No abstract

Linear alkylbenzene sulfonate (LAS) biodegrades easily and loses its tensioactive properties quickly through a primary biodegradation process, as many works of literature testify. Many studies have been carried out in laboratories or in pilot plants, whereas few have been undertaken in a wastewater treatment plant (WWTP). In Italy, unlike in other countries, no detailed investigation has been made so far to establish LAS biodegradation in real WWTP conditions. EniChem Augusta (EA) and Consorzio Po‐Sangone (CPS) have worked together for over two years on this problem, taking into consideration the large (flow rate: approximately 400 × 103 m3/d) and central active sludge WWTP of the metropolitan area of Torino, north of Italy. Specific LAS data have been obtained, using established HPLC techniques, in influent and effluent streams, in the dissolved (waters) and adsorbed (suspended solids and sludges) phases, to reach a complete mass balance. LAS removal >99% and LAS biodegradation of approximately 85% have been observed. Attention also has been given to LAS intermediates of biodegradation, namely the sulfophenyl carboxylates (SPC), using HPLC and GC‐MS techniques, the latter after derivatization. The SPCs have been found present only in the waters and not in the adsorbed phases (SS and sludges).

Aerobic biodegradation of the 2-butyl-octyl alcohol polyethoxylate (2Bu-C8AE) was investigated under laboratory standardized conditions (Organization for Economic Cooperation and Development 301E and 310B screening test protocols) to study the effect of the 2-alkyl chain length on the biodegradation mechanism of monobranched alcohol polyethoxylates (AEs). The 2Bu-C8AE was compared with linear and monobranched AEs with short 2-alkyl chains, which were simultaneously tested under the same inoculum conditions. The metabolites identified and the primary biodegradation rate constants obtained indicate that the alkyl chain length of the 2-alkyl substituent is the factor governing the biodegradation pathway of monobranched AEs. Short 2-alkyl substituents (i.e., methyl and ethyl groups) allow the central cleavage mechanism to occur, which leads to the formation of polyethylene glycols, whereas AEs with longer alkyl substituents, such as the 2Bu-C8AE, biodegrade through hydrolytic oxidation of the alkyl and polyethoxylic chains, which leads to formation of AE metabolites with carboxylic groups on both the hydrophobic and hydrophilic moieties

No abstract

A gas chromatography and gas chromatography mass spectrometry study was performed on four commercial linear alkylbenzenes (LAB). A preliminary detailed analysis was done on some model compounds: four tetralin mixtures obtained by alkylation of benzene with linear dichloro n-paraffins (C 10, C11, C12, and C 13), 1-methyl-4-heptyltetralin and 1-methyl-3octylindane. We concentrated on the minor components (5-10%) present in the linear alkylbenzenes. Three different types of compounds were identified: A) branched alkylbenzenes, B) 1,4-dialkyltetralins with linear alkyl groups, and C) 1,4-dialkyltetralins with branched alkyl groups. Quantitative evaluation of these minor components was also done. No evidence of 1,3-dialkylindane structures, at least those with linear alkyl groups, was found in the commercial linear alkylbenzenes studied.

No abstract

No abstract

The high‐resolution NMR spectra at 60 and 100 Mcps of poly(vinyl chloride)‐β,β‐d2 in o‐dichlorobenzene, pyridine, and C2HCl5 solutions are reported. The use of low molecular weight samples and of {D} spin‐decoupling experiments, which yield higher resolution spectra, results in the observation of a number of additional resonances for the α‐proton. These can be interpreted in terms of pentad configurational sequences of monomer units. It is found that, whereas the S syndiotactic pentads cannot be resolved, two components of the H heterotactic and all of the possible I isotactic pentads are clearly discernible. From the tacticity values of polymers prepared at +40, 0, and −40°C, enthalpy and entropy of activation for isotactic and syndiotactic monomer placement are found to be 630 cal/mole and 1.5 eu, respectively.