Loss Of Hydrogen Chloride Research Articles

ChemInform Abstract: SURPRISING REACTIVITY OF VERY CROWDED PHOSPHINIC DERIVATIVES

AbstractBei der Umsetzung des Phosphinsäurechlorids (I) mit Natriumazid erhält man anstelle des erwarteten Azids (III) den Phosphor‐Heterocyclus (II), der zu den Verbindungen (IV) und (V) gespalten wird.

Heterocyclic polyfluoro-compounds. Part 37. Diels–Alder reactions of trichloro- and trifluoro-1,2,4-triazine

Trichloro-1,2,4-triazine undergoes reaction at 70 °C with the olefins: ethylene, (Z)-but-2-ene, cyclopentene, and (Z)-cyclo-octene to give the 3,4-substituted 2,6-dichloropyridine derivatives, 3,4-R2C5HCl2N, where R2= H2(1%), Me2(75%), (CH2)3(77%), and (CH2)6(80%), respectively, in a reaction which appears to involve initial Diels–Alder addition, and loss of nitrogen, to form an intermediate dihydropyridine. This dihydropyridine then undergoes a [1,5] sigmatropic hydrogen shift and loss of hydrogen chloride to give the pyridine, but adds a second molecule of cyclopentene to the extent of 3% in a further Diels–Alder reaction, and this is the sole pathway with bicyclo [2.21] hept-2-ene.With trifluoro-1,2,4-triazine and the olefins cyclopentene, (Z)-cyclo-octene, and bicyclo[2.2.1]hept-2-ene, only products derived by addition of a second molecule of olefin to an intermediate dihydropyridine are obtained in 55, 13, and 52% yield respectively. Bis(trimethylstannyl)acetylene gives 3,4-bis(trimethylstannyl)-2,5,6-trifluoropyridine (11%), and bicyclo[2.2.1]hepta-2,5-diene gives 2,3,6-trifluoropyridine (43%).

Surprising reactivity of very crowded phosphinic derivatives

An example of intramolecular cyclisation of a crowded phosphinic chloride via loss of hydrogen chloride and formation of a phosporus–carbon bond is described; unexpected cleavage of an acyclic phosphorus-carbon bond is also reported.

Polymer modification and synthesis using sulphenyl derivatives. Part 8. Addition of arylsulphenyl chlorides to polyisoprene

Toluene-p-sulphenyl chloride reacts smoothly with cis-1,4-polyisoprene (PIP) in various proportions, but the resulting adducts decompose spontaneously via loss of hydrogen chloride. From an examination of model compounds and of the adducts of PIP with other sulphenyl chlorides, it is concluded that decomposition results from the saturation of successive double bonds along the polymer chain. The extent of decomposition indicates a high degree of regioselectivity in the original addition reaction. Some light is shed on the mechanisms of sulphenyl chloride additions to olefins and of the decomposition of aryl ω-halogenoalkyl sulphides.

Etude de la chloration du PVC en masse—II. Influence et evolution de la stereoregularite de la chaine en rapport avec les mecanismes de reaction

Bulk chlorination of PVC has been studied by i.r. and NMR. The evolution of chain stereoregularity during reaction and its significance to reaction mechanism have been specified. In particular, for temperatures <80°, the ratio Cl/C cannot exceed 0.75 because changes of conformation are impossible. To exceed this ratio, additional energy is necessary but then there is a parallel loss of hydrogen chloride. In all cases isotactic diads of TG conformation would be first chlorinated. At temperature above 100°, the microstructure of bulk chlorinated products is similar to that of products prepared in solution while their configuration and conformation are different.

Presence of dual mechanism in poly(vinyl chloride) dehydrochlorination

AbstractThermal dehydrochlorination of poly(vinyl chloride) was demonstrated to be capable of being maximally inhibited by triphenylmethane. Arrhenius parameters observed under conditions of full inhibition are consistent with a unimolecular loss of hydrogen chloride occurring concurrently with a radical‐chain process. At 194°C, the rate of the molecular process is about 30% of the overall reaction, but at higher temperatures it becomes the predominant pathway.

Stereospecific ring-contraction of 7,7-dichlorobicyclo[3.2.0]hept-2-en-6-ols with base

The epimeric alcohols, 7,7-dichlorobicyclo[3.2.0]hept-2-en-6-endo-and 6-exo-ol (2) and (3) when treated with aqueous base undergo Stereospecific ring contraction with loss of hydrogen chloride to give respectively 6-chloro-bicyclo[3.1.0]hex-2-en-6-exo- and 6-endo-carbaldehyde (5) and (6): the latter exists largely as its valence tautomer. The reaction involves a bent cyclobutane ring with the reacting hydroxy- and chloro-groups disposed trans and diequatorially, and it has been extended to the epimeric 6-methyl derivatives (19) and (20) and a 6-nitro-methyl analogue (24). The betaine (27) formed by addition of stable phosphoranes to 7,7-dichlorobicyclo-[3.2.0]hept-2-en-6-one (1) does not give ring contracted products, but instead the 6-alkoxycarbonylmethylene-bicyclic compound (28) by a normal Wittig reaction. Some spectroscopic properties of the starting alcohols are discussed.

Maritime and mixed maritime-continental aerosols along the coast of southern California

Interactions between marine aerosols and polluted continental air were studied at a coastal sampling station in the Los Angeles basin. Material was collected on filters and salt-sensitive impaction slides over a vertical distance of 30 meters in order to contrast differences between fresh aerosols generated in the surf and aged aerosols entering the basin from the open ocean. The diurnal onshore-offshore flow of air was monitored to characterize short-term interactions between heavily polluted air and the marine environment. In the absence of well-defined scavenging mechanisms, the removal of nonmarine aerosols and the addition of sea salt during the 12- to 16-hour residence time over the ocean at night was minimal. Analysis of cascade impactor samples collected in relatively clear air indicated a deficiency of chloride in the smaller marine aerosols due to the inclusion of nonchloride particulates from continental sources or other mechanisms. The formation of a highly conductive acid species in these aged aerosols was noted. Large-scale mixing of nitrogen dioxide from continental air is postulated with reactions between salt particles and the gas leading to the formation of nitric acid and the loss of hydrogen chloride in the gas phase. The use of the term ‘maritime aerosol’ is suggested for mixtures of marine and continental aerosols in the coastal zone.

Friedel–Crafts cyclisations. Part III. Synthesis of derivatives of 2(1H)-quinolone (carbostyril) by aluminium chloride-catalysed cycloeliminations of cinnamanilide and related compounds

For the conversion of cinnamanilide into 2(1H)-quinolone (carbostyril) the use of 3 mol. equiv. of the catalyst, aluminium chloride, is desirable; the low yield of 2(1 H)-quinolone obtained from 4-phenyl-3.4-dihydro-2(1H)-quinolone however, indicated that loss of the β-aryl group from cinnamanilide probably occurs virtually simultaneously with the cyclisation. Cyclisation was prevented by either a p-nitro- or a p-methoxy-group in the N-aryl nucleus, and also by an α-chloro-substituent in the cinnamoyl moiety. p-Chlorocinnamanilide was cyclised, however, to 4-phenyl-2(1H)-quinolone with loss of hydrogen chloride. The scope of the cycloelimination was indicated by the formation of 5,6,8-trichloro-2(1H)-quinolone from 2′,4′,5′-trichlorocinnamanilide. Although migration of a methyl group did not accompany the cyclisation of o′-methylcinnamanilide, cyclisation of 2′,6′-dimethylcin-namanilide was permitted by shift of an ortho-methyl group to the adjacent meta-position.

Mass spectrometric studies on platinum (II) complexes

AbstractSeveral platinum(I1) complexes were subjected to mass spectrometric investigation. The major fragmentation pathways for dichloro‐bis(phosphine) platinum(II) were elucidated to be: (i) successive loss of hydrogen chloride or chlorine depending on the structure of the phosphine, (ii) cleavage of P–R bond with the loss of R group, (iii) the presence of [R1R2R3P—Cl]+ in the mass spectra and (iv) fragmentation of the free phosphine.

Acylation of 2,2,6,6-tetramethylpiperidine and 2,2,5,5-tetramethylpyrrolidine

Treatment of 2,2,6,6-tetramethylpiperidine with carbonyl dichloride caused ring fission with loss of hydrogen chloride to give a mixture of 1,1,5-trimethylhex-4-enyl isocyanate and 1,1,5-trimethylhex-5-enyl isocyanate which on treatment with sodium carbonate gave N-(1,1,5-trimethylhex-4-enyl)-N′-(1,1,5-trimethylhex-5-enyl)urea. Ring fission also occurred on treatment with acetic anhydride or acetyl chloride, giving a mixture of N-(1,1,5-trimethylhex-4-enyl)acetamide and N-(1,1,5-trimethylhex-5-enyl)acetamide, although conditions could be modified to give 1-acetyl-2,2,6,6-tetramethylpiperidine. Treatment of 2,2,5,5-tetramethylpyrrolidine with carbonyl dichloride gave the 1-chlorocarbonyl derivative, which reacted normally with alcohols and amines.

Interaction of benzyl chloride with triphenylphosphine complexes of rhodium, iridium and platinum

The interaction of benzyl chloride with RhCl(PPh 3) 3, RhCl(CO)(PPh 3) 2, IrCl(CO)(PPh 3) 2, and Pt(PPh 3) 3 has been studied. The first two compounds produce the same species which is thought to have benzyl “allylic” bonds; this complex reacts with carbon monoxide and pyridine to form a σ-benzyl complex RhCl 2(CH 2Ph)(CO) 2(PPh 3) and an “allylic” benzyl complex RhCl 2(CH 2Ph) py(PPh 3), respectively. The iridium complex reacts to give an aryl complex of stoichiometry IrCl 2(C 6H 4CH 2Cl) CO(PPh 3) 2. Tris(triphenylphosphine)platinum merely causes polymerisation with loss of hydrogen chloride.

Polymerization of aromatic nuclei. XV. Polymerization of 2,5‐di‐ and 2,3,5‐trichlorothiophenes with aluminum chloride–cupric chloride

Abstract2,5‐Dichlorothiophene was polymerized to a solid in 93% yield on treatment with aluminum chloride–cupric chloride in carbon disulfide under mild conditions. The product is believed to be poly‐5‐chloro‐2,3‐thienylene on the basis of elemental analysis and infrared and NMR spectral data. Hydrogen chloride was collected in 90% of the theoretical amount. Dimer‐ and tetramer‐type fractions were isolated from the polymer. 2,3,5‐Trichlorothiophene underwent an analogous transformation in trichlorobenzene at 90–100°C. Polythienylenes coupled through the 2,3‐positions have not been reported previously. The net effect of the reaction is nuclear coupling by dehydrohalogenation. We believe that the mechanism involves cationic polymerization accompanied by loss of hydrogen chloride. 2‐Chlorothiophene and thiophene gave products of complex make‐up.

The reactions of oximes with covalent halides. Part I. Dimethylglyoxime, diphenylglyoxime, and the benzil monoximes with titanium tetrachloride

A suspension of dimethylglyoxime, DMGH2(n mol.) in light petroleum or chloroform at 20° gave with titanium tetrachloride the adducts TiCl4,nDMGH2(n= 1 or 2). At 40°, however, there was loss of hydrogen chloride and the compound TiCl3,DMGH was obtained. The analogous TiCl3,DPGH was formed at 20° from diphenylglyoxime, DPGH2. The two isomers of benzil monoxime, BMOH (1 mol.) with titanium tetrachloride (1 mol.) each gave the adducts, TiCl4,BMOH. With benzil monoxime (2 mol.) in chloroform the adducts TiCl4,2BMOH,0·5CHCl3 were obtained. The dimethylglyoxime adducts decomposed violently on heating, but the benzil monoxime adducts underwent a Beckmann fragmentation at ca. 120° to give phenyl cyanide.

Experiments with thioacetals and related substances. Part V. Reactions of some chloro-gem-bisalkylthiobutanes

1-Chloro-3,3-, 2-chloro-3,3-, and 1-chloro-2,2-bisalkylthiobutanes spontaneously eliminate hydrogen chloride forming either bisalkylthiobutenes, usually with accompanying rearrangement, or trisalkylthiobutanes. They are thus much less stable than 3-chloro-1,1-bisethylthiopropane or -butane. Rearrangement without loss of hydrogen chloride has not been encountered.

The structure of the highly conjugated polymers of dichloroprotoanemonin

AbstractThe copolymerization of dichloroprotoanemonin with methyl methacrylate is accompanied by the elimination of half of the chlorine that originally entered the copolymer. This result is consistent with a 1,4‐addition mechanism, the product of which would readily eliminate hydrogen chloride. A strong infrared band at 1770 cm.−1 and a weak band at 1810 cm.−1 indicates that the loss of hydrogen chloride proceeds primarily by 1,4‐elimination but to a small extent by 1,2‐elimination. The copolymerization of dichloroprotoanemonin with styrene results in the elimination of 10 to 20% of the total chlorine that entered the copolymer. Infrared bands at 1765 and 1800 cm.−1 reveal the presence of both conjugated and nonconjugated lactone carbonyl groups. Treatment of the copolymer with hot pyridine resulted in further elimination, up to about 30% of the total chlorine. The decrease in the intensity of the 1800 cm.−1 band relative to the 1765 cm.−1 band as a result of the pyridine treatment confirmed the conversion of the nonconjugated structure into the conjugated one. The failure to achieve 50% elimination indicates that in the styrene case copolymerization may have occurred in part by 1,2‐addition, the product of which would not be expected to lose hydrogen chloride. These results suggest that the ratio of 1,4‐ to 1,2‐addition may depend in part upon the nature of the comonomer. Thermal homopolymerization of dichloroprotoanemonin at 210°C. results in a solid, black polymer, insoluble in the common solvents. The elimination of 76% of the total chlorine suggests that under the conditions of the polymerization the lactone ring opens, giving an α‐chloroketone, which then undergoes further elimination.

Polymers of the vinyl esters of perchlorocyclopentadiene adducts of petroselinic and oleic acids

AbstractHomopolymers of vinyl 5‐(1,4,5,6,7,7‐hexachloro‐3‐undecylbicyclo [2.2.1]5‐hepten‐2‐yl)‐pentanoate and vinyl 8‐(1,4,5,6,7,7‐hexachloro‐3‐octylbicyclo [2.2.1]5‐hepten‐2‐yl)‐octanoate were prepared, as well as their copolymers with a vinyl tetrahydroabietate—tetrahydropimarate mixture, vinyl 12‐hydroxystearate, and vinyl chloride. The vinyl octanoate—12‐hydroxystearate copolymer gave light‐weight urethane foams with practically no volume change upon humid aging. The vinyl pentanoate and vinyl octanoate monomers lose hydrogen chloride during polymerization. The vinyl pentanoate homopolymer was hydrolyzed in an attempt to establish the position of the loss of hydrogen chloride. Fractionation of vinyl chloride copolymers of the vinyl petanoate and the vinyl octanoate derivatives showed that they possessed a rather homogeneous composition. Incorporation of the vinyl pentanoate monomer in a poly(vinyl chloride) copolymer imparted some internal plasticization with serious loss of tensile strength.

Application of thermal analysis to the study of aspects of boron-nitrogen chemistry—II Differential thermal analysis of some alkylammonium tetrachloro- tetraphenyl- and trichlorophenylborates

Thermal analysis studies of the alkylammonium tetrachloro-, tetraphenyl- and trichlorophenylborates demonstrates formation of 1:1 complex by loss of hydrogen chloride or benzene. Further decomposition in both the tetrachloro- and the trichlorophenylborate systems leads to formation of the B-trichloro-N-trialkylborazine. Decomposition of the tetraphenylborates stops at the borazene stage with formation of the alkylaminodiphenylborane.

Reactions of 8-quinolinol with covalent halides. Part I. Tin and titanium tetrachlorides

The adducts MCl4noxH (M = Sn or Ti)(n= 1 or 2) are precipitated when 8-quinolinol (oxH) and the appropriate tetrahalides are mixed in chloroform. In these adducts the ligand 8-quinolinol is probably unidentate. Solids having the same composition, but with n= 4, are similarly formed but are mixtures of 8-quinolinolium chloride and the metal dichlorodi-8-quinolinolates, MCl2ox2. The compounds TiCl3ox and TiClox3 have also been prepared; the latter may contain seven-co-ordinate titanium. 8-Quinolinol also forms adducts with antimony pentachloride, ferric chloride, and boron trifluoride, but, in contrast, reacts with boron trichloride with loss of hydrogen chloride and the formation of BCl2ox.

Thermal decomposition of chloroform in the presence of olefins

AbstractThe gas‐phase decomposition of chloroform at 400‐500°C in the presence of an alkene leads to a chlorodiene and hydrogen chloride.Evidence is presented that the primary step is the decomposition of chloroform to dichlorocarbene, which adds to the alkene; the resulting dichlorocyclopropane rearranges, with loss of hydrogen chloride, to a chlorodiene.