Increasing Chlorine Content Research Articles

The thermal and oxidative stability of polychlorinated metallocenes

An examination of the thermal and oxidative stability of polychlorinated ferrocenes indicated a decreasing trend in thermal stability and an increasing trend in oxidative stability with increasing chlorine content. The enhanced oxidative stability is best explained on the basis of inductive electron withdrawal from the iron atom by the chlorine atoms. The reduction in thermal stability may also be explained on the basis of the electron-withdrawing inductive effect of the chlorine substituents producing a weakening of the metal-to-ring bonding, although steric crowding due to an eclipsed conformation of the chlorine atoms is also a possible factor in the reduction. 1,1′, 2,2′-tetrachloroferrocene and 1,1′, 2,2′, 3,3′, 4,4′-octachloroferrocene were found to exhibit mesophase formation.

Chlorosulfonation of poly(2,6‐dimethoxy‐1,4‐phenylene ether)

AbstractChlorosulfonated derivatives of poly(2,6‐dimethoxy‐1,4‐phenylene ether) of varying chlorine content have been synthesized. Demethoxylation and chlorination is shown to occur in the reaction which is proposed to be of free‐radical type. Decrease of molecular weight, lowering of the glass transition point (Tg) and thermal degradation temperature (Td) with increasing chlorine content is indicated to take place during the progress of the reaction.

Endoanesthetic and narcotic activity in halogenated methane derivatives

Chlorine and fluorine derivatives and mixed substitutes of methane were tested with respect to their endoanesthetic and narcotic effects in guinea pigs. We found that these effects were enhanced with increasing chlorine content of the substances; with rising fluorine content these qualities decreased to pharmacological inactivity, i.e. in trifluoromethane and tetrafluorocarbon. The results are compared with the mole refraction according to the narcosis theory of Pauling (1961). There was a close correlation of the endoanesthetic and narcotic effect on one side and the mole refraction as an expression of polarization on the other: substances with a high refrection were active, while those with a low mole refraction were not.

Photochemical degradation of di- and octachlorodibenzofuran.

In the last few years, it has been shown that polychlorinated biphenyls undergo decomposition on irradiation with artificial ultraviolet light sources and sunlight (1-7). Reductive dehalogenation of one or more chlorine atoms was a major reaction, particularly in hydrocarbon solvents. In fluorocarbon solvents or thin films, small quantities of chlorobiphenyls with increased chlorine content could also be detected. Irradiation in hydroxylic solvents gave the dechlorinated species as well as photoproducts containing oxygen. In addition, chlorinated terphenyls and quaterphenyls were also detected in some instances, and on prolonged irradiation polymeric products were formed. It has been speculated for some time that chlorodibenzofurans may be formed from chlorobiphenyls under photochemical conditions which lead to oxygenated products. Although no chlorodibenzofurans could be detected in a number of chlorobiphenyl samples which had been exposed to sunlight for over 2 months (4), preliminary results indicated the formation of chlorodibenzofur-

Effect of polychlorinated biphenyls on hepatic microsomal enzymes in the rat

Polychlorinated biphenyls (PCB) are widely used industrial synergists and stabilizers that have been detected in various animal systems throughout the world. Although these chemicals possess a low acute toxicity, recent indications are that they may possess a high chronic toxicity. To evaluate further the toxicity of PCB mixtures, rats were fed diets containing 4 different Aroclors varying in chlorine content from 42 to 60% for 4 wk at levels of 0.5, 5, 50, and 500 ppm. The influence of PCB was studied by determining liver weights, hepatic triglyceride concentration and glucose-6-phosphatase activity, microsomal enzyme activities (nitroreduction, demethylation and hydroxylation) and microsomal cytochrome P-450 content. Liver-to-body weight ratios and cytochrome P-450 content were significantly increased at 50 and 500 ppm for all PCB mixtures; the increase in cytochrome P-450 was somewhat greater with increasing chlorine content. Significant increases in liver triglycerides were seen at 500 ppm, with a maximum effect occurring at approximately 50% chlorine content. A dose-related increase in demethylase activity was observed, with a 2.5- to 3-fold increase over control values at 500 ppm for all mixtures. Effects were maximum at approximately 50% chlorine content. A dose-related increase in pentobarbital hydroxylation was seen, and the induction of hydroxylation increased with increasing chlorine content. Nitroreductase activity was markedly stimulated with increasing doses of PCB, and induction was seen at levels as low as 0.5 ppm for all mixtures. The maximal effect appears to be at levels higher than 500 ppm. The highest levels of activity were seen with 60% chlorination.

Distribution of Chick Edema Factors in Chick Tissues

Abstract A study was made of hexa-, hepta-, and octachlorodibenzo-p-dioxin (higher chlorodioxins) absorption and tissue distribution in White Leghorn chicks fed a diet containing 3% toxic fat or the equivalent amount of the unsaponifiable fraction isolated from the toxic fat. Over 90% of the ingested higher chlorodioxins was excreted. Increasing chlorine content resulted in decreased absorption so that no octachlorodioxin could be detected in the tissues. Chlorodioxins were widely distributed in a number of tissues and it was estimated that 49% of the chlorodioxins detected in various tissues was present in the liver of the chicks fed the toxic unsaponifiable fraction.

Rheological studies of chlorinated poly(vinyl chloride)

AbstractChlorinated poly(vinyl chloride) (CPVC) is known to have a higher softening temperature than conventional poly(vinyl chloride) (PVC). Its processability characteristics are, however, different; and in the literature, it has been reported that CPVC is more difficult to process. However, no detailed characteristics of its processability appear in the current literature. This paper describes some of the studies we have made on the flow behavior of CPVC.Investigations on the melt properties of CPVC, made on a capillary rheometer, indicate that above 67% chlorine content the resin shows gross distortion of the extrudate even at low stresses. This “melt fracture” phenomenon might arise from the elastic nature of the melt. The simple treatment of the flow data, based on a modified form of Poiseuille equation for capillary flow, gave no direct evidence for the increased elasticity of the melt. The limitations of the assumptions made in the simplified treatment may be responsible for this.It is proposed that the elasticity of the melt can arise from the crosslinks produced in the melt due to dehydrochlorination, which is known to increase with increasing chlorine content. It is also suggested that modification of the simple approach to capillary flow might give a better idea of the elastic nature of the melt.

Molecular motion in chlorinated ethylene-propylene copolymer

The molecular motion in solid chlorinated ethylene-propylene copolymer (EPc) (0–66 wt.% Cl) has been studied by the dynamical-mechanical method. It has been found that the damping maximum ascribed to the motion of groups from (CH 2) 2 to (CH 2) 4 shifts to higher temperatures with increasing chlorine content. The dependence of T g on the chlorine content has an exponential character. The mixtures of EPc pairs with a low content of chlorine show a limited compatibility but the copolymers are not compatible at the higher contents of chlorine.

Structure and properties of polyvinylchloride. III. Dynamic‐mechanical properties of chlorinated PVC

AbstractDynamic‐mechanical measurements with a torsion pendulum for a series of chlorinated PVC samples have been made. Two transition intervals were recorded, one primary (I) related to segment motion at the glass transition and one secondary (II) interpreted as due to group vibrations along the chains. The I‐transition shifted from 78 to about 115°C with increasing chlorine content from 56.7 to 72.0% (by weight). The II‐transition shifted from −55 to about −35°C with increasing chlorine content from 56.7 to 63.5%. On further chlorination, the II‐transition broadened and could not be separated from the I‐transition. The temperature shifts of the two transitions were a linear function of the CHClCHCl content of the chlorinated PVC samples as previously analyzed by NMR measurements.

Mechanical and dielectric absorption of poly(vinyl chloride) and some related polymers

AbstractThe mechanical and dielectric low temperature absorptions of poly(vinyl chloride) (PVC) and several modified PVC's have been studied over the temperature range from −60 to +60°C. with some tests extending to −150°C. and others to +170°C. The results indicate that the low‐temperature absorption near −50°C (β2 absorption) decreases in intensity with chlorination, while the absorption at a higher temperature near 0°C (β1 absorption) decreases in intensity with hydrogenation. The apparent activation energies of the β1 and β2 absorptions were calculated to be 16 kcal/mole and 10.7 kcal/mole, respectively. Besides, the β2 absorption markedly decreases in intensity with addition of plasticizer, while the intensity of β1 absorption is not much affected by increasing plasticizer content. From these results, the β1 and β2 processes are concluded to be the results of molecular motion in crystalline and amorphous region in PVC, respectively. For samples of reduced Cl content, another low‐temperature absorption was located near −120°C (γ absorption) and attributed to the presence of short sequences of ethylene units. It has also been observed that the temperature location of the high temperature absorption near 100°C (α absorption) shifts linearly to higher temperature with increasing chlorine content and to lower temperature with increasing hydrogen content.

Studies of chlorinated polyisobutenes. Part I. Investigations of structure by proton magnetic resonance and of thermal stability by thermal volatilization analysis

AbstractPolyisobutene was chlorinated in carbon tetrachloride solution at 60°C. with radiochlorine, and the degree of chlorination was determined radiochemically. The extent of chlorination was varied by using a wide range of chlorine/polyisobutene ratios in the reaction mixture. The products were examined by PMR spectroscopy, which showed that both methyl and methylene groups were chlorinated but that the methylene hydrogens were more readily substituted and some disubstitution of the methylene groups occurred. The effect of chlorination on the thermal stability compared to the original polymer was studied by the new technique of thermal volatilization analysis. All the chlorinated derivatives were found to degrade at lower temperatures than polyisobutene. The stability dropped progressively as the chlorine content was increased to one chlorine atom per isobutene unit and then showed less change with further increase in chlorine content.

NMR studies of chlorinated poly(vinyl chloride) and polybutadiene

AbstractMolecular structures of chlorinated poly(vinyl chloride) and polybutadiene have been studied by high resolution NMR. The spectra of the chlorinated polymers give broad signals. New peaks appear in the lower fields of the CH2 and CHCl groups with increasing chlorine content. The chlorination of poly(vinyl chloride) takes place predominantly on CH2 rather than on CHCl, e.g., a 70% chlorinated polymer has about 10 mole‐% of CCl2 groups. Polybutadiene reacts first with chlorine by addition to give a head‐to‐head poly(vinyl chloride), and then the substitution of the hydrogen atom takes place. Chlorinated polybutadiene with 70% Cl has about 18 mole‐% of CCl2. The multiplets characteristic of spin‐spin couplings in the spectrum of the original poly(vinyl chloride) are still observed in that of the highly chlorinated product. This fact shows that a considerable number of poly(vinyl chloride) sequences of certain lengths persist in the highly chlorinated polymer.

Increase in chlorine content of cervical mucus as a simple test for impending ovulation and for oestrogenic stimulation in ewes

The chloride concentration in the cervical mucus of ewes was estimated by applying a sample of the mucus to paper impregnated with silver chromate. The concentration was equivalent to 0.1-0.3 per cent sodium chloride during dioestrus, rose to 0.7-0.9 per cent about 24 hours before the onset of oestrus and fell to about 0.4 per cent shortly before ovulation occurred. More precise measurements of the ionic concentration of the cervical mucus by a photometric method indicated that the chloride concentration rose from a mean level of 98 m.equiv. per litre (equivalent to 0.6 per cent NaCl) approximately 24 hours before oestrus to 122 m.equiv. per litre (equivalent to 0.7 per cent NaCl) during oestrus; the concentration of sodium increased from 105 to 137 m.equiv. per litre, and potassium decreased from 27 to 14 m.equiv. per litre. The rise in chloride concentration in the mucus was associated with an increase in the amount of mucus present. In ovariectomized ewes an increase in the chloride content of the cervical mucus from 0.1 to 0.7 per cent occurred within 24 hours after either the intramuscular injection of stilboestrol (4 to 20 �g) or feeding oestrogenic red clover (0.75 to 3 kg wet weight), and indicates that the method may be useful for rapid oestrogen bioassay in sheep. Progesterone given at the same time, but not when given 48 hours before, depressed the response.

Dielectric study of the transition temperature regions for poly (vinyl chloride) and some chlorinated poly(vinyl chlorides)

AbstractAudio frequency dielectric constant data versus temperature data for poly(vinyl chloride) exhibit a high temperature (glass) transition which becomes steeper and reaches higher values as the frequency is reduced. The same trend is demonstrated for a series of chlorinated poly(vinyl chlorides) although the transition decreases in magnitude and moves to higher temperatures systematically with increasing chlorine content. Corresponding loss data are presented. Dielectric constant values for poly(vinyl chloride), determined in the high temperature transition region from reversible (d.c.) polarization experiments, show that the trend to steeper and larger transitions continues as polarization lime increases. For 10,000 sec. polarization the curve exhibits a sharp peak with lambda point character and twice the highest a.c. value is reached. This dielectric constant peak is interpreted as a cooperative interaction in noncrystalline regions of long‐rod dipoles with moments perpendicular to the chain axes. This model is related to Natta's crystal structure for syndiotactic PVC where the assembly of planar molecules form an antipolar array. For PVC all the chlorines are on the same side of the axis but for chlorinated PVC, dipolar balancing due to 1,2‐dichloro groupings is responsible for the reduced transition magnitude. The high temperature process involves equilibrium of macroscopic volumes, whereas the low temperature transition, which is little affected by chlorination, involves local equilibrium only.

Water cocatalysis in the polymerization of benzene by ferric chloride

AbstractThe influence of change in water cocatalyst concentration on polymer yield and composition, and on reaction rate was investigated in the benzene‐ferric chloride system. For short reaction times, polymer yield passes through a maximum at a H2O/FeCl3 molar ratio of 1. The most rapid rate of hydrogen chloride evolution was observed at this same ratio. The data suggest that ferric chloride monohydrate constitutes the active catalyst‐cocatalyst complex. With more prolonged reaction times, the yield maximum shifted to lower values of H2O/FeCl3, accompanied by a progressive increase in polymer yield. As evidenced by the C/(H + Cl) atomic ratio, p‐polyphenyl formation is favored by short reaction times at H2O/FeCl3 ratios of 0, 1, and 2. Longer reaction times, gave C/(H + Cl) ratios greater than 1.5 for the polymer, indicating the presence of polynuclear structures. An increase in chlorine content attended the rise in C/(H + Cl) ratio. Interpretations of the data are presented.

Methods for the determination of cyclopropenoid fatty acids. I. Aqueous hydrochloric acid method

AbstractAn analytical method is described for the estimation of long‐chain cyclopropenoid fatty acid derivatives. It is based upon the quantitative addition of a molecule of hydrogen chloride at the cyclopropene ring when the sample is shaken with concentrated hydrochloric acid. The cyclopropenoid content can be calculated, as sterculic acid, from the increase in chlorine content. Epoxy compounds and hydroperoxides interfere and must be removed by one of the accepted pretreatment methods.

Polymerization of chlorophenyl esters of methacrylic acid

1. The kinetics of the polymerization of p-chloro-, 2,4-dichloro- and 2,4,6-trichlorophenyl methacrylates are similar in character to those of the polymerization of methyl methacrylate: an initial linear reaction period is followed by a sudden acceleration of polymerization accompanied by an increase in molecular weight of the polymer. 2. The influence of the chlorine in the phenyl ring of the methacrylic ester is manifested in a lower degree of conversion and in an earlier termination of the period of self-acceleration with increasing chlorine content. 3. Replacement of the methyl group of methacrylic ester by the bulkier chlorophenyl group is reflected in a higher reaction rate and in stoppage of polymerization after a lower degree of conversion. 4. A theory of the causes of these phenomena is advanced on the basis of the experimental data.

Partially Chlorinated Derivatives of Rubber

Abstract Chlorinated rubbers containing from 1 to 17 per cent of chlorine were prepared by direct chlorination, at ordinary temperature, of crepe rubber dissolved in carbon tetrachloride. These products retain, to a greater or lesser degree, rubberlike properties, and are capable of hot or cold vulcanization with or without the addition of vulcanizing agents. The resulting vulcanizates are considerably more resistant to the swelling action of solvents, and also to the action of chlorine, than corresponding products prepared from crepe rubber. The resistance to swelling agents increased with increase in combined chlorine content; tensile strength and elasticity, however, decreased with increasing chlorine content. As expected, hardness increased with increase of chlorine content, and vulcanizates from derivatives containing more than 10 per cent combined chlorine were not sufficiently rubberlike to warrant many experiments. Fully chlorinated rubber was compatible with partially chlorinated rubber, and addition of the former was necessary for vulcanizates to pass the Post Office flame test for cables.

Partially chlorinated derivatives of rubber

AbstractChlorinated rubbers containing from 1 to 17% of chlorine have been prepared by direct chlorination, at ordinary temperature, of crèpe rubber dissolved in carbon tetrachloride. It has been found that these products retain, to a greater or lesser degree, rubber‐like properties and are capable of hot or cold vulcanization with or without the addition of vulcanizing agents. The resulting vulcanizates have been shown to be considerably more resistant to the swelling action of solvents, and also to the action of chlorine, than corresponding products prepared from crèpe rubber. The resistance to swelling agents increased with increase of combined chlorine content; tensile strength and elasticity, however, decreased with increasing chlorine content. As expected, hardness increased with increase of chlorine content and vulcanizates from derivatives containing more than 10% combined chlorine were not sufficiently rubber‐like to warrant many experiments. It was found that fully Chlorinated rubber was compatible with partially chlorinated rubber and addition of the former was necessary for vulcanizates to pass the Post Office flame test for cables.

THE INSECTICIDAL ACTION OF SOME D.D.T. ANALOGUES AND CHLORINATED (4‐CHLOROPHENYL)‐ETHANES

The insecticidal effectiveness of D.D.T. is dependent upon the combination of the two chlorophenyl groups with the trichloroethane group. Modification of the latter group results in a loss of toxicity. The toxicity of the compounds possessing =CH.CC13, =CH.CHC12 and =CH.CH2C1 groups decreases as the degree of chlorination decreases.None of the chlorinated (4‐Chlorophenyl)‐ethane compounds are of the same order of toxicity as D.D.T. The relative potency increases with increasing chlorine content of the side‐chain, although complete chlorination results in a compound possessing negligible toxicity. A relationship between toxicity and chlorine content is also seen in the ethylenic compounds, which were formed as intermediates in the synthesis of the ethane derivatives. The comparatively non‐toxic ethylenic derivatives of D.D.T. when contrasted with (4‐CIC6H4) CC1=CC12, suggests that the spatial configuration of the molecule may be of importance.