Distillate Aromatic Extract Research Articles

EPOXIDIZED NATURAL OILS AS THE ALTERNATIVE SAFE PROCESS OILS IN RUBBER COMPOUNDS

Abstract Due to the toxicity of aromatic oils derived from polycyclic aromatic hydrocarbons (PAHs), safe process oils are required for a replacement in rubber compounds. The properties of tire tread compounds filled with high abrasion furnace black (HAF) when epoxidized palm oil (EPO) and epoxidized soybean oil (ESBO) are used as the processing oils, in comparison with the use of conventional distillate aromatic extract (DAE) were investigated. The oil characteristics were analyzed by spectroscopic techniques (FTIR and NMR), differential scanning calorimetry and elemental analysis. Influence of the oils on the properties of natural rubber (NR), NR/styrene butadiene rubber (SBR) blend, and SBR compounds was investigated. All compounds with the EPO and DAE oils have similar cure characteristics (i.e., scorch and cure times, torque differences) and processing properties (i.e., minimum torques and Mooney viscosities). However, the use of ESBO oil clearly retards the curing reaction, resulting in lower extent of crosslinking, and thus inferior vulcanizate properties. The mechanical properties, e.g., hardness, modulus, tensile strength, elongation at break, tear, and abrasion resistance, of the compounds utilizing the EPO and DAE oils are comparable and superior to those of the ESBO added compound. In addition, the use of EPO results in similar dynamic mechanical properties of rubber vulcanizates when compared with conventional DAE. The results indicate that EPO is a potential candidate for the placement of DAE oil in rubber compounds.

Evaluation of Pyrolytic Oil from Scrap Tires as Plasticizer of Rubber Compounds

A heavy fraction of oil obtained from pyrolysis of rubber crumb derived from scrap tires was studied by H-NMR and FT-IR spectroscopy in comparison to a distillate aromatic extract (DAE) derived from petroleum and currently used as plasticizer in rubber mixes. The spectral data suggest a rough chemical analogy between the two oils although the viscosity and the density of the pyrolysis oil are significantly lower that that of the aromatic extract suggesting a significantly lower average molecular weight for the pyrolytic oil in comparison to the reference DAE oil. The two oils were tested at 10 and 15 phr level in a NR-based formulation and the cure kinetics and the mechanical properties of the rubber compounds have been measured. The pyrolytic oil gives accelerated cure kinetics, reduced scorch safety and lower compound viscosity in comparison to reference compounds with DAE oil. The mechanical properties of the cured compounds prepared with pyrolysis oil from scrap tires appear similar to the reference compounds prepared with DAE oil. However, the ageing resistance of the pyrolysis oil are worse than the reference compound with DAE oil.

Gamma radiolysis of a heavy petroleum fraction

A relatively heavy petroleum fraction called distillate aromatic extract (DAE) which has been proposed to be the carrier of the emission bands of certain astronomical objects like protoplanetary nebulae (PPNe) and the so-called unidentified infrared bands (UIBs), has been radiolyzed with γ-radiation to a total dose of 1 MGy. The stability of DAE toward radiation was assessed by FT-IR and electronic spectroscopy. The gases produced during radiolysis have been identified by GC. They were essentially H2 and CH4. A certain degree of crosslinking has been verified on the radiation-processed material by measuring the hexane insoluble fraction of DAE, which increased dramatically after the radiation treatment. Further analyses were conducted using high performance liquid chromatography (HPLC) on the radiation processed sample in comparison to the pristine sample.

A new model for the interpretation of the unidentified infrared bands (UIBS) of the diffuse interstellar medium and of the protoplanetary nebulae

In this work we started from the basic idea that the pure polycyclic aromatic hydrocarbons (PAHs) cannot be the real carriers of the unidentified infrared bands (UIBs), the emission spectra coming from a large variety of astronomical objects. Instead we propose a new model taken from petroleum chemistry which, we can show, is able to match both the UIBs and even the protoplanetary nebulae (PPNe) spectra. PAHs such as phenanthrene, benzoperylene, coronene and pentacene, are too pure and too specific to really exist in the interstellar medium. Instead our model proposes that the carrier of UIBs and PPNe are complex molecular mixtures like those obtained as fractions during the petroleum refining processes. These molecular mixtures are so complex that practically the investigators did not try to identify each individual component but characterized the mixture with an average molecular structure that takes into account both the average molecular weight and the average content of aromatic, naphtenic (cycloaliphatic) and aliphatic (paraffinic) fraction. We show by infrared spectroscopy that petroleum fractions obtained at certain steps of the refining process are able to match the UIBs and the PPNe infrared bands with the advantage of not being so specific as PAHs are. Namely we have used as samples a distillate aromatic extract (DAE) a treated residual aromatic extract (T-RAE) and finally a naphtenic oil. Among the three samples examined, the DAE sample was the best in matching the UIBs and PPNe spectra.

Correlation of 32P-postlabelling-detection of DNA adducts in mouse skin in vivo with the polycyclic aromatic compound content and mutagenicity in Salmonella typhimurium of a range of oil products.

The in vivo genotoxic activities in mouse skin of the dimethyl sulphoxide (DMSO) extracts of a range of oil products [residual aromatic extract; untreated heavy paraffinic distillate aromatic extract; mildly refined light naphthenic base oil; bitumen (vacuum residue); high viscosity index base oil obtained by catalytic hydrogenation] were evaluated by 32P-postlabelling DNA analysis. The results of quantitative 32P-postlabelling analyses of epidermal DNA from mice treated with the DMSO extracts showed linear relationships with the total polycyclic aromatic compound (PAC) contents, determined by the Institute of Petroleum method IP 346 and also the 3-6 ring PAC contents, measured by on-line liquid-liquid extraction using flow injection analysis. The 32P-postlabelling data also showed a linear relationship with the mutagenicity indices of these oil products determined in S. typhimurium TA98 using the modified Ames Salmonella microsome test. The in vivo genotoxicity of the DMSO extracts from the oil products was low, judged by 32P-postlabelling analysis of DNA adducts measured in epidermal DNA of treated mouse skin, and ranging from 2 to 723 attomole/microg DNA per mg oil product. The in vivo 32P-postlabelling data from this study are consistent with these materials expressing low genotoxicity in mouse skin in vivo. The DMSO extraction procedure coupled with 32P-postlabelling DNA analysis is useful for ranking the relative genotoxic potency in vivo of a wide range of oil products. In general the trend observed is similar to rankings based on physicochemical measurements of total PAC contents or 3 6 ring PAC contents of the oil products.

Developmental toxicity of clarified slurry oil, syntower bottoms, and distillate aromatic extract administered as a single oral dose to pregnant rats.

Clarified slurry oil (CSO), syntower bottoms (STB), and distillate aromatic extract (DAE) are refinery streams produced by processing crude oil. Each of these refinery streams is rich in both hydrocarbons having carbon numbers of C20 or greater and polycyclic aromatic compounds. Available data indicate that some refinery streams are developmentally toxic (manifested primarily as increased embryolethality and growth retardation) by the dermal route of exposure. However, there is no conclusive evidence for their being teratogenic. The present studies were designed to further explore the suspected teratogenic potency of refinery streams while at the same time limiting embryolethality. To profile teratogenic effects as a function of gestation day, pregnant rats received a single oral dose (2000 mg/kg) of CSO, STB, or DAE on one of gestation days (GD) 11-14; DAE and STB were also administered on GD 15. To profile effects as a dose response function, rats received a single oral dose of CSO, DAE, or STB on GD 12 at 125, 500, and 2000 mg/kg. Control animals were similarly treated but were administered tap water. On GD 20, dams were necropsied and the fetuses evaluated for normal development. In general, evidence of maternal toxicity (i.e., decreased body weight gain, decreased thymus weight) was observed at doses greater than or equal to 500 mg/kg. For each refinery stream tested, the incidence of resorption was greatest on GD 11. A common pattern of fetal malformations was observed for all of the refinery streams tested and included cleft palate, diaphragmatic hernia, and paw and tail defects. The incidence and type of malformation observed were influenced by the gestation day of exposure. The incidences of external and skeletal malformations were greatest on GD 11 and 12 for fetuses exposed to CSO; on GD 13 and 14, the incidence of malformation was comparable for CSO- and STB-exposed fetuses. The incidence of visceral anomalies was greatest on GD 11-13 for fetuses exposed to CSO and STB; on Gestation D 14, the incidence was comparable for each of the refinery streams tested. In general, the ability to produce adverse effects on development was greatest for CSO and least for DAE. Effects produced by STB were comparable to or less severe than those observed for CSO.

Systemic and Developmental Toxicity of Dermally Applied Distillate Aromatic Extract in Rats

Distillate aromatic extract (DAE) was evaluated for subchronic and developmental toxicity. In the subchronic study, undiluted DAE was applied on the shaved backs of male and female rats at dose levels of 0, 30, 125, 500, and 1250 mg/kg for 13 weeks, 5 days per week. Exposure sites were not covered. In the developmental toxicity study, DAE was similarly applied, but to pregnant rats at dose levels of 0, 8, 30, and 125 mg/kg on Gestation Days 0–19, 500 mg/kg on Gestation Days 0–16, and 1000 mg/kg on Gestation Days 10–12. Evidence of toxicity observed in the subchronic study included death, decreased body weights, aberrant serum chemistry and hematology values, altered organ weights, and histopathologic changes in a variety of organs. Regardless of the length of the exposure period, DAE was toxic to the developing conceptus. Evidence of developmental toxicity observed included increased resorptions and reduced fetal body weights. Cleft palate and ossification delays were observed in fetuses exposedin uteroto DAE on Gestation Days 10–12, but not when exposure spanned all (Gestation Days 0–19) or most (Gestation Days 0–16) of gestation.

Systemic and Developmental Toxicity of Dermally Applied Distillate Aromatic Extract in Rats

Systemic and Developmental Toxicity of Dermally Applied Distillate Aromatic Extract in Rats

Correlation of Systemic and Developmental Toxicities with Chemical Component Classes of Refinery Streams

Correlation of Systemic and Developmental Toxicities with Chemical Component Classes of Refinery Streams. Feuston, M. H., Low, L. K., Hamilton, C. E., and Mackerer, C. R. (1994). Fundam. Appl. Toxicol. 22, 622-630.Refinery streams are complex mixtures, but of a relatively few homologous series of hydrocarbons (paraffins, olefins, naphthenics, and aromatics). Studies were performed to determine if systemic and developmental toxicity were related to the presence and levels of certain classes of refinery stream components. We have performed systemic toxicology studies in the rat on 13 refinery streams: Clarified Slurry Oil, Coker Light Gas Oil, Distillate Aromatic Extract, Heavy Atmospheric Gas Oil, Heavy Coker Gas Oil (from three refineries), Heavy Vacuum Gas Oil, Light Catalytically Cracked Naphtha, Light Cycle Oil, Syntower Bottoms, Vacuum Tower Overhead, and Visbreaker Gas Oil. Rats were exposed via repeated dermal administration (daily) at several dose levels. Developmental toxicology studies were performed on these same streams with the following exceptions: only two Heavy Coker Gas Oils were tested and Visbreaker Gas Oil was not tested. End points for systemic toxicity (13-week) studies included skin irritation, body and organ weights, hematology, and serum chemistry; for developmental toxicity studies some of these same end points (excluding hematology) were considered, but they also included resorption and fetal body weight. In general, toxicity was correlated with concentrations of polycyclic aromatic compounds (PAC) composed of 3, 4, 5, 6, and/or 7 rings (decreased thymus weight, increased liver weight, aberrant hematology and serum chemistry, increased incidence of resorption, decreased fetal body weight), PAC containing nonbasic nitrogen heteroatoms (increased mortality, decreased body weight, decreased thymus weight, increased liver weight, decreased hemoglobin content and hematocrit level, decreased fetal body weight), and/or PAC containing sulfur heteroatoms (decreased red blood cell and platelet counts, increased sorbitol dehydrogenase.) A relationship between 2-ring PAC and skin irritation was demonstrated. Severity of effect was ranked against concentration of component class and statistical significance determined by the rank-order correlation of Spearman. For the 13 streams tested, the presence and severity of systemic and developmental toxicity were dependent upon the levels of PAC and nonbasic nitrogen PAC. These classes of compounds are also believed to be major contributors to the dermal carcinogenic activity of crude oils, certain refinery streams, and poorly refined lube oils.