Fluorescent substances derived from the reaction of 13-monohydroperoxylinoleic acid and methylamine

Reaction of 13-monohydroperoxy linoleic acid and methylamine in the presence of ferric ions produced at least four fluorescent substances. They were separated by high performance liquid chromatography with a reverse phase column, and major fluorescent substances 1 and 3 were isolated. Fluorescent substances 1 and 3 showed the same fluorescence spectra with excitation maxima at 360 nm and emission maxima at 430 nm, and the same ultraviolet spectra with absorption maxima at 275 and 360 nm. Fluorescence of 1 and 3 was lost in alkaline media owing to the instability of the fluorophores. The fluorophores of 1 and 3 were destroyed on treatment with borohydride. The fluorescence characteristics of 1 and 3 were similar to those of the age-related fluorescent substances produced in tissues. They were different from those of the fluorescent substances derived from malonaldehyde and resembled those of the fluorescent substances derived from monofunctional aldehydes.     

叶面肥专用黄腐酸类物质的应用与筛选

在实验室对不同来源的腐植酸类物质进行了溶解能力、与微量元素的复配能力以及生物活性等性能的检验,结果表明,不同表源的腐植酸物质溶解性能有很大差异,与微量元素复合配置高水溶性营养液,表现出不同的沉淀性能,各物质均表现出一定的生物活性.通过对不同腐植酸产品性能的研究,给出了应用最终的筛选结论.     

柏斯托计划增加异氰酸酯在华产能

世界领先的精细化学品和材料供应商柏斯托公司计划增加其异氰酸酯的产能。柏斯托计划于2012年开始在中国实施新的生产设施运作,完成后年产量可达1.2万吨。于此同时,柏斯托计划对现有工厂实施各项改进措施,以支持亚太区外的市场增长。     

Kinetic study of the hydrolysis of isocyanic acid in the gas phase

The hydrolysis of isocyanic acid in the gaseous phase has been investigated at temperatures between 553 and 613 K by mass spectrometry and evaluated to obtain the corresponding kinetic data. The reaction order and reaction constant have been determined. Finally, the influence of water on the catalysed formation of melamine from isocyanic acid under the operating conditions employed has been investigated in order to determine whether there is a need to try the process gas.     

Bioassay of compounds derived from the honeybee sting

Nine compounds identified from honeybee,Apis mettifera L., sting extracts and one compound identified from the honeybee mandibular gland were evaluated in a standardized laboratory test for their effectiveness in eliciting an alarm response from caged honeybees. Two,n-decyl acetate and benzyl alcohol, were judged ineffective as alarm pheromones. The remaining eight—2-nonanol, isopentyl acetate,n-butyl acetate,n-hexyl acetate, benzyl acetate, isopentyl alcohol, andn-octyl acetate from the sting and 2-heptanone from the mandibular gland-produced responses of similar frequency and strength.in cooperation with Louisiana Agricultural Experiment Station. Mention of a proprietory product does not constitute an endorsement by the USDA.     

The reaction of dimethyldichlorosilane with polyorganosiloxanes derived from pseudowollastonite

The interaction of dimethyidichlorosilane with polyorganosiloxanes prepared by the trimethylsilylation of mineral silicates is catalysed by ferric chloride hexahydrate and results in the formation of higher molecular weight polyorganosiloxanes and also trimethylchlorosilane. The nature of the products and particularly the molecular weight depends on the relative amounts of reactants. It is also shown that during the course of the reaction a substantial proportion of the ferric chloride is reduced to ferrous.     

Surface chemistry and kinetics of the hydrolysis of isocyanic acid on anatase

In order to meet the stricter NO_x and particulate emission limits for commercial vehicles, the selective catalytic reduction (SCR) with urea is currently seen having the highest potential. The conversion of urea into ammonia and carbon dioxide consists of two consecutive reactions, in which isocyanic acid is an intermediate that is hydrolyzed over TiO₂. The intrinsic kinetics and the surface chemistry for this reaction are explored. Up to a temperature of 132 °C the reaction was in the intrinsic kinetic regime (E_A = 73 kJ/mol), while at higher temperatures the reaction was limited by pore and external diffusion constraints, respectively. In the presence of NO, NH₃ and NO₂, the catalytic activity was negatively influenced, increasing in severity in the sequence mentioned indicating that nitrates formed from NO₂ were most effective in blocking cations and anions of TiO₂. IR spectroscopy indicates that dissociative adsorption of HNCO on TiO₂ forms Ti–NCO and hydrogen bonded OH species. In the presence of water, isocyanic acid was so rapidly hydrolyzed that only adsorbed ammonia was observed on the catalyst surface. The presence of NO, NH₃ and NO₂ retards hydrolysis leading to the appearance of isocyanate species on the surface.     

Characteristic properties of cutting fluid additives derived from the reaction products of hydroxyl fatty acids with some acid anhydrides

Several adducts were prepared from the thermal reaction of hydroxyl fatty acids (ricinoleic acid oligomers, 12-hydroxystearic acid oligomers, oleyl alcohol, dehydrated castor oil fatty acids, and dimer acid) with maleic anhydride and screened as water-soluble cutting fluids. For example, aqueous solutions of triethanolamine salts with the products of ricinoleic acid oligomers, 12-hydroxystearic acid dimer, and 12-hydroxysteric acid hexamer showed good antirust properties for waterbased cutting fluids. Various half esters of hydroxyl fatty compounds with acid anhydrides were prepared. Aqueous solutions of triethanolamine salts of half esters of maleic anhydride and succinic anhydride and phthalic anhydride with hydroxyl fatty acids gave good antirust and antiwear properties for waterbased cutting fluids.     

Novel UV-autocurable methacrylo-urethane polymeric films derived from m-digallic acid: Preparation and characterization

A new acrylo-urethane film polymer was obtained from methacrylic m-digallic acid derivatives. The product was attained either by thermo- or photopolymerization, and the films were characterized by chemical and spectroscopic methods. Other studies of the properties of these polymers were also performed. The main characteristics found were brief curing times achieved with no photoinitiators, good thermal properties, and optical activity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2575–2583, 1998     

Insight into the chemical reaction of CH2OH with NO: Formation of N-hydroxy formamide as an isocyanic acid precursor

This study has explored the potential energy surface on the chemical reaction of CH₂OH with NO by using ab initio calculation. We have found the new reaction pathway producing N-hydroxy formamide, which can further decompose to generate isocyanic acid as a reducing agent of hydrocarbons selective catalytic reduction.     

Formation and reactions of isocyanic acid during the catalytic reduction of nitrogen oxides

Reactions which can produce and consume isocyanic acid (HNCO) over two types of catalysts active for the reduction of nitrogen oxides have been investigated. More than 1000 ppm HNCO can be produced by the reduction of 3000 ppm NO with H₂/CO mixtures over a Pt/SiO₂ catalyst. Complete hydrolysis of HNCO to ammonia and carbon dioxide occurs if even weakly catalytic materials, such as CeO₂/SiO₂ and BaO/SiO₂, are placed downstream. Isocyanic acid is also involved as an intermediate in the reaction of nitromethane over CoZSM5 and CuZSM5 under the conditions of hydrocarbon SCR. In the initial stages of reaction there is complete conversion through to N₂ with CuZSM5 but the process stops at ammonia with CoZSM5 at temperatures below 350°C. In both cases, but especially with CoZSM5, isocyanic acid becomes observable as the catalyst deactivates during continuous exposure at temperatures below about 290°C. In situ FTIR measurements indicate that deactivation is due to a reaction between isocyanic acid and ammonia which generates cyclic striazine compounds.     

Novel polyurethane insulating coatings based on polyhydroxyl compounds,derived from glycolysed PET and castor oil

To prepare versatile polyurethane material suitable as insulating coatings, novel kinds of polyhydroxy compounds (PHCs) were prepared via transesterification reaction of poly(ethylene terphthalate), different molecular weight of poly(ethylene glycol)s (PEGs), and castor oil. The final networks were prepared via crosslinking of PHCs with a novel blocked isocyanate curing agent (BPI) made from trimethylol propane (TMP), toluene diisocyanate (TDI), and N‐methyl aniline (NMA). Polyols and curing agent were characterized by conventional methods and the curing condition was optimized via gel content measurements. Curing kinetic of the polyurethane network formation was investigated by differential scanning calorimetric method and the kinetic parameters were derived. Crosslink density of the samples was determined via equilibrium swelling method and by using Flory‐Rehner equations. Effects of crosslink density on electrical, physical, mechanical, and dynamic mechanical (DMTA) properties of the polyurethane coatings were investigated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1222–1233, 2006     

Initiator complexes derived from dichlorobiscyclopentadienyl titanium and alkyl aluminium compounds: I. The reduction reaction

A general mechanism of the reduction of dichloro-biscyclopentadienyl titanium with triethyl aluminium has been derived from a study of the reaction at ?70° in toluene and n-heptane solutions. The reaction products were found to depend on the Al:Ti molar ratio. Each product was examined as active initiators for the homopolymerisation of styrene at 60°.     

Formation of isocyanic acid during the reaction of mixtures of NO, CO and H2 over supported platinum catalysts

On-line infrared spectroscopy has been used to show that isocyanic acid, HNCO, is a substantial primary product of the reaction between NO, CO and H₂ over a Pt/SiO₂ catalyst. At 230°C it accounts for more than 40% of the CO converted. No isocyanic acid is seen when Al₂O₃ is placed downstream of Pt/SiO₂, or when using a Pt/Al₂O₃ catalyst under the same conditions, due to rapid hydrolysis of HNCO on the alumina. Isocyanic acid may exist as a trace intermediate in automobile catalytic converters during their warm-up phase but it is unlikely to emerge from the pore system of aluminabased catalysts.     

Functionalized polymers derived from the reaction of polymaleic anhydride with amines and alcohols

In the present study the application of polymaleic anhydride as a reactive polymer is illustrated in its reactions with didodecylamine, diphenylamine, and dodeecanol. These polymers consisting of lipophilic segments (originating from the long aliphatic chains) or of the mesomorphic diphenyl moiety coupled with the polar carboxylic or carboxylate group can in principle exhibit mesomorphism in the melt and aggregate in dispersion. Of these derivatives didodecyl derivative froms mesomorphic-like structure in the melt, dodecanol monoester derivative dissolves freely in water whereas the sodium salts of the polymers disperse in water due to the presence of distinct polar and lipophilic moieties in their molecules.     

S-methyl derivatives from thiol compounds by the pyrolytic reaction with trimethylsulfonium hydroxide

Base-catalyzed transesterification of acyl lipids with methanol in the presence of trimethylsulfonium hydroxide (TMSH) is an easy and convenient method for the preparation of fatty acid methyl esters for gas chromatography (GC) analyses. Free fatty acids are converted to fatty acid methyl esters by the pyrolytic reaction with TMSH as well. We have found that lipids and other compounds containing thiol groups are also converted easily to the corresponding methyl sulfides (methyl thioethers) by the pyrolytic reaction with TMSH occurring in the injector of the gas chromatograph. For example, alkane thiols such as dodecane thiol and octadecane thiol are converted to the corresponding alkyl methyl sulfides, whereas bis(methylthio) derivatives are formed from α,ω-alkane dithiols, e.g., 1,8-octanedithiol, and from 2,3-dimercaptopropan-1-ol (dimercaprol). Furthermore, 3β-mercaptocholest-5-ene (thiocholesterol) is converted to 3-methylthiocholest-5-ene by the same reaction. The S-methylation reactions which finally lead to the corresponding methylthio derivatives of lipids and other compounds with thiol groups may be of diagnostic value for the structural analysis of such compounds by GC and GC/mass spectrometry.