Acid-activated organoclays: preparation, characterisation and catalytic activity of polycation-treated bentonites

Samples of SWy-2 and SAz-1 loaded with increasing amounts of the polycation magnafloc 206, [(Me₂NCH₂CHOHCH₂)_n]ⁿ⁺Cl_n, were acid-treated using 6 M HCl at 95°C for 30, 90 and 180 min. The activity of these acid-activated polycation-exchanged clays for the conversion of α-pinene to camphene and limonene was determined and compared with that from clay samples (without polycation) acid-treated in the same manner. Acid treatment of polycation-exchanged bentonites produced hybrid catalysts which enhanced the activity of the clays for the isomerisation of α-pinene to camphene and limonene. The presence of the polycation had a more marked influence on the activity of samples derived from SAz-1 increasing the yield from 25% for acid-activated SAz-1 with no added polycation to 50% camphene for acid-activated polycation-exchanged SAz-1. The increase in yield for corresponding samples derived from SWy-2 was only from 42 to 52%. This enhancement in yield for samples derived from SAz-1 was attributed to the increased hydrophobicity of the polycation loaded clay whilst the comparable yields for SWy-2 in the absence and presence of polycation may suggest that SWy-2 disperses well in the non-polar α-pinene. The total yields (based on α-pinene) for the most active catalysts was between 80 and 90%. These yields are directly comparable with those obtained by others using zeolites and pillared clays although the acid-activated polycation-treated clays were marginally less selective towards camphene.     

Anionic Clays as Potential Slow-Release Fertilizers: Nitrate Ion Exchange

Several nitrate containing anionic clays were synthesized at different temperatures and the kinetics of NO₃ ^– release were determined to test their suitability as slow-release N fertilizers. A sample (Mg:Al = 2:1) synthesized at 60°C with smaller particle size released 75, 86 and 100% of its NO₃ ^– in 1, 3 and 7 days, respectively when equilibrated with a simulated soil solution. On the other hand, the 175°C/2 hrs sample with larger particle size released 65, 77 and 84% of its nitrate in 1, 3 and 7 days, respectively. Another anionic clay (synthesized at 175°C/24 hrs) of higher charge density (Mg:Al = 2:1) containing NO₃ ^– was equilibrated with a 0.012 N NaCl or Na₂CO₃ to test the role of different anions in releasing the NO₃ ^– anion from the interlayers. The results showed that Cl^– released more NO₃ ^– than did CO₃ ^2– from this anionic clay after all the treatment times probably as a result of the CO₃ ^2– anion blocking the release of NO₃ ^– from the interior of the crystals. When a lower charge density (Mg:Al = 3:1) sample (synthesized at 175°C/48 hrs) was equilibrated with 0.02N solution of anions the release of nitrate was as follows: Cl^– < F^– < SO₄ ⁼ CO₃ ^2–. These results suggest that the divalent SO₄ ⁼ and CO₃ ^2– anions are more effective in the release of NO₃ ^– from this lower charge density anionic clay. Time-resolved structural analysis of NO₃ ^– exchange with CO₃ ^2– in the above anionic clay using synchrotron x-ray diffraction showed that ion exchange is rapid because of small crystal size and lower charge density. Thus the release of NO₃ ^– from anionic clays is an interplay among the type of anions present in soil solution, their concentration, pH of soil solution, the charge density and crystal size of anionic clay etc.     

Modeling of cadmium(II) adsorption on kaolinite-based clays in the absence and presence of humic acid

Cadmium adsorption on kaolinite-based clays in the absence and presence of humic acid was modeled with the aid of the FITEQL 3.2 computer program using a modified Langmuir approach for capacity calculations. Formation of surface–metal ion and surface–humate–metal ion complexes was assumed using the DLM approach. As Cd(II) adsorption was ionic strength-dependent, the adsorption experiments were carried out in solutions containing two different concentrations of an inert electrolyte (0.1 M and 0.005 M NaClO₄). The surface sites responsible for the adsorption were assumed to be the permanent charges, ≡S₁OH silanol groups and carboxyl groups having pK_a values close to that of the silanol groups, and ≡S₂OH aluminol groups and phenol groups with pK_a values close to that of the aluminol groups, because the studied clays (partly composed of clay soil) contained organic carbon. Cd²⁺ ions were assumed to bind to the surface in the form of outer-sphere X₂²⁻ Cd²⁺ and inner-sphere ≡SOCd⁺ monodentate complexes. When humic acid was added, Cd(II) adsorption was modeled using a multi-site binding model by the aid of FITEQL3.2. The fit between model and experimental values was excellent in each case. Since the stability of the ternary surface complexes in the presence of humic acid was higher than that of the corresponding binary surface–cadmium ion complexes, the adsorption vs. pH curves were much steeper (and distinctly S-shaped) compared to the tailed curves observed in binary clay–cadmium ion systems. The clay mineral in the presence of humic acid probably behaved more like a chelating ion-exchanger for heavy metal ions than as a simple inorganic ion exchanger.     

Electrochemical investigations of pitting corrosion behaviour of type UNS S31603 stainless steel in thiosulfate-chloride environment

The pitting corrosion behaviour of type UNS S31603 stainless steel (316L SS) in 0.01, 0.05 and 0.1 M thiosulfate ion (S₂O₃ ^2–) in the absence and presence of various concentrations of chloride ion (Cl^–) was studied using the cyclic potentiodynamic polarization method. The influence of major factors which affect pitting corrosion such as pH and temperature, were also investigated. It was found that both the pitting potential (E _pit) and the repassivation potential (E _rp) decreased with increase in Cl^– concentration and solution temperature and a more pronounced difference in E _pit values for various concentrations of S₂O₃ ^2– in 1.0 M Cl^– was obtained at lower temperatures. The effect of pH on E _pit, E _corr and E _rp values for different concentrations of S₂O₃ ^2– in the presence of 1.0 M Cl^– was also determined.     

Hematite and iron carbonate precipitation-coexistence at the iron–montmorillonite–salt solution–CO2 interfaces under high gas pressure at 150 °C

The hydrothermal reactivity of swelling clays has relevant implications on the geological storage of radioactive waste and greenhouse gases because the clay geo-materials have been proposed as engineered or natural barriers due to their low permeability in confined systems and their high capacity to sequester ions. In the present study, the iron–montmorillonite–salt solution–CO₂ interactions were investigated under high gas pressure (200 bar) at 150 °C.Various chemical processes were characterized at the solid–fluid interfaces such as the dissolution of montmorillonite fine particles and oxidative-dissolution of elemental iron. The ionic supersaturation of solution and possibly the surface complexation in the system produced the precipitation of hematite nanoparticles (< 200 nm) after 15 days of solid–fluid contact. The hematite nanoparticles dispersed and/or coagulated on the clay matrix caused a stable red coloration of the montmorillonite composite. We assume that initial dissolved oxygen was progressively consumed in this closed-stirred system favouring the presence of divalent iron (in-situ change of redox conditions) and then leading the surface precipitation of iron carbonate nanocrystals (< 500 nm) after 60 days of solid–fluid contact. Thus, an atypical mineral coexistence of hematite–iron carbonate was observed in our system. A qualitative comparison with the blank experiment, i.e. at the same P–T conditions, but without CO₂ injection, suggested that the carbon dioxide increased the hydrothermal reactivity of montmorillonite because the hematite and iron carbonate formation were not observed after the same reaction time.     

A reaction model for the electrochemical production of p-anisidine

The work examines the possibility of a simple reaction model describing a complex organic electrosynthesis, such as the formation of p-anisidine. The experimental results obey the linear relationships of the model and in consequence the kinetic constants obtained in this way define reaction behaviour. The paper demonstrates how such a model can play a useful role in the design of pilot plant experimentation. Results from a parallel plate cell fit prediction from the model.Nomenclature [X] Concentration of species X (kmol m^–3) - b Slope of Tafel plot (mV^–1) - E Electrode potential (mV) - F Faraday (C g-equiv^–1) - F Faraday based on k-equiv = 10³F (C k-equiv^–1) - i _A Partial current density for the primary reaction (A m^–2) - i _B Partial current density for the consecutive secondary reaction (A m^–2) - i _H Partial current density for the parallel secondary reaction (A m^–2) - i Total current density=i _A+i _B+i _H (A m^–2) - k Reaction rate constant (A m^–2 per kmolm^–3) - k _H Rate constant for the parallel secondary electrode reaction (A m^–2) - k _I Individual mass transfer coefficient (m s^–1) - N Flux (kmol m^–2 s^–1) - r Reaction rate (kmol m^–2 s^–1) Sufixes A Appertaining to primary electrode reaction or species A - B Appertaining to consecutive secondary electrode reaction or species B - b In the bulk of the electrolyte - H Parallel secondary electrode reaction - s Near the electrode surface     

Intrinsic kinetics of Fischer–Tropsch reactions over an industrial Co–Ru/γ-Al2O3 catalyst in slurry phase reactor

The rate of Fischer–Tropsch synthesis over an industrial well-characterized Co–Ru/γ-Al₂O₃ catalyst was studied in a laboratory well mixed, continuous flow, slurry reactor under the conditions relevant to industrial operations as follows: temperature of 200–240 °C, pressure of 20–35 bar, H₂/CO feed ratio of 1.0–2.5, gas hourly space velocity of 500–1500 N cm³ g_cat^− 1 h^− 1 and conversions of 10–84% of carbon monoxide and 13–89% of hydrogen. The ranges of partial pressures of CO and H₂ have been chosen as 5–15 and 10–25 bar respectively. Five kinetic models are considered: one empirical power law model and four variations of the Langmuir–Hinshelwood–Hougen–Watson representation. All models considered incorporate a strong inhibition due to CO adsorption. The data of this study are fitted fairly well by a simple LHHW form − R_H2 + CO = ap_H2^0.988p_CO^0.508 / (1 + bp_CO^0.508)² in comparison to fits of the same data by several other representative LHHW rate forms proposed in other works. The apparent activation energy was 94–103 kJ/mol. Kinetic parameters are determined using the genetic algorithm approach (GA), followed by the Levenberg–Marquardt (LM) method to make refined optimization, and are validated by means of statistical analysis. Also, the performance of the catalyst for Fischer–Tropsch synthesis and the hydrocarbon product distributions were investigated under different reaction conditions.     

Mechanism and Kinetics of Formation of Solid Solutions in the Nd2SrAl2O7–Ho2SrAl2O7 System

The processes of phase formation in the Nd₂O₃–Ho₂O₃–SrO–Al₂O₃ system are investigated in the temperature range 1100–1530°C. It is revealed that the structural–chemical mechanism of formation of (Nd _x Ho_{1 – x} )₂SrAl₂O₇ solid solutions depends on the temperature and composition. An increase in the holmium content and in the temperature leads to a crossover from the mechanism including the formation of LnAlO₃ and LnSrAlO₄ as intermediate products to the mechanism in which the interaction of Ln ₂O₃ and SrAl₂O₄ is a limiting stage.     

Copolymerizations of ethylene with 1–decene over various ansa–metallocene complexes combined with Al( i-Bu) 3/ [CPh 3] [B(C 6F 5) 4] cocatalyst

Copolymerizations of ethylene with 1-decene were carried out with a series of stereospecific metallocene compounds, rac–(EBI)Zr(NMe₂)₂ [ 1, EBI = ethylene–1,2–bis( 1–indenyl)], rac–(EBI)Hf(NMe₂ (2), rac–Me₂Si( 1–C₅H₂–2–Me–4– ^t Bu)₂Zr(NMe₂)₂ (3), ethylidene(cyclopentadienyl)(9-fluorenyl)ZrMe2 [4, Et(Flu)(Cp)ZrMe2] and isopropylidene(cyclopentadienyl)(9–fluorenyl)ZrMe₂ [5, iPr(Flu)(Cp)ZrMe₂], combined with Al(i–Bu)₃/[CPh₃] [B(C₆F₅)₄] cocatalyst. All catalyst systems showed very high copolymerization rates and the 1–decene reactivity decreased in the order of 2 > 5 > 1 4 > 3. The reactivity product of ethylene and 1–decene (r _E x r _D) was below 1 except 3 catalyst, corresponding to random copolymer structures with an alternating character. The melting point (T_m), crystallinity (X_C), intrinsic viscosity ([] and density of the 1–decene/ethylene copolymers decreased markedly with an increase in the 1–decene content, regardless of the type of catalytic system.     

Performances of mixed alcohols synthesis over potassium promoted molybdenum carbides

Molybdenum carbides, β-Mo₂C and α-MoC_1−X, promoted by K₂CO₃ were studied as catalysts for CO hydrogenation reactions at T = 573 K, P = 8.0 MPa, GHSV = 2000 h⁻¹, H₂/CO = 1.0. Unpromoted molybdenum carbides produced mainly light hydrocarbons under these conditions. Addition of K₂CO₃ as a promoter, however, both β-Mo₂C and α-MoC_1−X resulted in remarkable selectivity shift from hydrocarbons to alcohols. Moreover, the promoter of potassium enhanced the ability of chain propagation of β-Mo₂C and α-MoC_1−X with higher selectivity to C₂₊OH. Meanwhile, the investigation of the loadings of K₂CO₃ in β-Mo₂C and α-MoC_1−X revealed that the maximum of yield of alcohol was obtained at K/Mo (molar ratio) of 0.2 and 0.1, respectively. On K/β-Mo₂C catalysts, the distribution of hydrocarbons obeyed traditional linear A–S–F plot, while alcohols gave a unique linear A–S–F distribution with remarkable deviation of methanol compared with that of on β-Mo₂C catalyst. However, there was no significant difference between α-MoC_1−X and K/α-MoC_1−X catalysts about the distributions of alcohols and hydrocarbons; they both have similar linear A–S–F plots. Thus, the potassium promoter played a different role over β-Mo₂C and α-MoC_1−X catalysts upon the catalytic performance of mixed alcohols synthesis.     

Non-isothermal crystallization kinetics of MgO–BaO–B2O3–Al2O3–SiO2 glass

5MgO–9BaO–33B₂O₃–33Al₂O₃–20SiO₂ (mol%) glass was prepared by the melt quenching method at 1823 K for 2 h. Dilatometry and differential scanning calorimetry (DSC) curves of the glass have been investigated. Fragility index F was used to estimate glass formability. The crystallization kinetics of the glass was described by the activation energy (E) for crystallization and numerical factors (n, m) depending on the nucleation process and growth morphology. XRD and SEM analysis were also used to describe the crystals’ types and morphology precipitated from the MgO–BaO–B₂O₃–Al₂O₃–SiO₂ glass. The results show that the effective activation energy of the crystallization process E was 45.19 kJ/mol, and n up to 4.05. Two crystals phases, i.e. Al₄B₂O₉ and Al₂₀B₄O₃₆ were observed in the crystallized samples. SEM results were consistent with crystallization kinetics.     

Electrocoating of iron and other metals with polypyrrole

Galvanostatic electrodeposition of polypyrrole from more than 20 nonaqueous and aqueous electrolytes containing anions such as BF ₄ ^– , ClO ₄ ^– , HSO ₄ ^– , Tos^–, HCO ₃ ^– , H₂PO ₄ ^– , HPO ₄ ^2– , H₂BO ₃ ^– and NO ₃ ^– at the substrates Pt, Au, Cu, Ti, stainless steel/V2A and Fe was investigated. The passivating substrates Pt, Au, Ti and V2A could be electrocoated under a broad variety of conditions. Cu dissolved anodically. The same was true for Fe with only one important exception, namely aqueous nitrate. Smooth, well-adhering polypyrrole layers were obtained on iron at NO ₃ ^– concentrations of 0.01–1 M and at current densities of 0.5–10 mA cm^–2. The degree of insertion for nitrate ions was abouty=0.25, confirmed by elemental analysis. Current efficiencies with regard to thisy were about 90%. The layers were stable in air for a long time.     

Highly active hydrotreatment catalysts prepared with chelating agents

Hydrotreatment catalysts (Co–Mo/Al₂O₃, Ni–Mo/Al₂O₃ and Ni–W/Al₂O₃) were prepared by an impregnation method using an aqueous solution containing a chelating agent (nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) or trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid (CyDTA)). Co–Mo/Al₂O₃ and Ni–W/Al₂O₃ prepared with the chelating agents showed higher hydrodesulfurization (HDS) activity as well as hydrogenation (HYD) activity under high pressure (5.1 MPa) than those prepared without the chelating agents. Co–Mo/Al₂O₃ prepared with CyDTA showed ca. 70% higher HDS activity for benzothiophene (BT) than that prepared without it. HYD activity of Ni–W/Al₂O₃ for o-xylene was promoted about 65% by the addition of CyDTA. FT-IR of nitric oxide (NO) adsorbed on the sulfided Co–Mo/Al₂O₃'s suggested that Co was highly dispersed over the catalyst surface when the catalysts were prepared with the chelating agents.     

The Structure of Fusion-Cast High-Chrome Oxide Refractories in the Cr<Subscript>2</Subscript>O<Subscript>3</Subscript> - MgO - Al<Subscript>2</Subscript>O<Subscript>3</Subscript> System

The phase composition and structure of fusion-cast refractories composed of 57.0 – 84.2% Cr₂O₃, 4.3 – 36.1% MgO, 2.0 – 9.7% Al₂O₃, and 2.4 – 6.9% SiO₂ have been studied by petrographic and x-ray spectral microprobe analysis methods. Refractories high in MgO with modulus M = (Cr₂O₃ +Al₂O₃)/MgO = 1.64 – 3.1 are shown to consist of spinel phase Mg(Cr, Al)₂O₄ and silicate glass. Refractory materials (80.8 – 84.2% Cr₂O₃, 4.3 – 4.7% MgO, 2.0 – 9.7% Al₂O₃, and 2.7 – 6.9% SiO₂ with M = 18.7 – 20.2) are three-phase systems composed of spinel, escolaite, and glass phase. These materials, owing to their high corrosion resistance, have promising potentiality for practical applications.__________Translated from Novye Ogneupory, No. 12, pp. 69 – 74, December, 2004.     

Determination of overall mass transport coefficients in gas diffusion electrodes

Gas diffusion electrodes are used for many purposes, for example in fuel cells, in synthesis and as anodes in electrodeposition processes. The behaviour of gas diffusion electrodes has been the subject of many studies. In this work the transport of gas in the gas diffusion electrode, characterized by the overall mass transport coefficient, has been investigated using hydrogen-nitrogen mixtures. A reactor model for the gas compartment of the gas diffusion electrode test cell is proposed to calculate the concentration of hydrogen in the gas compartment as a function of the input concentration of hydrogen and the total volumetric gas flow rate. The mass transport coefficient is found to be independent of variations in hydrogen concentration and volumetric gas flow rate. The temperature dependence of the mass transport coefficient has been determined. A maximum was found at 40°C.Notation Agd geometric electrode surface area (m²) - C _in concentration of reactive component at the inlet of the gas compartment (mol m^–3) - c _out concentration of reactive component at the outlet of the gas compartment (mol m^–3) - E potential (V) - E _e equilibrium potential (V) - E _t upper limit potential (V) - F _v volumetric flow rate (m^–3 s^–1) - F _v,H volumetric flow rate of hydrogen (m^–3 s^–1) - F _v,N volumetric flow rate of nitrogen (m^–3 s^–1) - F _vin volumetric flow rate at the inlet of the gas compartment (m^–3 s^–1) - F _v,out volumetric flow rate at the outlet of the gas compartment (in ^–3 s^–1) - F _v,reaction volumetric flow rate of reactive component into the gas diffusion electrode (m^–3 s^–1) - Faraday constant (A s mo^–1) - I _gd current for gas diffusion electrode (A) - i _gd current density for gas diffusion electrode (A m^–2) - I _gd,1 diffusion limited current for gas diffusion electrode (A) - i _gd,1 diffusion limited current density for gas diffusion electrode (A m^–2) - I _gd,1,calc calculated diffusion limited current for gas diffusion electrode (A) - i _gd,1,calc calculated diffusion limited current density for gas diffusion electrode (A m^–2) - I _hp current for hydrogen production (A) - k _s mass transport coefficient calculated from c _out (m s^–1) - n number of electrons involved in electrode reaction - T temperature (°C) - V _m molar volume of gas (m³ mol^–1) - overpotential (V)     

Mechanism of the carbonitriding reactions of SiO2–Al2O3 minerals in the Si–Al–O–N system

Ceramics of the Si–Al–O–N system and SiC have a great technological interest because of their good thermomechanical properties at high temperatures. It is possible to obtain phases such as β-SiC, Si₃N₄, β′-sialons, O′-sialons, polytype sialons, AlN, Al₂O₃ or mixtures of these phases by means of carbonitriding reactions starting from minerals such as quartz, diatomite and other aluminosilicate minerals. The knowledge of the mechanism of these reactions permits to establish the necessary conditions to achieve the desired phases in the final product. The mechanisms of the carbonitriding reactions of several minerals with increasing aluminium content are studied. Their compositions are from diatomite up to mullite. Reactions of the mineral carbon mixture were carried out at 1300–1650°C in N₂ atmosphere. The phases formed were identified by X-ray diffraction in qualitative and, in some cases, in quantitative form. Intermediate compounds such as β-SiC, X-phase, mullite, glassy phases and gaseous silicon oxide were observed. The formation and importance of these phases depend on the mineral composition as well as on the reaction conditions (temperature, time, etc.). β-SiC, the main intermediate phase, may remain in the final products and may be the major phase depending on the temperature and the carbon content used. The final products of these reactions are phases of the Si–Al–O–N system. The phases obtained were characterized by EPMA, SEM and BET techniques.     

Preparation and properties of raney nickel electrodes on Ni-Zn base for H2 and O2 evolution from alkaline solutions Part I: electrodeposition of Ni-Zn alloys from chloride solutions

Experimental results for the electrodeposition of Ni-Zn alloys from chloride solutions, with addition of H₃BO₃ and without other additives, in a laboratory cell with a perforated nickel sheet cathode and with recirculating electrolyte are presented. The dependence of the zinc content in the alloy on the following operating conditions was investigated: cathodic current density, 1.0–20.0 A dm^–2; temperature, 35–65°C; pH 1.5–5.5; total molarity,M _tot=M _Ni ²⁺ +M _Zn ²⁺ =1.1–2.8 M; and, molar ratio,P=M _Ni ²⁺ /M _Zn ²⁺ =1.0–15. Depending on the operating conditions the Zn content in the alloy varied over the range 22–88 mol%. In separate experiments galvanostatic polarization curves were measured in the direction of increasing and then decreasing cathodic current density in the range 0.1–20.0 A dm^–2 with all other operating conditions as used for electroplating experiments. In all cases significant hysteresis effects were observed. It was found that the current efficiency for the electrodeposition of Ni-Zn alloys from chloride solutions as a function of the zinc content in the alloy showed a sharp minimum of about 55% atX _Zn=55 mol % irrespective of other operating conditions.     

Spectroscopic evidence for the formation of CHx species in the hydrogenation of carbidic carbon on Ni(100)

The CH _x species formed on Ni(100) by hydrogenation of carbidic carbon have been detected using high resolution electron energy-loss spectroscopy (HREELS). Exposures of carbidic carbon to 1×10^–7 Torr H₂ and D₂ at 313 K for 20 min produce CH _x and CD _x species, respectively. These species are identified by two energy-loss peaks for CH _x at 2970 and 1380 cm^–1 and only one peak for CD _x at 1980 cm^–1. Because of the existence of the intense peak at 1380 cm^–1, in the range of a scissors mode for CH₂ and a symmetric deformation mode for CH₃, the CH _x species are tentatively ascribed to CH₂ and/or CH₃. The CD _x species undergo decomposition at 330–370 K in UHV as well as in hydrogen below 10^–7 Torr. No stable CH _x species are observed above 400 K, which is lower than the normal reaction temperature of the methanation reaction (500 K).     

Transparent Photochromic Glasses in the BaO–R2O3–SiO2 (R = Al, B, and La) System for Applications in Fiber Optics

Photochromic glasses of new compositions in the BaO–R ₂O₃–SiO₂ (R = Al, B, and La) system are synthesized. The glasses prepared are characterized by the additional optical density of saturation D _s (for 5-mm-thick samples, D _s = 0.1–0.9), the relaxation criterion after dark bleaching for 3 min (K _{r, 3} = 35–90%), the optical transmission in the visible range (73–96%), and the softening temperature (650–710°C). These glasses can be used both for preparing an optical fiber core in photochromic glass fiber products of different types with an enhanced resolution and as a recording medium for random-access memory in optoelectronics.     

A New, Improved, Solid-Acid Catalyzed Process for Generating Linear Alkylbenzenes (LABs)

Linear alkylbenzenes (LABs) comprising >80% 2-phenyl isomer content, have been prepared in high yields from detergent-range linear olefins via regioselective benzene alkylation. HF-treated mordenites, acidic Beta-zeolites, and fluorided montmorillonite clays, each provide enhanced shape-selective alkylation performance when employed as heterogeneous catalysts in the subject syntheses. Both individual C₈–C₁₂ -olefins, as well as mixed, commercial plant-derived, C₁₀ through C₁₄ paraffin dehydrogenate feedstocks containing ca. 8.5% internal olefins, have been successfully alkylated for extended periods using reactive distillation technology.