Ether Pyridine Research Articles

Alternating bio‐based pyridinic copolymers modified with hydrophilic and hydrophobic spacers as sorbents of aromatic pollutants

AbstractThe main objective of this work was to design new advanced sorbent phases, alternating copolymers, derived from isosorbide and 2,6‐difluorpyridine, to be used for the removal of aromatic organic pollutants present in water at low concentrations. Six different monomers, dianhydrohexitols isomers and bisphenol derivatives, were synthesized in order to make it possible to study their hydrophilic and hydrophobic effect on the sorption efficiency of the resulting polymeric phases. Before this study, we have confirmed the chemicals structures, molecular weights, and thermal properties of the obtained polymeric phases. Sorption results show a higher adsorption efficiency of P6 co‐poly(ether‐pyridine) based on bisphenol substituted with pyridine units, for all tested pollutants, hydrophobic and hydrophilic ones, due to its less compact structure. Two aromatic organic pollutants, p‐hydroxybenzoic acid and toluic acid, were selected as sorbates to study the adsorption characteristic, kinetics and isotherms of the co‐poly(ether pyridine) P6. Langmuir model led to a better fitting of the sorption isotherms; the sorption of toluic acid is easier than of that p‐hydroxybenzoic acid. Comparing 1/n values for benzoic acid was two time lower for P6 compared to that for biochar and for cross‐linked methacrylate resin, showing a higher efficiency.

Adsorption characteristics of aromatic pollutants and their halogenated derivatives on bio-based poly (ether-pyridine)s

In this work, innovative poly(ether pyridine) polymers obtained from bio-based monomers and pentafluoropyridine derivatives were elaborated in order to adsorb aromatic pollutants and their halogenated derivatives. These polymers were obtained with satisfactory yields by polycondensation of four pyridinium monomers (respectively based on morpholine, piperazine, dimethylamine and phenol) with isosorbide or bisphenol A. The adsorption efficiency data demonstrate that the poly(etherpyridine) based on isosorbide and morpholine-based monomer (P2) is the more efficient sorbent toward aromatic pollutants and their derivatives. Four aromatic pollutants, p-hydroxybenzoic acid, toluic acid, deisopropylatrazine, and 2,4,6-trichlorophenol, were chosen as the adsorbate to investigate the adsorption efficiency, kinetics and isotherms of the poly(ether pyridine) P2. The results demonstrate that the pseudo-second order was the best to describe the adsorption of the four target pollutants by the efficient sorbent P2 with good correlation. The experimental data of the four target pollutants adsorption were analyzed by Langmuir and Freundlich isotherms. Polymer P2 shows very high affinity (low 1/n value) for p-hydroxybenzoic acid and for 2,4,6-trichlorophenol, compared to other adsorbents. Three consecutive adsorption/desorption cycles toward eight aromatic pollutants were obtained for the efficient sorbent P2.

Reaktionen von Z,Z-1,2,3,4-tetrachlor-1,3-butadien-1-carbonitril mit thiolaten

The title compound 2 is prepared from the amide 1 with trifluoroacetic acid anhydride and pyridine in ether at 0°. 2 is substituted by thiolates in dioxane at room temperature in δ-position with formation of 3. A second RS-group may be introduced in β-position of 3 giving 5. The structure and configuration of the new compounds is determined by 13C-NMR-spectroscopy.

ChemInform Abstract: CHEMISTRY OF ORGANO HALOGENIC MOLECULES. XLVIII. STEREOCHEMISTRY OF HALOFLUORINATION OF 1,2‐ AND 1,4‐DIHYDRONAPHTHALENE

AbstractDie Halofluorierung des Dihydronaphthalins (III) erfolgt regioselektiv entsprechend der Markownikoff‐Regel und ist stereospezifisch anti; das gebildete Addukt (I) isomerisiert sich bei längerer Reaktion zu syn‐Produkten (IV), die unter basischen Bedingungen Halogenwasserstoff eliminieren [→(V)].

Chemistry of Organo Halogenic Molecules. XLVIII. Stereochemistry of Halofluorination of 1,2- and 1,4-Dihydronaphthalene

Abstract Halofluorination of 1,2-dihydronaphthalene with a mixture of N-chlorosuccinimide or N-bromosuccinimide or N-iodosuccinimide–hydrogen fluoride–pyridine in ether proceeds with Markovnikov type regioselectivity. The reaction is stereospecifically anti, the anti adduct isomerizing to syn products under the reaction conditions. The elimination of hydrogen halide under basic conditions occurs only from the syn adduct, thus forming 1-fluoro-3,4-dihydronaphthalene. Halofluorinations of 1,4-dihydronaphthalene also occur stereospecifically anti, and elimination under basic conditions gives naphthalene.

Derivatives of cis-NPCl2 (NSOCl)2 and (NPCl2)2NSOCl, VI Pyridinium Derivatives of cis-NPCl2(NSOF)2 and cis-NPCl2(NSOCl)2

The compounds with composition NPCl(NSOF)2(C5H5N)OH (1) and NPCl(NSOCl)2 (C5H5N)OH (2) are prepared by reaction of cis-NPCl2(NSOX)2 (X = F, Cl) with pyridine in ether. The pyridinium derivatives are colourless crystalline solids. Tentative structure assignments are given based on NMR data.

Stereochemistry of bromofluorination of phenyl-substituted olefins

Bromofluorination of phenyl-substituted olefins, e.g. 1,1-diphenylethylenes, β-alkylstyrenes, and stilbene, with N-bromosuccinimide–hydrogen fluoride–pyridine in ether proceeds with Markovnikov-type regioselectivity. The reaction is sterospecific (anti) for trans- and nonstereospecific for cis-olefins.