Properties of reaction products of hydroxymethylated 2-substituted 4,6-diamino-s-triazines with cotton

A study has been made of the reaction products of hydroxymethylated 2-substituted (X) 4,6-diamino-s-triazines (MXT) with cotton fabrics in the presence of zinc nitrate as catalyst. The reagents used were MXT having the following substituents: methoxy (MMT), isopropoxy (MIPT), methyl (acetoguanamine) (MAG), monoethylamino [N-(2-ethyl)melamine] (MEM), monohydroxyethylamino [N-(2-hydroxyethyl)melamine] (MHEM), and dihydroxyethylamino [N,N-bis(2-hydroxyethyl)melamine] (MBHEM) groups. Trimethylolmelamine (TMM), dimethylolurea (DMU), dimethylolethyleneurea (DMEU), and dimethylolethyltriazone (DMET) were also used for comparison. The molar ratio of total formaldehyde to 2-substituted 4,6-diamino-s-triazine (XT) residue in treated fabrics is larger in high-temperature curing than in low-temperature curing. In case of curing at 150°C for 5 min, MHEM and MBHEM crosslinked primarily with cellulose in a monomeric state, and the others in a oligomeric state. From these facts, the crosslinked structures were presumed. Infrared absorption spectra of the fabrics treated with MXT are discussed and a few physical properties of the fabrics are compared with those of the fabrics finished with TMM, DMU, DMEU, and DMET.     

Preparation and properties of polyethylene/montmorillonite nanocomposites formed via ethylene copolymerization

BACKGROUND: In situ formation of polyethylene/clay nanocomposites is one of the prevalent preparation methods that include also solution blending and melt blending with regard to process simplification, economy in cost, environment protection and marked improvement in the mechanical properties of the polymeric matrix. In the work reported here, the preparation of linear low‐density polyethylene (LLDPE) and fabrication of polymer/clay nanocomposites were combined into a facile route by immobilizing pre‐catalysts for ethylene oligomerization on montmorillonite (MMT). RESULTS: [(2‐ArN?C(Me))₂C₅H₃N]FeCl₂ (Ar = 2,4‐Me₂(C₆H₃)) was supported on MMT treated using three different methods. The MMT‐supported iron complex together with metallocene compound rac‐Et(Ind)₂ZrCl₂ catalyzed ethylene to LLDPE/MMT nanocomposites upon activation with methylaluminoxane. The oligomer that was formed between layers of MMT promoted further exfoliation of MMT layers. The LLDPE/MMT nanocomposites were highly stable upon heating. Detailed scanning electron microscopy analysis revealed that the marked improvement in impact strength of the LLDPE/MMT nanocomposites originated from the dispersed MMT layers which underwent cavitation upon impact and caused plastic deformation to absorb most of the impact energy. In general, the mechanical properties of the LLDPE/MMT nanocomposites were improved as a result of the uniform dispersion of MMT layers in the LLDPE matrix. CONCLUSION: The use of the MMT‐supported iron‐based diimine complex together with metallocene led to ethylene copolymerization between layers of MMT to form LLDPE/MMT nanocomposites. The introduction of exfoliated MMT layers greatly improved the thermal stability and mechanical properties of LLDPE. Copyright © 2009 Society of Chemical Industry     

Activity of Laccase Immobilized on TiO2-Montmorillonite Complexes

The TiO₂-montmorillonite (TiO₂-MMT) complex was prepared by blending TiO₂ sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO₂-MMT calcined at 800 °C (TiO₂-MMT800) were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO₂-MMT, and TiO₂-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO₂ nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the “d value” of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO₂-MMT complexes had a good affinity to the substrate. It has been proved that TiO₂-MMT complex is a good candidate for enzyme immobilization.     

PE/OMMT nanocomposites prepared by in situ polymerization approach: Effects of OMMT‐intercalated catalysts and silicate modifications

In this article, the surfactants, (2‐hydroxylethyl) octadecyl dimethylammonium nitrate (OH‐C18), hexadecyltrimethylammonium bromide(C16), and mixture of trimethylchlorosilane (TM) and OH‐C18 were ion‐exchanged with cations in the montmorillonite (MMT) to generate three organic MMTs (named as OH‐C18‐MMT, C16‐MMT, and MMMT), leading to different environments of catalyst species in MMT interlayer gallery. Et[Ind]₂ZrCl₂ (abbreviated as EI) was supported on the above three types of OMMTs to prepare the PE/OMMT nanocomposites via in situ polymerization. By contrast, EI/MMMT showed higher activity than EI/OH‐C18‐MMT and EI/C16‐MMT under the same polymerization conditions. The other two types of catalysts, such as [(tert‐Bu)NSi(Me₂)C₅Me₄]TiCl₂ (CGCT) and Bis[N‐(3‐tert‐butylsalicylidene)anilinato] titanium (IV) dichloride (FI) were also supported on the OH‐C18‐MMT for in situ ethylene polymerization. It was found that the activity of FI/OH‐C18‐MMT for ethylene polymerization was much lower than the other two corresponding catalysts under the similar reaction conditions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of montmorillonite on syndiotactic polymerization behavior of styrene

The influence of montmorillonite (MMT) on the syndiotactic polymerization behavior of styrene was studied. To avoid the hydrophilic surface of the MMT coming into contact with the catalyst, which could poison it, SAN was introduced between the MMT and Cp*Ti (OCH₃)₃. MMT was introduced into the catalytic system as a supporter for the Ti catalyst (supported catalytic system) or just dispersed in the polymerization solvent directly (in situ polymerization system). The polymerization results showed that surface modification of MMT dramatically affected the catalytic activity as well as the syndiotacticity of the polymers. This is mainly explained by the insulator SAN preventing the formation of the inactive/little active species Si? O? Ti and other atactic active species resulting from the reaction of the ? OH on the MMT layer surface with Cp*Ti(OCH₃)₃. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Critical temperature for production of MAG by esterification of different FA with glycerol using <Emphasis Type="Italic">Penicillium camembertii</Emphasis> lipase

Production of MAG by a lipase-catalyzed reaction is known to be effective at low temperature. This phenomenon can be explained by assuming that synthesized MAG are excluded from the reaction system because MAG, which have low m.p., are solidified at low temperatures. Consequently, MAG are efficiently accumulated and do not serve as the precursor of DAG. If this hypothesis is correct, the critical temperature for MAG production, defined as the highest temperature at which DAG synthesis is repressed, should depend on the m.p. of the MAG. Esterification of FFA with glycerol using Candida rugosa, Rhizopus oryzae, and Penicillium camembertii lipases produced MAG efficiently at low temperatures. However, Candida lipase showed very low esterification activity at high temperatures (>20°C), and Rhizopus lipase produced not only MAG but also DAG even at low temperatures. Meanwhile, P. camembertii lipase catalyzed synthesis of MAG only from FFA and glycerol at low temperatures, although the enzyme catalyzed synthesis of DAG from MAG in addition to synthesis of MAG at high temperatures. We thus studied the effect of temperature on esterification of C₁₀−C₁₈ FFA with glycerol using Penicillium lipase as a catalyst and determined the critical temperatures for production of MAG. The critical temperature for production of each MAG showed a linear correlation with m.p. of the MAG, which supported the hypothesis. In addition, because the m.p. of MAG are estimated from that of the constituent FA, the optimal temperature for production of MAG can be predicted from the m.p. of the FFA used as a substrate.     

Montmorillonite intercalated with vitamin B1 as drug carrier

Vitamin B₁ (thiamine hydrochloride, VB₁) intercalated into montmorillonite (MMT), which was characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), and thermo gravimetric analysis (TGA). The adsorption of VB₁ on MMT increased with increase in reaction temperature. The adsorption isotherms were fitted by the Langmuir model. About 34 and 64% of the intercalated VB₁ was released within 10 h, in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) respectively at 37 ± 0.5 °C. The release profile of VB₁ followed the Higuchi kinetic model and the diffusion-controlled mechanism. During in vitro release experiments VB₁ was released from MMT–VB₁ steadily as a function of pH.     

Preparation and evaluation of nanocomposites of polyfuran with Al2O3 and montmorillonite clay

High yield oxidative polymerization of furan was accomplished in CHCl₃ solvent at 0 °C. A nanocomposite of polyfuran (PF)–Al₂O₃ was prepared through polymerization of furan in a suspension of nanodimensional Al₂O₃ in CHCl₃ at 0 °C. High yield polymerization of furan was also achieved in montmorillonite clay (MMT) without any extraneous oxidant. The formation of PF was confirmed by FTIR and elemental analysis. Thermogravimetric analyses revealed the following trends in thermal stability: PF < PF–Al₂O₃ < Al₂O₃ and PF < PF–MMT < MMT. Scanning electron microscopy showed the average particles sizes to be ca 51 nm and ca 40 nm for PF–Al₂O₃ and PF–MMT composites, respectively. The occurrence of a peak at 19.84 Å in the X‐ray diffraction pattern of the PF–MMT composite was indicative of the intercalation of PF in MMT lamellae. Transmission electron microscopic analyses for the PF–MMT composite also showed incorporation of PF moieties in‐between the MMT layers. The dc conductivity values (S cm^?1) of PF–FeCl₃, PF–Al₂O₃–FeCl₃, PF–MMT and PF–MMT–FeCl₃ systems were in the order of 10^?6, 10^?7, 10^?8 and 10^?7, respectively, and the values were significantly enhanced compared to the dc conductivity value of PF homopolymers (10^?11). Copyright © 2004 Society of Chemical Industry     

Synthesis and antimicrobial activity of biocidal polymer–montmorillonite nanocomposites

The bioactive agents p‐hydroxymethylbenzoate, 2,4‐dihydroxymethylbenzoate and methylsalicylate were reacted with polyoxyalkylene (D_230–2000)–montmorillonite (MMT) intercalated nanocomposites. D_230–2000–MMT were prepared by an ion exchange process of Na‐MMT and? NH₃⁺ groups in polyoxyalkylene amine hydrochloride of three different molecular masses (D₂₃₀, D₄₀₀ and D₂₀₀₀). The results of X‐ray analysis and transmission electron microscopy show that D₂₀₀₀–MMT/p‐hydroxymethylbenzoate is an exfoliated nanocomposite, whereas in D₂₃₀–MMT/p‐hydroxymethylbenzoate, D₂₃₀–MMT/2,4‐dihydroxymethylbenzoate, D₂₃₀–MMT/methylsalicylate and D₄₀₀–MMT/p‐hydroxymethylbenzoate, having lower molecular mass and polymer loading, the MMT rearranges in an intercalated and flocculated structure. The amount of intercalated polymer and interaction between polymer and layered silicate were determined using thermogravimetric analysis and Infrared spectroscopy. The antimicrobial activities of the nanocomposites were qualitatively and quantitatively assessed by agar diffusion tests and minimal inhibitory concentration values against a Gram‐negative bacterium (Escherichia coli NCIM 2065), a Gram‐positive bacterium (Bacillus subtilis ATCC) and fungi (Candida albicans SC5314 and Cryptococcus neoformans). The D₂₀₀₀–MMT/p‐hydroxymethylbenzoate nanocomposite strongly inhibits the growth of all the micro‐organisms tested. The diameter of the inhibition zone varies according to the type of micro‐organism tested. The effect of nanocomposite concentration on morphology, respiration and release of calcium, potassium and sodium ions of the test micro‐organisms was examined. Copyright © 2011 Society of Chemical Industry     

Gelatin/montmorillonite hybrid nanocomposite. I. Preparation and properties

Gelatin/montmorillonite (MMT) hybrid nanocomposite was directly prepared with unmodified MMT and gelatin aqueous solution. Thermal and mechanical properties of the composite were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests. The results indicated that an intercalated or partially exfoliated nanocomposite could be achieved, and the properties of the composite were significantly improved. A T_g peak of high temperature disappeared in the DSC curve of the composite, and the thermogravity and thermally decomposed rate decreased obviously. The tensile strength and Young's modulus were also improved notably, which varied with MMT content, as well as the pH of gelatin matrix. Meanwhile, SEM photographs showed a plasticizing trend of gelatin fracture surface due to intercalation with MMT. Furthermore, the wet mechanical behavior was initially studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1189–1194, 2002     

Crystallization kinetics of poly (L‐lactic acid)/montmorillonite nanocomposites under isothermal crystallization condition

Poly(L ‐lactic acid)/o‐MMT nanocomposites, incorporating various amounts of organically modified montmorillonite (o‐MMT; 0–10 wt %), were prepared by solution intercalation. The montmorillonite (MMT) was organically modified with dilauryl dimethyl ammonium bromide (DDAB) by ion exchange. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) reveal that the o‐MMT was exfoliated in a poly(L ‐lactic acid), (PLLA) matrix. A series of the test specimens were prepared and subjected to isothermal crystallization at various temperatures (T₁–T₅). The DSC plots revealed that the PLLA/o‐MMT nanocomposites that were prepared under nonisothermal conditions exhibited an obvious crystallization peak and recrystallization, but neat PLLA exhibited neither. The PLLA/o‐MMT nanocomposites (2–10 wt %) yielded two endothermic peaks only under isothermal conditions at low temperature (T₁), and the intensity of Tm₂ (the higher melting point) was proportional to the o‐MMT content (at around 171°C). The melting point of the test samples increased with the isothermal crystallization temperature. In the Avrami equation, the constant of the crystallization rate (k) was inversely proportional to the isothermal crystallization temperature and increased with the o‐MMT content, especially at low temperature (T₁). The Avrami exponent (n) of the PLLA/o‐MMT nanocomposites (4–10 wt %) was 2.61–3.56 higher than that of neat PLLA, 2.10–2.56, revealing that crystallization occurred in three dimensions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Structural characterization of hydrophilic polymer blends/montmorillonite clay nanocomposites

The nanocomposite films comprising polymer blends of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), poly(ethylene oxide) (PEO), and poly(ethylene glycol) (PEG) with montmorillonite (MMT) clay as nanofiller were prepared by aqueous solution casting method. The X‐ray diffraction studies of the PVA–x wt % MMT, (PVA–PVP)–x wt % MMT, (PVA–PEO)–x wt % MMT and (PVA–PEG)–x wt % MMT nanocomposites containing MMT concentrations x = 1, 2, 3, 5 and 10 wt % of the polymer weight were carried out in the angular range (2θ) of 3.8–30°. The values of MMT basal spacing d₀₀₁, expansion of clay gallery width W_cg, d‐spacing of polymer spherulite, crystallite size L and diffraction peak intensity I were determined for these nanocomposites. The values of structural parameters reveal that the linear chain PEO and PEG in the PVA blend based nanocomposites promote the amount of MMT intercalated structures, and these structures are found relatively higher for the (PVA–PEO)–x wt % MMT nanocomposites. It is observed that the presence of bulky ester‐side group in PVP backbone restricts its intercalation, whereas the adsorption behavior of PVP on the MMT nanosheets mainly results the MMT exfoliated structures in the (PVA–PVP)–x wt % MMT nanocomposites. The crystallinities of the PEO and PEG were found low due to their blending with PVA, which further decreased anomalously with the increase of MMT concentration in the nanocomposites. The decrease of polymer crystalline phase of these materials confirmed their suitability in preparation of novel solid polymer nanocomposite electrolytes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40617.     

Preparation and photocatalytic activity of silver and TiO2 nanoparticles/montmorillonite composites

Ag–TiO₂/montmorillonite (Ag–TiO₂/MMT) was synthesized as photocatalyst using TiCl₄ hydrolysis to introduce nanosized TiO₂ into the interlayer space of the montmorillonite (MMT). Stable pillared TiO₂/MMT was obtained by calcination at 500 °C, then silver was loaded by reduction of silver nitrate. The physico–chemical properties of the photocatalyst were determined by X-ray diffraction (XRD), infrared spectroscopy (IR), atomic absorption spectrophotometer (AAS), nitrogen gas adsorption (BET method) and UV–Visible spectra. The photooxidation activity for methylene blue (M.B.) degradation was as follows: Ag–TiO₂/MMT > TiO₂/MMT > TiO₂(P25). Among them Ag–TiO₂/MMT had the highest photooxidation activity because of its larger specific surface caused by pillaring and loading of silver for improving its light absorption.     

Preparation and photocatalytic activity of silver and TiO2 nanoparticles/montmorillonite composites

Ag–TiO₂/montmorillonite (Ag–TiO₂/MMT) was synthesized as photocatalyst using TiCl₄ hydrolysis to introduce nanosized TiO₂ into the interlayer space of the montmorillonite (MMT). Stable pillared TiO₂/MMT was obtained by calcination at 500 °C, then silver was loaded by reduction of silver nitrate. The physico–chemical properties of the photocatalyst were determined by X-ray diffraction (XRD), infrared spectroscopy (IR), atomic absorption spectrophotometer (AAS), nitrogen gas adsorption (BET method) and UV–Visible spectra. The photooxidation activity for methylene blue (M.B.) degradation was as follows: Ag–TiO₂/MMT > TiO₂/MMT > TiO₂(P25). Among them Ag–TiO₂/MMT had the highest photooxidation activity because of its larger specific surface caused by pillaring and loading of silver for improving its light absorption.     

Rheology of PVAc–MMT–STAB

Polyvinyl acetate (PVAc) is considered to be an acceptable environmental friendly adhesive, and montmorillonite (MMT) is a cheap and accessible natural nano-mineral. In this work, MMT was first organically activated by octadecyl trimethyl ammonium bromide (STAB). The intercalated nano-composite, MMT–STAB, was then polymerized with VAc. The influence of various additions of MMT–STAB on the rheology of PVAc–MMT–STAB was analysed using the power-law function equation and the Cross–Williamson model viscous equation. The results showed that MMT–STAB was able to improve the rheology of PVAc. The PVAc and PVAc–MMT–STAB all were pseudo-plastic non-Newtonian fluids, with a flow index (i) of 0.93. The apparent viscosity (η), fluid consistency (Ï), characteristic time of materials (ζ), zero shear viscosity (η ₀), weight average molecular weight (M _w), number average molecular weight ( M _n) and the solid content (O), all increased with increasing additions of MMT–STAB as a result of the polymerization process. All properties, apart from ζ, showed a maximum with the addition of 2.0 wt%. The limiting viscosity (η _∞) was 0 mPa s for all samples of PVAc or PVAc–MMT–STAB. Their storage stability was found to be excellent. The reasonable addition of MMT–STAB in polymerization was found to be no more than 2.0 wt% of VAc. In addition, both PVAc and PVAc–MMT–STAB exhibited the normal stress effect (or Weissenberg effect), also known as the 'pole-climbing phenomenon'.     

Ultra-deep hydrodesulfurization on MoS2 and Co0.1MoS2: Intrinsic vs. environmental factors

A hydrogenation index (HI), measured in the hydrodesulfurization (HDS) of dibenzothiophene (DBT), is used to estimate the intrinsic hydrogenation selectivities of MoS₂, Co_0.1MoS₂, and two supported HDS catalysts. The HI and catalyst activity for desulfurizing 4,6-diethyl-DBT follow the same trend: MoS₂ ? Co_0.1MoS₂ ? supported catalysts. For desulfurizing a petroleum fraction rich in 4,6-alkyl-DBTs and 4-alkyl-DBTs, the activity decreases as follows: Co_0.1MoS₂ > supported catalysts ? MoS₂. These results introduce an apparent conundrum: MoS₂ has such a high hydrogenation power and activity for desulfurizing 4,6-diethyl-DBT, why does it perform poorly in real-feed tests? This conundrum is resolved by showing that an ultra-deep HDS catalyst requires an optimum balance between an intrinsic factor (hydrogenation function) and an environmental factor (tolerance of organonitrogen). Incorporating Co into MoS₂ lowers the hydrogenation function of MoS₂ and hence improves tolerance of organonitrogen. This conclusion corroborates the prediction of an early modeling study.     

Well-defined sterically hindered zinc aryloxides: Excellent catalysts for ring-opening polymerization of ?-caprolactone and l-lactide

Three novel sterically hindered zinc aryloxides have been prepared and well characterized. Their catalytic activities toward ring-opening polymerization (ROP) of ?-caprolactone and l-lactide have been investigated. The reaction of 2,2′-ethylidene-bis(4,6-di-tert-butylphenol) (EDBP-H₂), 2,2′-(2-methoxybenzylidene)bis(4-methyl-6-tert-butylphenol) (MEBBP-H₂) and 2,2′-(2-methoxybenzylidene)bis(4,6-di(1-methyl-1-phenylethyl)phenol) (MEMPEP-H₂) with ZnEt₂ in THF yields dimeric zinc complexes [(μ-EDBP)Zn(THF)]₂ (1), [(μ-MEBBP)Zn(THF)]₂ (2) and [(μ-MEMPEP)Zn(THF)]₂ (3), respectively. Experimental results show that all three compounds are good catalysts for ROP of ?-caprolactone and l-lactide yielding polymer in a controlled fashion with low polydispersity indexes.     

Recovery of uranium by tannin immobilized on matrices which have amino group

Tannin, which contains polyhydroxy groups, has a high affinity for uranium. Various tannin–protein complexes were prepared to develop new adsorbents for uranium recovery from seawater. Albumin tannate has a high ability to adsorb uranium from seawater. Tannin was immobilized on matrices which have multiple active amino groups, such as aminopolystyrene and poly(vinyl-4,6-diamino-s-triazine)—poly VT. Of these complexes, tannin immobilized on poly VT adsorbed uranium most efficiently from seawater and highly selectively from a solution containing various heavy metals; the uranium adsorption was very rapid and was pH dependent. This adsorbent therefore appears to have potential for use in a commercial process for uranium recovery from seawater or from uranium-containing waste water.     

Preparation and characterization of crosslinked and heat-treated PVA-MA films

Two kinds of water-insoluble PVA-MA hydrogel films were prepared from PVA-MA, an esterification product of poly(vinyl alcohol) and maleic anhydride, by heat treatment and a crosslinking reaction, respectively. Both films changed their dimensions upon environmental pH changes. The crosslinked gel expanded to approximately 230% of its original length, with most changes occurring in the pH range of 2–7. The heat-treated PVA-MA film swelled stepwisely, with about 45% of the total expansion occurring at pH 2–7 and the remaining 55% at pH 9–12. Results from IR spectra analysis and acid-base titration suggest that the ionization of carboxylic acid accounts for the pH-induced gel swelling irrespective of the differences in the swelling behavior of these two gels. The pK_a values of the heat-treated PVA-MA gel increased from 4 to 10 while the degree of dissociation varied from 0 to 80%, whereas that of the crosslinked PVA-MA film is limited in a range of 3.3–4.2. The permeability of glucose across the crosslinked PVA-MA film increased when pH was raised from 2 to 7. No significant change of permeability was noticed between pH 7 and 12. For the heat-treated PVA-MA film, glucose permeability increased when pH was changed from 2 to 7 and from 7 to 12. © 1996 John Wiley & Sons, Inc.     

Upgrading of gas oils: the HDS kinetics of dibenzothiophene and its derivatives in real gas oil

The hydrodesulphurization (HDS) of dibenzothiophene (DBT), 4-methyl dibenzothiophene (4 M-DBT), 4,6-dimethyl dibenzothiophene (4,6 DM-DBT) and 4,6-diethyl dibenzothiophene (4,6 DE-DBT) as real gas oil components on NiMo/Al₂O₃ catalyst was investigated. On the basis of the first order rate constants of HDS of the individual sulphur compounds reactivities of the investigated compounds decreased in the order DBT ≫ 4 M-DBT > 4,6 DE-DBT ≈ 4,6 DM-DBT. Apparent activation energies of HDS of above sulphur compounds increased from 80.0 to 120.5 kJ/mol.