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Fourier transform infrared spectroscopy (FT-IR) and temperature programmed desorption mass spectrometry (TPD-MS) data of O-glycoside MDP in pristine and immobilized on silica surface states indicate that O-glycoside MDP binds to the silica surface by means of carboxylic and NH moieties of isoglutamine. Moreover, pyrolysis of O-glycoside MDP on the silica surface proceeds through formation of additional product 3-iminopyridine-2(3H)-one, which identified in mass spectra as molecular ion with m/z 108 and its fragment ions with m/z 79, 77, 51. FTIR and TPD-MS data confirm existence of a MDP first β-turn on the silica surface resulting from the formation of a hydrogen bond between the NAc carbonyl and the L-Ala NH for MDP and its analogs, as reported previously.

Lignin processing products have an extensive using range. Because products properties depend on lignin precursor quality it was interesting to study lignin isolated from rice husk being a large tonnage waste of rice production and its structural transformations during carbonization. Lignin isolated by the thermal hydrolysis method with H2SO4 1 wt % solution and its carbonized products prepared under different carbonization conditions were characterized using elemental analysis, IR, TPD-MS, XRD, TEM, and EPR. It was shown lignin degradation takes place over the wide (220&ndash, 520 &deg, C) temperature range. Silica presenting in lignin affects the thermal destruction of this polymer. Due to the strong chemical bond with phenolic hydroxylic group it decreases an evaporation of volatile compounds and as a result increases the temperature range of the lignin degradation. Rice husk hydrolytic lignin transformations during carbonization occur with generation of free radicals. Their concentration is decreased after condensation of aromatic rings with carbon polycycles formation, i.e., the graphite-like structure. Quantity and X-ray diffraction characteristics of the graphite-like phase depend on carbonization conditions. Morphology of the lignin-based carbonized products is represented by carbon fibers, carbon and silica nanoparticles, and together with another structure characteristics provides prospective performance properties of lignin-based end products.

Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability.

The interaction of acetic, propionic, butyric, isobutyric, valeric, nonanoic, decanoic, and pivalic acids with the surface of fumed silica was investigated by temperature-programmed desorption mass spectrometry (TPD–MS). Mechanisms of the formation of ketenes from chemisorbed fragments of carboxylic acids on the surface of fumed silica were proposed and the kinetic parameters of the reaction were calculated. The Taft correlation equation and the reaction parameter ρ could be obtained by application of the linear free energy relationship (LFER) principle for this reaction series. The applicability of the LFER method to the study of reactions of adsorbed organic molecules on mineral surfaces occurring during TPD–MS experiments was demonstrated using a series of acids.

Temperature-programmed desorption mass spectrometry was used to study the reaction of a series of primary amines (isobutylamine, isopentylamine, 1-pentylamine, 1-hexylamine, and 1-heptylamine) with a fumed silica surface. A mechanism was proposed and the kinetic parameters of the formation of alkenes from the chemisorbed aliphatic amine fragments on the silica surface were determined. A linear correlation was found between the activation energy and Taft constants for the substituents at the reaction site.

Pyrolysis of biologically active cinnamic acid derivatives: cinnamic, coumaric, ferulic and caffeic acids was studied by the method of thermal programmed desorption mass spectrometry. It was found that pyrolysis of coumaric and caffeic acid proceeds as a thermal decarboxylation reaction of the first order. Kinetic parameters of the reaction of decarboxylation including its order, the activation energy and pre-exponential factor were calculated. Under conditions of TPD MS experiment cinnamic acid sublimates at temperatures above 200 °C. Thermal decomposition of ferulic acid proceeds in several stages.

Curves representing the dependence of the pressure of volatile products formed in the destruction of chitin or chitosan on the thermolysis temperature were analyzed. The curves were obtained using temperature programmed desorption mass spectrometry. It was shown that the shape and positions of the maxima in the curves depend on the ratio of the numbers of pyranose rings bearing amine and acetamide groups in the polymer chain. A new approach was proposed for determining the deacetylation degree of chitin or chitosan based on the data of temperature programmed desorption mass spectrometry.

N-Acetylmuramyl- l -alanyl- d -isoglutamine or muramyl dipeptide is a cleavage product of peptidoglycan by lysozyme. This study explored the use of the temperature-programmed desorption mass spectrometry (TPDMS) in analysis of glycoside of muramyl dipeptide: O-{(4-tert-butylcyclohexyl)-2-acetamido-2,3-dideoxy-β- d -glucopyranoside-3-yl}- d -lactoyl- l -alanyl- d -isoglutamine (MDP) on the surface of fumed silica. Stages of pyrolysis of MDP in condensed state and on the silica surface have been determined. Three stages have been clear identified under pyrolysis of MDP on the silica surface. Kinetic parameters of thermal reactions on the fumed silica surface and in the condensed state have been calculated.

The interactions of bioactive ferulic acid with fumed silica were studied by UV/vis spectroscopy, FT-IR, TPD MS techniques and quantum chemical methods. It was found that surface complexes may form through phenol or carboxyl group of ferulic acid depending on its coverage value. The structure of surface complexes and mechanisms of the ferulic acid chemosorption on the silica surface are discussed. The kinetic parameters of the chemical reactions on silica surface are calculated. The mechanisms of thermal transformations of the ferulic chemosorbed surface complexes are proposed.

The interaction of cinnamic acid with the surface of highly dispersed silica is studied. The mechanisms of adsorption, chemisorption, and thermal transformations of cinnamic acid on the silica surface are proposed. The kinetic parameters of the chemical reactions on the surface of silica are calculated.

In this study, chemical transformations of benzyl ester of О-(phenyl-2-acetamido-2,3-dideoxy-1-thio-β-d-glucopyranoside-3-yl)-d-lactoyl-l-alanyl-d-isoglutamine (SPhMDPOBn) on the fumed silica surface were examined, and the surface complex structure was characterized by temperature-programmed desorption mass spectrometry (TPD-MS), infrared spectroscopy (FTIR) and electrospray ion trap mass spectrometry (ES IT MS). Stages of pyrolysis of SPhMDPOBn in pristine state and on the silica surface have been determined. Probably, hydrogen-bonded complex forms between silanol surface groups and the C = O group of the acetamide moiety NH-(CH3)-C = O…H-O-Si≡. The thermal transformations of such hydrogen-bonded complex result in pyrolysis of SPhMDPOBn immobilized on the silica surface under TPD-MS conditions. The shifts ∆ν of amide I band (measured from 1,626 to 1,639 cm(-l) for SPhMDPOBn in pristine state) of 33 and 35 cm(-l) which occurred when SPhMDPOBn was immobilized on the silica surface may be caused by a weakening of the intramolecular hydrogen bonding of the SPhMDPOBn because the interaction with the silica surface as hydrogen bond with silanol groups is weaker than that in associates.