Studies on structural properties, surface acidity and benzene isopropylation activity of sulphated ZrO2–TiO2 mixed oxide catalysts

A series of sulphated ZrO₂–TiO₂ mixed oxide with different nominal sulphate loadings in the range of 2–15 wt.% was prepared and characterized for their structural properties, surface acidity and benzene isopropylation activity. The catalyst with 10 wt.% nominal sulphate loading showed highest surface area and uniform pore size distributions. Surface acidity, measured by NH₃–TPD method, showed increase in acidity with sulphate loading and the 10 wt.% sulphate loaded catalyst showed highest acidity. The activities of these catalysts were tested for isopropylation of benzene to cumene using 2-propanol as the alkylating agent. The 10 wt.% sulphate-loaded catalyst also showed highest activity for this reaction with 97% cumene selectivity. The higher activity of this catalyst was attributed to its higher acidity.     

Preparation and characterization of TiO2–SiO2 nano-composite thin films

TiO₂ nanocrystalline particles dispersed in SiO₂ have been prepared by the sol-gel method using titanium- and silicon-alkoxides as precursors. Nano-composite thin films were formed on the glass substrates by dip-coating technique and heat treated at temperatures up to 500 °C for 1 h. The size of the TiO₂ nanocrystalline particles in the TiO₂–SiO₂ solution ranged from 5 to 8 nm. The crystalline structure of TiO₂ powders was identified as the anatase phase. As the content of SiO₂ increased, the anatase phase tended to be stabilized to higher temperature. TEM results revealed the presence of spherical TiO₂ particles dispersed in a disk-shaped glassy matrix. Photocatalytic activity of the TiO₂–SiO₂ (1:1) thin films showed decomposition of 95% of methylene blue solution in 2 h and a contact angle of 10°. The photocatalytic decomposition of methylene blue increased and the contact angle decreased with the content of TiO₂ phase. TiO₂–SiO₂ with the molar ratio of 1:1 showed a reasonable combination of adhesion, film strength, and the photocatalytic activity.     

A study of the abatement of VOC over V2O5–WO3–TiO2 and alternative SCR catalysts

The conversion of C3 organic compounds (propane, propene, 1- and 2-propanol, allyl alcohol, propanal, acrolein, acetone and 1- and 2-chloropropane) in the presence of excess oxygen has been investigated over two V–W–TiO₂ commercial SCR catalysts differing in the V content and over Mn–TiO₂ alternative SCR catalysts. V–W–Ti catalysts show poor activity in the oxidation of hydrocarbons and oxygenates and give significant amounts of partial oxidation products. Moreover they give rise to CO in excess of CO₂. The sample higher in V is more active. Mn–TiO₂ is definitely more active in oxidation of hydrocarbons and oxygenates, and produces, at total conversion, CO₂ as the only detectable product.

V–W–Ti catalysts are very active in dehydrochlorination of the two 2-chloropropane isomers and retain the same oxidation activity also in the presence of HCl. On the contrary, Mn-based catalysts in the presence of chlorocarbons convert into dehydrochlorination catalysts but lose their catalytic activity in oxidation. V–W–Ti catalysts can be used in Cl-containing atmospheres while Mn–TiO₂ can be proposed for DeNO_x and VOC abatement in Cl-free atmospheres such as for diesel engine exhaust gas purification.     

Evaluation of V2O5–WO3–TiO2 and alternative SCR catalysts in the abatement of VOCs

Two different commercial SCR catalysts belonging to the V₂O₅–WO₃–TiO₂ system, and different alternative catalysts based on Mn, Fe, Cr, Al and Ti oxides have been tested in the conversion of VOCs in excess oxygen in a temperature range typical of the SCR process (500–700 K). Propane, propene, isopropanol, acetone, 2-chloropropane and 1,2-dichlorobenzene have been fed with excess oxygen and helium. The industrial catalysts are poorly active in the conversion of propane, giving mainly rise to propene by oxy-dehydrogenation. The conversion of propene is higher with CO as the predominant product. In any case, the oxidation activity depends on the vanadium content of the catalyst. Isopropanol is mainly converted into acetone and propene, while acetone is burnt predominantly to CO. Mn- and Fe- containing systems are definitely more active in the conversion of hydrocarbons and oxygenates, giving rise almost exclusively to CO₂. 2-Chloropropane is selectively dehydrochlorinated to propene and HCl starting from 350 K, propene being later burnt to CO on the industrial V₂O₅–WO₃–TiO₂ catalysts, whose combustion activity is, apparently, not affected by chlorine. On the contrary, chlorine strongly affects the behavior of Mn-based catalysts, that are active in the dehydrochlorination of 2-chloropropane, but are simultaneously deactivated with respect to their combustion catalytic activity. The conversion of 1,2-dichlorobenzene gives rise to important amounts of heavy products in our experimental conditions with relatively high reactant concentration.     

The SMSI between supported platinum and CeO2–ZrO2–La2O3 mixed oxides in oxidative atmosphere

CeO₂–ZrO₂–La₂O₃ (CZL) mixed oxides were prepared by citric acid sol–gel method. The as-received gel was calcined at 500, 700, 900 and 1050 °C to obtain the so-called C5, C7, C9 and CK, respectively. The C5, C7 and C9 powders were impregnated with H₂PtCl₆ and then calcined at 500 °C to prepare P5C5, P5C7 and P5C9, respectively. The impregnated CK powders were calcined at 500, 700 and 900 °C to prepare P5CK, P7CK and P9CK, respectively. The XRD and XPS analyses show that the surface distribution of Pt is evidently influenced by the structural and textural properties of the support. The CO adsorption followed by FTIR reveals that the dispersion and the chemisorption sites of Pt are reduced as the calcination temperature of CZL support increases. The chemisorption ability of the CK samples is even completely deactivated. The encapsulation mechanism, which has been applied to explain the so-called strong metal–support interaction (SMSI) after reductive treatment, is introduced here to demonstrate the abnormal observations though the samples were prepared in oxidative atmosphere. The HRTEM results also confirm this explanation. The effects of oxygen vacancies, the chemisorption sites on the Pt surface and Pt/Ce interfacial sites on the three-way catalytic activities are discussed.     

Preparation, characterization and catalytic properties of Co–Nb2O5–SiO2 catalysts

Co–Nb₂O₅–SiO₂ catalysts were prepared using three different sol–gel procedures: (i) the colloidal sol–gel method using NbCl₅ and SiCl₄ as precursors; (ii) the polymeric sol–gel method using niobium ethoxide and tetraethyl-orthosilicate (TEOS); (iii) an intermediate procedure between the colloidal and polymeric sol–gel method in which the precursors were those utilized in the CSG but dissolved in a mixture of anhydrous ethanol and CCl₄. In all procedures, the elimination of the solvent carried out between 80 and 110°C was followed by a reduction in hydrogen flow (30 ml min⁻¹) at 773 K. Following these procedures, samples containing 10 wt.% Co and 15 wt.% niobium oxide (expressed as Nb₂O₅) were obtained. The characterization of the catalysts was performed using various techniques: N₂ adsorption and desorption curves at 77 K, NH₃- and H₂-chemisorption, TPO, XPS, XRD, and solid state ¹H MAS-NMR. Hydrogenolysis of butane was evaluated. The low reaction rates are assigned to the effect of the metal size, whereas the isobutane selectivity as well as the relatively high stability is due to the acidity of the support.     

Microwave dielectric ceramics in the system BaO–Li2O–Nd2O3–TiO2

Ceramics in the system BaO-Li₂O–Nd₂O₃–TiO₂ (BNT–LNT) were prepared by the mixed oxide route. Powders were mixed, milled, calcined and sintered at 1475°C for 4 h. Fired densities decreased steadily along the series from BNT to LNT. The microstructures of samples rich in BNT were dominated by small needle-like grains; the LNT samples comprised larger (6 μm) cubic grains. X-ray diffraction showed that there was a transition from orthorhombic BNT to cubic LNT; small amounts of LNT could be accommodated in BNT, but between 10–20% LNT there was the development of the second phase. Small additions of LNT led to a small increase in relative permittivity, but decreased the dielectric Q-value (from the maximum of 1819 at 4 GHz). As BNT and LNT exhibit negative and positive temperature dependencies of permittivity respectively, the addition of 10–20% LNT to BNT should yield samples with zero temperature dependence of _r Impedance spectroscopy showed that data could only be acquired at elevated temperatures for BNT rich samples (above 500°C), but at modest temperatures (less than 100°C) for the more conductive LNT.     

Local structure and photocatalytic activity of B2O3–SiO2/TiO2 ternary mixed oxides prepared by sol–gel method

The local structure and the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides (SiO₂ content was fixed as 30 at.% with respect to TiO₂) was investigated by using XRD, FT-IR, BET, UV-vis spectra, and electron paramagnetic resonance (EPR) measurement. In FT-IR analysis, boron was incorporated into the framework of titania matrix with replacing Ti---O---Si with Si---O---B or Ti---O---B bonds. Also, paramagnetic species such as O⁻ and Ti³⁺ defects were formed by the boron incorporation. In SiO₂/TiO₂ mixed oxides, a blue shift in the light absorption band was observed due to the quantization of band structure. All B₂O₃–SiO₂/TiO₂ samples had pure anatase phase and no rutile phase was formed even though the calcination temperature was over 900 °C. Incorporating boron oxides of more than 10% enlarges the grain size of anatase phase and causes a red shift of the light absorption spectrum. The surface area was monotonically decreased with increasing the content of boron content. As a result, the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides was greatly influenced by the content of boron oxide. The highest photoactivity (g moles/min l) was obtained when the boron content was 5% and seven times higher than that of silica/titania binary mixed oxide. In addition, the specific photoactivity (g moles/m² l) was maximum still at 5%. It was concluded that the large reduction of surface area, the change of band structure, and more formation of bulk Ti³⁺ sites are responsible for the deterioration in the photoactivity of B₂O₃–SiO₂/TiO₂ ternary mixed oxides when the content of boron is over 10%, although their crystallinity was enhanced by increasing the calcination temperature with keeping anatase phase.     

V2O5 catalysts supported on Al2O3–SiO2 mixed oxide: V, H MAS solid-state NMR, DRIFTS and methanol oxidation studies

Alumina–silica mixed oxide, synthesized by the sol–gel technique, was used as a support for dispersing and stabilizing the active vanadia phase. The catalysts were characterized employing ⁵¹V and ¹H solid-state MAS NMR, diffuse reflectance FT-IR, BET surface area measurements. The partial oxidation activities of the catalysts were tested using methanol oxidation as a model reaction. ⁵¹V solid-state NMR studies on the calcined catalysts showed the peaks corresponding to the presence of both tetrahedral and distorted octahedral vanadia species at low vanadia loadings and with an increase in V₂O₅ content, the ⁵¹V chemical shifts corresponding to amorphous V₂O₅ like phases were observed. DRIFTS studies of the catalysts indicated the vibrations corresponding tetrahedral vanadia species at low and medium loadings and at high V₂O₅ contents the vibrations corresponding V=O bonds of V₂O₅ agglomerates were observed. The V/Al–Si catalysts exhibited high selectivity for the dehydration product dimethyl ether in the methanol partial oxidation studies showing the predominance of the acidic nature of the alumina–silica support over the redox properties of the active vanadia phase.     

Thermal ageing of Pt on low-surface-area CeO2–ZrO2–La2O3 mixed oxides: Effect on the OSC performance

This work aims at exploring the thermal ageing mechanism of Pt on ceria-based mixed oxides and the corresponding effect on the oxygen storage capacity (OSC) performance of the support material. Pt was supported on low-surface-area CeO₂–ZrO₂–La₂O₃ mixed oxides (CK) by impregnation method and subsequently calcined in static air at 500, 700 and 900 °C, respectively. The evolutions of textural, microstructural and redox properties of catalysts after the thermal treatments were identified by means of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and high-resolution transmission electron microscope (HRTEM). The results reveal that, besides the sintering of Pt, encapsulation of metal by the mixed oxides occurs at the calcination temperature of 700 °C and above. The burial of Pt crystallites by support particles is proposed as a potential mechanism for the encapsulation. Further, the HRTEM images show that the distortion of the mixed oxides lattice and other crystal defects are distributed at the metal/oxides interface, probably indicating the interdiffusion/interaction between the metal and mixed oxide. In this way, encapsulation of Pt is capable to promote the formation of Ce³⁺ or oxygen vacancy on the surface and in the bulk of support. The OSC results show that the reducibility and oxygen release behavior of catalysts are related to both the metal dispersion and metal/oxides interface, and the latter seems to be more crucial for those supported on low-surface-area mixed oxides. Judging by the dynamic oxygen storage capacity (DOSC), oxygen storage capacity complete (OSCC) and oxygen releasing rate, the catalyst calcined at 700 °C shows the best OSC performance. This evident promotion of OSC performance is believed to benefit from the partial encapsulation of Pt species, which leads to the increment of Ce³⁺ or oxygen vacancies both on the surface and in the bulk of oxides despite a loss of chemisorption sites on the surface of metal particles.     

Characterization and photocatalytic activity of transition-metal-supported surface bond-conjugated TiO2/SiO2

TM/TiO₂/SiO₂ photocatalysts were prepared by the photodeposition method using transition metal salts (TM=Fe³⁺, Co²⁺, Ni²⁺ and Cu²⁺) as precursors and the surface bond-conjugated TiO₂/SiO₂ as supporter in N₂ atmosphere, and were characterized by XRD, XPS, UV-Vis diffuse reflection and zeta-potential. Their photocatalytic activities were evaluated using reactive brilliant red K-2G (K-2G) and cationic blue X-GRL (CBX) showing different adsorption behavior on the oxides. Fe, Cu supported TiO₂/SiO₂ can efficiently extend the light absorption to the visible region. XPS analysis verified that the introduction of transition metal lead to the changes of the electronic environmental of Ti cations and the zeta-potential of oxides. As a result, K-2G has higher adsorption on the modified TiO₂/SiO₂ than that on the baked one, while the adsorption of CBX has a little change on the both oxides. At the same time, for the photodegradation of K-2G, Fe³⁺, Co²⁺, Ni²⁺-modified catalysts show that their photoactivities are 3.3–2.2 times higher than the bare one. On the contrast, all transition-metal-supported catalysts have no significant activity improvement except that Fe/TiO₂/SiO₂ shows 1.68 times higher activity for the photodegradation of CBX. The results indicate that the photoactivity could be increased in photodegradation of dyes by changing the performances of adsorption to dyes and absorption to light of photocatalyst.     

Catalytic hydrolysis of dichlorodifluoromethane (CFC-12) on unpromoted and sulfate promoted TiO2–ZrO2 mixed oxide catalysts

The mixed oxide of zirconium and titanium was investigated for the catalytic hydrolysis of dichlorodifluoromethane. The mixed oxide was further promoted by doping with sulfate ions. It was found by both powder X-ray diffraction and Raman spectroscopy that addition of hydrogen peroxide to the methanol solution of ZrOCl₂ and TiCl₄ before gelation was induced by ammonia addition promoted the formation of the mixed oxide phase with the anatase structure in addition to the expected phase of columbite structure. This increased the surface area and activity of the mixed oxide. Promotion with sulfate enhanced the acidity and activity of the catalysts. When sulfate was added by treatment with sulfuric acid, phase transformation, depending on the concentration of the acid used, in addition to sulfate deposition on the oxide surface, occurred. The treatment with 96% sulfuric acid resulted in a catalyst with nearly entirely the anatase structure. This catalyst was found to be the most active, capable of complete conversion of CFC-12 and 100% selectivity to carbon dioxide at 280°C. Prolonged reaction of this catalyst at 280°C for 211 h resulted neither in reduction of activity nor reduction in CO₂ selectivity. The performance of this catalyst is among the highest reported in the literature.     

Effect of phosphate ion on the textural and catalytic activity of titania–silica mixed oxide

Phosphate-modified TiO₂-SiO₂ mixed oxide catalysts have been prepared by varying the method of preparation, source and concentration of phosphate ion. The prepared catalysts were compared for their catalytic activity/selectivity in nitration of toluene. The characterisation of the catalysts was performed using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermal analysis (TG–DTA), nitrogen adsorption–desorption methods, surface acid strength measured by Hammett indicator method, surface acid sites measured by amine titration method, and phosphate content measured by UV–VIS spectrophotometry. The XRD patterns revealed that phosphate ion stabilises the anatase phase up to 1173 K activation. FT-IR results show that phosphate species strongly bound bidentately, and that both the internal weakly H-bonded hydroxyl groups and free hydroxyl groups are present on TiO₂–SiO₂ mixed oxide support. Surface area and surface acidity are found to increase with the increase in phosphate loading up to 7.5 wt.% and thereafter the values decrease drastically. However, average pore radius and total pore volume shows the reverse order. Phosphated samples prepared using H₃PO₄ as the source of phosphate ion exhibit higher acidity, and surface area but lower porosity than the samples prepared from (NH₄)₃PO₄, though both the samples contain the same amount of phosphate (7.5 wt.%). Similar results were also observed when varying the method of preparation. TiO₂–SiO₂ samples prepared at pH=3 exhibit higher acidity and surface area but lower porosity than the samples prepared at pH=7. The acid strength of 7.5P/TiO₂–SiO₂ (H) is found to be stronger than that of 100% concentrated H₂SO₄. The material modified with phosphate ion was found to be an efficient and selective catalyst for solvent-free mono-nitration of toluene. Selectivity to the para-product is correlated with the porosity of the material.     

Co3O4–CeO2 mixed oxide-based catalytic materials for diesel soot oxidation

Co₃O₄–CeO₂ type mixed oxide catalyst compositions have been prepared by using co-precipitation method and, their catalytic activity towards diesel particulate matter (PM)/carbon oxidation has been evaluated under both loose and tight contact conditions. These catalysts show excellent catalytic activity for PM/carbon oxidation, despite their low surface area. The activation energy observed for non-catalyzed and catalyzed reactions are 163 kJ/mol and 140 kJ/mol, respectively, which also confirm the catalytic activity of catalyst for carbon/soot oxidation. The promotional effects of an optimum amount of cobalt oxide incorporation in ceria and presence of a small amount of potassium appears to be responsible for the excellent soot oxidation activity of this mixed oxide type material. The catalytic materials show good thermal stability, while their low cost will also add to their potential for practical applications.     

Support effects in Pt/TiO2–ZrO2 catalysts for NO reduction with CH4

ZrO₂–TiO₂ mixed oxides, prepared using the sol–gel method, were used as supports for platinum catalysts. The effects of catalyst pre-reduction and surface acidity on the performance of Pt/ZT catalysts for the reduction of NO with CH₄ were studied. The diffuse reflectance infrared Fourier transformed (DRIFT) spectra of CO adsorbed on the Pt/ZT catalysts, and also on the Pt/T and Pt/Z references, pre-reduced at 773 K in hydrogen, revealed that an SMSI state is developed in the Ti-rich oxide-supported platinum catalysts. However, no shift in the binding energy of Pt 4f_7/2 level for Pt/T and Pt deposited on Ti-rich support counterparts pre-reduced at 773 K was found by photoelectron spectroscopy. The DRIFT spectra of the catalysts under the NO+O₂ co-adsorption revealed the appearance of nitrite/nitrate species on the surface of the Zr-containing catalysts, which displayed acidic properties, but were almost absent in the Pt/T catalyst. The intensity of these bands reached a maximum for the Pt/ZT(1:1) catalyst, which in turn exhibited a larger specific area. In the absence of oxygen in the feed stream, the NO+CH₄ reaction showed DRIFT spectra assigned to surface isocyano species. Since the intensity of this band is higher for the Pt/ZT (9:1) catalyst, it seems that such species are developed at the Pt–support interface.     

Synthesis of nanosized TiO2/SiO2 particles in the microemulsion and their photocatalytic activity on the decomposition of p-nitrophenol

Nanosized pure TiO₂ particles were prepared by hydrolysis of TTIP in the sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles. TiO₂/SiO₂ nanoparticles were also prepared from TEOS as a silicon source and TTIP as a titanium source. These particles were characterized by TEM, XRD, FT-IR, BET, TGA and DTA. From thermal analysis and XRD analysis, the anatase structure of pure titania appeared in the 300–600 °C calcination temperature range and the rutile structure was showed above 700 °C. However, no rutile phase was observed for the TiO₂/SiO₂ particles up to 800 °C. The crystallite size decreased and the surface area of TiO₂/SiO₂ particles monotonically increased with an increase of the silica content. From FT-IR analysis, the band for Ti–O–Si vibration was observed and the band intensity for Si–O–Si vibration increased with an increase of the silica content. The micrographs of TEM showed that the TiO₂/SiO₂ nanoparticles had a spherical and a narrow size distribution. In addition, TiO₂/SiO₂ particles showed higher photocatalytic activity than pure TiO₂ and the TiO₂/SiO₂ (90/10) particles showed the highest activity on the photocatalytic decomposition of p-nitrophenol.     

Synthesis, characterization and evaluation of NiMo/SiO2–Al2O3 catalysts prepared by the pH-swing method

NiMo/(X)SiO₂–Al₂O₃ catalysts were synthesized with various SiO₂ contents (X = 0, 10, 25 and 50 wt%) using the pH-swing method. In order to find the optimum SiO₂ content, the catalysts were evaluated in the hydrodesulfurization of 4,6-DMDBT, hydrogenation of naphthalene and hydrodenitrogenation of carbazole. Kinetic parameters of Langmuir–Hinshelwood type equations for all the reaction systems were estimated. FTIR analysis of CO adsorption for the sulfided catalysts shows that the amount of coordinatively unsaturated Mo sites promoted by nickel (CUS-NiMoS) follows the order NiMo/10ASA > NiMo/25ASA > NiMo/0ASA. This tendency agrees with the results obtained in catalytic activity.     

Hydrodesulfurization activity of CoMo and NiMo supported on Al2O3–TiO2 for some model compounds and gas oils

Catalytic activities of Al₂O₃–TiO₂ supporting CoMo and NiMo sulfides (CoMoS and NiMoS) catalysts were examined in the transalkylation of isopropylbenzene and hydrogenation of naphthalene as well as the hydrodesulfurization (HDS) of model sulfur compounds, conventional gas oil (GO), and light cycle oil (LCO). Al₂O₃–TiO₂ supporting catalysts exhibited higher activities for these reactions except for the HDS of the gas oil than a reference Al₂O₃ supporting catalyst, indicating the correlation of these activities. Generally, more content of TiO₂ promoted the activities. Inferior activity of the catalyst for HDS of the gas oil is ascribed to its inferior activity for HDS of dibenzothiophene (DBT) in gas oil as well as in model solvent decane, while the refractory 4,6-dimethyldibenzothiophene (4,6-DMDBT) in gas oil as well as in decane was more desulfurized on the catalyst. Characteristic features of Al₂O₃–TiO₂ catalyst are discussed based on the paper results.     

Surface characterization of Al2O3–SiO2 supported NiMo catalysts: An effect of support composition

Al₂O₃–SiO₂ mixed oxide has been investigated as a support for hydrotreating catalyst with variation of its composition [Si/(Si + Al) = 0.06, 0.12, 0.31, 0.56, 0.78] and its interaction with the surface active metals (NiMo). The composition of support and surface species (NiMo) of catalysts were characterized by specific surface area, atomic absorption, SEM-EDX, XRD, temperature programmed reduction (TPR), Raman analysis, scanning electron microscopy (STEM) and transmission electron microscopy (TEM). Incorporation of SiO₂ in Al₂O₃ promotes a weak interaction between the active phases and particularly catalyst that predominated with SiO₂ content. The oxide and sulfided catalysts characterization indicated that the effect of support is responsible to form different catalytic sites. Crystallization of MoO₃ phases and a relatively longer crystal of MoS₂ in the sulfided catalyst were attributed to an increasing SiO₂ content in the support. The catalytic behavior of the NiMo supported catalysts is explained in terms of structural changes on the surface due to the support and active metal interactions. The activity of the different catalysts evaluated in the thiophene hydrodesulfurization reaction was higher for the catalyst having lower SiO₂ content in the support.     

Hydroisomerization and hydrocracking of long chain n-alkanes on Pt/amorphous SiO2–Al2O3 catalyst

The hydroisomerization and hydrocracking of n-hexadecane, n-octacosane and n-hexatriacontane on a 0.3% platinum/amorphous silica–alumina (MSA/E) catalyst was investigated in a stirred microautoclave at 345, 360 and 380°C and between 2 and 13.1 MPa hydrogen pressure. For each n-paraffin, the reaction pathway and the kinetic parameters were determined. The results were used to elucidate the effect of chain length and operating conditions on isomerization and cracking selectivity. The conversion of the n-paraffins lead to the formation of a mixture of the respective isomers, as the main product, together with cracking products. At every temperature, the iso-alkane/n-alkane ratio of cracking products increased considerably with increasing conversion degree. At the same conversion level, higher reaction temperatures lead to cracking products characterized by a lower iso-alkane/n-alkane ratio. The conversion rate constants showed a considerable increase between n-C₁₆ and n-C₂₈, whereas a slight decrease between n-C₂₈ and n-C₃₆ was observed. The hydroisomerization selectivities showed a decrease as a function of chain length and with increasing conversion levels. The increase in reaction temperature leads to a small decrease in the isomerization selectivities only at low-medium conversion degrees and at the highest temperature investigated, while the effect of this parameter on the maximum yields achievable in iso-C16, iso-C28 and iso-C36 was negligible. The results indicate that the conversion of the n-paraffins follows a first-order kinetic in hydrocarbon while the order in hydrogen pressure was −1.1 ± 0.21 for n-C₁₆ and −0.66 ± 0.15 for n-C₂₈. Furthermore, an increase in hydroisomerization selectivity at higher hydrogen pressure for n-C₂₈ conversion was observed.