The kinetics of the adsorption of lysozyme and bovine serum albumin (BSA) onto zeolites of BEA and MFI structural types and onto silica adsorbents of the same structural types was studied. The rate constants of the reversible adsorption step were calculated. The adsorption rate constants are 0.4–0.8 L mol–1 s–1 for lysozyme and 0.7–1.4 L mol–1 s–1 for BSA. The rate constants of the desorption from the surface of all the samples are in the range from 1.3 × 10–5 to 1.6 × 10–5 s–1 for both enzymes.

One-step gas-phase synthesis of butadiene from formaldehyde and propylene on aluminum (AlP), zirconium (ZrP), and niobium (NbP) phosphates with the pore volumes of 0.51, 0.25, and 0.19 cm3/g, respectively, was studied for the first time. The physicochemical properties of the catalysts were studied by X-ray fluorescence analysis, low-temperature nitrogen adsorption, X-ray diffraction analysis, scanning electron microscopy, temperature-programmed NH3 desorption, IR spectroscopy of adsorbed pyridine, and 31Р MAS NMR. Evaluation of the catalytic properties of the phosphates showed that they can be ranked in the following order with respect to the formaldehyde conversion and target product (butadiene) formation selectivity: AlP < ZrP < NbP, which correlates with metal electronegativity series. The СН2О conversion on the most active NbP was 4.5

Thermodynamic characteristics of adsorption of different classes of organic compounds on nanoporous silicas with chemically grafted methylsiloxane have been determined by gas chromatography. It was shown that an increase in the concentration of grafted groups from 1.5 to 1.7 nm –2 leads to an increase in the Henry’s constants and heats of adsorption and, as a rule, to a decrease in the standard entropies of adsorption. With respect to arenes, the polarity of the samples is practically the same as that of the liquid phase OV-1. The set of gas chromatographic and static data on vapor adsorption, taking into account the values ​​of the contact angles of wetting with water and hexadecane for similar monolayers fixed on silicon wafers, allows us to conclude that the degree of lyophobization of the surface of the methylsiloxane layers is significantly higher than that of the hexadecyl layers, but inferior to that of the polyfluoroalkyl layers.

Features of the benzene adsorption in polyfluoroalkyl layers of different structures grafted on surfaces of silica gel (SG) are studied using gas chromatography, static adsorption, and diffuse reflectance IR spectroscopy. After modification, Henry’s law constants determined from the gas chromatography data and the static benzene adsorption values fall in the order SG > SG–F(III) > SG–F > SG–iso-F(III), where samples SG–F(III), SG–F, and SG–iso-F(III) are produced using silanes n‑C6F13(CH2)2SiCl3, n‑C6F13(CH2)2Si(CH3)2Cl, and iso-C3F7(CH2)2SiCl3, respectively. It is found that the energy characteristics of adsorption of benzene and other hydrocarbons on the SG–F(III) sample with the linear trifunctional modifier are 3–7 kJ/mol higher than the respective characteristics determined on the initial support. The contact angles for nanoporous silica gels with polyfluoroalkyl layers are calculated from desorption data in the region of the capillary condensation hysteresis of the benzene adsorption isotherms.

The dependence of the thermodynamic characteristics of adsorption of various classes of organic compounds on the chemical nature of the silica surface modified with 3-bromopropyltrichlorosilane to form a monolayer coating (Br-2 sample), a grafted polymer type layer (Br-5 sample), and additionally silanized layer (Br-5* sample) was studied by gas chromatography. The dispersion interactions on bromosilicas were more active than on the starting support or the NH2 sample with a grafted aminopropyl layer of the polymer type. The role of specific interactions generally decreases in the series Br-2 > Br-5 > Br-5* > NH2. An analysis of the obtained data indicates that the retention mechanism on silicas with bromopropyl groups is determined by the penetration of adsorbed molecules into the grafted layer. In contrast, the aminopropyl polymer layer has a more rigid structure with limited conformational mobility of the grafted aminopropyl groups, the adsorption retention mechanism dominating in this case.

The results from studying the physicochemical characteristics of the adsorption of n-alkanes, arenes, and acetonitrile on silicas of different origins, silica gels, and silochromes are presented. It is shown that increasing the concentration of silanol groups reduces the role of dispersion interactions accompanied by the intensification of specific interactions on silica gels, compared to silochromes. According to diffuse reflectance FTIR spectroscopy data, the acidity of silanol groups on silica gel is in this case less pronounced.

Surface properties of silica gels modified by trifunctional polyfluorosilanes n -C 6 F 13 (CH 2 ) 2 SiCl 3 and iso -C 3 F 7 (CH 2 ) 2 SiCl 3 are studied using the methods of adsorption and gas chromatography with respect to nitrogen, hydrocarbon, and water molecules. It is shown that the branched structure of the grafted group and high concentration of grafted groups (2.7 nm –2 ) provide better screening of both residual silanols of the support and of additional hydroxyl groups formed in the course of synthesis as a result of hydrolysis. Comparison with the properties of silica gel with grafted monofunctional silane n -C 6 F 13 (CH 2 ) 2 Si(CH 3 ) 2 Cl shows that, in the case of an overall decrease in the adsorption values and considerable surface lyophobization, modification by trifunctional silanes irrespective of the modifier chain length allows obtaining adsorbents containing more polar centers than those in silica gel due to the possible participation in adsorption of additional silanols and a polar fragment of the grafted chain of–CH 2 –CF 2 –. A considerable difference in the course of isotherms of nitrogen and hexane adsorption–desorption is found in the range of capillary condensation hysteresis related to liophobicity of polyfluoroalkyl layers, a significant decrease in the pore wetting and the corresponding increase in wetting angle θ by hexane. Adsorption of water on fluorinated silicas is negligible and capillary condensation is not observed due to nonwettability of the pore surface by liquid adsorbate (θ > 90°).

Interaction between vapors of organic compounds and water with surfaces of mesoporous silica SBA-15 and silica SBA-15 modified with n-C6F13(CH2)2Si(CH3)2Cl via adsorption under static conditions is studied by means of gas chromatography and IR diffuse reflectance spectroscopy. It is shown that modification notably reduces the energy of disperse and specific interactions, along with the acidity of adsorption centers. Even low concentrations of the grafted groups (0.76 nm–2) allows us to obtain highly hydrophobic coatings on SBA-15 surfaces.

Using the static method and gas chromatography, the adsorption of nitrogen and hydrocarbons by SBA-15 silicas and commercially available silica gel (SG), as well as changes in the surface properties of these samples as a result of chemical modification with multifunctional perfluorohexylsilane ClSi(CH3)(2)(CH2)(2)(n-C6F13), are studied. The main factor that causes the high values of thermodynamic characteristics of adsorption on SBA-15 and its modified form is a relatively small pore size. The differences in the polarities of the samples testify to a high concentration of silanol groups on the initial and modified SG.

For lyophobic porous surfaces, structural analysis by vapor adsorption is complicated due to weak adsorbate-adsorbent interactions and limited wetting of the pores (nonzero contact angles). To investigate further, adsorption isotherms of three distinct adsorbates (nitrogen - 77 K, n-hexane and benzene - 298 K) were studied for SBA-15 ordered mesoporous silica where the surface was functionalized with lyophobic perfluoroalkyl groups (C6F13 termini). The results demonstrated a clear advantage of the combined use of the adsorption isotherms of less surface sensitive (nitrogen) and more surface sensitive (hydrocarbons) adsorbates. The adsorption of nitrogen provided basic structural characteristics like surface area, pore volume, and pore size distribution, while the isotherms of benzene and n-hexane were used to characterize wetting (contact angles) and surface energy of the C6F13 surfaces within the pores. For the first time, the statistical film thickness for nitrogen, benzene, and n-hexane are being reported for the adsorption on fluorinated surfaces, thereby providing critical data for the pore size and the contact angle determination of the lyophobic materials.