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.     

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.     

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.     

Investigation of pyridine sorption in USY and Ce/USY zeolites by liquid phase microcalorimetry and thermogravimetry studies

USY (ultrastabilized Y) and Ce/USY (5 wt.% supported) zeolite acidities were characterized by microcalorimetric and adsorption studies of pyridine using liquid phase (Cal-Ad), thermogravimetry, and infrared analysis. The average adsorption enthalpies determined by microcalorimetry were −125.0 kJ mol⁻¹ for USY and −97.2 kJ mol⁻¹ for Ce/USY. A heterogeneous distribution of acid sites with heats of adsorption ranging from −134.0 (maximum heat value for USY) to −73.5 (minimum heat value for Ce/USY) kJ mol⁻¹ was found for both zeolites. A two-site model was best fitted by the Cal-Ad method for HUSY (n₁ = 0.1385 mmol g⁻¹ with ΔH₁ = −134.0 kJ mol⁻¹, and n₂ = 0.7365 mmol g⁻¹ with ΔH₂ = −101.5 kJ mol⁻¹) and Ce/HUSY (n₁ = 0.0615 mmol g⁻¹ with ΔH₁ = −117.6 kJ mol⁻¹, and n₂ = 0.7908 mmol g⁻¹ with ΔH₂ = −83.6 kJ mol⁻¹). DRIFTS measurements after pyridine adsorption showed that USY zeolite possesses only Brønsted acidity and that cerium impregnation leads to the appearance of Lewis sites. Based on these results, three families of acid strength were distinguished: (i) strong Brønsted sites (ΔH > −130 kJ mol⁻¹); (ii) Brønsted sites with intermediate strength (−100 < ΔH < −130); and (iii) weak Brønsted and Lewis sites (ΔH < −100). Thermogravimetric analysis showed that the strongest sites were able to retain pyridine up to 800 °C and that cerium incorporation leads to a more stable zeolite. A loss of strength was observed after impregnation. The total number of sites desorbed after gas adsorption (0.88 and 0.95 mmol for HUSY and Ce/HUSY, respectively) supports the Cal-Ad results (0.88 and 1.19 mmol for HUSY and Ce/HUSY, respectively) and indicates that not all Al sites are available to pyridine. The methodology used in this work for solid acid characterization (Cal-Ad) proved to be efficient in the evaluation of acid strength, total number and distribution of acid sites. XRPD, ICP-AES, ²⁷Al NMR, and FTIR were used for additional structural characterization.     

Alumina-supported cobalt-molybdenum catalyst for slurry phase Fischer–Tropsch synthesis

An evaluative investigation of the Fischer–Tropsch performance of two catalysts (20%Co/Al₂O₃ and 10%Co:10%Mo/Al₂O₃) has been carried out in a slurry reactor at 2 MPa and 220–260 °C. The addition of Mo to the Co-catalyst significantly increased the acid-site strength suggesting strong electron withdrawing character in the Co-Mo catalyst. Analysis of steady-state rate data however, indicates that the FT reaction proceeds via a similar mechanism on both catalysts (carbide mechanism with hydrogenation of surface precursors as the rate-determining step). Although chain growth, , on both catalysts were comparable (  0.6), stronger CH₂ adsorption on the Co-Mo catalyst and lower surface concentration of hydrogen adatoms as a result of increased acid-site strength was responsible for the lower individual hydrocarbons production rate compared to the Co catalyst. The activation energy, E, for Co (96.6 kJ mol⁻¹), is also smaller than the estimate for the Co-Mo catalyst (112 kJ mol⁻¹). Transient hydrocarbon rate profiles on each catalyst are indicative of first-order processes, however the associated surface time constants are higher for alkanes than alkenes on individual catalysts. Even so, for each homologous class, surface time constants for paraffins are greater for Co-Mo than Co, indicative that the adsorption of CH₂ species on the Co-Mo surface is stronger than on the monometallic Co catalyst.     

Dechlorination kinetics of monochlorobiphenyls by Fe/Pd: Effects of solvent, temperature, and PCB concentration

Well-known, yet undefined, changes in the conditions and activity of palladized zerovalent iron (Fe/Pd) over an extended period of time hindered a careful study of dechlorination kinetics in long-term experiments. A short-term experimental method was, therefore, developed to study the effects of temperature and solvent on the dechlorination of monochlorobiphenyls (MCBs), 2-chlorobiphenyl (2-ClBP), in particular by Fe/Pd. The experiments started with specified initial conditions and lasted only for 10 min. The average value (k) of the first-order rate constant for the dechlorination of 2-ClBP was 0.13 ± 0.03 L m⁻² h⁻¹, not significantly different from the average values for 3-chlorobiphenyl and 4-chlorobiphenyl. The apparent activation energy was 20 ± 4 kJ mol⁻¹ and 17 ± 7 kJ mol⁻¹, in a temperature range between 4 °C and 60 °C, for the dechlorination of 2-ClBP using two batches of Fe/Pd catalyst. The k values decreased significantly in mixtures with a methanol concentration higher than 10%. The values of the rate constant were slightly influenced by the initial concentrations in the experiments at a low temperature and in a solution with a high methanol concentration. The concentration dependence was described with a Langmuir equation, based on the Langmuir–Hinshelwood mechanism that includes an adsorption step of a single species preceding a rate-determining catalytic reaction.     

Study on kinetics of polymerization of dimer fatty acids with ethylenediamine in the presence of catalyst

A generally applicable stoichiometric and kinetic model was developed for the polymerization of dimer fatty acids with ethylenediamine in the presence of phosphoric acid as catalyst. Rate equation used is based on second order and the temperatures are between 405 and 475 K with mixing rate of 75 rpm. The parameters of the rate equations are determined using nonlinear regression analysis. Comparison of the model predictions with the experimental data show that the approach is useful in predicting the polymerization kinetic. Equilibrium constant changes from 2.432 to 17.765. Frequency factor and activation energy for forward rate constant are 362306102.681 kg mol⁻¹ min⁻¹ and 83.24 kJ mol⁻¹, respectively. The equilibrium constant is independent of temperature with frequency factor and activation energy values of 17317.97 and 28.65 kJ mol⁻¹, respectively.     

Catalytic wet air oxidation of low molecular weight carboxylic acids using a carbon supported platinum catalyst

Aqueous solutions of low molecular weight carboxylic acids, such as acetic, propionic and butyric acids, were treated by catalytic wet air oxidation (CWAO) using a carbon supported platinum catalyst. Oxidation in the presence of the catalyst, in a stirred reactor, was carried out at 200°C and 6.9 bar of oxygen partial pressure, with conversions (after 2 h) ranging from 59.4 to 75%, and selectivities to gaseous products of up to 100%. Initial rates for conversion varied from 184 (butyric acid) to 260 mmol h⁻¹ g_Pt⁻¹ (propionic acid). The activation energy for butyric acid conversion was found to be 56.7 kJ mol⁻¹.     

Kinetic studies of CH4 oxidation over Pt–NiO/δ-Al2O3 in a fluidised bed reactor

The oxidation of CH₄ over Pt–NiO/δ-Al₂O₃ has been studied in a fluidised bed reactor as part of a major project on an autothermal (combined oxidation–steam reforming) system for CH₄ conversion. The kinetic data were collected between 773 and 893 K and 101 kPa total pressure using CH₄ and O₂ compositions of 10–35% and 8–30%, respectively. Rate–temperature data were also obtained over alumina-supported monometallic catalysts, Pt and NiO. The bimetallic Pt–NiO system has a lower activation energy (80.8 kJ mol⁻¹) than either Pt (86.45 kJ mol⁻¹) and NiO (103.73 kJ mol⁻¹). The superior performance of the bimetallic catalyst was attributed to chemical synergy. The reaction rate over the Pt–NiO catalyst increased monotonically with CH₄ partial pressure but was inhibited by O₂. At low partial pressures (<30 kPa), H₂O has a detrimental effect on CH₄ conversion, whilst above 30 kPa, the rate increased dramatically with water content.     

Degradation of maleic acid in a wet air oxidation environment in the presence and absence of a platinum catalyst

Over a temperature range of 415–478 K, the catalytic and non-catalytic degradation of an aqueous solution of maleic acid (0.03 M) has been studied both in the presence of oxygen and under an inert atmosphere (nitrogen). These reactions were first-order for maleic acid. The non-catalytic oxidation reaction was zero-order in oxygen over a partial pressure range of 0.4–1.4 MPa. The apparent activation energies for the non-catalytic removal of maleic acid under both a nitrogen (66.7 kJ mol⁻¹) and an air (131.5 kJ mol⁻¹) environment have been calculated. The use of 0.5 wt.% platinum on γ-alumina catalyst significantly enhanced the degradation rate of maleic acid. A kinetic expression was developed accounting for both homogeneous and heterogeneous routes in maleic acid elimination. Although maleic acid removal was zero-order for oxygen concentration, the presence of oxygen is shown to result in significant chemical oxygen demand (COD) removal in both the catalytic and the non-catalytic process. Finally, the stability of a platinum catalyst has been tested for eight consecutive runs without any noticeable loss in catalyst activity.     

Production of gasoline range hydrocarbons from catalytic reaction of methane in the presence of ethylene over W/HZSM-5

The catalytic conversion of a methane and ethylene mixture to gasoline range hydrocarbons has been studied over W/HZSM-5 catalyst. The effect of process variables, such as temperature, percentage of volume of ethylene in the methane stream and catalyst loading on the distribution of hydrocarbons was studied. The reaction was conducted in a fixed-bed quartz-micro reactor in the temperature range of 300–500 °C using percentage of volume of ethylene in methane stream between 25 and 75% and catalyst loading of 0.2–0.4 g. The catalyst showed good catalytic performance yielding hydrocarbons consisting of gaseous products along with gasoline range liquid products. The mixed feed stream can be converted to higher hydrocarbons containing a high-liquid gasoline product selectivity (>42%). Non-aromatics C₅–C₁₀ hydrocarbons selectivity in the range of 12–53% was observed at the operating conditions studied. Design of experiment was employed to determine the optimum conditions for maximum liquid hydrocarbon products. The distribution of the gasoline range hydrocarbons (C₅–C₁₀ non-aromatics and aromatics hydrocarbons) was also determined for the optimum conditions.     

Optimisation of degradation conditions of 1,8-diazabicyclo[5.4.0]undec-7-ene in water and reaction kinetics analysis using a cocurrent downflow contactor photocatalytic reactor

The photocatalytic degradation of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, a non-biodegradable nitrogenous organic compound) in water was optimised under UV radiation using titanium dioxide photocatalyst. The reactor used was a pilot scale cocurrent downflow contactor photocatalytic reactor (CDCPR), a system offering very high mass transfer efficiency. The effect of photocatalyst loading, initial substrate concentration, temperature, pH, and different combinations of UV, O₂, H₂O₂ and TiO₂ on the photocatalytic oxidation of DBU was investigated. The TiO₂ photocatalyst used was Degussa VP Aeroperl P25/20, a granulated form of Degussa P-25, recently developed to ameliorate downstream catalyst separation problems. The CDCPR was fitted with an internally and vertically mounted 1.0 kW UV lamp. The reactions were carried out at 40–60 °C and 1 barg, with the reactor being operated in closed loop recycle mode and suspended photocatalyst being re-circulated. Optimisation of reaction conditions using a combination of TiO₂, UV radiation and O₂ gave the most rapid degradation and mineralisation of the DBU in comparison with other processes. Under optimised conditions, 100% degradation of DBU was achieved in 45 min, with a quantum yield of 7.39, using a 1 kW lamp, 0.5 g/dm³ TiO₂, 100 mg/dm³ DBU, 1 barg, 50 °C and pH of 3.17. Investigating the reaction pathway and its modelling showed a first order dependency, incorporating the effect of first intermediates of degradation. The activation energy was found to be 54.68 kJ mol⁻¹ showing a significant influence of temperature on the photocatalytic degradation of DBU.     

Determination of relative acid strength and acid amount of solid acids by Ar adsorption

Relative acid strength and acid amount of solid acids (alumina, silica-alumina, sulfated zirconia, mordenite, ZSM-5, beta, Y, and reduced MoO₃) are determined by argon adsorption technique. To obtain the heat of Ar adsorption and saturated adsorption amount, the adsorption isotherm is analyzed using the theory reported by Cremer and Flügge. The obtained heats of Ar adsorption and saturated adsorption amounts of sulfated zirconia catalysts and proton-type zeolites correspond well with the activities of acid-catalyzed pentane isomerization of these catalysts. The heats of adsorption were −22 kJ mol⁻¹ for sulfated zirconia, and ca. −19 kJ mol⁻¹ for mordenite, ZSM-5, and beta. Molybdenum oxides reduced at 623 and 773 K show large heat of adsorption (−19.3 and −19.7 kJ mol⁻¹, respectively), and these are classified into the superacid.     

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.     

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.     

In situ IR and pulse reaction studies on the active oxygen species over SrF2/Nd2O3 catalyst for oxidative coupling of methane

Pulse reaction method and in situ IR spectroscopy were used to characterize the active oxygen species for oxidative coupling of methane (OCM) over SrF₂/Nd₂O₃ catalyst. It was found that OCM activity of the catalyst was very low in the absence of gas phase oxygen, which indicated that lattice oxygen species contributed little to the yield of C₂ hydrocarbons. IR band of superoxide species (O₂⁻) was detected on the O₂-preadsorbed SrF₂/Nd₂O₃. The substitution of ¹⁸O₂ isotope for ¹⁶O₂ caused the IR band of O₂⁻ at 1128 cm⁻¹ to shift to lower wavenumbers (1094 and 1062 cm⁻¹), consistent with the assignment of the spectra to the O₂⁻ species. A good correlation between the rate of disappearance of surface O₂⁻ and the rate of formation of gas phase C₂H₄ was observed upon interaction of CH₄ with O₂-preadsorbed catalyst at 700 °C. The O₂⁻ species was also observed on the catalyst under working condition. These results suggest that O₂⁻ species is the active oxygen species for OCM reaction on SrF₂/Nd₂O₃ catalyst.     

Low-temperature H2 and N2 transport through thin Pd66Cu34Hx layers

The single gas H₂ and N₂ permeability of a 4 μm thick dense fcc-Pd₆₆Cu₃₄ layer has been studied between room temperature and 510 °C and at pressure differences up to 400 kPa. Above 50 °C the H₂ flux exhibits an Arrhenius-type temperature dependence with J_H2=(5.2±0.3) mol m⁻² s⁻¹ exp[(−21.3 ± 0.2) kJ mol⁻¹/(R·T)]. The hydrogen transport rate is controlled by the bulk diffusion although the pressure dependence of the H₂ flux deviates slightly from Sieverts’ law. A sudden increase of the H₂ flux below 50 °C is attributed to embrittlement.     

An FTIR/ATR in situ study of sorption and transport in corrosion protective organic coatings: Paper 2. The effects of temperature and isotopic dilution

A detailed temperature variation (18–50 °C) FTIR/ATR study of sorption and desorption of water into a series of cured epoxy resins has been reported. For higher temperatures (35–50 °C) the data were modelled with a single Fickian diffusion equation, giving an increased D as the temperature increased and an activation energy (E_A) in the 55–60 kJ mol⁻¹ region. At lower temperatures (18–35 °C)—well-below the T_g—a two-stage sorption equation was needed and the apparent E_A was negative. This is probably associated with changes in water clustering among the distributed ‘voids’ in the glassy polymer associated with chain relaxation at extended times. The use of D₂O as a penetrant allowed diffusion coefficient measurements for highly dense epoxy matrices, where FTIR/ATR cannot detect the ν(OH) band of water over and above the residual polymer–OH groups (in the dry state). The data for the D₂O studies were notably influenced by isotopic exchange; which was found to be a diffusion controlled process, even in a polymer matrix.     

The condensation/polymerisation of dimethyl siloxane fluids in a three-phase trickle flow monolith reactor

For the production of siloxane fluids, the viability of using a multi-channel monolith as a catalyst support system in a three-phase reactor has been studied. The catalyst was tripotassium phosphate (K₃PO₄). Experiments were performed in a single-channel flow reactor (15 mm i.d. and 500 mm catalyst coated length). The rate of reaction was followed by monitoring the disappearance of the hydroxyl group (–OH). Reaction experiments were performed at a hydroxyl group concentration range from 150 to 170 mol m⁻³, T=373–413 K and P=7.9 kPa with a nitrogen purge. The maximum temperature of operation was restricted to 413 K to avoid the formation of undesirable by-products. In the regime controlled by chemical kinetics, reaction was of an apparent first order with respect to –OH concentration, and in the apparent rate constant, the pre-exponential factor was 4.19×10⁻⁴ ms⁻¹, and the apparent activation energy was 16.1 kJ mol⁻¹. These are only valid for the operating pressure and purge gas flowrate used, as both of these are shown to affect water removal from the liquid phase and, hence, reaction rates. Mass transfer coefficients from the liquid to the catalyst surface were estimated and these increased rapidly with flowrate and were higher than expected for a falling liquid film.