Elimination Of Hydrogen Chloride Research Articles

Factors that Influence the Kinetics of the Degradation of Poly(vinyl Chloride)

Abstract The degradation of five samples of PVC having different degrees of polymerization has been studied by a technique that permits a precise measurement of the rate of hydrogen chloride elimination as % HCl/min. All samples followed acceleratory kinetics at both low and high conversions. The conversion rate, which changed from the beginning to the end of a degradation, depended primarily upon the fraction of chains producing hydrogen chloride. The fraction of producing chains and the kinetic pattern were influenced by the presence of hydrogen chloride, the physical state of the sample, the previous degradation history, and the presence of intentionally added substances. Zipper kinetics permit the reproduction of kinetic data in terms of three parameters: k1, the fraction of chains initiating per second, k2, the fraction of a zip chain that zips per second, and k3, an arbitrary parameter that accounts for residual hydrogen chloride after degradation has ceased.

Enzyme-induced aziridine formation by rat liver microsomes

The metabolic reaction of 2-chloroethylaminobenzoquinone derivatives with rat liver microsomes was studied. In buffer solution containing cellular macromolecules such as DNA or protein, 2-chloroethylaminobenzoquinones were unusually stable and could be recovered quantitatively after an appropriate period of incubation. However, in microsomal solution, they were gradually converted into aziridinobenzoquinones via elimination of hydrogen chloride by NADPH-dependent enzyme action. Based on the study of the enzymatic cyclization reaction of 4-chlorobutylaminonaphthoquinone, we concluded that the hydroquinone derivative is an important intermediate for aziridine formation.

Interesting Errors in Sulfur Chemistry, 3

Abstract 3,6-DICHLORO-l,4,2,5-DITHIADIAZINE In 1963 it was found that trichloromethanesulfenyl chloride and ammonia could be made to react with elimination of hydrogen chloride according to (l):1 N CCI3SCI + n NH3 ← (CCINS)n + 3 n HCI

ChemInform Abstract: PHOTOCHEMISTRY OF CHLORO‐2‐VINYLSTILBENES

AbstractPhotolyse der Chlorvinylstilbene (I), (VII), (IX) bzw. (XI) unter angegebenen Bedingungen führt zu den Produkten (I)+(II) bis (VI), (III) + (V) + (VII) + (VIII), (X) bzw. (XII) + (XIII).

Photochemistry of chloro‐2‐vinylstilbenes

AbstractShort irradiation at 300 nm of α‐chloro‐ and β‐chloro‐2‐vinylstilbene (20 and 21) leads to a mixture of 2‐vinyltolane (35) and 2‐vinylstilbene (1) accompanied by the cis‐ and trans‐isomers of the starting compounds. Evidence is found for the occurrence of an ionic intermediate during the photolysis of 20 in methanol. At 360 nm, an additional, small amount of 1‐chloro‐endo‐ and 1‐chloro‐exo‐6‐phenylbenzobicyclo[3.1.0]hex‐2‐ene (39) is formed from 20. The elimination of hydrogen chloride also occurs during the irradiation of 2‐(2‐chlorovinyl)stilbene (23) and leads to 2‐ethynylstilbene (41). The acetylenic compounds are photocyclized into 2‐phenylnaphthalene (38). However, 2‐(1‐chlorovinyl)stilbene (22) reacts without loss of chlorine to give 1‐chloro‐exo‐5‐phenylbenzobicyclo[2.1.1]‐hex‐2‐ene (40). This exceptional reaction mode is due to a much higher rate of photocyclization resulting from less distortion in the stilbene moiety and a preference for a conformation better suited to the reaction of the 2‐(1‐chlorovinyl)stilbene molecule. It is shown that both isomers of 22 can photocyclize into 40.

Chemical determination of microstructure of diene units in 1-chloro-1,3-butadiene copolymers

Microstructure of 1-chloro-1,3-butadiene (CB) units in the copolymers with styrene and with 1,3-butadiene was elucidated by chemical reactions. The reactivities of the two chlorines, i.e., that of 1,4-microstructure CB units and that of 3,4-microstructure, were drastically different from each other in the substitution by diethyldithiocarbamate group as well as in the hydrogen chloride elimination during thermogravimetric measurements. This difference enabled us to determine the microstructure of CB units in poly(CB-co-styrene) and poly (CB-co-1,3-butadiene). The results showed ca. 60 percent of CB units was of 1,4-microstructure and the rest was of 3,4-microstructure. These results were in good agreement with those by spectroscopies.

Preparation of polyphosphonates

AbstractPolyphenylphosphonates have been prepared by (i) the elimination of hydrogen chloride from mixtures of PhPOCl2 and PhPO(OH)2, (ii) the elimination of methyl chloride from PhPOCl2 and PhPO(OMe)2, and (iii) the elimation of methanol from PhPO(OMe)2 and PhPO(OH)2. Products have been characterised by elemental analyses, gel permeation chromatography, molecular weight measurement and infrared spectroscopy. In each case mixtures of rings and chains were obtained. Polyphosphonates were also obtained by the elimination of hydrogen chloride from mixtures of MePOCl2 and MePO(OH)2 and from mixtures of PhOCl2 and MePO(OH)2.

ChemInform Abstract: FORMATION OF ETHYNYL METALLOCENYL KETONE FROM 1,1,1‐TRICHLORO‐3‐ALKOXY‐3‐METALLOCENYLPROPANE

AbstractMit einer ungewöhnlichen Eliminierung von HCl gehen die Trichlorethoxy‐propyl‐metallocene (I) in die Ethinylcarbonylmetallocene (II) über.

FORMATION OF ETHYNYL METALLOCENYL KETONE FROM 1,1,1-TRICHLORO-3-ALKOXY-3-METALLOCENYLPROPANE

Abstract 1,1,1-Trichloro-3-ethoxy-3-ferrocenylpropane(1a) gives ethynyl ferrocenyl ketone(2a) via an unusual elimination of hydrogen chloride, when 1a is treated with alkali and then acid. The ruthenium analog(1b) also affords ethynyl ruthenocenyl ketone(2b). No migration of the side chain is involved in this process.

Synthesis of antimicrobial agents. IV. Synthesis and antimicrobial activities of imidazo[4,5-b][1,8]naphthyridine derivatives.

As part of a search for new antimicrobial agents, some 3, 5-disubstituted 5, 8-dihydro-8-oxoimidazo and triazolo [4, 5-b] [1, 8] naphthyridine-7-carboxylic acids and related compounds, which contain a new ring system, were prepared. The reactions of 6-amino-7-alkylamino-1-ethyl-1, 4-dihydro-4-oxo-1, 8-naphthyridine derivatives (3, 7, 11, 12 and 35) with acid, acetic anhydride, ethyl orthoformate and ethylxanthate afforded several imidazo [4, 5-b] [1, 8] naphthyridine derivatives. Treatment of the diamines (11 and 12) with sodium nitrite gave the triazolo [4, 5-b] [1, 8] naphthyridine derivatives (15 and 16). Reaction of the 7-acetylamino-4-hydroxy-1, 8-naphthyridine-3-carboxylate (17) with 1, 2-bromochloroethane gave different products (24 and 27), depending upon the reaction conditions. 3-Methyl-5-vinyl-5, 8-dihydro-8-oxoimidazo [4, 5-b] [1, 8]naphthyridine-7-carboxylic acid (38) was prepared by successive chloroethylation, nitration, chlorination, substitution with methylamine, reduction of the nitro group, imidazole cyclization and elimination of hydrogen chloride with simultaneous hydrolysis of the ester group. Some compounds obtained in this work showed activity nearly equal to that of pipemidic acid, but were slightly less active against Ps. aeruginosa.

Pyrolytic elimination of hydrogen halide and halogen from 2,3-dihalogenoketones

The thermal elimination of hydrogen chloride from 2′-hydroxychalcone dichlorides occurred in two stages, initially forming 3-chloroflavanones and then flavones; α-chloro-2′-hydroxychalcones, the likely intermediates in the formation of 3-chloroflavanones, also yielded the same products. The pyrolysis of 2′-hydroxychalcone dibromides resulted in debromination as well as dehydrobromination with the consequent appearance of brominated flavones among the products. The formation of 3-bromoflavanones was not observed but the isomeric (E)-α-bromo-2′-hydroxychalcones thermally isomerized to their (Z)-isomers and then underwent cyclization and dehydrobromination. The bromides were considerably more reactive than the dichlorides but, as a synthetic procedure, the pyrolysis of the dichlorides is cleaner and more productive.

ChemInform Abstract: ASYMMETRIC CYCLIZATION OF PROPYLENE CHLOROHYDRINS CATALYZED BY AN OPTICALLY ACTIVE COBALT(SALEN) TYPE COMPLEX

AbstractDurch asymm. Eliminierung von HCl mittels K2CO3 aus den racemischen Chlorhydrinen (IIa) bzw. (IIb) in Gegenwart des optisch aktiven Cobalt‐Komplexes (I) wird jeweils (S)‐(‐)‐Methyl‐oxiran (III) erhalten [1.

NEW STEREOSPECIFIC SYNTHESIS OF VINYL SULFIDES VIA CIS–TRANS OLEFIN INVERSION

Abstract A new stereospecific synthesis of vinyl sulfides (4) was achieved via complete cis–trans olefin inversion in which benzenesulfenyl chloride addition to olefins (1) and trans elimination of hydrogen chloride are involved.

The kinetics and mechanisms of the gas phase pyrolyses of exo-2-norbornyl chloride and cyclopentyl chloride

The gas phase pyrolyses of exo-2-norbornyl chloride and cyclopentyl chloride were studied in the temperature range 570–670 K. The results obtained show that these compounds behave as typical secondary halides insofar as the kinetics of their hydrogen chloride elimination reactions are concerned. Labelling experiments showed that in the formation of both norbornene and cyclopentene, a cis-1,2 elimination with a deuterium isotope effect of ∼3 was involved. Nortricyclene also was produced from exo-2-norbornyl chloride, via a trans 1,3 elimination; this process is analogous to a fragmentation of the ionized molecule. No gas phase Wagner–Meerwein rearrangement was involved in the formation of either norbornene or nortricyclene.

Asymmetric Cyclization of Propylene Chlorohydrins Catalyzed by an Optically Active Cobalt(salen) Type Complex

Abstract By using an optically active cobalt complex, N,N′-disalicylidene-(1R,2R)-1,2-cyclohexanediaminatocobalt(II), as a catalyst, optically active methyloxirane was synthesized by the asymmetric elimination of hydrogen chloride with a base from racemic propylene chlorohydrins. The highest optical purity of methyloxirane so far obtained was 35%, observed when 2-chloro-1-propanol and potassium carbonate were used as substrate and base, respectively. The optical rotations of the products and of the unchanged substrates indicate that (S)-1-chloro-2-propanol reacted selectively to produce (S)-methyloxirane, whereas in the case of 2-chloro-1-propanol, the (R)-isomer was preferentially cyclized to give (S)-methyloxirane with inversion of the asymmetric carbon. The physicochemical data of the circular dichroism and absorption spectra indicated a complexation of the optically active cobalt(II) species with potassium carbonate, either the (R)- or (S)-substrate interacting selectively with the Co*/K2CO3complex formed, followed by cyclization of the substrate.

Synthesis of Epichlorohydrin by Elimination of Hydrogen Chloride from Chlorohydrins. 1. Kinetic Aspects of the Process

Synthesis of Epichlorohydrin by Elimination of Hydrogen Chloride from Chlorohydrins. 1. Kinetic Aspects of the Process

Synthesis of Epichlorohydrin by Elimination of Hydrogen Chloride from Chlorohydrins. 2. Simulation of the Reaction Unit

Synthesis of Epichlorohydrin by Elimination of Hydrogen Chloride from Chlorohydrins. 2. Simulation of the Reaction Unit

Selective Hydrogen Chloride Elimination from Primary Chlorides Induced by the Fluoride Anion. Anchimeric participation of the chloromethyl group in the heterolytic opening of an epoxide. Stereospecific syntheses of 5,6‐bis (methylidene)‐syn‐2‐norbornen‐7‐ol and 5,6‐bis (methylidene)‐endo‐3‐chloro‐exo‐2‐norbornanol

AbstractSyntheses of the alcohols 10 and 18, and the corresponding ketones 11 and 19 are presented. Endo‐5, exo‐6‐bis (chloromethyl)‐endo‐3‐chloro‐exo‐2‐norbornanol (16) and endo‐5‐(bromomethyl)‐exo‐6‐(chloromethyl)‐endo‐3‐chloro‐exo‐2‐norbornanol (17) were obtained by HCl‐ and, respectively, HBr‐addition to endo‐5, exo‐6‐bis (chloromethyl)‐exo‐2, 3‐epoxynorbornane (5). The Wagner‐Meerwein rearrangement was precluded in these reactions probably because of the formation of a relatively stable chloronium ion 15 arising from the participation of the 1,4‐chlorine atom of the endo‐5‐chloromethyl group in the heterolytic ring opening of the epoxide 5.The ‘naked’ fluoride anion (excess CsF in DMF or KF in DMF with 18‐crown‐6‐ether) permitted the selective elimination of 2 equivalents of HCl from 16 and yielded the chlorohydrin‐diene 18.

Rearrangement reactions of a Reissert compound chlorohydrin

The Reissert compound, 2-benzoyl-1-cyano-1,2-dihydroisoquinoline, reacted with hypochlorous acid to yield a crystalline chlorohydrin. Base-catalysed elimination of hydrogen chloride from this led to an array of rearranged products in a controlled manner. In this way, simple preparative routes to 1-benzoylamino-1-cyanoisochromene, 1-benzoyliminoisochromene (and thence isocoumarin), 1-ethoxy-4-formyl-3-phenylisoquinoline, and 1-ethoxy-3-phenylisoquinoline were devised. The mechanism of the consecutive rearrangements is discussed.

Energy disposal by the four-centered unimolecular hydrogen chloride elimination reaction

Energy disposal by the four-centered unimolecular hydrogen chloride elimination reaction