Reactions of coal with nitrogen/ hydrogen mixtures in a discharge

In-discharge reaction of coal with nitrogen/hydrogen mixtures rather than nitrogen alone raises rates of hydrogen cyanide generation by a factor of 10–50, and makes hydrogen cyanide account for ≈70–90% of the total product-gas volume. From these results and parallel tests with a pure carbon, it is concluded that enhanced formation of hydrogen cyanide is controlled by transient hydrogenation of aromatic carbon and consequent creation of additional (non-aromatic) reaction centres which can be abstracted by N^*.     

Chlorination kinetics of pyrite mineral in two Turkish lignites

The kinetics of the chlorination of pyrite in two Turkish lignites in water and water-carbon tetrachloride media at ambient pressure ( 610 mm Hg) are investigated. The effects of speed of stirring (5–20 s⁻¹), particle size (74–88, 150–180 and 250–425 μm), temperature (13–70°C) and reaction time (0–18 000 s) were studied. The experimental data were analyzed on the basis of the unreacted shrinking core model. The fine pyrite particles are assumed to be embedded inside the coal particles. The rate-controlling step was found to be diffusion of chlorine through the ash (the coal matrix). The activation energies were calculated as 25.1 kJ mol⁻¹ for Dada i coal in water medium and 25.0 kJ mol⁻¹ for Mengen coal in water-carbon tetrachloride medium.     

Electro-oxidation of dimethyl ether on Pt/C and PtMe/C catalysts in sulfuric acid

The electro-oxidation of dimethyl ether (DME) on PtMe/Cs (Me = Ru, Sn, Mo, Cr, Ni, Co, and W) and Pt/C electro-catalysts were investigated in an aqueous half-cell, and compared to the methanol oxidation. The addition of a second metal enhanced the tolerance of Pt to the poisonous species during the DME oxidation reaction (DOR). The PtRu/C electro-catalyst showed the best electro-catalytic activity and the highest tolerance to the poisonous species in the low over-potential range (<0.55 V, 50 °C) among the binary electro-catalysts and the Pt/C, but at the higher potential (>ca. 0.55 V, 50 °C), the Pt/C behaved better than PtRu/C. The apparent activation energy for the DOR decreased in the order: PtRu/C (57 kJ mol⁻¹) > Pt₃Sn/C (48 kJ mol⁻¹) ≈ Pt/C (46 kJ mol⁻¹). On the other hand, the activation energy for the MOR showed a different turn, decreased in the following order: Pt/C (43 kJ mol⁻¹) > Pt₃Sn/C (35 kJ mol⁻¹) ≈ PtRu/C (34 kJ mol⁻¹). The temperature dependence of the DOR was greater than that of the oxidation of methanol (MOR) on the PtRu/C.     

Use of unsupported and silica supported molybdenum carbide to treat chloroarene gas streams

The gas phase catalytic hydrodechlorination (HDC) of mono- and di-chlorobenzenes (423 K ≤ T ≤ 593 K) over unsupported and silica supported Mo carbide (Mo₂C) is presented as a viable means of detoxifying Cl-containing gas streams for the recovery/reuse of valuable chemical feedstock. The action of Mo₂C/SiO₂ is compared with MoO₃/SiO₂ and Ni/SiO₂ (an established HDC catalyst). The pre- and post-HDC catalyst samples have been characterized in terms of BET area, TG-MS, TPR, TEM, SEM, H₂ chemisorption/TPD and XRD analysis. Molybdenum carbide was prepared via a two step temperature programmed synthesis where MoO₃ was first subjected to a nitridation in NH₃ followed by carbidization in a CH₄/H₂ mixture to yield a face-centred cubic (-Mo₂C) structure characterized by a platelet morphology. Pseudo-first order kinetic analysis was used to obtain chlorobenzene HDC rate constants and the associated temperature dependences yielded apparent activation energies that decreased in the order MoO₃/SiO₂ (80 ± 5 kJ mol⁻¹) ≈ MoO₃ (78 ± 8 kJ mol⁻¹) > Ni/SiO₂ (62 ± 3 kJ mol⁻¹) ≈ -Mo₂C (56 ± 6 kJ mol⁻¹) ≈ -Mo₂C/SiO₂ (53 ± 3 kJ mol⁻¹). HDC activity was lower for the dechlorination of the dichlorobenzene reactants where steric hindrance influenced chloro-isomer reactivity. Supporting -Mo₂C on silica served to elevate HDC performance, but under identical reaction conditions, Ni/SiO₂ consistently delivered a higher initial HDC activity. Nevertheless, the decline in HDC performance with time-on-stream for Ni/SiO₂ was such that activity converged with that of -Mo₂C/SiO₂ after three reaction cycles. A temporal loss of HDC activity (less extreme for the carbides) was observed for each catalyst that was studied and is linked to a disruption to supply of surface active hydrogen as a result of prolonged Cl/catalyst interaction.     

Thermodynamic studies on hydrogen adsorption on the zeolites Na-ZSM-5 and K-ZSM-5

Adsorption of dihydrogen onto the zeolites Na-ZSM-5 and K-ZSM-5 renders the fundamental H–H stretching mode infrared active. The corresponding infrared absorption bands were found at 4101 and 4112 cm⁻¹ for H₂/Na-ZSM-5 and H₂/K-ZSM-5, respectively. Thermodynamic characterization of the adsorbed state was carried out by means of variable-temperature infrared spectroscopy; simultaneously measuring integrated band intensity, temperature and equilibrium pressure of the gas phase. For the H₂/Na-ZSM-5 system, the standard adsorption enthalpy and entropy resulted to be ΔH° = −10.3 (±0.5) kJ mol⁻¹ and ΔS° = −121 (±10) J mol⁻¹ K⁻¹. For H₂/K-ZSM-5 corresponding values were −9.1 (±0.5) kJ mol⁻¹ and −124 (±10) J mol⁻¹ K⁻¹, respectively.     

F2, H2O, and O2 etching rates of diamond and the effects of F2, HF and H2O on the molecular O2 etching of (110) diamond

Oxidation kinetics of natural (110) diamond by oxygen and water were investigated using in situ Fizeau interferometry. Apparent activation energies of 53 and 26 kcal mol⁻¹ were obtained for the etching of (110) type Ia diamond by O₂ and H₂O respectively. The etch rate was found to follow second-order kinetics with respect to O₂ pressure in the pressure range 0.04–10 Torr. For water over the vapour pressure range 0.1–2 Torr, the reaction has a reaction order near unity. The diamond (110) surface was impervious to etching by molecular fluorine at all temperatures up to 1300 °C. Fluorine, hydrogen fluoride and water were found to inhibit the molecular oxygen etching of diamond. Below 900 °C, oxidation is inhibited by the addition of F₂ and HF presumably by blocking reactive sites on the diamond surface through formation of C---F bonds. Above 900 °C, the fluorine is thought to desorb from the diamond (110) surface, rendering the surface susceptible to further oxidation. Addition of water below 800 °C was found to retard etching by molecular oxygen. This is attributed to the formation of C---OH bonds, analogous to C---F.     

Catalytic dechlorination of 1-chlorooctadecane in supercritical carbon dioxide

Palladium catalyzed hydrodechlorination of 1-chlorooctadecane in supercritical carbon dioxide (SC–CO₂) was performed and compared to dechlorination in isopropanol at atmospheric pressure (liquid isopropanol). The reaction utilized isopropanol as a hydrogen donor and its rate in SC–CO₂ was significantly faster than in isopropanol at atmospheric pressure. The dechlorination yield in liquid isopropanol was increased by addition of NaOH, while the presence of either NaOH or triethylamine in SC–CO₂ lowered the dechlorination yield significantly. Experimental parameters such as pressure, temperature, and the concentrations of reagents (isopropanol and palladium) in the absence of base were optimized in SC–CO₂ to obtain complete dechlorination. Kinetic studies of the reaction were then performed to deduce the reaction mechanism. The apparent activation energies of the reaction were 43±5 kJ mol⁻¹ in SC–CO₂ and 35±3 kJ mol⁻¹ in liquid isopropanol. The rate determining step of the reaction was deduced to be adsorption of 1-chlorooctadecane on the palladium surface.     

Catalytic hydrodechlorination of 1-chlorooctadecane, 9,10-dichlorostearic acid, and 12,14-dichlorodehydroabietic acid in supercritical carbon dioxide

Kinetic and thermodynamic analyses of catalytic hydrodechlorinations in supercritical carbon dioxide (SC-CO₂) were performed using 5% Pd supported on γ-Al₂O₃. The selected standard compounds used for the study represented chlorinated wood resins commonly found in pitch deposits; 1-chlorooctadecane (C₁₈-Cl), 9,10-dichlorostearic acid (Stearic-Cl₂), and 12,14-dichlorodehydroabietic acid (DHA-Cl₂). The reaction utilized isopropanol as a hydrogen donor. Pressure, temperature, and the concentrations of isopropanol and palladium were varied to study the effect of each parameter and to optimize the dechlorination yield. The reaction in SC-CO₂ was compared to the one in liquid solvents at atmospheric pressure. By applying a Langmuir–Hinshelwood kinetic model, the rate-determining step of the reaction was deduced to be adsorption of the chlorinated molecules on the palladium surface. The apparent activation energies of the reactions for C₁₈-Cl, Stearic-Cl₂, DHA-Cl₂ were 43±5, 40±7, and 135±7 kJ mol⁻¹, respectively, in SC-CO₂. The relatively high activation energy for DHA-Cl₂ was apparently due to structural differences from the other two compounds. The apparent activation energy of dechlorination of C₁₈-Cl in liquid isopropanol at atmospheric pressure was determined to be 35±3 kJ mol⁻¹, leading to the conclusion that the rate-determining step is the same for this compound in both fluid systems. The enthalpies of desorption of stearic acid and dehydroabietic acid were determined to be 18±2 and 12±2 kJ mol⁻¹, respectively. These values being less than half of the apparent activation energies of dechlorination of their corresponding chlorinated compounds indicates that desorption of the dechlorinated products is not the rate-determining step of the reaction. This was consistent with the conclusion that the rate-determining step is adsorption, on the understanding that the reaction mechanism is same in both fluid systems.     

Catalytic decomposition of nitrous oxide over Ru-exchanged zeolites

We report that ultrastable faujasite-based ruthenium zeolites are highly active catalysts for N₂O decomposition at low temperature (120–200°C). The faujasite-based ruthenium catalysts showed activity for the decomposition of N₂O per Ru³⁺ cation equivalent to the ZSM-5 based ruthenium catalysts at much lower temperatures (TOF at 0.05 vol.-% N₂O: 5.132 × 10⁻⁴ s⁻¹ Ru⁻¹ of Ru-HNaUSY at 200°C versus 5.609 × 10⁻⁴ s⁻¹ Ru⁻¹ of Ru-NaZSM-5 at 300°C). The kinetics of decomposition of N₂O over a Ru-NaZSM-5 (Ru: 0.99 wt.-%), a Ru-HNaUSY (Ru: 1.45 wt.-%) and a Ru-free, Na-ZSM-5 catalyst were studied over the temperature range from 40 to 700°C using a temperature-programmed micro-reactor system. With partial pressures of N₂O and O₂ up to 0.5 vol.-% and 5 vol.-%, respectively, the decomposition rate data are represented by: −dN₂O/dt=itk(P_N2O) (P_O2)^−0.5 for Ru-HNaUSY, −dN₂O/dt=k(P_N2O) (P_O2)^−0.1 for Ru-NaZSM-5, and −dN₂O/dt=k(P_N2O)^−0.2 (P_O2)^−0.1 for Na-ZSM-5. Oxygen had a stronger inhibition effect on the Ru-HNaUSY catalyst than on Ru-NaZSM-5. The oxygen inhibition effect was more pronounced at low temperature than at high temperature. We propose that the negative effect of oxygen on the rate of N₂O decomposition over Ru-HNaUSY is stronger than Ru-NaZSM-5 because at the lower temperatures (<200°C) the desorption of oxygen is a rate-limiting step over the faujasite-based catalyst. The apparent activation energy for N₂O decomposition in the absence of oxygen is much lower on Ru-HNaUSY (E_a: 46 kJ mol⁻¹) than on Ru-NaZSM-5 (E_a: 220 kJ mol⁻¹).     

Aggregation of o,o′-dihydroxyazo dyes–1. Concentration, temperature, and solvent effect

The aggregation behavior and tautomerism of three o,o′-dihydroxy and one o-hydroxy-o′-methoxy azo dyes were studied by UV-visible spectroscopy. Concentration dependent spectroscopic changes with the formation of isosbestic points were observed indicating dimer–monomer equilibria. Combining all obtained data, the conclusion was reached that the spectroscopic changes were due to a shift of the monomer–dimer equilibrium of the hydrazo form caused by the inversion of the intermolecular hydrogen bonding to intermolecular hydrogen bonding. The k_aggregation for the dye selected as an example was evaluated statistically and was found [(1.82±0.30)×10⁴ 1iter mol⁻¹]. The effect of temperature (10–60°C) on the monomer–dimer ratio and the effect of solvents upon stabilization of one form over the other, supported the conclusion that the driving forces for the dimerization were the hydrophobic effect and the high degree of entropy in solution.     

Effect of Re loading on the structure, activity and selectivity of Re/C catalysts in hydrodenitrogenation and hydrodesulphurisation of gas oil

A series of Re-containing catalysts supported on activated carbon, with Re loading between 0.74 and 11.44 wt.% Re₂O₇, was prepared by wet impregnation and tested in the simultaneous hydrodesulphurisation (HDS) and hydrodenitrogenation (HDN) of a commercial gas oil. Textural analysis, XRD, X-ray photoelectron spectroscopy (XPS) and surface acidity techniques were used for physicochemical characterisation of the catalysts. Increase in the Re concentration resulted in a rise in the HDS and HDN activity due to the formation of a monolayer structure of Re and the higher surface acidity. At Re concentrations >2.47 wt.% Re₂O₇ (0.076 Re atoms nm⁻²) the reduction in the catalytic activity was related to the loss in specific surface area (BET) due to reduction in the microporosity of the carbon support. The magnitude of the catalytic effect was different for HDS and HDN, and depended strongly on the Re content and reaction temperature. The apparent activation energies were about 116–156 kJ mol⁻¹ for HDS and 24–30 kJ mol⁻¹ for HDN. This led to a marked increase in the HDN/HDS selectivity with decreasing temperature (values >3 at 325 °C), due to the large differences in the apparent activation energies of HDS and HDN found for all catalysts. A gradual increase in the HDN/HDS selectivity with increased Re loading was also found and related to the observed increase of catalyst acidity. The results are compared with those obtained for a series of Re/γ-Al₂O₃ catalysts.     

The reduction of perchlorate by hydrogenation catalysts

Perchlorate competes with thyroid uptake of iodide, an essential nutrient for the production of thyroid hormones. Despite the extensive attempts to reduce perchlorate in aqueous solution, the process is slow and requires high temperatures even in the presence of catalysts. Therefore, perchlorate reduction under hydrogen atmosphere was employed. Monometallic and bimetallic Pt based catalysts (e.g., Pt/C, Ni-Pt/C, Co-Pt/C, and W-Pt/C) supported on activated carbon were prepared by successive incipient wet impregnation method and used for gas-phase reduction of perchlorate pre-adsorbed onto the activated carbon. The catalysts were characterized for hydrogen chemisorption and XPS. Hydrogen uptake was in the order: Co-Pt/C > W-Pt/C ≈ Pt/C > Ni-Pt/C. The least H₂ uptake by Ni-Pt/C was likely due to lower dispersion on activated carbon surface with 11.5% vs. 36% for Pt/C. There was a good correlation between hydrogen uptake by impregnated activated carbon (IAC) and perchlorate reduction. The Co-Pt/C exhibited the highest hydrogen uptake and the best perchlorate reduction while Ni-Pt/C was the least reducing system. When Co-Pt/C was used almost 90% of perchlorate was reduced at 25 °C and initial surface concentration of perchlorate of 11.47 mg g⁻¹ in 24 h. The reaction rate increased 10-folds when the reaction temperature was raised to 75 °C. In 24 h reaction time, increase of temperature from 25 to 75 °C resulted in additional 10% (Co-Pt/C) and 30% (Ni-Pt/C) increase in perchlorate reduction for Co-Pt/AC and Ni-Pt/AC, respectively, which brought the reduction efficiency close to 100%. The only reaction product that evolved was Cl⁻, indicating that the cleavage of the first oxygen atom of perchlorate was the rate-limiting step. The lowest activation energy for the reduction of perchlorate was 39.5 kJ mol⁻¹ for Co-Pt/C. Results also showed that the activation of gaseous hydrogen molecules on metal catalysts was the major reducing step, although deposited metals also participated in the perchlorate reduction directly. Results of XPS analysis revealed that during adsorption/reduction some portion of the second metal in the bimetallic catalysts was lost due to dissolution while Pt was very stable.     

Inhibition of hydrogasification of brown coals by moisture: Influence of heating rate, temperature and pressure

Two types of Rheinische Braunkohle with different mineral matter contents, each with two different moisture contents plus a coke produced from the coal with the lower ash content, were gasified at total pressures between 0.2 and 5 MPa with pure or dry hydrogen, hydrogen/water vapour and argon/water vapour mixtures. In studies with controlled heating (4 K min⁻¹ up to 850 °C) it was found that: 1. methane formation rates and methane yields during gasification in dry hydrogen are drastically lowered with increased moisture of the coals but only at high pressures which reduce evaporation of water; 2. methane formation rates and methane yields during gasification with wet hydrogen (x_H2o = 0.02) are generally lowered with all materials; 3. increasing the water content does not further lower the yields or lead to water vapour gasification. Studies at constant temperature (after rapid heating, 100 K s⁻¹) confirmed these results. It was found that increasing the temperature to 950 °C does not eliminate the inhibiting effect of moisture (in hydrogen) if hydrogen pressure is low ≈ ≤ 1 MPa. It was also determined that raising the temperature above 850 °C with a simultaneous increase in pressure up to 5 MPa hydrogen effectively prevented the inhibition by moisture. It was concluded that extremely stable ether bridges are blocking the active sites at the carbon suface and are therefore responsible for the inhibitory effect of moisture in hydrogasification.     

Kinetic aspects of the formation of lead zirconium titanate

The kinetics of the second calcination step in the formation of PZT solid solution (with perovskite ABO₃ lattice) has been investigated by using two different particle sizes of the B-site precursor (1.91 and 5.08 μm), the finer size being obtained by prolonged milling. In-situ analysis performed by high-temperature X-ray diffractometry in a non-isothermal mode (20–800 °C) revealed a reduction of the calcination temperature by 100 °C with a decrease in particle size of the precursor. In order to clarify the mechanism of the solid-state reaction to PZT, isothermal heat treatment of the mixtures was performed in the temperature range 540–700 °C. The activation energies for the fine and the coarse powders were estimated as 150 and 210 kJ mol⁻¹ respectively, and the reaction was found to follow the Jander model for diffusion-controlled solid-state reaction kinetics.     

Voltammetric study of halide ion adsorption on platinum in perchloric acid solutions

Periodic current/potential curves were taken potentiostatically at 30 mV/sec on smooth platinum in 1 N HClO₄ with different additions of HCl, HBr, and HI, in the potential range between hydrogen evolution and deposition of oxygen or of the respective halide ion. The effect of increasing halide ion concentration, starting at 10⁻⁶ M, on hydrogen adsorption and oxygen adsorption was studied systematically. Impedance measurements were made at 1000 c/s under the same conditions as the measurements of the current/potential curves. It is concluded from the dependence of the double layer capacitance upon the bulk concentration of halide ions in the double layer region that nearly a monolayer of adsorbed ions is present there for ₀c_Cl⁻ ≈ 10⁻² M, ₀c_Br ≈ 10⁻⁴ M, and ₀c_HI ≈ 10⁻⁵ M. The measurements at larger concentrations, especially for I⁻, show additional effects which are due to the deposition of halides and to the reverse reaction.     

Isosteric heat of sorption of CO2 in poly(ethylene terephthalate)

Sorption isotherms for carbon dioxide in poly(ethylene terephthalate) have been measured at 35–55°C. The isotherms were measured gravimetrically on a Mettler Thermoanalyzer-1 from vacuum to 1 atmosphere. The sorption data were used to generate sorption isotherms from which the isosteric heat of sorption of CO₂ in PET was determined. At 45°C the isosteric heat of sorption increases from −10 kcal/mole at a concentration of 0.5 cm³ (STP)/cm³ (polymer) to −8 kcal mole⁻¹ at a concentration of 1.5 cm³ (STP)/cm³ (polymer). It has been reported in the literature that the isosteric heat of sorption for this system decreased through a minimum before increasing with increasing concentration. Our measurement of the low-pressure sorption isotherms shows that this is not the case.     

Viscoelastic properties of cellulose derivatives: 1. Cellulose acetate

The dynamic mechanical spectrum of cellulose acetate (CA) from −130°C to 240°C has been determined at different frequencies (from 0.1 to 30 Hz). Three relaxations, designated , β and γ in order of decreasing temperature, and one shoulder (β*) above room temperature were found. Comparison with calorimetric and thermogravimetric measurements yields the conclusion that the relaxation (197°C at 3 Hz) is related to the glass-to-rubber transition and the β* shoulder (50°C–100°C) is due to loss of moisture. The β relaxation (−38°C at 3 Hz, ΔH = 100 kJ mol⁻¹) is tentatively assigned to local motions of the main chain (glucopyranose rings). The low-temperature γ relaxation (−88°C at 3 Hz, ΔH = 46 kJ mol⁻¹), is humidity-dependent: its intensity decreases when the samples are dried to moisture contents lower than that obtained by normal room conditioning (about 3%). Higher water contents shift the relaxation to lower temperatures without increasing the intensity of the mechanical loss. It is suggested that water associated with the unesterified methylol groups of cellulose acetate is responsible of the dynamic mechanical γ dispersion.     

Physicochemical surface and catalytic properties of CuO–ZnO/Al2O3 system

A series of CuO–ZnO/Al₂O₃ solids were prepared by wet impregnation using Al(OH)₃ solid and zinc and copper nitrate solutions. The amounts of copper and zinc oxides were varied between 10.3 and 16.0 wt% CuO and between 0.83 and 7.71 wt% ZnO. The prepared solids were subjected to thermal treatment at 400–1000°C. The solid–solid interactions between the different constituents of the prepared solids were studied using XRD analysis of different calcined solids. The surface characteristics of various calcined adsorbents were investigated using nitrogen adsorption at −196°C and their catalytic activities were determined using CO-oxidation by O₂ at temperatures ranged between 125°C and 200°C.

The results showed that CuO interacts with Al₂O₃ to produce copper aluminate at ≥600°C and the completion of this reaction requires heating at 1000°C. ZnO hinders the formation of CuAl₂O₄ at 600°C while stimulates its production at 800°C. The treatment of CuO/Al₂O₃ solids with different amounts of ZnO increases their specific surface area and total pore volume and hinders their sintering (the activation energy of sintering increases from 30 to 58 kJ mol⁻¹ in presence of 7.71 wt% ZnO). This treatment resulted in a progressive decrease in the catalytic activities of the investigated solids but increased their catalytic durability. Zinc and copper oxides present did not modify the mechanism of the catalyzed reaction but changed the concentration of catalytically active constituents (surface CuO crystallites) without changing their energetic nature.     

First principles study of heavy oil organonitrogen adsorption on NiMoS hydrotreating catalysts

The adsorption of quinoline, acridine, indole, and carbazole on the well-defined NiMoS hydrotreating catalyst edge surface has been studied by means of density-functional theory (DFT) using a periodic supercell model. Quinoline and acridine, the basic nitrogen-containing molecules present in heavy oils, are preferably adsorbed on the Ni-edge surface through the lone pair electrons of the nitrogen atom, which produces relatively high adsorption energies (−ΔE_a = 16–26 kcal mol⁻¹). Indole and carbazole, the non-basic nitrogen-containing molecules, primarily interact with the NiMoS catalyst edge surface through the π-electrons of the carbon atoms. While indole preferentially adsorbs on the NiMoS surface through the β-carbon of the pyrrolic ring (−ΔE_a = 19 kcal mol⁻¹), carbazole primarily interacts with the NiMoS surface through the phenyl rings (−ΔE_a = 13 kcal mol⁻¹). The relative adsorptivities and energetically preferred adsorption modes of the nitrogen-containing molecules in heavy oils can provide insights into experimental observations about hydrodenitrogenation (HDN) kinetics and reaction pathways.     

Ultrapyrolysis of n-hexadecane in a novel micro-reactor

A novel reaction system, which provides better control compared with the tubular flow reactors of previous researchers, was employed to study the ultrapyrolysis kinetics of n-hexadecane, a gas oil model compound. Ultrapyrolysis, or ultra rapid pyrolysis, refers to thermal cracking under conditions of high temperature, very short reaction time, high heating rate and rapid product quench. Modern-day ‘millisecond’ furnaces, operating under such conditions, have demonstrated significantly higher ethylene yields due to improved selectivity. The automated micro-reaction system employed a Curie point pyrolyser to rapidly heat microgram n-hexadecane samples to high temperature. The Curie point phenomenon ensured that a reproducible and well-defined temperature was attained. A rapid direct quench system was used to stop the reactions and transfer the products to the analyser. n-Hexadecane was pyrolysed at 576–842 °C for 100–3200 ms. Peak ethylene production (28 wt%) was exhibited at ultrapyrolytic conditions of 842 °C and 500 ms. A first-order kinetic analysis performed on the pyrolysis data yielded an activation energy of 39.4 kcal mol⁻¹.