ILs), i.e. 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) and 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) as well as with two organic solvents, i.e. methanol and ethanol. All ILs and organic solvents were able to remove more than 20% lignin. The [Emim][OAc] was found to be the most effective IL in removing lignin (i.e. 26.2 wt% lignin was removed) amongst all pre-treatment studies. Noticeable structural differences were observed in the cellulose-rich materials obtained from IL and organic solvent pre-treatments and several analytical instruments such as XRD, FTIR, TGA and SEM were employed for their detailed understandings. ILs, in contrast to organic solvents, produced porous and low crystalline cellulose-rich material. This was believed to be due to the transformation of crystalline cellulose I to amorphous cellulose II during IL pre-treatment. The exciting findings of producing high porosity and low crystallinity cellulose-rich material along with the removal of lignin using IL treatment have the potential to transform the future bio-processing and bio-refining industry. More than 80% IL recovery was achieved in this investigation. A minor structural alteration was observed in the recovered [Bmim][Cl] while no structural change was observed in the recovered [Emim][OAc] and [Bmim][OAc], and this was confirmed by FTIR spectroscopic analyses. This establishes the recyclability and reusability of ILs in the cost effective pre-treatment of biomass.

The experimental solubility data of l-glutamic acid in pure water, formic acid, methanol, 1-propanol, 2-propanol, acetonitrile, and binary mixtures (formic acid + water, methanol + water, 2-propanol + water, acetonitrile + water) with different compositions were carried out at temperatures ranging from (283.15 to 328.15) K by the static analytic method. The solubility measurements showed that formic acid and its aqueous mixtures recorded a higher solubility than methanol + water, 2-propanol + water, and acetonitrile + water for the same composition at each temperature. Moreover, except formic acid the addition of methanol, 2-propanol, and acetonitrile to its aqueous mixtures resulted in the decrease in solubility of l-glutamic acid. The experimental data was fitted using different thermodynamic models such as the Buchowski-Ksiazczak equation, the Van't Hoff equation, the modified Apelblat equation, and the NRTL model, and the optimum values of the regressed parameters were obtained. The modified Apelblat equation, Buchowski-Ksiazczak equation, and NRTL activity coefficient model were fitted to the pure solvents solubility data, while the modified Apelblat, modified Apelblat-Jouyban-Acree, and NRTL models were used for the binary solvent systems. The results demonstrated formic acid as a cosolvent in the dissolution of l-glutamic acid in formic acid + water binary mixtures, while others exhibited an antisolvent effect on the solubilization of l-glutamic acid in their respective aqueous mixtures.

Carbon dioxide present in natural gas/biogas lowers the heating value of fuel and is associated with environmental pollution. In addition to this, bio-oil contains a significant amount of oxygenates, which limits its wide range of applications and reduces its performance as a fuel. The sulfur compounds in diesel, gasoline, and crude oil is another issue along with its rapid depletion. Therefore, an efficacious method is essential for the reduction or separation of impurities from gaseous and liquid fuels. The implication of ionic liquids (ILs) for the separation of carbon dioxide from biogas/natural gas and oxygenates from bio-oil can be a green and efficient treatment method because of no volatile organic compounds emission, some inherent advantages, and task-specific properties of ILs. The objective of this chapter is to analyze the previous research on the application of ionic liquid for the absorption of carbon dioxide and the removal of sulfur compounds and oxygenates. The paper outlines the research gap, application, and potential future of ionic liquids in the reduction of the impurities from gaseous and liquid fuels.

This paper describes an alternative process for chloroform decomposition via nonthermal plasma polymerization at atmospheric pressure and investigates the effect of methane and hydrogen addition on the process. The effect of both additives was assessed separately, where experiments were conducted in a double dielectric barrier discharge reactor under nonoxidative conditions. The most profound impact of the additives was a significant increase in the yield of non-cross-linked polymer produced compared to that in their absence. The addition of methane resulted in a 120% increase in polymer yield, while in hydrogen the increase was 31%. Critical parameters such as effect of the methane and hydrogen concentration on the conversion of chloroform at various applied voltages, the product distribution, mass balance, and polymer characterization are elucidated in this paper. Single pass conversions of 61% and 68% (with corresponding mass balances of 98% and 95%, respectively) were achieved for CHCl3 + CH4 and CHCl3 + H2 feed scenarios, respectively. Furthermore, a polymerization mechanism which explains the formation of major chain structures as well as structural defects in the polymer is expounded upon in the paper.

This article reports an investigation on the explosion characteristics of methane–coal dust hybrid mixtures in a ducted spherical vessel. Methane–coal dust hybrid mixture explosion can occur in coal mines and spread into mine tunnels. While investigating the effects of methane addition to coal dust–air mixtures, the violence of coal dust explosions was found to increase significantly in the presence of methane. The energy of ignition was found to impact on the pressure rises in the vessel and in the duct. The experimental data and scientific analysis presented can assist in addressing ducted explosions originating from hybrid mixtures in process industries such as coal mines.

Production of high value biochemicals from lignocellulose biomass via pyrolysis, particularly levoglucosan (LG) has received immense attention in recent years. LG production via fast pyrolysis has recorded a continuous development over the past years, which demands a state-of-the-art review, covering the LG recovery methods and commercial feasibility analysis of the process. This paper provides an in-depth review of the progress and current status of bio-LG production with a focus on formation mechanisms, influential variables, recovery methods and techno-economic prospects. Based on the experimental findings of the previous studies, this review concluded that the LG yield from biomass via pyrolysis could be proposed as a function of biomass structural properties, cellulose content, inorganic minerals content as well as pyrolysis process conditions. An essential aspect of maximising the overall efficiency of LG production process is the adoption of efficient in-situ or post-pyrolysis LG extraction techniques, which has been critically reviewed for the first time. The paper also summarises the techno-commercial assessment studies of LG facility, highlighting the limiting factors towards the economic attractiveness of the process. Finally, the review highlights the knowledge gaps and provides future recommendations, which will be helpful for the improvement of productivity and economic feasibility of bio-LG production process.

Two lignite samples (150–212 μm) were treated with four ionic liquids (ILs); 1-butylpyridinium chloride ([Bpyd][Cl]), 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and 1-butyl-3-methylimidazolium tricyanomethanide ([Bmim][TCM]) at 100 °C for 3 h to establish the utility of ILs for lignite pre-treatment in conversion processes. ILs are room temperature molten salts that have remarkable physical and chemical properties including high thermal and electrochemical stabilities, low vapour pressures and, critically for this work, the capacity to solubilise a diverse range of materials. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and optical microscopy were employed in this study to gain insight into the physical and chemical interactions occurring between lignite and ILs at low temperatures. The FTIR results indicate that the majority of the ILs employed were able to break apart the macro-structure of coal resulting in an increase in short chain aliphatic hydrocarbons. Additionally, FTIR analysis revealed a significant decrease in the presence of COOH and CO groups for lignites treated with [Emim][DCM]. The TGA data revealed that the IL treated lignites had significantly lower devolatilisation temperatures than the untreated lignite, indicating an increase in lower molecular weight species after treatment. Microscopy showed a sizeable decrease in particle size after IL treatment due to fragmentation, and these coals appeared to be considerably swollen. Analysis of the recovered ILs showed no denaturing after the treatment process, indicating their recyclability potential in the treatment process.

Paunch waste is the wet waste generated from the cattle/sheep yard, paunch material, skin-shed, boning rooms, blood stream and rendering plant in an abattoir. It contains around 3% solids. It mainly consists of grass, grain, grease, fat, protein, blood, intestinal content, manure and cleaning products. In this study, paunch waste was treated under hydrothermal carbonisation conditions at different temperatures (160 to 240 ℃ ), residence time (5–150 min) and initial N2 pressure (10–30 bar) in a laboratory scale 600 mL Parr reactor system. The main objective of this study was to quantify the product distribution and further characterise the products produced from the hydrothermal carbonisation of paunch waste. The product distribution results reveal that higher bio-oil yield was obtained at relatively mild hydrothermal carbonisation conditions which is mainly attributed to fragile nature of paunch waste, higher water, volatile matter and carbohydrate content, and lower lignin and ash content. The resultant hydrochar was found to have higher HHV (∼24.48 M J k g - 1 ) and BET surface area (68.1 m 2 g - 1 ) which demonstrates their suitability as a coal substitute (in energy generation processes) or a porous medium (in soil conditioning, remediation or catalysts applications). Biodiesel-like compounds were found in the heavy bio-oil with the HHV of around 38 M J k g - 1 . Higher bio-oil production and excellent physico-chemical properties of hydrochar at milder hydrothermal carbonisation conditions have demonstrated significant improvement in the commercial viability of hydrothermal carbonisation of the paunch waste.

A dielectric barrier discharge non-equilibrium plasma was employed to study the reaction of HCFC-22 (CHClF2) with methane (in an argon bath gas) at atmospheric pressure and in the absence of oxygen and nitrogen. The reaction produced a fluorine-containing polymeric product, as well as gaseous species including H2, HF, HCl, CHF3, C2H3F, CH3Cl, CH2ClF, C2HClF4, CHCl2F, CH2Cl2 and CCl2F2. While the main polymeric fraction is non-crosslinked, a small portion of the solid product is crosslinked. The polymers contain a wide range of functional groups including CH3, CH2, CHCl, CHF, CHClF, CHF2, CF2 and CF3. The conversion level of CHClF2 increased from 53% to 78%, with an increment in input energy density from 3 kJ L-1 to 13 kJ L-1. A reaction mechanism is proposed explaining the formation of gaseous as well as polymeric products.

This paper presents the results of dichloromethane (DCM) decomposition to polymers utilising dielectric barrier discharge under non-oxidative reaction conditions. The conversion levels, mass balance, reaction mechanism and polymer characterisation in relation to DCM reaction are presented in this paper. Reaction pathways describing the decomposition of DCM and subsequent formation of the major products are outlined. Speculation of the mechanism of formation of CHCl3 and C2HCl3 are supported by quantum chemical calculations. In addition, the effect of introducing methane in the reaction feed on the conversion level of DCM and the polymer structure is also examined in this paper.

The effect of methane on the conversion of HFC-134a (CF3CH2F) in a dielectric barrier discharge non-equilibrium plasma reactor was examined. Reactions were conducted in an argon bath gas and in the absence of oxygen and nitrogen. The products of the reaction include H2, HF, CHF3, CH2F2, C2H6, C3H8, C2H3F, CHF2CHF2, C2H4F2, C3H7F as well as a polymeric solid deposit. The polymeric materials are predominantly fluorine containing random copolymers, which can be categorised as fluoropolymers, constituted from various functional groups including CF3, CF2, CHF, CHF2, CH2F, CH2 and CH3. While the presence of methane in the feed stream reduces the conversion level of CF3CH2F, it also modifies the polymer architecture. The addition of 1.25% methane with 12.5% CF3CH2F in an argon bath gas at 100cm3min-1 feed rate reduces the conversion of CF3CH2F from 74.5% to 46.8% and increases the formation of HF from 1500μmolh-1 to 2640μmolh-1. The effect of methane addition on the electrical discharge and the reaction pathways are discussed.

Solid-liquid equilibrium (SLE) data and thermodynamic properties play an important role to understand the crystallization phenomenon as it became an important step for purification and separation to get a required specific product. In this study, solubility of L-aspartic acid (L-ASP) in different binary mixtures (formic acid/trimethylamine(TMA)/methanol/iso-propylalcohol(IPA) + water) were carried out at temperatures from 283.15 to 328.15 K. The experimental data was generated using the gravimetric and titrimetric method. For a binary system, the solubility of L-ASP increased with increasing temperature. The effect of solvent on mole fraction solubility of L-ASP decreased with increasing methanol/IPA mole fraction in mixture, whereas solubility increased with increased formic acid/TMA fractions in mixture. The order of solubility for binary solvents systems as follows: TMA + water > formic acid + water > methanol + water > IPA + water. Different thermodynamic models like Apelblat equation, Apelblat-Jouyban-Acree model, NRTL model, and general single model were applied to correlate the experimental data. It was found that Apelblat equation and general single model was the best-fit for correlating solubility of L-ASP in binary mixtures with average relative deviation (ARD) less than 2% and root mean square deviation (RMSD) are below 5.3E-04. It can also be concluded that formic acid and TMA act as co-solvent in dissolution of L-ASP in their respective binaries, wheras methanol and IPA exhibited anti-solvent effect in the aqueous solution. The generated SLE data would be helpful in technological research for production of drugs in purification and separation process.

Two Australian thermal coals were treated with four different ionic liquids (ILs) at temperatures as low as 100 °C. The ILs used were 1-butylpyridinium chloride ([Bpyd][Cl]), 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCM]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), and 1-butyl-3-methylimidazolium tricyanomethanide ([Bmim][TCM]). Visual comparisons were made between the raw and IL-treated coals via optical microscopy. Changes in thermal behavior of these treated coals were compared against raw coals via pyrolysis experiments in a thermogravimetric analyzer (TGA). Changes in functional group composition in the treated coals were probed via Fourier transform infrared (FTIR) spectroscopy. The recovered ILs were also analyzed via FTIR and nuclear magnetic resonance (NMR) spectroscopies to observe any changes after recovery. Low-temperature IL treatment of each of the coals resulted in fragmentation and fracturing, reducing the average particle size. An increase in mass loss in the treated coals ...

In this paper we focus on the development of a methodology for treatment of carbon tetrachloride utilising a non-equilibrium plasma operating at atmospheric pressure, which is not singularly aimed at destroying carbon tetrachloride but rather at converting it to a non-hazardous, potentially valuable commodity. This method encompasses the reaction of carbon tetrachloride and methane, with argon as a carrier gas, in a quartz dielectric barrier discharge reactor. The reaction is performed under non-oxidative conditions. Possible pathways for formation of major products based on experimental results and supported by quantum chemical calculations are outlined in the paper. We elucidate important parameters such as carbon tetrachloride conversion, product distribution, mass balance and characterise the chlorinated polymer formed in the process.

Slow pyrolysis of regenerated cellulose-rich material (RCRM) and recovered lignin produced from imidazolium-based ionic liquid (IL) pre-treatment of sugarcane straw (SCS) was investigated employing a Thermogravimetric Analyser (TGA) instrument coupled with a Fourier-Transform Infrared (FTIR) spectroscopy. 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) pre-treatment of SCS altered the hydrogen bonds of cellulose and produced amorphous Cellulose II structure in RCRM. FTIR spectroscopic analysis of liquid products showed that the IL pre-treatment increased the production of furans from the pyrolysis of RCRM, because the presence of amorphous Cellulose II in RCRM enhanced the dehydration reaction during pyrolysis. Moreover, the recovered lignin from IL pre-treatment enhanced the production of phenol-rich pyrolysis oil due to the cleavage of β-O-4 ether bonds of lignin during pre-treatment. Scanning electron microscope (SEM) analysis indicated highly porous structure of both RCRM and recovered lignin derived biochars. The kinetic analysis using a hybrid approach (a combination of model-fitting and model-free methods) indicated a reduction in the activation energy for both RCRM and recovered lignin pyrolysis. It is concluded that IL pre-treatment of lignocellulosic biomass followed by low-temperature pyrolysis can be an efficient route for biorefinery production.

This paper focuses on the conversion of 1,2-dichloroethane (EDC) using non-thermal plasma under reaction conditions that can decompose EDC and yield a value-added product. A cylindrical double dielectric barrier discharge system has been used to generate non-thermal plasma and quartz has been used as a dielectric. Our findings show that under non-oxidative reaction conditions employed in this study, vinyl chloride, a commercially important compound, is the major gas phase product produced. This paper also encompasses a preliminary characterisation of polymer during the reaction. Possible mechanisms for gaseous product formation and polymerisation are presented.

A dielectric barrier discharge (DBD) nonthermal plasma was used to convert a range of fluorocarbons into useful polymeric products. Reactions were conducted at atmospheric pressure, in an argon bath gas and where methane was added as reactant. The bulk gas temperature was less than 150 °C and yielded polymers from a number of methane/fluorocarbon mixtures, including fluorocarbons such as halons, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). The results of gel permeation chromatography (GPC) reveal that a potentially valuable polymer is synthesized, with a number average molecular weight of between 60 000 and 130 000 g mol -1 and a polydispersity index (PDI) of between 1.2 and 2.9, depending on the fluorochemical converted.

Non-oxidative conversion of methane into higher hydrocarbons was studied under argon, at atmospheric pressure, in the non-equilibrium environment of the dielectric barrier discharge (DBD). In this study, two concentric dielectric barriers, a short plasma zone with a wide discharge gap have been used to investigate methane conversion in reactors employing alumina and quartz as dielectrics. As energy transfer to the plasma in a DBD system is determined by the capacitive properties of the dielectrics, discharge energy varies between quartz and alumina reactors at the same applied voltage and the conversion of methane and yield of hydrogen therefore also varies between quartz and alumina reactors. Although the dielectric strength of alumina is lower than that of quartz, this disadvantage is offset by increased dielectric permittivity resulting in greater dielectric capacity, in turn leading to increased gap voltage and associated higher conversion rates. Methane conversion was performed in a majority argon carrier. The addition of methane in low concentrations results in a modified argon discharge, one operating in the transition region between homogeneous glow and filamentary discharge regimes. Under these conditions, methane conversion rates were observed to vary with methane concentration, applied voltage and residence time. Experimental results are presented and interpreted in terms of ionization phenomena, metastable species activity and discharge power.

A detailed reaction mechanism is developed and used to model experimental data on the pyrolysis of CHF 3 and the non-oxidative gas-phase reaction of CHF 3 with CH 4 in an alumina tube reactor at temperatures between 873 and 1173 K and at atmospheric pressure. It was found that CHF 3 can be converted into C 2F 4 during pyrolysis and CH 2=CF 2 via reaction with CH 4. Other products generated include C 3F 6, CH 2F 2, C 2H 3F, C 2HF 3, C 2H 6, C 2H 2 and CHF 2CHF 2. The rate of CHF 3 decomposition can be expressed as 5.2×10 13[s -1]e -295[kJmol -1]/RT. During the pyrolysis of CHF 3 and in the reaction of CHF 3 with CH 4, the initial steps in the reaction involve the decomposition of CHF 3 and subsequent formation of CF 2 difluorocarbene radical and HF. It is proposed that CH 4 is activated by a series of chain reactions, initiated by H radicals. The NIST HFC and GRI-Mech mechanisms, with minor modifications, are able to obtain satisfactory agreement between modelling results and experimental data. With these modelling analyses, the reactions leading to the formation of major and minor products are fully elucidated.

The reaction of CCl 3 F (CFC-11) with CH 4 in a non-equilibrium plasma has been examined. CFC-11 has the highest ozone depleting potential (ODP) among all refrigerants used commercially (ODP value of 1) and also has very high global warming potential (GWP) of 4680 and an atmospheric lifetime of 45 years.1 The manufacture of CFC-11 was banned by the Montreal Protocol in 1996 due to its deleterious effects on Earth's ozone layer. It is widely recognized that significant quantities of CFC-11 remain in polyurethane foams in discarded refrigerators or refrigerators awaiting disposal. While there are several methods developed to recover CFC-11 from polyurethane foams, a suitable process is required for its disposal. In this study, a dielectric barrier discharge reactor, employing alumina dielectrics (the detail description can be founds in2, 3), has been applied for the conversion of CFC-11 with the aim of synthesizing value-added materials. It has been found that polymers of non-crosslinked architecture can be synthesized from the reaction of CFC-11 and CH 4 . This work is focused on structural analyses of the polymers as well as discussions on conversion of CFC-11 under various conditions and characterization of the electrical discharge.

The reaction of CCl2F2 (CFC-12) with methane (in an argon bath gas) in a dielectric barrier discharge (DBD) non-thermal plasma reactor at atmospheric pressure has been investigated. The reaction (where oxygen and nitrogen are excluded from the feed gas) produced a range of gas phase products, including H2, HCl, HF, CHF3, CF 3CH2F, CHClF2, CH3Cl, CH 2ClF, CH2Cl2, CHCl2F and CHCl 3 as well as solid products which were primarily non-crosslinked polymers. The conversion of CCl2F2 increased, from 44 to 71%, when the input energy density of the plasma was raised from 3 to 13 kJ · L-1 (applied voltage range is 13.4-14.8 kV, peak-peak). The relatively low input feed concentration of CCl2F2 and methane in the argon bath gas modifies the strong filamentary appearance of the pure argon discharge to a more diffuse appearance. The refrigerant CFC-12, harmful for atmospheric ozone layer and a major contributor to global warming, is treated with methane, in an argon bath gas and in the absence of oxygen and nitrogen using a dielectric barrier discharge nonequilibrium plasma reactor. Significant levels of CFC-12 conversion are achieved at temperatures below 100 °C and the process avoids producing toxic chemicals like CO and HCN. A simplified reaction mechanism is presented.

Summary form only given. In this paper we present the results of a study of the reaction of chloroform under non-oxidative conditions, in a non thermal plasma. Reactions were at atmospheric pressure, in a double dielectric barrier discharge reactor. The non-oxidative atmosphere provides a distinct advantage as it precludes the formation of hazardous and undesired products such as COCl2, compounds which have been observed during reaction under oxidative conditions1. We postulate a mechanism for formation of major gas phase product species in the reaction, along with the characterization of the polymer formed during the reaction. A detailed description of the reactor and power supply are provided in our prior publication2. The concentration of chloroform in the feed was maintained at a constant level of 1 %, the remainder being argon. Applied voltage for the experiments was varied over the range 12-16 kV (peak to peak). The conversion of chloroform was found to increase with an increase in the applied voltage, the highest being 66.7% at 16 kV. Micro-GC and GC were used to analyze the gas phase products except the acid gases, for which an FTIR was used. The major gas phase product species observed were CH2Cl2, C2HCl3, C2Cl4, CCl4 and HCl. A mass balance of 97% was obtained for reaction at 16 kV. GPC and NMR (1-D and 2-D) techniques were employed to characterize the polymer obtained. The polymer is non-cross linked and dissolves readily in THF. This is a very important characteristic from a practical point of view. Molecular weight of the polymer obtained were characterized as follows: Mn 47400 g mol-1, Mw 80100 g mol-1. The polydispersity was estimated to be 1.69. Evidence of CH2 groups adjoining CHCl groups in the polymer backbone chain, CHCl2 groups and double bonds is seen in the NMR spectra.