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Landfill leachate (LL) is a complex wastewater and an important potential source of environmental contamination. LL can contain high concentrations of ammonia, metals, other inorganic species, and dissolved organic carbon; however, bulk composition of dissolved LL organic matter (LLOM) is poorly understood. A better understanding of LLOM composition will inform treatment development and improve LL pollution tracing. In this study, we addressed this need for compositional and treatment information by characterizing LL from an active bioreactor municipal solid waste (MSW) landfill as well as from a closed MSW landfill. Through non-targeted ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) we were able to assign chemical formulas to thousands of singly charged molecular ions and compare samples to natural dissolved organic matter (DOM). LLOM was differentiated by a higher presence of sulfur-, nitrogen-, and chlorine-, particularly nitrogen–sulfur-, containing formulas. The abundance of chlorine-containing molecular formulas supports the existence of a non-volatile organochlorine component in MSW LL. We performed tandem MS (MS-MS) analyses to tentatively identify the presence of the flame retardant, chlorendic acid, and likely related compounds. Additionally, we measured contaminants of emerging concern (CECs) and other chemical parameters to further characterize LLs and found evidence suggesting a significant percent of Fe may be bound in Fe–organic complexes.

Removal of chlorendic acid, an emerging water pollutant and potential carcinogenic, was investigated by gamma radiation in the absence and presence of peroxymonosulfate (PMS, HSO 5 − ). The removal of chlorendic acid (1.40 μM initial concentration) by gamma radiation was promoted with PMS, i.e., 95% compared to 82% in the absence of PMS, at an absorbed dose of 1000 Gy. The removal of chlorendic acid by gamma-ray/PMS process was due to OH and SO 4 − . Second-order rate constants of 5.90 × 10 9 , 1.75 × 10 9 , and 2.05 × 10 9 M −1 s −1 for chlorendic acid with e aq − , OH, and SO 4 − , respectively, were determined. The removal efficiency of chlorendic acid was promoted with increasing initial PMS concentration and decreasing initial target contaminant concentration. The removal of chlorendic acid by gamma-ray/PMS was inhibited in the presence of CO 3 2− , NO 2 − , p -CBA, m -TA, and alcohols. The presence of Fe 2+ , Cu + , and Fe 3+ with gamma-ray/PMS promoted removal efficiency of chlorendic acid from 78% to 99, 94, and 89%, respectively, at 592 Gy. The degradation of chlorendic acid by OH and SO 4 − was found to be initiated at the carboxylate group as could be revealed from nature of the transformation by-products. Nevertheless, this study concluded that gamma-ray/PMS is of practical importance in treatment of natural water containing chlorendic acid, as potential detoxification of chlorendic acid solution can be revealed from 83% loss of chloride ion at 3000 Gy. In addition, gamma-ray/PMS process achieved efficient removal of chlorendic acid even in the presence of commonly found inorganic ions in natural water.

The oxidation of chlorendic acid (CA), a polychlorinated recalcitrant contaminant, by heat-, mineral-, and base-activated persulfate was investigated. In pH 3–12 homogeneous (i.e., solid-free) solutions, CA was oxidized by •OH and SO4•- radicals, resulting in a nearly stoichiometric production of Cl−. The rate constants for the reaction between these radicals and CA were measured at different temperatures by electron pulse radiolysis, and were found to be kOH = (8.71 ± 0.17) × 107 M−1s−1 and kSO4 = (6.57 ± 0.83) × 107 M−1s−1 at 24.5 °C for •OH and SO4•-, respectively. CA was oxidized at much slower rates in solutions containing iron oxyhydroxide or aquifer soils, partially due to the adsorption of CA on these solids. To gain further insight into the effect of solids during in-situ remediation of CA, the adsorption of CA onto iron (hydr)oxide, manganese dioxide, silica, alumina, and aquifer soils was investigated. The fraction of CA that was adsorbed on these materials increased as the solution pH decreased. Given that the solution pH can decrease dramatically in persulfate-based remedial systems, adsorption may reduce the ability of persulfate to oxidize CA. Overall, the results of this study provide important information about how persulfate can be used to remediate CA-contaminated sites. The results also indicate that the groundwater pH and geology of the subsurface can have a significant influence on the mobility of CA.

Chlorendic acid is a recalcitrant, highly chlorinated organic pollutant for which no microbial degrader has yet been identified. To address this knowledge gap, fungi were isolated from bulk soil, rhizosphere, and roots of the common bent (Agrostis capillaris) and the hybrid poplar [Populus deltoides x (Populus trichocarpa x P. deltoides) cv. Grimminge], both of which grow on a chlorendic acid polluted site in Belgium. Isolates were taxonomically identified and phenotypically screened for chlorendic acid degradation. Several fungal isolates could degrade chlorendic acid in liquid media up to 45%. The chlorendic acid degrading fungal isolates produced higher levels of hydroxyl radicals when exposed to the pollutant when compared to non-exposed controls, suggesting that the oxidative degradation of chlorendic acid occurs through production of Fenton-mediated hydroxyl radicals. In addition, the isolated Ascomycete Penicillium sp. 1D-2a degraded 58% of the original chlorendic acid concentration in the soil after 28 days. This study demonstrates that the presence of fungi in a chlorendic acid polluted soil can degrade this highly chlorinated organic pollutant. These results indicate that recalcitrant, seemingly non-biologically degradable organic pollutants, such as chlorendic acid, can be remediated by using bioremediation, which opens new perspectives for in situ bioremediation. This work was supported by the UHasselt Methusalem project 08M03VGRJ and Arcadis Belgium NV to IJ and ST. ST was also supported by a grant from FWO-Flanders, Belgium.

A set of new N-substituted chlorindylimides and a chlorendic acid sodium-coordination polymer were synthesized. The synthetic chemical advantages of hexachlorobornenyl moiety and the presence of diverse substituents on the imide scaffold encouraged the exploration of the supramolecular crystal networks of all compounds based on Hirshfeld surface analysis which verified the participation of chlorine atoms in at least 70% of the total intermolecular interactions. The predominance of Cl…Cl vs C-H…Cl interactions is based on the structural features of the incorporated imide. Unprecedentedly, the sodium 1D-polymer is composed by dimer unites of two partially deprotonated chlorendic acids with two Na(I) nodes.

Chlorendic acid (CA) is a recalcitrant groundwater contaminant for which an effective treatment technology does not currently exist. In this study, a series of batch experiments were conducted to investigate the treatment of CA by zero-valent iron (ZVI) under various water chemistry conditions. It was observed that CA was removed by ZVI via both adsorption and degradation, with the degradation rate being proportional to the fraction of CA adsorbed onto ZVI. The rate of CA degradation decreased as pH increased, presumably due to the passivation of ZVI and diminishing CA adsorption. Chloride (Cl-) did not appreciably affect CA adsorption and degradation, while sulfate (SO42-) significantly inhibited both processes because SO42- competed with CA for ZVI adsorptive sites. The rate of CA degradation was significantly accelerated by ZVI-associated Fe(II). Nine byproducts of CA transformation were identified by high-resolution mass spectrometry. The formation and subsequent degradation of these products revealed that the transformation of CA by ZVI occurred via a step-wise reductive dechlorination pathway. Overall, this study suggests that ZVI may be effective at remediating CA-contaminated sites.

Artificial waters containing the xenobiotics atrazine, bisphenol A and chlorendic acid were treated by use of micro-disinfection apparatus, based on electrochemical ozone production. The design and working principle, as well as the applicability of the apparatus for the degradation of the target compounds is presented. The initial concentrations of the analytes were chosen to be in the mg L−1 order. Degradation and transformation of the analytes was determined via LC-MS, UV/Vis, and IC. Bisphenol A was degraded completely within short ozonation times, but complete mineralization could not be achieved. Ion chromatography indicated formic and oxalic acid to be transformation products. For atrazine a degradation of 96% could be achieved within 3 h. Intermediate transformation products, like desethylatrazine, desisopropylatrazine, and desethyl-desisopropylatrazine, are formed and further degraded to formic acid and chloride. Chlorendic acid was degraded by up to 40% of the initial concentration. Analyses by UV/Vis and IC again showed formic acid, chloride, and also chlorate to be transformation products.

A new complex based on chlorendic acid (HET), [Cd8(HET)8(DMF)4(H2O)12]·8DMF (1) was synthesized by liquid evaporate method from the mixture of HET and Cd(NO3)2·4H2O. Single crystal X-ray analysis reveals that the structure of complex 1 features a one-dimensional (1D) wave chain that is further assembled into three-dimensional (3D) framework directed by supramolecular interactions, including hydrogen bond, Cl···Cl halogen bond, and so on. To the best of our knowledge, this is the first metal-organic coordination polymer based on chlorendic acid (HET). The luminescent property and thermal stability of complex 1 were also discussed.

Optically clear poly(methyl methacrylate) (PMMA) blends with HET-EG oligoester (synthesized by condensation of chlorendic acid with ethylene glycol) at six different compositions were prepared by bulk polymerization. The effect of HET-EG in the PMMA matrix on the optical clarity of PMMA blend was measured using ultraviolet-visible spectroscopic study. The thermal stability of PMMA blends was investigated using differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses. The parameters to deduce the thermal stability of pure PMMA and PMMA blends were calculated from DSC and TG results. The thermal stability of PMMA was found to increase effectively by loading 5% of HET-EG oligoester without marring optical clarity. The probable physical and chemical actions of HET-EG oligoester on the thermal stability of PMMA are discussed. Copyright © 2011 John Wiley & Sons, Ltd.

Flame retardants are chemicals that are added to plastic materials in order to prevent them from catching fire and to slow down the burning process. Due to the widespread occurrence of flame retardants in the environment, it can be expected that especially the more hydrophilic compounds already contaminate raw water resources of water utilities. In this paper results of laboratory-scale experiments on the behaviour of ten brominated and chlorinated flame retardants during different steps of drinking water treatment will be presented. The target compounds were selected based on their production volumes and physical-chemical properties. The final list includes 1- and 2-bromostyrene, 2,4- and 2,6-dibromophenol, tetrabromophthalic acid, tetrachlorophthalic anhydride, chlorendic acid, tris(1,3-dichloro-2-propyl) phosphate, tris(2-chloroethyl) phosphate (TCEP), and tris(1-chloro-2-propyl) phosphate (TCPP). The results obtained from the laboratory-scale experiments clearly indicate that from the selected flame retardants only 1- and 2-bromostyrene are well biodegradable under aerobic conditions whereas the other flame retardants under investigation turned out to be persistent. Flocculation with either iron or aluminium salts is not an efficient option for removal of the selected flame retardants. For 1- and 2-bromostyrene removal rates of ca. 50% can be achieved whereas for the other compounds removal rates are in the range of 10 to 30% even when dosing 50 mg/L of flocculation agent. Oxidation with either ozone or ozone/hydrogen peroxide proved also to be rather inefficient for removal of the flame retardants under investigation, even at elevated doses of oxidant of 10 mg/L. However, results showed that the selected flame retardants adsorb well onto activated carbon and thus GAC adsorption seems to be a promising option for their removal.

Recently some novel alternative flame retardants (NFRs), which have been widely applied to meet demands for mandated flame retardation of products, have been detected in various matrices of the environment. However, knowledge on toxic effects and associated molecular mechanisms of these chemicals was limited. Here, toxic mechanisms of action of six NFRs, bis (2-ethylhexyl) phosphate (BEHP), chlorendic acid (Het acid), 2,2-bis (bromomethyl)-1,3-propanediol (BMP), tris (2-butoxyethyl) phosphate (TBEP), triethyl phosphate (TEP), tributyl phosphate (TBP) were investigated by use of a library containing ∼1820 modified green fluorescent protein (GFP) expressing promoter reporter vectors constructed from Escherichia coli K12(E.coli). BEHP, Het acid, BMP, TBEP, TEP, TBP inhibited growth of E. coli with 4 h 10%-inhibition concentrations of 53.0-3102.3 μM. A total of 119, 44, 26, 131, 62, 103 genes out of 336 genes selected during preliminary screening were significantly altered with fold-changes greater than 1.5 by BEHP, Het acid, BMP, TBEP, TEP and TBP, respectively. GO analyses of responsive genes suggested that RNA and primary metabolism process were involved in molecular mechanisms of toxicity. Chemical clustering based on expression of 62 multi-responsive genes showed that BEHP, TBP and TBEP were grouped together, which is consistent with similarity of their chemical structures, especially for BEHP and TBP. Clustering by molecular descriptors and molecular activity by use of the multivariate classification system ToxCast was consistent with that by profiles of multi-responsive genes. The results of this study demonstrated the utility of the E. coli, whole-cell assay for determining mechanisms of toxic action of chemicals.

Chlorendic acid-based and tetrabromophthalate polyesters are major flame-retardant polyester resins, often used with antimony trioxide. For translucency, colloidal antimony pentoxide is preferred. Brominated diols are occasionally used. In the vinyl ester group, the adducts of acrylic or methacrylic acid with the diglycidyl ether of tetrabromobisphenol A are prodominant, and the styrene-cured resins often have advantageous physical properties and hydrolytic stability. Low styrene versions have air pollution advantages. Hydrated mineral fillers, notably ATH, are widely used at high loadings. ATH tend to reduce smoke, as does use of MMA instead of styrene. Oligourethane unsaturated resins, cured with MMA, also favor low smoke. Triethyl phosphate and dimethyl methylphosphonate enable viscosity reduction and enhance flame retardancy. Red phosphorus, ammonium polyphosphate and a char-forming organophosphate have also found niches. Phosphoruscontaining reactives have been largely unsuccessful. In situ melamine phosphate shows promise. Protective veils offer an alternative to flame retarding the resin itself.

The photo-catalytic degradation of chlorendic acid in the presence of TiO 2 was conducted to investigate the reaction pathways and possible degradation products as a means of assessing the environmental legacies of polyesters that are designed with both chlorendic acid and TiO 2 chemicals. Comparison of liquid chromatography/mass spectrometry spectra of chlorendic acid and degradation solutions suggests HCl, H 2 O and chlorendic acid anhydride as the main products of the degradation process.

The destruction of pentachlorophenol (PCP), oxalic acid, chlorendic acid, and a mixture of pentachlorophenol, 1,3-dichlorobenzene (DCB), and trichloroethylene (TCE) were studied using a two-phase ozonation system. A two-phase ozonation system consists of water containing the pollutant and a second solvent phase which houses the ozone. The solvent phase is an inert fluorinated hydrocarbon (FC40) that is nonpolar and reusable. The solvent phase is desirable because it has a high ozone stability (k = 0.0033 min−1) and an ozone solubility of 120 mg/L at 25°C, 10 times that of water. In addition to an enhanced oxidation rate of PCP, less ozone was utilized. At high pH (10.3), a first-order rate constant of 200 min−1 in the two-phase system was found for PCP degradation compared to kapp = 0.154 min−1 in a single aqueous-phase system. Within 15 s, the concentration of PCP (100 mg/L initially) was degraded more than 90%, and 100% dechlorination was obtained with longer reaction times. This system also demonstrated the ability to selectively oxidize PCP while in the presence of free radical scavengers existing in the water phase. PCP was also successfully oxidized using actual wastwater which contained alkalinity, hardness, many inorganics, and trace hazardous organics. Oxalic acid, an intermediate formed during the degradation of PCP, was also degraded by two-phase ozonation. Preliminary work with chlorendic acid showed that two-phase ozonation was faster than single aqueous-phase ozonation at dechlorinating the compound. TCE and DCB degraded slightly faster when PCP was added to the mxture, possibly due to the production of other radicals during the oxidation of PCP.

Chlorendic acid, a fire retardant, was subjected to sequential chemical/biological oxidation. Degradation of chlorendic acid was achieved by ozonation with chlorinated and non-chlorinated by-product production. The destruction of chlorendic acid and by-product distribution was a function of ozone contact time. After 450 min of ozonation, chlorendic acid and TOC removal percentages equaled 98% and 62.5%, respectively. When subject to 210 min of UV oxidation, chlorendic acid and TOC removal equaled 70 and 31%, respectively. With combined ozone/UV, near complete removal of chlorendic acid and TOC was achieved in 90 and 120 min, respectively. In biodegradation testing, chlorendic acid was not degradable. Biodegradation efficiency (DOC removal) of chlorendic acid ozonation by-products was a function of ozone contact time and approached 80%. Chlorendic acid UV oxidation products (210 min contact time) were poorly biodegraded. Ozone/UV oxidation products (40 min contact time) from chlorendic acid achieved 89% biodegradation. Biodegradation rates of chlorendic acid chemical oxidation by-products also were assessed. Based on the computed biokinetic values of biodegradation rates for the chemical oxidation products of chlorendic acid are sufficiently high to enable use of existing biological process infrastructure for treatment of chemical oxidation products.

The title compounds were isolated from acidified (pH 1) water by extraction with methyl t-butyl ether. Analytes were concentrated by back-extracting the ether with 0.1 N sodium hydroxide which was separated and acidified. This solution was analyzed by C18 reversed-phase HPLC with water/acetonitrile/ acetic acid eluent and UV detection at 222 nm. The method has detection limits of 200 μg/L for chlorendic acid and 100μg/L for benzoic acid and each isomer of chlorobenzoic acid. Validation studies with water which was fortified with the analytes at concentrations ranging from one to ten times detection limits resulted in average recoveries of >95%.

In this study, a continuous-flow UV-induced mutation (CUM) device and the CUM device coupled to a selector (CUMS) reactor were fabricated and tested for their ability to enhance the probability of obtaining populations capable of chlorinated organic biodegradation. A mixed culture of bacteria were used as the starting strain for both the CUM and CUMS processes. Populations were obtained from the CUM and CUMS systems capable of 4-chlorobenzoic acid, 2,4-dichlorobenzoic acid and chlorendic acid biodegradation. Non-UV irradiated population served as controls for the experiments and did not demonstrate chlorinated organic biodegradation over the test duration.

An experimental study was conducted to investigate the use of ozone to dechlorinate chlorendic acid [1,4,5,6,7,7-hexachlorobicyclo-(2,2,1)-hept-5-ene-2,3-dicarboxylic acid; CAS Number 115-28-6]. The dechlorination and subsequent degradation of chlorendic acid by ozonation is influenced by the pH, applied ozone dose and bicarbonate concentration. A change in the initial chlorendic acid concentration to 50, 100 and 200 mg/l did not influence the rate of degradation of chlorendic acid. Ultraviolet radiation alone also dechlorinated chlorendic acid. Ultraviolet radiation (u.v.) was also shown to greatly enhance the oxidation of chlorendic acid in the presence of ozone. In a typical case, 80% dechlorination of chlorendic acid was obtained in 60 min when using an ozone dose of 125 mg/min ozone at pH 7.4. In addition to the experimental results, a model describing the dechlorination of chlorendic acid is presented. The pseudo-first order rate constants for a two-step model were calculated and ranged from 0.002 to 0.295 min−1 for the first step and 0.008 to 6 × 1012 min−1 (calculated) for the second step. The magnitude of the rate constants and corresponding rates of dechlorination of chlorendic acid were shown to be dependent upon the production and/or scavenging of hydroxyl radicals in solution. Conditions favoring radicals in solution, such as high pH and the addition of u.v., resulted in much faster dechlorination. The conditions which did not favor radicals, such as low pH and the addition of bicarbonate, resulted in slower dechlorination.

The adsorption behavior of chlorendic acid (1, 4, 5, 6, 7, 7-hexachlorobicyclo-(2, 2, 1) -hept-5-ene-2, 3-dicarboxylic acid) onto hydrophilic fumed TiO2 (P-25, Degussa) in aqueous suspension was investigated. Results indicate that chlorendic acid adsorbed strongly in short times (2-5 mins) onto TiO2. Adsorption data is consistent with Langmuir-Hinshelwood isotherm model for monolayer adsorption and the shape of the isotherm indicates second order behavior. Calculated adsorption constant K, and maximum adsorbable quantity at 20oC were obtained as (0.12 ± 0.03) l/mg and (4.4 ± 0.2) mg/g TiO2 respectively. Adsorption of chlorendic acid in water onto TiO2 is exothermic.

Polyester resins were prepared from chlorendic acid, maleic anhydride, and ethylene- and/or propylene-glycol. The resins were cured at room temperature with two different crosslinking agents including styrene and methyl methacrylate. The thermal behaviour of these polyester resins and their cured products was studied. From the thermogravimetric data it was observed that the polyester resins cured with styrene are thermally more stable than the methyl methacrylate cured products. It was also observed that the polyester resin prepared from propylene glycol is thermally more stable relatively than the ethylene glycol based polyester resin. The activation energies of thermal degradation of the resins and their cured products were calculated. The implications of these results are discussed. Es wurden Polyesterharze aus Chlorendicsaure, Maleinsaureanhydrid und Ethylen-und/oder Propylenglykol hergestellt. Die Harze wurden bei Raumtemperatur mit zwei verschiedenen Vernetzern, Styrol und Methylmethacrylat, gehartet. Das thermische Verhalten dieser Polyesterharze und ihrer geharteten Produkte wurde untersucht. Aus den thermographischen Messungen wurde geschlossen, das die Polyesterharze, die mit Styrol gehartet wurden, thermisch stabiler sind als die mit Methylmethacrylat geharteten Produkte. Es wurde auch beobachtet, das das aus Propylenglykol hergestellte Polyesterharz thermisch stabiler ist als das auf Ethylenglykol basierende Harz. Die Aktivierungsenergien des thermischen Abbaus der Harze und ihrer geharteten Produkte wurden berechnet. Die Schlusfolgerungen aus diesen Ergebnissen werden diskutiert.

The effect of gamma ray irradiation on chlorendic acid based unsaturated polyesters was studied. Four different types of unsaturated polyesters, made by varying the molar ratios of chlorendic acid to isophthalie acid were irradiated with a Co60 qource. After irradiation, the chlorine content decreases rapidly as the isophthalate content in the polyester chain increases. As the chlorendle acid content increases, the change in acid value after irradiation decreases. The increase in intrinsic viscosity is quite marked in high isophthalate containing polyesters after gamma ray irradiation and there is a noticeable decrease in intrinsic viscosity after gamma irradiation of high chlorendic acid containing polyesters. The effect of gamma irradiation on the percentage of cis and trans forms of these polyesters was studied with the help of infrared spectra. It appears that as the chlorendic acid content increases, on gamma irradiation conversion from trans unsaturation to cis unsaturation increases rapidly. Der Einflus von γ-Strahlen auf Hexachlorendomethylenhexahydrophthalsaure (HCPS) enthaltende ungesattigte Polyester wurde untersucht. Dazu wurden vier Polyester mit verschiedenem Molverhaltnis an Chlorendic-Saure zu Isophthalsaure mit einer Co60-Quelle bestrahlt. Durch die Bestrahlung erniedrigt sich der Chlorgehalt stark mit zunehmendem Gehalt an Isophthalsaure. Mit steigendem Gehalt an HCPS nimmt die durch die Bestrahlung hervorgerufene Anderung der Saurezahl ab. Die Grenzviskositat steigt bei Polyestern, die viel Isophthalat-Gruppen enthalten, und falt bei solchen mit hohem Gehalt an HCPS. Der Einflus der γ-Be-strachlung auf das Verhatnis von cis- und trans-Form in diesen Polyestern wurde an Infrarotspektren untersucht. Es zeigt sich, das mit zunehmendem Gehalt an HCPS die durch die Bestrahlung verursachte trans-cis-Umwandlung stark ansteigt.

For study of maleate/fumarate isomerisation in unsaturated polyesters infrared technique was used without using model compounds. This was done by solving the following equation for two different polyesters or one polyester with two concentrations for the molar extinction coefficients at 675 cm−1 for maleate and 980 cm−1 for fumarate. Percentages of maleate and fumarate are given by following equations: The out of plane vibration of CH for maleate appeared at slightly lower frequency, i.e. at 675 cm−1 due to steric hindrance. It was noted that the increase of the ratio of maleate to saturated acid in the polyester enhances the conversion from maleate to fumarate due to coiling tendency of the chain and causing steric compression. This tendency was also shown by phthalic anhydride based polyesters due to ortho carboxylic group compared with adipic acid and isophthalic acid. It is evident from more conversion from maleate to fumarate in case of phthalic anhydride based polyesters than that of isophthalic acid and adipic acid based polyesters. In case of bisphenol-A based polyesters, low conversion from maleate to fumarate took place, because of less coiling of between the two segments of the chain which are phenyl groups associated through carboxyl group of maleate. Conversion was more pronounced in polyesters based on 2.2-di-(4-hydroxy-3.5-dibromophenyl) propane and 2.2-di-(4-hydroxy-3.5-dichlorophenyl)-propane due to steric hindrance. An alternative explanation for more conversion from maleate to fumarate in case of halogenated bisphenol based polyesters may be due to catalysing effect of the small amount of halogen evolved during polycondensation. Similarly in chlorendic acid (1.4.5.6.7.7-hexachloro-5-norbornene-2.3-dicarboxylic acid) based polyesters, the isomerisation from maleate to fumarate increases as the chlorendic acid content in the polyester increases. In this case catalysing effect of chlorine evolved during polycondensation may be more effective because dissociation of halogen from non-aromatic system is easier than from aromatic system. Die Maleinsaure/Fumarsaure-Isomerisierung in ungesattigten Polyestern konnte mittels IR-Spektren untersucht werden, ohne das Modellverbindungen notwendig waren. Hierzu diente die Losung folgender Gleichung fur zwei verschiedene Polyester oder fur einen Polyester bei zwei Konzentrationen, um die molaren dekadischen Extinktionskoeffizienten fur den Maleinsaurebaustein bei 675 cm−1 und fur den Fumarsaurebaustein bei 980 cm−1 zu ermitteln Die Prozentgehalte an Malein- und Fumarsaurebausteinen sind durch folgende Gleichungen gegeben: Wegen sterischer Hinderung erscheint die CH-Schwingung (out of plane) fur Maleinsaure bei der etwas niedrigeren Frequenz 675 cm−1. Steigendes Verhaltnis Maleinsaure zu gesattigter Saure im Polyester vermehrte die Inversion von Maleinsaure zu Fumarsaure wegen der vergroserten Knauelung und Erhohung der Knaueldichte. Das gleiche zeigte sich bei Polyestern aus Phthalsaureanhydrid wegen der o-standigen Carboxylgruppe und im Vergleich mit Adipinsaure und Isophthalsaure, denn die Isomerisierung von Maleinzu Fumarsaure war in Polyestern aus Phthalsaureanhydrid groser als bei jenen aus Isophthalsaure und Adipinsaure. Enthielten die Polyester auch Bisphenol-A-bausteine, so war die Isomerisierung gering, weil die Phenylbausteine eine geringere Knauelung verursachen. Dagegen stieg der Isomerisierungsgrad bei Polyestern mit 2.2-Di-(4-hydroxy-3.5-dibromphenyl)-propan und 2.2-Di-(4-hydroxy-3.5-dichlorphenyl)-propan wegen der groeren sterischen Hinderung. Jedoch ist es auch moglich, das geringe, wahrend der Polykondensation frei gewordene Halogenmengen die Isomerisierung katalysierten. Das gleiche wurde mit Polyestern, die auch Chlorendicsaure (1.4.5.6.7.7-Hexachlor-5-norbornen-2.3-dicarbonsaure) enthielten, beobachtet ; der Grad der Isomerisierung stieg mit wachsendem Saureanteil. Die starkere Katalyse wird auf die kleinere Bindungsenergie nicht aromatisch gebundenen Halogens zuruckgefuhrt.

The flame resistance of wool fabrics is usefully increased by treating them with aliphatic haloorganic acid halides in dimethylformamide for 15 -30 min at 50°C. Both chlorine and bromine derivatives are effective. At least 2% com bined halogen by weight appears necessary to protect woolen fabrics. 'I'he flame resistance is durable to drycleaning and laundering. Prior stabilization of the fabric to felting shrinkage was needed to evaluate durabihty of flame resistance to laundering.

It was found that DL-allothreonine forms scarcely any soluble compounds with 5-nitronaphthalene-1-sulfonic acid, α-naphthylphosphoric acid, chlorendic acid, and tetrachlorophthalic acid in water. DL-Threonine formed soluble or unstable compounds in water with these acids. The synthetic threonine mixture was successfully separated into DL-threonine and DL-allothreonine.

The solvent extraction of Cu(II) with chlorendic acid has been studied The composition of the extracted species appears to be a function of pH. In the pH range 3.2-4.6, a monomeric species exists [Cu(II)(L(2-)], while at pH values greater than 4.5, a dimer in the form of [Cu(II)(L(2-)). H(2)L](2) and/or [Cu(II)(HL(-))(2)](2) is extracted.

Partial hepatectomy (PH) and neonatal rat short-term liver focus models were used to examine the effects of selected chemicals that had been previously tested in the National Toxicology Program (NTP) 2-yr carcinogenicity studies. C.I. Solvent Yellow 14, monuron, chlorendic acid, and 4-hydroxyacetanilide were tested for initiating and promoting activity in the PH model. Chlorendic acid, 4,4-oxydianiline, 1-amino-2,4-dibromoanthraquinone (ADBAQ), and 4-hydroxyacetanilide were similarly tested in a neonatal rat liver focus model. With the exception of 4-hydroxyacetanilide which was not carcinogenic in the NTP studies, all chemicals tested showed clear evidence of hepatocarcinogenicity. While none of the chemicals showed initiating activity in either the PH or neonatal models, promoting activity, as indicated by increased number, size, or volume fraction of histochemically detected hepatic foci of cellular alteration, was evident for all chemicals with previously demonstrated hepatocarcinogenicity. Liver tumor incidence was documented at 14 months in the PH model and at 300 days in the neonatal model. On the basis of the results obtained from these few chemicals, it is suggested that the use of short-term rat liver focus models may represent a reliable means for identifying chemicals with hepatocarcinogenic potential.

The absorption, distribution, and excretion of a highly chlorinated dicarboxylic acid, chlorendic acid, was studied in the male Fischer 344 rat. [14C]Chlorendic acid was absorbed after an oral dose of 7.7 mumol per kilogram of body weight. The distribution in various tissues was similar whether the treatment was by the oral or the intravenous route. The major site of [14C]chlorendic acid deposition was the liver, with smaller amounts found in the blood, muscle, skin, and kidneys. Chlorendic acid-derived radioactivity was excreted primarily through the bile and into the feces. The urine contained less than 6% of the total dose. Within 1 d, more than 75% of the total dose was excreted in the feces, primarily as metabolites. Radioactivity in the liver was also primarily metabolites of chlorendic acid. Thus, chlorendic acid was absorbed, metabolized, and excreted primarily in the feces as metabolites. The rapid metabolism and biliary excretion of chlorendic acid contrast with observations for the closely related lipophilic compounds aldrin and dieldrin.