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Zhihua Zhang - One of the best experts on this subject based on the ideXlab platform.
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the difference in hydrogenation performance between ni in al2o3 and ni on al2o3 for hydrotreating of crude 2 Ethylhexanol
Korean Journal of Chemical Engineering, 2010Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Two mesoporous material Ni/γ-Al2O3 catalysts were prepared and characterized by ICP-AES, XRD, and TPR. The differences in reaction activity between Ni-in-Al2O3 and Ni-on-Al2O3 were investigated for hydrotreating of crude 2-Ethylhexanol. The results show that the Ni species (Ni-on-Al2O3) exhibit excellent hydrogenation activities at a wide range of H2 pressure and space velocity, while the Ni species (Ni-in-Al2O3) exhibit similar activities with those of Ni-on-Al2O3 only at higher H2 pressure and lower space velocity. Due to the presence of extensively exposed Ni species on the Ni-on-Al2O3 catalyst, its hydrogenation performance was increased significantly because of the low interphase mass transfer resistance.
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hydrotreating of crude 2 Ethylhexanol over ni al2o3 catalysts surface ni species catalytic activity correlation
Applied Catalysis A-general, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua Zhang, Yufeng Cheng, Jintao GuoAbstract:Abstract A series of supported Ni/γ-Al 2 O 3 samples were prepared and then used to identify the surface Ni species. The samples were characterized by ICP-AES, XRD, TPR, and XPS. The results indicated that two types of Ni species occurred on the samples with Ni loading 9.1 wt%. The reduction temperatures around 350, 500–520, 620–650, and 750–800 °C corresponding to Ni species were related to amorphous NiO, crystal NiO, NiAl 2 O 4 , and NiAl x O y ( x > 2), respectively. A correlation was made between the catalytic activities and the surface Ni species. For the catalysts that were difficult to reduce (Ni loading 9.1 wt%), the activities were excellent in a wider reduction temperature range from 400 to 800 °C.
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promotion effects of copper and lanthanum oxides on nickel gamma alumina catalyst in the hydrotreating of crude 2 Ethylhexanol
Journal of Physical Chemistry C, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Nickel/gamma-alumina (Ni/γ-Al 2 O 3 ) catalysts promoted with Cu and La were prepared by the impregnation method and characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). XRD and HRTEM indicated that the addition of La and Cu was helpful to decrease the size of active particles and increase the dispersion of Ni species. TPR showed that Cu can effectively decrease the reduction temperatures of its own and Ni oxides, whereas La can change the proportion of various Ni species and increase the content of easily reducible Ni species. XPS and UV-vis DRS indicated that electron shift occurred on the Ni-based sample modified by Cu and enhanced remarkably by adding La. These findings suggest that Cu and La species induce both structural and electronic promotion effects, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately enhancing the crude 2-Ethylhexanol hydrotreating catalytic performance.
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promotion effects of la and ce on ni γ al2o3 catalysts in hydrotreating of crude 2 Ethylhexanol
Catalysis Letters, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Promotion effects of La and Ce on Ni/γ-Al2O3 catalysts in hydrotreating of crude 2-Ethylhexanol were studied. The results indicated that La was helpful to increase the content of octahedral Ni2+ ions while Ce had no such modification effect. Activity test indicated that catalysts modified by La exhibited higher activities compared with the unmodified and Ce modified catalysts. The sample modified with 1.5 wt% La presented the best activities in a wide range of space velocity from 1.5 to 12 h−1.
James A Nicell - One of the best experts on this subject based on the ideXlab platform.
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origin of 2 Ethylhexanol as a voc
Environmental Pollution, 2006Co-Authors: Sandro Nalli, Owen J Horn, David G Cooper, Adam R Grochowalski, James A NicellAbstract:2-Ethylhexanol has been identified as a volatile organic compound (VOC) that contributes to the deterioration of indoor air quality. Plasticizers are common components of dust and building materials and are shown to be degraded by a variety of bacteria and fungi to produce 2-ethyhexanol and other metabolites. Of these, the 2-Ethylhexanol has significant volatility and was observed in appreciable quantities. The degree to which 2-Ethylhexanol is observed as a VOC in air samples would be limited by the fact that many of the microorganisms that are capable of producing this compound are also able to oxidize it to 2-ethylhexanoic acid, which is much less volatile. It is argued that an abiotic degradation mechanism of plasticizers that results in the generation of 2-Ethylhexanol is unlikely and, if this did occur, other metabolites should have been observed. Thus, the microbial degradation of plasticizers is the most likely source of 2-Ethylhexanol in indoor air.
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plasticizer metabolites in the environment
Water Research, 2004Co-Authors: Owen J Horn, Sandro Nalli, David G Cooper, James A NicellAbstract:Earlier work with pure cultures had shown that the interaction of microbes with plasticizers leads to the formation of metabolites including 2-ethylhexanoic acid and 2-Ethylhexanol that resist further degradation. The presence of these metabolites is now reported in a variety of environmental samples. Thus, even in a complex ecosystem, when plasticizers are degraded, the breakdown is not complete and significant amounts of 2-ethylhexanoic acid and 2-Ethylhexanol are observed. These compounds have been shown to exhibit acute toxicity using Microtox, Daphnia, rainbow trout and fathead minnow toxicity assays. Since it is already well established that plasticizers are ubiquitous in the environment, it is expected that their recalcitrant metabolites will also be ubiquitous. This is of concern because, while the plasticizers do not exhibit acute toxicity, their metabolites do.
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Biodegradation of plasticizers by Rhodococcus rhodochrous
Biodegradation, 2002Co-Authors: Sandro Nalli, D. G. Cooper, James A NicellAbstract:Rhodococcus rhodochrous was grown in the presence of oneof three plasticizers: bis 2-ethylhexyl adipate (BEHA), dioctyl phthalate (DOP) ordioctyl terephthalate (DOTP). None of the plasticizers were degraded unless anothercarbon source, such as hexadecane, was also present. When R. rhodochrous was grownwith hexadecane as a co-substrate, BEHA was completely degraded and the DOP was degraded slightly. About half of the DOTP was degraded, if hexadecane were present.In all of these growth studies, the toxicity of the media, which was assessed usingthe Microtox assay, increased as the organism degraded the plasticizer. In each case, therewas an accumulation of one or two intermediates in the growth medium as the toxicityincreased. One of these was identified as 2-ethylhexanoic acid and it was observed forall three plasticizers. Its concentration increased until degradation of the plasticizershad stopped and it was always present at the end of the fermentation. The other intermediatewas identified as 2-Ethylhexanol and this was only observed forgrowth in the presence of BEHA. The alcohol was observed early in the growth studies with BEHA and haddisappeared by the end of the experiment. Both the 2-Ethylhexanol and 2-ethylhexanoicacid were shown to be toxic and their presence explained the increase of toxicity asthe fermentations proceeded. The appearance of these intermediates was consistent with similar degradation mechanisms for all three plasticizers involving hydrolysisof the ester bonds followed by oxidation of the released alcohol.
Renchun Yang - One of the best experts on this subject based on the ideXlab platform.
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the difference in hydrogenation performance between ni in al2o3 and ni on al2o3 for hydrotreating of crude 2 Ethylhexanol
Korean Journal of Chemical Engineering, 2010Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Two mesoporous material Ni/γ-Al2O3 catalysts were prepared and characterized by ICP-AES, XRD, and TPR. The differences in reaction activity between Ni-in-Al2O3 and Ni-on-Al2O3 were investigated for hydrotreating of crude 2-Ethylhexanol. The results show that the Ni species (Ni-on-Al2O3) exhibit excellent hydrogenation activities at a wide range of H2 pressure and space velocity, while the Ni species (Ni-in-Al2O3) exhibit similar activities with those of Ni-on-Al2O3 only at higher H2 pressure and lower space velocity. Due to the presence of extensively exposed Ni species on the Ni-on-Al2O3 catalyst, its hydrogenation performance was increased significantly because of the low interphase mass transfer resistance.
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hydrotreating of crude 2 Ethylhexanol over ni al2o3 catalysts surface ni species catalytic activity correlation
Applied Catalysis A-general, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua Zhang, Yufeng Cheng, Jintao GuoAbstract:Abstract A series of supported Ni/γ-Al 2 O 3 samples were prepared and then used to identify the surface Ni species. The samples were characterized by ICP-AES, XRD, TPR, and XPS. The results indicated that two types of Ni species occurred on the samples with Ni loading 9.1 wt%. The reduction temperatures around 350, 500–520, 620–650, and 750–800 °C corresponding to Ni species were related to amorphous NiO, crystal NiO, NiAl 2 O 4 , and NiAl x O y ( x > 2), respectively. A correlation was made between the catalytic activities and the surface Ni species. For the catalysts that were difficult to reduce (Ni loading 9.1 wt%), the activities were excellent in a wider reduction temperature range from 400 to 800 °C.
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promotion effects of copper and lanthanum oxides on nickel gamma alumina catalyst in the hydrotreating of crude 2 Ethylhexanol
Journal of Physical Chemistry C, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Nickel/gamma-alumina (Ni/γ-Al 2 O 3 ) catalysts promoted with Cu and La were prepared by the impregnation method and characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). XRD and HRTEM indicated that the addition of La and Cu was helpful to decrease the size of active particles and increase the dispersion of Ni species. TPR showed that Cu can effectively decrease the reduction temperatures of its own and Ni oxides, whereas La can change the proportion of various Ni species and increase the content of easily reducible Ni species. XPS and UV-vis DRS indicated that electron shift occurred on the Ni-based sample modified by Cu and enhanced remarkably by adding La. These findings suggest that Cu and La species induce both structural and electronic promotion effects, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately enhancing the crude 2-Ethylhexanol hydrotreating catalytic performance.
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promotion effects of la and ce on ni γ al2o3 catalysts in hydrotreating of crude 2 Ethylhexanol
Catalysis Letters, 2009Co-Authors: Renchun Yang, Xin Zhang, Zhihua ZhangAbstract:Promotion effects of La and Ce on Ni/γ-Al2O3 catalysts in hydrotreating of crude 2-Ethylhexanol were studied. The results indicated that La was helpful to increase the content of octahedral Ni2+ ions while Ce had no such modification effect. Activity test indicated that catalysts modified by La exhibited higher activities compared with the unmodified and Ce modified catalysts. The sample modified with 1.5 wt% La presented the best activities in a wide range of space velocity from 1.5 to 12 h−1.
Yanji Wang - One of the best experts on this subject based on the ideXlab platform.
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preparation and catalytic performance of nio mno2 nb2o5 tio2 for one step synthesis of 2 Ethylhexanol from n butyraldehyde
Catalysis Communications, 2021Co-Authors: Jiaxun Zhang, Xinqiang Zhao, Yanji WangAbstract:Abstract One-pot synthesis of 2-Ethylhexanol(2EHO) from n-butyraldehyde is of commercialimportance. The promotion of 2EHO selectivity requires suppressing direct hydrogenation of n-butyraldehyde. In this work, a series of NiO-MOx/Nb2O5-TiO2 catalysts were prepared and utilized by means of reduction-in-reaction technique, aiming at delaying the formation of metal sites and suppressing the direct hydrogenation. NiO-MnO2/Nb2O5-TiO2 with a Ni/Mn mass ratio of 10 and NiO-MnO2 loading of 14.3 wt% shows the best catalytic performance; 2-EHO selectivity could reach 90.0% at a complete conversion of n-butyraldehyde. Furthermore the catalyst could be used for four times without a substantial change in its catalytic performance.
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preparation of highly selective and stable cu mg fe catalyst and its catalytic performance for one step synthesis of 2 Ethylhexanol from n butyraldehyde
Reaction Kinetics Mechanisms and Catalysis, 2019Co-Authors: Shuang Miao, Xinqiang Zhao, Yanji WangAbstract:A Cu–Mg–Fe catalyst was prepared by a coprecipitation–impregnation method and some influential factors such as Cu/Fe molar ratio, Mg/Fe molar ratio, calcination temperature and reduction temperature were investigated by means of XRD, XPS, NH3(or CO2)-TPD, H2-TPR and SEM analyses. Suitable preparation conditions were obtained as follows: a Cu/Mg/Fe ratio of 1:2:1, a calcination temperature of 550 °C, and a reduction temperature of 450 °C. The Cu–Mg–Fe catalyst showed a high catalytic performance for one-step synthesis of 2-Ethylhexanol from n-butyraldehyde; the yield and selectivity of 2-Ethylhexanol were 68.6% and 72.4% while the overall selectivity of C8 + C4 products was greatly improved to 96.9% under suitable reaction conditions.
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catalytic performance of cu mg al in the one step synthesis of 2 Ethylhexanol from n butyraldehyde
Reaction Kinetics Mechanisms and Catalysis, 2018Co-Authors: Shuang Miao, Xinqiang Zhao, Yanji WangAbstract:2-Ethylhexanol (2EHO), an important plasticizer alcohol, is industrially produced through three consecutive reaction processes. In this work, the one-step synthesis of 2EHO from n-butyraldehyde was exploited using Cu/Mg2.5AlOx catalyst. The effect of reaction conditions was investigated and the suitable reaction conditions were obtained as follows: a catalyst mass percentage of 10%, a H2 pressure of 4 MPa, a reaction time of 10 h and a reaction temperature of 180 °C. Under these reaction conditions, the yield of 2-Ethylhexanol reached 62.8% and the selectivity ratio of 2-Ethylhexanol to n-butanol (S2EHO/SBO) was 5.02. Based on designed experiments and the results of catalyst characterization using NH3-TPD, CO2-TPD and XPS techniques, it was clarified that the synergistic effect of acid–base and the interaction between Mg and Al were responsible for the better catalytic performance of Cu/Mg2.5AlOx. Then a plausible reaction mechanism of n-butyraldehyde self-condensation catalyzed by Cu/Mg2.5AlOx was presumed.
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One-Pot Sequential Aldol Condensation and Hydrogenation of n-Butyraldehyde to 2-Ethylhexanol
Industrial & Engineering Chemistry Research, 2016Co-Authors: Xiaohong Liu, Xinqiang Zhao, Yanji WangAbstract:2-Ethylhexanol (2EHO) is an important organic chemical. The industrial production of 2EHO comprises three units: propylene hydroformylation to n-butyraldehyde, n-butyraldehyde self-condensation to 2-ethyl-2-hexenal (2E2H), and 2E2H hydrogenation to 2EHO. In the present work, 2EHO was synthesized by one-pot sequential aldol condensation and hydrogenation of n-butyraldehyde. Among a series of metal–solid acid bifunctional catalysts, Ni/La–Al2O3 showed a better catalytic performance. The effect of reaction conditions on the one-pot sequential synthesis of 2EHO catalyzed by Ni/La–Al2O3 was investigated, and the suitable reaction conditions were obtained as follows: weight percentage of Ni/La–Al2O3 = 15%, self-condensation reaction conducted at 180 °C for 8 h, and then hydrogenation reaction conducted at 180 °C for 6 h under 4 MPa H2 pressure. Under the above reaction conditions, n-butyraldehyde conversion attained 100% at a 2EHO selectivity of 67.0%. The inhibition of Ni to n-butyraldehyde self-condensation r...
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direct synthesis of 2 Ethylhexanol via n butanal aldol condensation hydrogenation reaction integration over a ni ce al2o3 bifunctional catalyst
Green Chemistry, 2015Co-Authors: Ning Liang, Xinqiang Zhao, Xiaolong Zhang, Yanji WangAbstract:Direct synthesis of 2-Ethylhexanol from n-butanal via the reaction integration of n-butanal self-condensation with 2-ethyl-2-hexenal hydrogenation is of crucial interest for industrial production of 2-Ethylhexanol. Furthermore, as an important and versatile chemical, n-butanol can be produced simultaneously by reaction integration. In the present work, several bifunctional catalysts based on γ-Al2O3 were prepared by the impregnation method and were characterized by means of H2-TPR, XRD, TEM and H2-TPD, and their catalytic performance for direct synthesis of 2-Ethylhexanol from n-butanal was investigated. The results showed that Co/Al2O3 had a low activity for hydrogenation and Cu/Al2O3 had a high selectivity for the hydrogenation of the CO group while a Ru/Al2O3 catalyst only favored the hydrogenation of n-butanal to n-butanol. Among them, the Ni/Al2O3 catalyst showed the best catalytic performance and the yield of 2-Ethylhexanol was the highest (49.4%). Ce-modified Ni/Al2O3 enhanced the competitiveness of aldol condensation versus hydrogenation of n-butanal and improved the selectivity of 2-Ethylhexanol; the yield of 2-Ethylhexanol rose to 57.8%. Then the influence of preparation conditions on the catalytic performance of Ni/Ce-Al2O3 was investigated and the suitable preparation conditions were obtained as follows: Ni loading = 10%, calcined at 550 °C for 5 h, and reduced at 570 °C for 4 h. The effect of reaction conditions on the integration reaction catalyzed by Ni/Ce-Al2O3 was investigated and the suitable reaction conditions were obtained as follows: weight percentage of Ni/Ce-Al2O3 = 15%, reaction temperature = 170 °C, reaction pressure = 4.0 MPa and reaction time = 8 h. Under the above reaction conditions, the yield of 2-Ethylhexanol attained 66.9% and that of n-butanol was 18.9%. In addition, the components existing in the integration reaction system were identified by GC-MS analysis, and the main by-products were n-butyl butyrate, 2-ethylhexyl butyrate, n-butyric acid, etc. Based on the analysis of the reaction system, a reaction network for the direct synthesis of 2-Ethylhexanol from n-butanal was proposed. Finally, an evaluation of the reusability of Ni/Ce-Al2O3 showed that the recovered Ni/Ce-Al2O3 catalyst lost its catalytic activity for the hydrogenation of the CO group. The main reason for deactivation was that Ni species were covered by the flaky boehmite γ-AlO(OH) formed from the hydration of γ-Al2O3 in the reaction process.
Ronald G. Thurman - One of the best experts on this subject based on the ideXlab platform.
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wy 14 643 but not 2 Ethylhexanol increases intracellular free calcium in cultured kupffer cells
Toxicology Letters, 1991Co-Authors: Hijioka Taizo, Barbara J Keller, Ronald G. ThurmanAbstract:Abstract Hypolipidemic drugs and phthalic ester plasticizers induce peroxisomes and cause hepatocellular carcinoma in rodents by mechanisms which remain unknown. Recent evidence from this laboratory suggests that many agents in this class of chemicals are uncouplers of mitochondrial oxidative phosphorylation both in vitro and in vivo. Uncoupling of oxidative phosphorylation decreases ATP required for ion pumps and could thereby indirectly increase intracellular free calcium. The goal of these experiments, therefore, was to compare the effect of the potent uncoupler and non-genotoxic carcinogen Wy-14,643 with the weaker agent 2-Ethylhexanol on intracellular free calcium in cultured Kupffer cells. Kupffer cells, the resident hepatic macrophages, are activated by calcium and release a variety of mitogenic growth factors that may modulate cell proliferation. In this study, the cytosolic free calcium concentration in Fura-2-loaded cultured Kupffer cells was increased significantly from 78 ± 11 to 838 ± 112 nM following incubation with Wy-14,643 (1.25 mM). The increase in intracellular calcium due to Wy-14,643 was both time- and dose-dependent. At equimolar concentrations, Ethylhexanol had no effect on intracellular calcium (65 ± 20 nM). However, at higher concentrations (3 mM), Ethylhexanol also increased intracellular calcium. These data suggest that elevation of intracellular calcium in Kupffer cells may be involved in the mechanism of action of this interesting class of non-genotoxic carcinogens.
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2 Ethylhexanol uncouples oxidative phosphorylation in rat liver mitochondria
Toxicology Letters, 1991Co-Authors: Barbara J Keller, Decai Liang, Ronald G. ThurmanAbstract:Abstract 2-Ethylhexanol (70 μM), a non-genotoxic carcinogen and peroxisome proliferator, stimulated oxygen uptake in the perfused rat liver by about 10%6 during the first 10 min of infusion. Perfusion with a higher, hepatotoxic dose of Ethylhexanol (3 mM) led to a transient increase in oxygen uptake followed by a rapid inhibition of respiration of over 50% in 10 min. Lactate dehydrogenase (LDH) release, indicative of irreversible cell death, was detected in the effluent perfusate after 20 min. After 10 min of perfusion with Ethylhexanol, livers were freeze-clamped, acid extracts were prepared and adenine nucleotides were measured by high-pressure liquid chromatography. Ethylhexanol decreased the ATP/ADP ratio from 2.5 to 0.9. Thus, marked decreases in hepatic energy state due to inhibition of respiration preceded cell death. To attempt to understand this phenomenon, the effect of Ethylhexanol on isolated mitochondria was studied. Similar to classical uncoupling agents, Ethylhexanol stimulated state-4 rates of respiration, diminished coupled rates of respiration, and decreased the P/O ratio in a dose-dependent manner in isolated mitochondria. Ethylhexanol also decreased uptake of radiolabeled 45 CaCl 2 by isolated mitochondria 4- to 5-fold. Therefore, we hypothesize that Ethylhexanol initially uncouples oxidative phosphorylation leading to diminished ATP synthesis and collapse of ion gradients across the mitochondrial membrane.
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oxygen tension is a major determinant of hepatotoxicity due to 2 Ethylhexanol in isolated tissue cylinders from periportal and pericentral regions of the liver lobule from phenobarbital treated rats
Toxicology and Applied Pharmacology, 1991Co-Authors: Decai Liang, Barbara J Keller, Uma K. Misra, Ronald G. ThurmanAbstract:Abstract 2-Ethylhexanol, a metabolite of the commonly used plasticizer di(ethylhexyl)phthalate, was shown to cause toxicity exclusively to periportal regions of the perfused liver (Keller et al., 1990, J. Pharmacol. Exp. Ther. , 252, 1355–1360.) To determine whether this toxicity was due to local oxygen tension or to drug delivery, isolated cylinders (plugs) of periportal and pericentral regions of the liver lobule from rats pretreated with phenobarbital were collected with a micropunch following brief perfusion of the organ. Plugs were 0.2 mm wide and 0.5 mm long and weighed between 0.5 and 1 mg each. Following incubation for at least 2 hr in Eagle's medium, they were judged viable based on production of urea at high rates and minimal leakage of lactate dehydrogenase (LDH). Plugs could be cultured for up to 24 hr with minimal loss of activity. Urea synthesis from ammonium chloride (3 m m ) by plugs incubated in Krebs-Henseleit buffer equilibrated with 95% O 2 :5% CO 2 was proportional to protein concentration and was linear with time for up to one hour at rates around 75 μmol/g/hr. Icubation of plugs with 2-Ethylhexanol (0.1 to 3 m m ) diminished urea synthesis in a dose-related manner (half-maximal effect = 0.5 m m ). Ethylhexanol also caused extensive cell damage assessed from LDH leakage in incubations at 800 μ m O 2 but significantly less injury at 200 μ m O 2 . Concomitantly, urea synthesis was inhibited by Ethylhexanol by over 80% at 800 μ m O 2 but less than 50% at 200 μ m O 2 . Plugs isolated from both regions of the liver lobule were affected similarly by Ethylhexanol and O 2 . Taken together, these data indicate that Ethylhexanol toxicity is dependent on oxygen tension in isolated sublobular regions of the liver lobule, and therefore it is unlikely that drug delivery can explain the selective injury to periportal regions in studies with the perfused liver.
