Concentrations Of Butadiene Research Articles

Overview of Butadiene Chemical Reaction Fouling in Steam Crackers and Its Control by Carbon Steel Surface Modification

The main objective of the Steam Cracker is to produce monomers prone to polymerization. The drawback is that polymerization can occur in the Steam Cracker itself. The main monomers fouling precursor is Butadiene. All along the separation process, Butadiene concentration and process temperature change. This implies step changes in polymer structure and fouling level. Several techniques are used to control this fouling, including oxygen ingress control, the use of additives such as antioxidants and free radical scavengers. By a catalytic effect, the metal surfaces can also be a polymerization initiator. The objective of passivation is to modify the Carbon Steel surface into stable magnetite and maghemite. Using electrochemistry to characterize different Carbon Steel samples, we were able to improve our passivation procedure. And when applying metal passivation, we were able to increase run length of Depropanizer reboilers limiting the fouling rate and its impact on operation.

Source Contribution of 1,3 Butadiene in the Vicinity of Petrochemical Industrial Area

Emissions and ambient concentrations of 1,3 butadiene released from the synthetic rubber industries in the largest petroleum and petrochemical complex in Thailand were evaluated in this study. The industrial emissions in this analysis were those emitted from process fugitive, combustion stack, flare, and wastewater treatment facility. It was found that wastewater treatment units were the largest emission source among other potential sources. The contribution of emission from wastewater treatment plants were about 92% of total 1,3 butadiene emission. The extent and magnitude of 1,3 butadiene in ambient air were further evaluated through the simulation of AERMOD dispersion model using these emission data together with local meteorological and topographical characteristics. Predicted annual 1,3 butadiene concentrations at every receptor were lower than its ambient air quality standard (< 0.33 μg m-3). Source apportionment analysis was performed with the objective to reveal the contribution of each emission source to the ambient concentrations at each receptor. Analytical results indicated that wastewater treatment units were the major emission source affected to the environmental concentrations of 1,3 butadiene in the study area. Evaluation of the potential adverse health impact of this chemical revealed that there may be a potential carcinogenic risk from inhalation exposure of 1,3 butadiene. Therefore, an effort in controlling emission of 1,3 butadiene should be given the priority to effectively manage the level of this compound in the environment.

Ethylene‐Butadiene Copolymerization and Ethylene‐1‐Hexene‐Butadiene Terpolymerization with a MgCl2‐Supported Ziegler‐Natta Catalyst: Polymer Structure and Active Centers

AbstractIn this work, systematic studies on ethylene/butadiene copolymerization and ethylene/1‐hexene/butadiene terpolymerization with a TiCl4/ID/MgCl2(ID=diester) type Z−N catalyst were conducted in slurry process under 1 atm ethylene pressure, and the effects of initial butadiene concentration ([Bd]0) on polymerization activity, copolymer structure, active center number ([C*]/[Ti]) and active center distribution were studied. Activity of the co‐ and terpolymerization was evidently lowered by raising [Bd]0. The butadiene incorporations were highlytrans‐1,4 regio /stereoselective. Addition of 1‐hexene caused increase in polymerization activity, and 1‐hexene incorporation rate was reduced by raising [Bd]0. Both the copolymer and terpolymer were composed of two fractions with high and low butadiene content, respectively. The fraction with low butadiene content (insoluble in boilingn‐heptane) accounted for more than 85 % of the copolymer and more than 70 % of the terpolymer. [C*]/[Ti] was determined by quench‐labeling the propagation chains by thiophene‐2‐carbonyl chloride. [C*]/[Ti] first increase to about 80 % and then decreased with increase of [Bd]0. A part of active centers was deactivated by butadiene when [Bd]0was higher than 0.2 mol/L. Addition of 1‐hexene slightly increased [C*]/[Ti] ratio. By using supported Z−N catalysts, it is feasible to synthesize ethylene‐butadiene copolymer and ethylene‐1‐hexene‐butadiene terpolymer with relatively low butadiene content (≤1 mol %) at acceptable catalyst efficiency (about 50 % of the polymerization systems without butadiene).

Influence of binary waste mixtures on road performance of asphalt and asphalt mixture

The utilization of processed waste materials in road construction is of utmost significance from the environmental and economic viewpoints. In this paper, waste cooking oil (WCO) and ground tire rubber (GTR) were applied to modify the asphalt binder. Based on the optimal content of both modifiers, sixteen asphalt samples with different combinations of the two wastes were designed. Relevant tests including basic properties along with rheological behavior and chemical characterization were carried out on the modified asphalt. The results indicated that the modified asphalt with 20 wt % GTR and 2.5 wt %-5 wt. % WCO exhibited satisfactory high temperature resistance and low temperature rheological properties. The Fourier transform infrared spectroscopic investigation revealed that the presence of GTR increased the concentration of styrene and butadiene while the addition of WCO introduced fatty acids and esters to modified asphalt. Overall, the road performance studies demonstrate that modified asphalt mixture with 5 wt % WCO and 20 wt % GTR displayed a markedly improved anti-rutting properties, water stability and superior low-temperature performance compared to normal asphalt mixture.

Butadiene hydroformylation to adipaldehyde with Rh-based catalysts: Insights into ligand effects

Rh-catalyzed hydroformylation of butadiene to adipaldehyde is a promising alternative route for producing valuable C6 compounds such as adipic acid and hexamethylenediamine. Fundamental insights into reaction pathways, aimed at enhancing adipaldehyde yield, were obtained from temporal concentration profiles and in situ ReactIR studies of butadiene hydroformylation on Rh complexes at 80 °C and 14 bar syngas (molar CO/H2 = 1) pressure in a batch reactor. Specifically, the effects of operating conditions and eight commercially available ligands on activity and selectivity were systematically investigated. It was found that the adipaldehyde selectivity is independent of the ligand/Rh ratio, rhodium concentration, butadiene concentration and syngas pressure, but significantly dependent on the type of ligand used. For example, while the DIOP ligand provided an adipaldehyde yield of ∼40% with butadiene as a substrate, the 6-DPPon ligand gave a maximum adipaldehyde yield of ∼93% with 4-pentenal as substrate. Furthermore, the adipaldehyde selectivity correlates well with the natural bite angle of the various ligands. ReactIR studies suggest that the preferential formation of the stable rhodium η3-crotyl complex with the various Rh complexes may be the main reason for the low adipaldehyde selectivity.

Exposure to ambient volatile organic compounds in an area with excess cancer and asthma morbidity

TPS 671: Cardiometabolic effects of long-term air pollution exposure, Exhibition Hall, Ground floor, August 26, 2019, 3:00 PM - 4:30 PM Background: The Haifa Bay Area (HBA) has been documented to experience relatively high morbidity from asthma and cancer. Previously, association with emissions from industrial facilities in the HBA has been examined. However, ambient concentrations of fine particulate matter, nitrogen oxides and BTEX (benzene, toluene, ethylbenzene and xylene) are lower in HBA than in other districts (such as the Tel-Aviv area). It has been proposed that this discrepancy may possibly result from unmeasured concentrations of certain volatile organic compounds and/or heavy metals, which are uniquely emitted by industrial facilities and are not characteristic of traffic, such as 1,2-dichloroethane and Isoamyl alcohol. A list of such compounds was formulated by the regulatory bodies and bi-weekly measurements began in 2015. Methods: Data on 25 distinct pollutants was collected from 30 locations spread within and outside of HBA. The measurements were generally performed on a bi-weekly basis from the start of 2015 until the end of 2018. The annual mean measurements within HBA were compared to those in other regions using a Mann-Whitney U-test. Results: A preliminary analysis indicates that there are significantly lower concentrations of butadiene, benzo(a)pyrene, and trichloroethylene in HBA than in other regions. The only pollutant whose concentrations seem to be significantly higher in HBA is particulate vanadium, which is commonly emitted into the atmosphere by metallurgical industries, oil refineries and the combustion of fossil fuels. No significant differences were found in the concentrations of the remaining 21 pollutants. Conclusion: The excess morbidity in the HBA was not found to be related to ambient air pollution. Future research of this issue should perhaps focus on indoor exposures and explanatory variables rather than on ambient air pollution.

Procedure LIAM (LDAR, IR Camera, Analyzing & Modeling) to determine the contribution of ambient emissions and combustion of hydrocarbon

In special petroleum areas where the petrochemical, petroleum and gas industries are located, ambient emissions are the first and most environmental pollutants that are undetectable. The present study aims to assess the environmental pollutants resulting from leaks and fixed resources of Olefin unit in the Arya Sasol Petrochemical Complex located in Asaluyeh, south of Iran. In this study, the LIAM method (LDAR, IR Camera, Analyzing & Modeling) was for sampling process during four seasons from 2016 to 2017. Leak points of the unit were detected by IR Camera and LDAR program. AERMODE software was also used to model the dispersion of SO2, NOX, CO2 and particulate matters released from the fixed resources. In the next, IDW method in ArcGIS 10.2 was conducted to interpolate the environmental pollutants. The interpolation of the annual average of pollutants showed that the concentration of benzene, butadiene, ethylbenzene, heptane and SO2 in some sections is higher than the environmental standards. The results of AERMODE modeling showed that the maximum 24-h concentration and annual average of SO2 only in autumn have exceeded the clean air standard. The combination of proposed methods in this study can be used as a smart way to evaluate the industrial pollutants.

Formation and Conversion of Surface Compounds upon Interaction of Ethanol with Cu/CeO2 Catalyst According to in situ IR Spectroscopy

In the conditions of ethanol conversion on the surface of a 5%Cu/CeO2 catalyst, the method of in situ IR spectroscopy reveals ethoxy groups, acetate and formiate complexes, and consolidation products. Acetaldehyde, acetone, croton aldehyde, butadiene, hydrogen, CO, and CO2 are observed in the reaction products. As the temperature of the experiment increases, the concentration of acetaldehyde passes through a maximum at T = 250°C. This product is formed due to the interaction of ethoxy and hydroxyl surface groups. The concentration of acetone, croton aldehyde, and butadiene also passes through a maximum in the 350–400°C range. These products are associated with the decomposition of the consolidation products. The concentration of hydrogen, CO and CO2 steadily increases with temperature and only these reaction products are left at T > 400°C. A mechanism of hydrogen formation based on the conversion of the highest temperature formiate surface complex is discussed.

Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol – A kinetic study combined with model-based experimental analysis

The telomerization of butadiene with methanol was investigated in the presence of different palladium catalysts modified either with triphenylphosphine (TPP) or 1,3-dimesityl-imidazol-2-ylidene (IMes) ligand. When pure butadiene was used as substrate, a moderate selectivity for the Pd-TPP catalyst toward the desired product 1-methoxy-2,7-octadiene (1-Mode) of around 87% was obtained, while the IMes carbene ligand almost exclusively formed 1-Mode with 97.5% selectivity. The selectivity remained unchanged when the pure butadiene feed was replaced by synthetic crack-C4 (sCC4), a technical feed of 45mol% butadiene and 55mol% inerts (butenes and butanes). The TPP-modified catalyst showed a lower reaction rate, which was attributed to the expected dilution effect caused by the inerts. Surprisingly, the IMes-modified catalyst showed a higher rate with sCC4 compared to the pure feed. By means of a model-based experimental analysis, kinetic rate equations could be derived. The kinetic modeling supports the assumption that the two catalyst systems follow different kinetic rate equations. For the Pd-TPP catalyst, the reaction kinetics were related to the Jolly mechanism. In contrast, the Jolly mechanism had to be adapted for the Pd-IMes catalyst as the impact of the base seems to differ strongly from that for the Pd-TPP catalyst. The Pd-IMes system was found to be zero order in butadiene at moderate to high butadiene concentrations and first order in base while the nucleophilicity of the base is influenced by the methanol amount resulting in a negative reaction order for methanol.

Rhodium-Catalyzed Hydroformylation of 1,3-Butadiene to Adipic Aldehyde: Revealing Selectivity and Rate-Determining Steps

The reaction mechanism of Rh-catalyzed hydroformylation of 1,3-butadiene with triptycene-derived bisphosphite ligands L was studied by in situ NMR and IR experiments, kinetic measurements, and deuterioformylation. Under CO pressure the η3-crotyl complex (κ2-L)Rh(η3-crotyl)(CO) is a stable intermediate that slowly liberates 3-pentenal when hydrogen is added. It also represents the most stable intermediate under real hydroformylation conditions and exists in high concentrations during the catalysis. The rate law of the reaction is found to be second-order in syngas pressure and independent of the butadiene concentration. This agrees with the total barrier between the η3-crotyl complex and one of the transition states of hydrogen addition or reductive elimination being rate determining. The olefin insertion step is found to be partly reversible depending on the pressure, which means that n/iso regioselectivity is not controlled by this step alone.

Thermal Recycling of Solid Tire Wastes for Alternative Liquid Fuel: The First Commercial Step in Bangladesh

Abstract The first small scale commercial tire waste pyrolysis plant has been installed by the Radiant Renewable Energy (RRE) Ltd. at Gazipur, Dhaka for reducing liquid fuel crisis in Bangladesh. The plant has two pyrolysis unit, each of them consists of a horizontal axis rotary type batch mode reactor with a recycling capacity of 4.5 tons/run. Solid tire wastes in half/whole size are feed into the reactor chamber, operating at 420oC with a light over-pressure of 0.03 bar. The reactor is heated externally by burning product pyrolysis liquids for first three hours and by burning product pyro-gas for rest five hours. The products distribution at optimum reactor operating condition were found oil: 45 wt%, char: 35 wt%, and gases: 10 wt%, in addition to the steel cords: 10 wt% of solid tire waste. The product liquids have been found to have a high gross calorific value (GCV) of around 44 MJ/kg, which would encourage their use as replacements for conventional liquid fuels. Pyrolytic char may be used as a solid fuel, activated carbon, priters ink etc. Pyrolysis gas contains high concentrations of methane, ethane, butadiene and other hydrocarbon gases with a GCV of approximately 37 MJ/m3, a value sufficient to provide the energy required by the tire pyrolysis process. However, the presented plant should be followed some recommended pionts for better operation and its further extension, and also for our sincere corner to safe environment. The plant can be run only under continuous monitoring and consultancy support of a tire pyrolysis specialist team because of new technology and waste material concern.

Analysis of solution polybutadiene polymerizations performed with a neodymium catalyst

AbstractThis article is regarding the polymerization of 1,3‐butadiene with a neodymium catalyst activated by diisobutylaluminum‐hydride and diethylaluminum chloride (DEAC). The effects of the polymerization conditions (ratio between DEAC and neodymium molar concentrations, polymerization temperature, catalyst concentration, and butadiene concentration) on the polymer yield and molecular weight distribution (MWD) of polybutadiene (PB) samples were evaluated. It is shown that the DEAC/Nd ratio and the polymerization temperature are the reaction variables that influence the MWD and the catalyst performance most significantly. PBs with broad and sometimes bimodal MWD were produced at the analyzed reaction conditions. For this reason, the MWD of the obtained polymer materials was deconvoluted with the help of the Flory most probable distribution, indicating that three or more catalyst sites are required to explain the final MWD of the polymer samples. Finally, it was observed that the analyzed neodymium catalyst is able to produce branched PBs at mild reaction conditions and that the branching frequency depends on the polymerization conditions, which may be useful for development of operation policies at plant site and production of materials with improved performances. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

Challenge assay: A functional biomarker for exposure-induced DNA repair deficiency and for risk of cancer

A variety of biomarkers have been used to monitor exposed populations to determine potential health hazards from their exposure to environmental toxic agents. However, the majority of these biomarkers have been focused onto the identification of biological damage from the exposure. Therefore, there is a need to develop functional biomarkers that can identify exposure-induced functional deficiencies. More importantly, these deficiencies should be positioned along pathways that are responsible for the development of specific diseases. One of such pathways belongs to the extensive and complex DNA-repair machinery. The machinery thus becomes a large target for damage from environmental toxic agents. The hypothesis is that damage to any component of a repair pathway will interfere with the pathway-specific repair activities. Therefore, when cells from exposed populations are challenged with a DNA-damaging agent in vitro, the in vivo exposure-induced repair deficiency will be dramatically amplified and the deficiency will be detectable in a challenge assay as increased chromosome aberrations, micronuclei or un-repaired DNA strand breaks. The challenge assay has been used in different laboratories to show that a variety of exposed populations (with exposure to air pollutants, arsenic, benzene, butadiene, cigarette smoke, incense smoke, lead, mercury, pesticides, uranium or xylene but not to low concentrations of air pollutants or butadiene) expressed abnormal challenge response. The predicted health consequences of some of these studies have also been validated. Therefore, the challenge assay is a useful functional biomarker for population studies. Details of the challenge assay and its application will be presented in this review.

Stochasticity in Physiologically Based Kinetics Models: Implications for Cancer Risk Assessment

In case of low-dose exposure to a substance, its concentration in cells is likely to be stochastic. Assessing the consequences of this stochasticity in toxicological risk assessment requires the coupling of macroscopic dynamics models describing whole-body kinetics with microscopic tools designed to simulate stochasticity. In this article, we propose an approach to approximate stochastic cell concentration of butadiene in the cells of diverse organs. We adapted the dynamics equations of a physiologically based pharmacokinetic (PBPK) model and used a stochastic simulator for the system of equations that we derived. We then coupled kinetics simulations with a deterministic hockey stick model of carcinogenicity. Stochasticity induced substantial modifications relative to dose-response curve, compared with the deterministic situation. In particular, there was nonlinearity in the response and the stochastic apparent threshold was lower than the deterministic one. The approach that we developed could easily be extended to other biological studies to assess the influence of stochasticity at macroscopic scale for compound dynamics at the cell level.

Risk Perception and Communication

Many health risks are the result of deliberate decisions by individuals consciously trying to get the best deal possible for themselves and for those important to them. Some of these choices are private ones, such as whether to wear bicycle helmets and seatbelts, whether to read and follow safety warnings, whether to buy and use condoms, and how to select and cook food. Other choices involve societal issues, such as whether to protest the siting of hazardous waste incinerators and half-way houses, whether to vote for fluoridation and "green" candidates, and whether to support sex education in the schools. In some cases, single choices can have a large effect on health risks (e.g. buying a car with airbags, taking a dangerous job, getting pregnant). In other

Kinetics of the Anionic Polymerization of Buta‐1,3‐diene Considering Different Reactivities of the cis, trans and vinyl Structural Units

AbstractThe anionic solution polymerization of buta‐1,3‐diene was modeled, considering the reactivity of the active sites to be different due to varying geometric configurations. With the first‐order Markov model, expressions for the fraction of active sites and dyad distribution were obtained. The rate constants were determined by fitting to the conversion and dyad experimental data using the nonlinear least squares method. The kinetic model shows that the microstructure and the dyads do not depend on initiator and butadiene concentration but only on rate constants. Without a modifier, the butadiene addition mechanism is entropic; with a modifier, the mechanism changes to entropic‐enthalpic.magnified image

Analysis and applications of measurements of source dominated hydrocarbon concentrations from the PUMA campaigns in June/July 1999 and January/February 2000 at an urban background site in Birmingham, UK

Approximately, hourly C 2 –C 7 hydrocarbon concentrations from gas chromatographic measurements are reported for an urban background site in Birmingham, UK, from summer 1999 and winter 1999–2000. Comparison with another measurement site suggests that the observed behaviour is typical of the urban background in the whole conurbation. The lack of any correlation between seasonal variation and OH rate coefficient shows that hydrocarbon concentrations are dominated by local sources. Chemical mass balance techniques have been applied and indicate the main sources are vehicle emissions (exhaust and fugitive) and natural gas leakage. Winter concentrations of isoprene correlate well with butadiene concentrations suggesting an automotive related source. This correlation disappears during the summer when isoprene displays a high correlation with radiation. During a period of the summer campaign ethane and propane concentrations displayed a regular diurnal behaviour, which has been utilized to estimate the ratios of the day/night boundary layer height and natural gas emission rates for the West Midlands conurbation.

The reactivity of 1,3-butadiene with butadiene-derived popcorn polymer

Adiabatic calorimetry performed on butadiene-derived popcorn polymer samples from industrial facilities has revealed exothermic behavior accompanied by non-condensible gas production, indicative of possible decomposition, at elevated temperatures. In the presence of low concentrations of 1,3-butadiene, reactivity is observed at temperatures of 60–70 °C; that is, 20–30 °C below those usually seen for butadiene alone. Once the butadiene is consumed, the reaction behavior reverts to that of the popcorn polymer alone. At higher butadiene concentrations, the low temperature reaction persists, eventually merging with typical butadiene behavior. The butadiene reactivity with popcorn polymer is attributed to polymerization reaction at free radical sites in the popcorn polymer. Different popcorn polymer samples exhibit distinct extents of reactivity, presumably depending on the nature and concentration of the free radical sites and the structure of the material. Uninhibited butadiene exposed to 100 psia air, which may act to generate peroxide species, shows a small, additional exotherm around 50–80 °C. Contact of butadiene with lauroyl peroxide, providing free radicals upon decomposition, generates an exotherm at temperatures as low as 60 °C.

Dose responses for the formation of hemoglobin adducts and urinary metabolites in rats and mice exposed by inhalation to low concentrations of 1,3-[2,3- 14C]-butadiene

Blood and urine were obtained from male Sprague–Dawley rats and B6C3F1 mice exposed to either a single 6 h or multiple daily (5×6 h) nose-only doses of 1,3-[2,3- 14 C ]-butadiene at atmospheric concentrations of 1, 5 or 20 ppm. Globin was isolated from erythrocytes of exposed animals and analyzed for total radioactivity and also for N-(1,2,3-trihydroxybut-4-yl)-valine adducts. The modified Edman degradation procedure coupled with GC–MS was used for the adduct analysis. Linear relationships were observed between the exposures to 1,3-[2,3- 14 C ]-butadiene and the total radioactivity measured in globin and the level of trihydroxybutyl valine adducts in globin. A greater level of radioactivity (ca. 1.3-fold) was found in rat globin compared with mouse globin. When analyzed for specific amino acid adducts, higher levels of trihydroxybutyl valine adducts were found in mouse globin compared with rat globin. Average levels of trihydroxybutyl valine adduct measured in globin from rats and mice exposed for 5×6 h at 1, 5 and 20 ppm 1,3-[2,3- 14 C ]-butadiene were, respectively, for rats: 80, 179, 512 pmol/g globin and for mice: 143, 351, 1100 pmol/g globin. The profiles of urinary metabolites for rats and mice exposed at the different concentrations of butadiene were obtained by reverse phase HPLC analysis on urine collected 24 h after the start of exposure and were compared with results of a previous similar study carried out for 6 h at 200 ppm butadiene. Whilst there were qualitative and quantitative differences between the profiles for rats and mice, the major metabolites detected in both cases were those representing products of epoxide hydrolase mediated hydrolysis and glutathione (GSH) conjugation of the metabolically formed 1,2-epoxy-3-butene. These were 4-( N-acetyl- l-cysteine- S-yl)-1,2-dihydroxy butane and ( R)-2-( N-acetyl- l-cystein- S-yl)-1-hydroxybut-3-ene, 1-( N-acetyl- l-cystein- S-yl)-2-( S)-hydroxybut-3-ene, 1-( N-acetyl- l-cystein- S-yl)-2-( R)-hydroxybut-3-ene, ( S)-2-( N-acetyl- l-cystein- S-yl)-1-hydroxybut-3-ene, respectively. The former pathway showed a greater predominance in the rat. The profiles of metabolites were similar at exposure concentration in the range 1–20 ppm. There were however some subtle differences compared with results of exposure to the higher 200 ppm concentrations. Overall the results provide the basis for cross species comparison of low exposures in the range of occupational exposures, with the wealth of data available from high exposure studies.

Carbon black used as a fluidization aid in gas phase elastomer polymerization: I. Carbon black–monomer interactions

The adsorption of butadiene on carbon black is a function of surface properties, high reinforcing, high surface area carbon black adsorbs more butadiene than low reinforcing big particle size carbon black. It is found that the functional groups on modified carbon blacks, oxidized or sulfur modified carbon blacks significantly reduces the butadiene concentration in headspace. Chemisorption of butadiene on the carbon black surface strongly holds butadiene on the surface, which prevents desorption of butadiene from the carbon black surface. These modified carbon blacks result in a very low concentration of butadiene in the headspace, usually 50–100 times lower than unmodified carbon black.