SYNTHESIS OF DIALKOXYMETHANE AT HIGH ALKALINE CONCENTRATION VIA PHASE TRANSFER CATALYSIS

The phase-transfer catalytic reaction (PTC) of 2,4,6-tribromophenol and dibromomethane by quaternary ammonium salt was carried out in a high alkali content of KOH/dibromomethane two-phase medium. A large conversion of 2,4,6-tribromophenol is obtained at a region of high KOH content. Dibromomethane acts both as the organic-phase reactant and the organic solvent; thus, no extra organic solvent is required. Two main products, i.e., α -bromomethyl 2,4,6-tribromophenyl ether (mono-substituted product) and bis-(2,4,6-tribromophenoxide)methane (bis-substituted product), were detected in the solution during the phase-transfer catalytic reaction. The active catalyst (tetrabutylammonium 2,4,6-tribromophenoxide, ArOQ), which was produced from the reaction of 2,4,6-tribromophenol, potassium hydroxide, and tetrabutylammonium bromide (TBAB or QBr), is purified as the crystalline product from the reaction solution. A kinetic model is developed to describe the behaviors of the two organic-phase reactions on the basis of the experimental observation. The two intrinsic rate constants of the two organic-phase reactions, which are the rate-determining steps of the whole reaction system, are determined. Effects of the reaction conditions, such as agitation speed, amount of water, amount of TBAB catalyst, temperature, and amount of dibromomethane, quaternary ammonium salts, and inorganic salt KBr, on the conversion of 2,4,6-tribromophenol and the reaction rate are investigated in detail.     

不同胺取代三嗪衍生物对高密度聚乙烯阻燃性能的影响

以三聚氯氰、甲胺和二甲胺水溶液为原料,合成了2,4,6-三甲胺基-1,3,5-均三嗪(TMM)和2,4,6-三二甲胺基-1,3,5-均三嗪(HMM),并用FT-IR和DSC对其进行了表征。研究了用多聚磷酸胺(APP)和季戊四醇(PER)作为酸源和炭源,分别用三聚氰胺(MEL)、TMM和HMM作为气源的膨胀型阻燃剂对高密度聚乙烯(HDPE)力学性能和阻燃性能的影响。结果表明:含TMM的HDPE复合材料的阻燃性能和力学性能都优于含MEL或HMM的HDPE复合材料。     

A sensitive method for the determination of carbonyl compounds

2,4,6-Trichlorophenylhydrazine was tested as a reagent for carbonyl compounds. As little as 0.1 of the 2,4,6-trichlorophenylhydrazones (2,4,6-TCPH) could be measured with an electron capture detector, so this reagent should be useful in measuring the carbonyl compounds in oxidized fats at levels near their flavor thresholds. Mixtures of 2,4,6-TCPHs were separated by thin layer chromatography. Alkan-2-one-2,4,6-TCPHs were separated from aldehyde-2,4,6-TCPHs on alumina plates. The alkanal, alk-2-enal and alk-2,4-dienal-2,4,6-TCPHs were separated from each other either on silica gel plates or silica gel-silver ion plates. The derivatives within each carbonyl class were separated by chain length on chromatography media impregnated with phenoxyethanol. The 2,4,6-TCPHs eluted from thin layer plates were determined with an electron capture detector after gas chromatography on a 30 cm column of freeze-dried detergent base coated with a silicone oil. Journal Paper No. J-6842 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, project No. 1856.     

Liquid-liquid Extraction Methods to Determine Reductive Dechlorination of 2,4,6-trichlorophenol by Zero-valent Metals and Zero-valent Bimetals

Abstract

The reductive dechlorination of 2,4,6-trichlorophenol (2,4,6-TCP) was studied using zero-valent metals (ZVMs) and bimetals. A reliable extraction method was required to distinguish the removal by chemical transformation from the removal by physical adsorption on the ZVMs or bimetal. Three liquid–liquid extraction methods with ethyl acetate were evaluated by conducting mass recovery tests in the ZVM-chlorophenol systems. A typical liquid–liquid extraction showed low recoveries for 2,4,6-TCP and the reaction products while the modified liquid–liquid extraction involving acid addition gave increased recoveries. The Mg system needed an additional modification since the modified extraction method was not working on the Mg and Pd/Mg system. Pd/Fe and Pd/Zn gave the highest reaction rate for 2,4,6-TCP dechlorination, producing less or no chlorinated daughter compounds while the plain metals such as Fe and Zn showed much slower degradation rates for 2,4,6-TCP.     

Production of Exploding Materials for Detonators: Control of Crystal Growth of Lead and Barium 2,4,6‐trinitroresorcinate

The production of lead and barium 2,4,6‐trinitroresorcinate in a suitable form for loading by gravity in detonator production has been investigated. During the work, we discovered that the synthesis of the mentioned salts in the presence of some crystal habit additives gives such characteristics of the products. A goal of our work was to investigate the role of some crystal growth additives in the nucleation, growth, size, and shape of lead 2,4,6‐trinitroresorcinate and barium 2,4,6‐trinitroresorcinate crystals. Among several crystal growth additives mentioned in the bibliography, we chose carboxymethylcellulose (sodium salt, viscosity 3–4 Pa⋅s), polyvinyl alcohol, as well as two new ones, cationic acrylamide copolymer salt, polyelectrolyte AS‐3605 and acrylic acid–acrylamide copolymer salt, Haicat (Praestrol^R 835BS). As a synthesis pattern, we chose an aqueous procedure of synthesis, using solutions of lead(II) or barium salts and magnesium 2,4,6‐trinitroresorcinate. The crystal growth additives were added to one of the solutions, depending on their nature. During the research, most of the attention was focused on crystal size and shape, on safety handling and manipulation, as well as on the yield and process performing facility. The final products were qualified by chemical (Pb and NO₂ group contents) and physical (crystal shape and size, bulk density, flowability, and impact and friction sensitivity) analyses.     

Studies on Energetic Salts Based on (2,4,6‐Trinitrophenyl)guanidine

(2,4,6‐Trinitrophenyl)guanidine was synthesized and its thermal and energetic properties were investigated. The reaction of (2,4,6‐trinitrophenyl)guanidine with different acids, such as nitric, picric, perchloric, and hydrochloric acid results in protonation of (2,4,6‐trinitrophenyl)guanidine and the formation of the corresponding salts (cation : anion ratio 1 : 1). The reactions are performed at ambient temperature in H₂O or EtOH and produce qualitatively pure products with energetic properties, which are typical of those of secondary explosives. The compounds were characterized using multinuclear NMR spectroscopy, IR and Raman spectroscopy, as well as mass spectrometry. Single crystal X‐ray diffraction studies were performed and the structures of the four different salts at low temperatures were determined. The thermal stabilities were measured using differential scanning calorimetry (DSC). The sensitivities were determined using the BAM drophammer and friction tests. The heats of formation were calculated by the atomization method based on CBS‐4M enthalpies. Using these values as well as the X‐ray or pycnometric densities, several detonation parameters such as the detonation pressure, velocity, energy, and temperature were computed using the EXPLO5 code.     

Electrochemical and spectral properties of meta-linked 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenoles, and their polymers

We present electrochemical and spectral properties of symmetric monomers 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenols and their polymers. These compounds contain thienyl, furyl or EDOT moieties attached to central benzene or phenol ring at the meta-position, synthesized by a Stille cross-coupling procedure. All monomers are electroactive and undergo electropolymerization creating thin films on an electrode surface. Polymers with meta-linkages were obtained by electrochemical oxidation. Detailed cyclic voltammetry and in situ UV-vis spectroelectrochemistry show that polymers with hydroxy groups exhibit higher conductivity and better stability than with benzene core. Interesting and different behavior occurs for 2,4,6-tris(2-thienyl)-1-phenol, for which the characteristic, sharp, redox peak is observed.     

2，4，6-三硝基-2，4，6-三氮杂环己酮的合成Ⅱ以DPT或PHX为原料的合成

报道了以DPT（或PHX）与脲（或硝基脲）为原料在几种硝化剂中合成2,4,6－三硝基－2,4,6－三氮杂环己酮（RDX酮）的方法,对由DPT、PHX和BSX这三种反应物的硝解碎片分子参加反应的形式和反应副产物的特点作了初步分析,结果表明：在硝解碎片中,非硝基取代的N,N－二羟甲基胺类碎片分子参加了与脲（或硝基脲）的缩合反应,生成了产物RDX酮,N,N－二羟甲基硝胺碎片分子不参加反应。以DPT为原料时,RDX酮得率为69％,副产物为HMX、RDX和小分子碎片;用PHX作原料时,RDX酮得率最高达36％,副产物为HMX和小分子碎片;用BSX作原料时则无产物和环状硝胺副产物生成。     

Pyryliumverbindungen. 37. Arylbenzene aus 2,4,6-Triaryl-pyryliumsalzen und Carbonsäureanhydriden

Pyrylium Compounds. 37. Arylbenzenes from 2,4,6-Triarylpyrylium Salts and Carboxylic Acid Anhydrides Refluxing 2,4,6-triarylpyrylium salts 1 with excess carboxylic acid anhydrides (RCH₂CO)₂O ( 2a : R = H, 2b : R = Me) in the presence of condensing agents like sodium or potassium acetate, sodium carbonate or methoxide, triethylamine or pyridine results in 1,3,5-triarylbenzenes 3 (R = H, Me). Under similar conditions, phenylacetic acid anhydride ( 2c ), generated in situ from sodium phenylacetate and excess 2a or 2b , yields 1,2,3,5-tetraarylbenzenes 3 (R = Ph). Thus, the reaction 1 + 2 → 3 represents a new and simple method for replacing the pyrylium heteroatom =O^⊕– by the =CR– moiety (R = H, Me, Ph). The structure of the arylbenzenes 3 was proved by spectroscopic methods, by comparison with literature data or by independent synthesis. As by-products 2-acyloxy-benzophenones 10 are formed. Reaction of 3,5-dimethyl-2,4,6-triphenyl-pyrylium perchlorate ( 11 ) with acetic acid anhydride/sodium acetate (or sodium phenylacetate) takes another course leading to 2-acetoxy-3,5-dimethyl-4,6-diphenyl-benzophenone ( 15 ), whereas treatment of 11 with propionic acid anhydride/sodium acetate follows the reaction scheme 1 + 2 → 3 giving 1,3,5-trimethyl-2,4,6-triphenylbenzene ( 16 ). The mechanisms of the different pyrylium ring transformations are discussed.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2,4,6-三甲基苯甲醛的合成

用2,4,6-三甲基苯基溴化镁分别和原甲酸三乙酯、N,N-二甲基甲酰胺和N,N-甲基苯基甲酰胺进行加成反应,分别以70%、62.5%和22%的收率得到了2,4,6-三甲基苯甲醛。     

六(2,4,6-三溴苯氧基)环三磷腈(BPCPZ)的合成、热性能及应用

以六氯环三磷腈与2,4,6-三溴苯酚反应,制得有机磷腈化合物六(2,4,6-溴苯氧基)环三磷腈(BPCPZ).用红外、核磁、质谱及元素分析对产物结构进行了表征.研究了溶剂、原料配比、反应温度和反应时间对产物收率的影响.结果表明,合成的最佳条件是:四氢呋喃为溶剂,反应物料配比为n(三溴苯酚) ∶n(六氯环三磷腈)=6.5...     

2,4,6-TCP removal mechanism in the process of leaching manganese

ABSTRACT

2,4,6-trichlorophenol (2,4,6-TCP) was used in the leaching system of manganese/pyrite to achieve the simultaneous utilization and removal of 2,4,6-TCP. When the initial concentration of 2,4,6-TCP was 300 mgL^?1 and the weight percentage of pyrite was 12.8%, the removal of 2,4,6-TCP was 83.3%, meanwhile, the leaching efficiency of manganese was 97.6%. Fourier Transform Infrared Spectroscopy (FTIR) showed that the removal of 2,4,6-TCP mainly relied on the chemical oxidative degradation by Mn (IV) and the surface adsorption by leaching residue, including physical adsorption and chemical adsorption. Gas Chromatography–Mass Spectrometry analysis and Chemical Oxygen Demand (COD) indicated that 2,4,6-TCP was degraded to inorganic substances eventually.     

Synthesis of amino-modified ordered mesoporous silica as a new nano sorbent for the removal of chlorophenols from aqueous media

Contamination of natural water with organic pollutants is a problem of major concern and the demand for effective adsorbents for the removal of toxic compounds is increasing. Present work deals with the adsorption of 2-chlorpphenol (2-CP) and 2,4,6-trichlorophenol (2,4,6-TCP) from aqueous solutions on a new nano sorbent; amino-modified ordered mesoporous silica (APS-MCM-41) material. It was found that APS-MCM-41 shows significant adsorption for 2-CP and 2,4,6-TCP. This might be due to the acid and alkaline interactions among the amino functional groups and chlorophenols. Batch adsorption studies were carried out to study the effect of various parameters like adsorbent dose, pH, initial concentration and contact time. It was found that adsorption of 2-CP and 2,4,6-TCP depends upon the solution pH. From the sorption studies it was observed that the uptake of 2,4,6-TCP was higher than that of 2-CP. Freundlich and Langmuir adsorption isotherms were used to model the equilibrium adsorption data for 2-CP and 2,4,6-TCP.     

Pyryliumverbindungen. XXIX [1] Substituierte Benzophenone aus 2,4,6-Triaryl-pyryliumsalzen und Methyl(en)ketonen

Pyrylium Compounds. XXIX. Substituted Benzophenones from 2,4,6-Triarylpyrylium Salts and Methyl(ene) Ketones In the presence of piperidine acetate (or similar salts of certain dialkylamines), 2,4,6-triarylpyrylium perchlorates 5 react with methyl(ene) ketones 6 to give benzophenones 7 , the structure of which was proved by spectroscopic methods as well as by independent synthesis. Besides acetone and other acyclic ketones (e. g. alkyl methyl ketones, phenylacetone, desoxybenzoin, dibenzyl ketone) cyclic ketones (e. g. cyclopentanone, cyclohexanone, cycloheptanone, acenaphthenone) can also be used as ketone component 6 ; acetophenones react differently leading to hydrocarbons of the 1,3,5-triarylbenzene type 15 . The varying efficiency of the diverse amine salts and the mode of incorporation of the unsymmetrically substituted ketones suggest the intermediate formation of enamines 10 as crucial step of the ring transformations observed. This assumption is supported by isolation of the iminium salt 18 on reacting 3,5-dimethyl-2,4,6-triphenylpyrylium perchlorate ( 16 ) with acetone/piperidine acetate.     

Mechanism research of copper(II)-catalyzed polymerization of 2,4,6-trichlorophenols

The copper(II)-catalyzed polymerization of 2,4,6-trichlorophenol and 2,4,6-trichloro-3-methylphenol were studied. Their polymer structures were confirmed by elemental analysis, infrared (IR), and nuclear magnetic resonance (NMR). The 2,4,6-trichlorophenoxo–copper(II) complex and 2,4,6-trichloro-3-methylphenoxo–copper(II) complex intermediates were isolated. The elemental analysis and electron spin resonance (ESR) measurement of the phenoxo–copper(II) complexes were discussed in relation to their structures. Decomposition of the phenoxo–copper(II) complex in refluxing benzene yielded poly(dichlorophenylene oxide). ESR measurements on the phenoxo–copper(II) complex in the solid state at 120°C indicated that the phenoxy radical was generated during the period of decomposition and the intensity of the ESR spectra based on the copper(II) ion decreased with the measurement time. A single-electron transfer reaction mechanism was proposed for the phenoxo–copper(II) complex intermediate. © 1996 John Wiley & Sons, Inc.     

丙醛与硫化铵环化缩合反应产物研究

采用乙醇作溶剂,以0.1 mol丙醛与0.18 mol硫化铵水溶液为原料,在0℃下反应5 h,制得2,4,6-三乙基-5,6-二氢-4H-1,3,5-二噻嗪香料化合物;并采用FTIR、傅里叶离子回旋变换质谱、1HNMR和13CNMR对其进行了结构表征。通过GC-MS对反应后所得粗品进行分析,确定了其组成成分主要为2,4,6-三乙基-5,6-二氢-4H-1,3,5-二噻嗪、六氢-1,3,5-三嗪、N-亚丙基-1-胺基-1-丙烯、3,5-二乙基-1,2,4-三硫杂环戊烷、2,4,6-三乙基-四氢-1,3,5-噻二嗪、N,N'-二亚丙基丙二胺、3,5-二乙基-4,5-二氢-1,2,4-二噻唑。文中探讨了该反应生成2,4,6-三乙基-5,6-二氢-4H-1,3,5-二噻嗪及其副产物的机理,也探讨了2,4,6-三乙基-5,6-二氢-4H-1,3,5-二噻嗪、2,4,6-三乙基-六氢-1,3,5-三嗪和2,4,6-三乙基-四氢-1,3,5-噻二嗪等在GC-MS分析过程中发生分解的情况;最后对2,4,6-三乙基-5,6-二氢-4H-1,3,5-二噻嗪作为潜在的食品香料化合物的安全性问题做了相关的评价。     

DBS类凝胶因子的合成及性能

以取代的苯甲醛和山梨醇为原料,环己烷为溶剂和夹带剂,甲醇为促进剂,对甲苯磺酸为催化剂,用共沸脱水法合成了1,3∶2,4-O-二苄叉-D-山梨醇(DBS),收率91.2%;1,3∶2,4-O-二(4-甲基苄叉)-D-山梨醇(MDBS),收率90.5%;1,3∶2,4-O-二(3,4-二甲基苄叉)-D-山梨醇(DMDBS),收率89.0%。用原甲酸三甲酯作化学脱水剂,合成了1,3∶2,4-O-二(2,4,6-三甲基苄叉)-D-山梨醇(2,4,6-TMDBS),收率37.1%;1,3∶2,4-O-二(2,4,5-三甲基苄叉)-D-山梨醇(2,4,5-TMDBS),收率30.9%;1,3∶2,4-O-二(5,6,7,8-四氢萘-2-亚甲叉)-D-山梨醇(DTHNS),收率74.1%。其结构经1HNMR确认。测定了它们对21种有机溶剂的凝胶性能。发现苯环上取代基的位置、数量、大小等因素对凝胶性能有重要影响。2,4,6-TMDBS无凝胶性能,其余化合物对多种溶剂具有良好的凝胶性能,DTHNS对非极性化合物有极优良的凝胶性能。测试并比较了上述化合物的最低凝胶浓度,证实了凝胶-溶胶解缔温度随凝胶因子质量分数增加而增加;随着溶剂(一元直链伯醇)碳原子数的增加而增加。     

Pyryliumverbindungen. 31 [1]. Reaktion 3-alkylsubstituierter 2,4,6-Triaryl-pyryliumsalze mit 1,3-Diketonaten: Ein Weg zur Darstellung 3-acylsubstituierter Benzophenone

Pyrylium Compounds. 31. Reaction of 3-Alkyl-2,4,6-triarylpyrylium Salts with 1,3-Diketonates: A Method for the Preparation of 3-Acylsubstituted Benzophenones Reaction of 3-alkyl-2,4,6-triarylpyrylium salts with 1,3-diketones in the presence of one equivalent of triethylamine or potassium tert-butoxide does not lead — as originally suspected — to the primary adducts of 2H-pyran structure 6 , but to the open-chain valence isomers 7 . Treatment of the latter with one equivalent of tert-butoxide in tert-butyl alcohol gives the same 3-alkyl-2,4,6-triarylacetophenones 9 which are obtained directly from 5 , 1,3-diketones and two equivalents of potassium tert-butoxide. However, on treating 7 with aqueous ethanolic sodium hydroxide 3-acylsubstituted benzophenones 10 are formed in good yields. The reaction sequence 5→7→10 can also be performed through a one-pot-procedure. — The i.r., u.v., n.m.r. and mass spectroscopic data of the novel products 7, 9 , and 10 are reported.