New oxo acids of the seed oil ofGaleopsis bifida

Oxoacylglycerols have been isolated from the lipids of the seeds ofG. bifida that contain in any of the three positions of the molecule a set of the 9(10)-oxo-18:0, 12-oxo-9-18:1, 9(10)-oxo-10(8)-18:1, 9-oxo-10,12-18:2, and 12(13)-oxo-9,13,15-(9,11,15)-18:3 acids.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 286–291, May–June, 1984.     

Epoxy and hydroxy acids of the seed oil ofGaleopsis bifida

The lipids of the seeds of the hemp nettle, which is toxic for ruminants have been studied. The composition of the fatty acids of five classes of lipids and the position-species composition of the triacylglycerols have been determined. The presence of epoxyacyl- and hydroxyacylglycerols in the oil and the structures of the acids of these lipids have been established. Squalene has been isolated from the oil.     

Hydroxy acids of the reserve lipids of Galeopsis bifida

The structures of fatty monohydroxy acids of the lipids of the seeds ofGaleopsis bifida Boenn. have been studied by the methods of chromatographic, spectral, and chemical analysis. (31) Acids with chain lengths of from 14 to 20 carbon atoms, with from 0 to 3 double bonds, and with the hydrolyls in positions characteristic for the products of the direct hydroxylation and the lipoxygenase and photosensitized oxidation of unsaturated fatty acids were detected. Of them, the 13-OH-9Z, 11E-17:2, the 15-OH-9, 12-18:2, the 16-OH-9, 12-18:2, and 17-OH-11, 14-20:2 acids were new, while this is the first time that the 15-OH-9Z, 12Z, 16E-18:3 acid has been described as a natural compound. The behavior of the TMS derivatives of the hydroxy acids on a polyester phase in GLC is discussed.Institute of the Chemistry of Plant Substances, Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 744–753, November–December, 1991.     

Hydroxy acids of the reserve lipids of Galeopsis bifida

The structures of fatty monohydroxy acids of the lipids of the seeds ofGaleopsis bifida Boenn. have been studied by the methods of chromatographic, spectral, and chemical analysis. (31) Acids with chain lengths of from 14 to 20 carbon atoms, with from 0 to 3 double bonds, and with the hydrolyls in positions characteristic for the products of the direct hydroxylation and the lipoxygenase and photosensitized oxidation of unsaturated fatty acids were detected. Of them, the 13-OH-9Z, 11E-17:2, the 15-OH-9, 12-18:2, the 16-OH-9, 12-18:2, and 17-OH-11, 14-20:2 acids were new, while this is the first time that the 15-OH-9Z, 12Z, 16E-18:3 acid has been described as a natural compound. The behavior of the TMS derivatives of the hydroxy acids on a polyester phase in GLC is discussed.     

New trends in creation of epoxy adhesives

Modern trends in development of production of epoxy adhesives with the purpose of obtaining high-strength, waterproof, and high-temperature adhesives are described. Such adhesives are developed and manufactured at ZAO ENPTs EPITAL based on the epoxy-diane and cycloalphatic epoxy resins. The modified aromatic amines, aromatic polyaminoamides, alkylamino phenols, as well as original curing systems are used as curing agents.     

Highly efficient separation of isomeric epoxy fatty acids by micellar electrokinetic chromatography

A capillary electrophoresis (CE) method has been developed for simple and direct separation of cis- and trans-12,13-epoxy-9(Z)-octadecenoic acid and 9,10-epoxy-12(Z)-octadecenoic acid isomers. Separation was performed in micellar electrokinetic capillary chromatography (MEKC) using a buffer consisting of 25 mM borate (pH 9.20), 10 mM sodium dodecyl sulfate (SDS) and 10% v/v acetonitrile. The key variables, concentrations of SDS and organic modifier, were optimized by the application of a factorial experimental design. The use of a low micellar concentration, just above critical micelle concentration (CMC), in a background electrolyte containing an organic modifier not only made it possible to dissolve and separate highly hydrophobic fatty acid isomers, but also resulted in improved separation efficiency and selectivity. Separation efficiency up to 4 x 10(5) theoretical plates/m was achieved under an optimized condition. Also investigated were the influence of temperature on separation and the effect of organic modifier concentration on the dynamic exchange of the analytes between micelles and the bulk of the buffer solution. Direct UV was applied for detection of the fatty acids.     

New waterborne epoxy coatings based on cellulose nanofillers

New nanocomposites based on a waterborne epoxy emulsion and a suspension of cellulose crystallites were prepared by film casting in order to obtain coatings displaying both flexibility and stiffness. Tunicin cellulose whiskers are attractive reinforcing fillers due to their high aspect ratio, large interface area, and, significant mechanical properties). Typical processing problems for this type of composite are related to high viscosity values of filled polymers in the in the molten state, the incompatibility between hydrophobic matrices and hydrophilic cellulose and the formation of hydrogen bonds between cellulose of this type of natural fibres in an epoxy matrix. The aim of this work is to solve some of the problems above mentioned by selecting the nature of the components used for coating synthesis film processing. The dynamic mechanical properties display an important improvement of the composite modulus in the rubbery state of the matrix at low concentrations of fillers, which can not be expected other cellulose based fibers.     

New approaches to reversible crosslinking in epoxy resins

The objective of the research is to investigate epoxy resins where crosslinks formed in curing reactions can be cleaved and reformed without significant sacrifice in resin properties. Experimental disulfide-containing crosslinking agents have been selected for the study, including dihydrazides of dithiodicarboxylic acids (aliphatic and aromatic) and dithioaromatic diamines. Conditions for curing reactions and for subsequent cleavage of crosslinks by reduction have been determined in model systems and confirmed for a prototype epoxy resin. A comparative evaluation of cure kinetics, crosslink density, and thermal and mechanical properties has been carried out for resin cured with aromatic curing agents (dithiodianiline and methylenedianiline) and with aliphatic compounds (3, 3′-dithiopropionic acid dihydrazide and hexamethylenediamine). It has been shown that in resin fully cured with disulfide-containing crosslinking agents, crosslinks are ruptured by reduction, and re-established by oxidation under mild conditions, or by reaction of thiol groups with bifunctional alkylating agents.     

New curing agents for epoxy resins: protoporphyrins

Two similar macrocycles protoporphyrin IX and zinc protoporphyrin IX (ZPP) have been used as cross‐linking agents for curing the epoxy resin of bisphenol A diglycidyl ether (BADGE, n = 0). The enthalpies and the activation energies of the esterification reaction of the 2 systems are very close to each other. However, the temperature of the minimum in the differential scanning calorimetry thermogram is 38°C lower for BADGE (n = 0)/ZPP, thus requiring a less energy expenditure for curing the system. By the contrary, the enthalpy and activation energies for the etherification reaction are lower and higher, respectively, for BADGE (n = 0)/ZPP suggesting that the zinc ion affects it, although the involved mechanism is unknown.     

New carborane-containing acids and amines

Alkylation of nido-carborane methyl sulfide derivative [9-MeS-7,8-C₂B₉H₁₁]^– was used to synthesize a series of new carborane-containing acids 9-HOOC(CH₂) _n (Me)S-7,8-C₂B₉H₁₁ (n = 1—4) and amines 9-H₂N(CH₂) _n (Me)S-7,8-C₂B₉H₁₁ (n = 2, 3). The compounds obtained can be used for the development of BNCT agents.     

New esters of O-ethylalkylphosphonic acids

Conclusions A number of new O-ethyl S-alkyl alkylthiophosphonates, O-ethyl O-lupinine alkylphosphonates, and N-[(O-ethylalkylphosphinyl)hydroxyethyl]anabasines was synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 419–421, February, 1976.     

Optimized thiol derivatizing reagent for the mass spectral analysis of disubstituted epoxy fatty acids

A novel procedure is described for the derivatization of fatty acid epoxides in the presence of their corresponding diols. The acidic character of 2,3,5,6-tetrafluorobenzenethiol promotes favorable mass fragmentation of linoleate and arachidonate derived epoxide derivatives and reduces alkene isomerization to a manageable side reaction, eliminated through the addition of a thiol scavenger. After silylation, regioisomeric mixtures of epoxy- and dihydroxylipids are simultaneously detected and discriminated using gas chromatography with electron impact mass spectral detection. Silylated hydroxysulfanyloctadecanoids yielded instrumental detection limits of 5 pg/microl, sufficient sensitivity for the quantification of endogenous epoxylipids.     

GC-MS analysis of hydroxy and epoxy acids from seed oil of Hippopha? rhamnoides

By the GC-MS method using a packed column, in the mixture of TMS derivatives of hydroxy acid methyl esters obtained from the seed oil of the sea buckthorn, in ten chromatographic peaks (CPs) 13 monohydroxy compounds have been characterized by their mass spectra, the main ones being derivatives of dimorphecolic and coriolic acids. Structures are proposed for four dihydroxy acids of the C₁₇–C₂₀ series. The mixture of methyl esters of di- and tetra-TMS derivatives obtained from the mixture of epoxy acids from the same source has been analyzed by a similar method. In seven CPs, 11 compounds, reflecting the presence of nine epoxy acids in the initial mixture, have been characterized by their mass spectra. The main component of the mixture was 15,16-epoxyoctadeca-9,12-dienoic acid.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 626–634, September–October, 1989.     

GC-MS analysis of hydroxy and epoxy acids from seed oil of Hippophaë rhamnoides

By the GC-MS method using a packed column, in the mixture of TMS derivatives of hydroxy acid methyl esters obtained from the seed oil of the sea buckthorn, in ten chromatographic peaks (CPs) 13 monohydroxy compounds have been characterized by their mass spectra, the main ones being derivatives of dimorphecolic and coriolic acids. Structures are proposed for four dihydroxy acids of the C₁₇–C₂₀ series. The mixture of methyl esters of di- and tetra-TMS derivatives obtained from the mixture of epoxy acids from the same source has been analyzed by a similar method. In seven CPs, 11 compounds, reflecting the presence of nine epoxy acids in the initial mixture, have been characterized by their mass spectra. The main component of the mixture was 15,16-epoxyoctadeca-9,12-dienoic acid.     

New flame retardant epoxy resins based on cyclophosphazene-derived curing agents

To obtain high-efficiency flame retardancy of epoxy resins, a cyclophosphazene derivative tri-(o-henylenediamino)cyclotriphosphazene (3ACP) was successfully synthesized and used as a curing agent for the thermosetting of an epoxy resin system. The flame retardant properties, thermal stability, and pyrolysis mechanism of the resultant thermosets were investigated in detail. The experiments indicated that the synthesized thermoset achieved a UL-94 V-0 rate under a vertical burning test as well as a limiting oxygen index (LOI) of 29.2%, which was able to reach V-0 even when a small amount of 3ACP was incorporated. Scanning electronic microscopic observation demonstrated that the char residue of the thermosets was extremely expanded after the vertical flame test. Thermal analysis showed that the samples had a lower initial decomposition temperature when 3ACP was introduced into the epoxy resin systems. This indicates that the carbonization ability of the thermosets was significantly improved at elevated temperatures. In addition, the incorporation of 3ACP can effectively suppress the release of combustible gases during the pyrolysis process, and the decomposition of E-44/DDS-3ACP curing systems also promotes the formation of polyphosphoramides charred layer in the condensed phase. The investigation on the chemical structures of both the gaseous and condensed phase pyrolysis process confirmed the flame-retardant mechanism of the 3ACP-cured epoxy resins. Therefore, the nonflammable halogen-free epoxy resin developed in this study has potential applications in electric and electronic fields for environment protection and human health.     

New nitrogen-containing derivatives of dicarboxylic acids

Conclusions New nitrogen-containing derivatives of dicarboxylic acids have been prepared and characterized: tetramethylenediphthalimide, decamethylenedisuccinimide, and tetramethylene- and decamethylene-diglutarimides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2132–2133, September, 1970.