Production Of Phthalic Anhydride Research Articles

Profile of the Effectiveness Factor under Optimal Operating Conditions for the Conversion of Ortho-Xylene to Phthalic Anhydride in a Fixed-Bed Tubular Reactor

The objective of this research is to find the effectiveness factor of the catalyst particles for the most favorable conditions of the phthalic anhydride production in a fixed bed reactor, with the aim of achieving the highest rate of phthalic anhydride production compared to other secondary products and analyzing the areas of lower effectiveness for the modification of the reactor design. Initially, the material and the energy balances in the catalytic bed are solved to obtain the concentration and temperature profiles based on the radius and length of the reactor, using polymath software(Polymath® v6.2 Software Minitab 19 Matlab 2019) with the data from literature. Once the profiles reproducibility was verified using the initial data (inlet temperature, pressure in the reactor, reactor wall temperature, reactor radius and mass flow rate) the experimental design 35 carry out, which generates 243 “experiments”, whose response variable (phthalic anhydride concentration) was obtained using Matlab. Subsequently, the variables were analyzed using the Minitab 18® that, through the response surface analysis method, allowed us to obtain the optimal values of the tested variables. Then, Subsequently, material and energy balances coupled with Fourier and Fick’s laws, along with the effectiveness factor equation, were applied, resulting in the generation of 9 coupled differential equations. Upon implementing the finite difference method, this yielded 90 nonlinear algebraic equations, which were solved using the Polymath software. A total of 78 particles were preselected based on their radial and axial positions to determine the effectiveness factor profile, with values ranging from 0.83 to near unity. The lower values correspond to the points with higher temperature, as evidenced by the calculations performed.

Solving the Optimal Control Problem with Terminal Constraints in Modeling Chemical Processes

The paper presents a method for solving the problem of optimal control of a chemical process in the presence of terminal constraints based on the application of artificial immune systems. The formulation of the problem of optimal control of a chemical process in which the constraints on the control parameter and phase variables are given is formulated. An algorithm for solving this problem based on the penalty method and artificial immune systems is given. The penalty method allows to reduce the problem with terminal constraints to the problem without constraints by changing the optimality criterion. The new optimal control problem without terminal constraints is solved by the method of artificial immune systems. The described methodology is tested on the example of an industrially significant process of phthalic anhydride production. A mathematical description of the process, which is a system of ordinary differential equations, is given. The problem of search of optimal temperature regime with terminal constraints is formulated. As a result of calculations, the optimal temperature regime and the corresponding optimal concentrations of substances are determined. At the same time, the restrictions on the concentration value of the reaction by-product and the conversion of substances at the end of the reaction are fulfilled. It is shown that the solution of the optimal control problem with terminal constraints for the process of phthalic anhydride production satisfies the constraints of the problem and provides the highest value of the concentration of the target reaction product.

Synthesis and Weak Hydrogelling Properties of a Salt Resistance Copolymer Based on Fumaric Acid Sludge and Its Application in Oil Well Drilling Fluids

Fumaric acid sludge (FAS) by-produced from phthalic anhydride production wastewater treatment contains a large amount of refractory organic compounds with a complex composition, which will cause environmental pollution unless it is treated in a deep, harmless manner. FAS included saturated carboxylic acid, more than 60%, and unsaturated carboxylic acid, close to 30%, which accounted for the total mass of dry sludge. A new oil well drilling fluid filtrate loss reducer, poly(AM-AMPS-FAS) (PAAF), was synthesized by copolymerizing FAS with acrylamide (AM) and 2-acrylamide-2-methyl propane sulfonic acid (AMPS). Without a refining requirement for FAS, it can be used as a polymerizable free radical monomer for the synthesis of PAAF after a simple drying process. The copolymer PAAF synthesis process was studied, and the optimal monomer mass ratio was determined to be AM:AMPS:FAS = 1:1:1. The temperature resistance of the synthesized PAAF was significantly improved when 5% sodium silicate was added as a cross-linking agent. The structural characterization and evaluation of temperature and complex saline resistance performance of PAAF were carried out. The FT-IR results show that the structure of PAAF contained amide groups and sulfonic acid groups. The TGA results show that PAAF has good temperature resistance. As an oilfield filtrate loss reducer, the cost-effective copolymer PAAF not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min after 16 h of hot rolling and aging at 150 °C in the complex saline-based mud, which is smaller compared with other filtrate loss reducer copolymers, but it also has little effect on the rheological properties of drilling fluid.

The pathways of the phthalic anhydride selectivity and yield increase at C4-C5-hydrocarbons oxidation

The investigation of n-butane and n-pentane oxidation in system with two consecutive reactors confirmed the mechanism of phthalic anhydride formation by Diels-Alder reaction between maleic anhydride and C4 unsaturated hydrocarbons. The process is limited by low stationary concentration of C4 unsaturated hydrocarbons in reaction mixture which is connected with high rate of their oxidation to maleic anhydride. It was shown that n-butane oxidation leads to formation of maleic anhydride only but the introduction of unsaturated C4-hydrocarbons on inlet of the second catalytic reactor accompanied by phthalic anhydride appearance on outlet of these two consecutive reactors system. It was established that in case of 1,3-butene introduction in the second reactor the quantity of phthalic anhydride formed is more than in case of 2-butene addition. It was predicted that a decrease of the temperature in the second reactor can leads to an increase the phthalic anhydride selectivity and its yield as result of Diels-Alder reaction effectiveness. This assumption was confirmed by experimental results. In results the method of phthalic anhydride production by the use of two consecutive reactors was proposed. The summary yield of this product on this new process can reach up to 35 mol. %. In the case of n-pentane oxidation the formation of maleic and phthalic anhydrides was observed with excess of first product but the introduction of unsaturated C4-hydrocarbons in the inlet of second reactor leads to an increase of the phthalic anhydride concentration and its selectivity and yield. In result the yield of phthalic anhydride equal to 35 mol. % can be obtained. So, the proposed by us mechanism of phthalic anhydride was confirmed by new experimental results and other pathways for the selectivity and yield of this product can be predicted.

Green Production of Phthalic Anhydride from Biobased Furan and Maleic Anhydride by an Acid Resin Catalyst

The production of chemicals such as phthalic anhydride (PA) from renewable biomass is of crucial significance for sustainable social development. Herein, we demonstrate that a 99.0 mol % yield of PA can be achieved from a Diels–Alder adduct of furan and maleic anhydride on an acid resin catalyst. The active sites on the catalyst were produced by pretreating the resin with acetic anhydride. The excellent performance of the resin catalyst is attributed to its surface enrichment effect on the reactant and good ability to suppress the side reactions. Moreover, the catalyst deactivation mechanism was clarified to be the destruction of the resin skeleton during the reaction. These results will provide a practical route for the future industrial production of PA from renewable biomass.

The duration of labor activity of workers in the production of phthalic anhydride and the imbalance of cellular immunity indicators

Introduction. The phthalic anhydride, which widely used in chemical industry in conditions of chronic ingestion, chronically leads to a disadaptation of immunity, which is a risk factor in the formation of associated production related pathology. The aim of the work is to study the subpopulation profile of lymphocytes and cytokine status in workers engaged in the production of phthalic anhydride with their work experience. Materials and methods. The observation group, totally 68 men, consisted of employees working at the main phthalic anhydride production facility. The workers of the observation group were divided into two subgroups with their work experience at the enterprise: 44 persons with 0 to 10 years of work experience and 24 persons with more than 10 years of work experience. The comparison group - 40 men who had no professional contact with harmful production factors. The chemical-analytical, cytofluorimetric, immunoenzyme methods use during the study. Results. The workers being exposed to phthalic anhydride with up to 10 and more than 10 years of work experience at the enterprise have a phthalic acid content in their blood that is 2.3 and 3.3 times higher, respectively than related to persons who are not in contact with the analyzed harmful production factor (p=0.002-0.033). It was found that longtime workers, engaged in the production of phthalic anhydride, manifested the immune response cellular link dysfunction. Workers employed in the main production of phthalic anhydride with more than 10 years of work experience revealed a prevalence of activation processes (according to CD25+ criterion), inhibition of cytotoxic cell-mediated response (according to CD3+CD16+CD56+ criterion), gyperexpression of Th2-cytokines (according to criterion IL4) relative to values obtained from workers of the production with less than 10 years of work experience in hazardous production conditions (p=0.002-0.033). Conclusions. The duration of employment of the workers, contacting with excessive concentrations of phthalic anhydride in workplace air, contributes to negative dynamics in the imbalance between T-cells and cytokine products. The dynamic monitoring of immunoregulatory indicators in workers occupied in the production of phthalic anhydride will contribute to just-in-time revealing of the immune system violations in order to reduce the risks of formation of associated production-related pathology induced by the chemical production factors.

Mechanochemystry as advanced methodology in green chemistry for applied catalysis

In this survey we have assessed how mechanochemistry techniques comply with the aims of Green Chemistry to minimise the use of environmentally damaging reactants and unwanted by-products. In the publications the preparation of vanadium-phosphorus oxides as industrial catalysts for maleic anhydride production from n-butane and perspective catalysts of phthalic anhydride manufacture by direct n-pentane oxidation were analyzed. It is shown that mechanochemical activation and synthesis reduces the amount of harmful waste used in the production of the catalyst and increases its effectiveness. Improvement of a catalyst’s properties, help limit production of harmful emissions such as carbon oxides and hydrocarbons. It was established that mechanochemical treatment can by successfully used in the process of industrial vanadium-phosphorus oxide catalysts modification or in the process of introduction in its composition of additives which lead to increase of activity and selectivity of hydrocarbons oxidation. The possibility of the mechanochemistry use in the vanadium-titanium oxide catalysts preparation which are the base catalysts in industrial phthalic anhydride production from o-xylene was determined. It was established that mechanochemical treatment of the vanadium and titanium oxides mixture permits to delete the nitrogen oxides emission in atmosphere and prepared catalysts demonstrate the same phthalic anhydride yield but at low reraction temperature. Catalysts, manufactured by mechanochemical treatment (on the base of molybdenum oxide), provide new techniques for producing compounds as exemplified by the direct oxidation of benzene to form phenol which can replace industrial two-step process from cumene or proposed process of benzene oxidation by N2O. Mechanochemistry treatment could produce catalysts which eliminated the need to use highly toxic nitrogen oxides as reducing agents. The article describes activating Cu-Ce-O catalysts which reduce the temperature of the process for removing carbon monoxide from exhaust gases and as a method for purifying hydrogen u sed in fuel cells. Finally, there is a description of mechanochemically treated catalysts, containing metals and supported on stainless steel supports which are used to remove aromatic hydrocarbons from water sewers.

Features of immune regulation in working at the enterprise for the production of phthalic anhydride

Introduction. Employees of the chemical industry engaged in the production of phthalic anhydride are characterized by multi-level morphofunctional disorders of the health profile, characterized by an imbalance in the regulation of metabolism, sensitization of the body, membranotoxic effects, and the formation of secondary immunodeficiency. The aim of study was to assess the immune status of workers engaged in the production of phthalic anhydride. Materials and methods. The observation group included workers in contact with phthalic anhydride (31 persons). The comparison group consisted of administrative employees who were not in contact with phthalic anhydride (23 persons). Chemical exposure in the workplace is associated with the presence of phthalic anhydride - a harmful substance of hazard class 2. The full lymphocytes was performed on a flow cytometer FACSCalibur company "Becton Dickinson". The expression level of p53 and TNFR was determined using the corresponding MCAT. Cancer markers (CA 19-9, CEA, PSA) were determined by enzyme immunoassay. Changes in the content of phthalic anhydride-specific IgE were determined in an allergosorbent test with an enzyme label. The statistical analysis was performed using the software package Statistica 6.0. The reliability of differences between the groups were considered significant at p<0.05. Results. A significant deficiency in the content of the CD95+ cell death receptor relative to the reference level was established (p<0.05). There is a significant overexpression of the TNFR receptor in relation to the norm and the comparison group (2.5 times) (p<0.05). The level of p53 expression was significantly increased in relation to the comparison group (p<0.05). The observation group had an increased level of cancer markers CA 19-9, CEA, and PSA relative to the comparison group (p<0.05). There was a significantly increased content of IgE specific to phthalic anhydride (by its metabolite phthalic acid) in relation to the reference level (in 61.6%) and the comparison group (p<0.05). The results obtained verify the information in the scientific literature about the nature of the effect of phthalic anhydride on the immune system, its ability to cause allergic reactions (IgE specific to phthalic anhydride). Conclusions. Thus, the employees employed at the phthalic anhydride production facility had significantly reduced CD95+ levels, overexpression of TNFR, p53, CA 19-9, CEA, PSA, as well as hyperproduction of phthalic anhydride-specific reagins, which indicates insufficient immune control over the duration of the cell life cycle, and does not exclude the development of allergic, autoimmune, and oncoproliferative scenarios of production-related pathology.

Highly efficient selective oxidation of 2-methylnaphthalene to vitamin K3 over mesoporous Al/Ti-SBA-15 catalysts: The effect of acid sites and textural property

Catalytic oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone (vitamin K3) is a significant pathway to produce vitamin groups K. High pollution and low-productivity of the traditional method require a greener catalyst and process. In this work, Al/Ti-SBA-15 with different nSi/nAl and nSi/nTi ratios were hydrothermally prepared in mild acidic condition and tested in partial oxidation of 2-methylnaphthalene. Commercial zeolites NaY, β and ZSM-5 were applied to investigate the influence of mass transfer resistance and acidity on catalytic performance. Catalysts were characterized by XRD, N2 adsorption-desorption, TEM, NH3-TPD, FTIR and Py-FTIR. We have found that the 2-methylnaphthalene conversion and vitamin K3 selectivity depend strongly on the mesoporous structure as well as Brönsted acid concentration and strength. Irregular micropores and strong acidity will accelerate the cleavage of C = C in aromatic rings, leading to the production of phthalic anhydride. DFT calculation reveals that incorporation of aluminum in SBA-15 can reduce the energy gap, facilitating the electron transfer. And as a consequence of the substitution of Al in tetrahedral positions in SBA-15, Al-SBA-15 (10) gives the best result with 72% yield to vitamin K3. This catalyst markedly reduces the activation energy due to the modified activated center. Repeated experiments recommend that Al-SBA-15 is a steady and high-efficiency catalyst for the production of vitamin K3.

Stepan resumes phthalic anhydride and surfactants production after outage in Illinois

Stepan resumes phthalic anhydride and surfactants production after outage in Illinois

Production of Commercial Naphthalene by Coal-Tar Processing

The derivation of commercial naphthalene by rectification is a possible approach in coal-tar processing. Naphthalene is widely used in chemical synthesis for the production of phthalic anhydride, superplasticizers, and intermediate products such as Cleve’s acids in dye production. The quality of the naphthalene derived from petroleum is markedly higher than that of coal-tar naphthalene, primarily in terms of the thionaphthene content, since the thionaphthene content in the initial petroleum fractions is much less than in the naphthalene fraction of coal tar. Simulation of the vapor–liquid equilibrium of binary and ternary mixtures of the components in coal tar by means of the NRTL activity model, at different pressures, indicates that 2,3-xylenol–naphthalene, naphthalene–thionaphthene, and 3-xylenol–naphthalene–thionaphthene mixtures are characterized by positive homogeneous azeotropes. The composition and boiling points of the azeotropes are determined. The presence of the azeotropes significantly complicates the derivation of naphthalene from the naphthalene fraction of coal tar, in which the naphthalene content exceeds 97%. Analysis of the composition of the initial mixture and the azeotropes suggests a design for a three-column system for the distillation of commercial naphthalene, with the preliminary separation of water without the need for special separating agents or chemical extraction of impurities. Optimization of the proposed equipment by means of HYSYS software indicates high technological flexibility of the process and the production of naphthalene from coal tar that matches the quality of the naphthalene derived from petroleum. The naphthalene content in the commercial product derived from coal tar by the proposed method is 99.99 wt %. The yield of naphthalene is 90.5 wt %. The energy consumption in the basic three-column system is 0.92 Gcal/t of commercial naphthalene (of purity 99.99 wt %). If heat is recycled in the three-column system, the energy consumption is reduced to 0.6 Gkal/t of product (with the same degree of purity). That is comparable with the energy consumption in a two-column system, and the commercial naphthalene produced is characterized by greater yield and purity.

Selective vapor‐phase oxidation of o‐xylene to phthalic anhydride over Co‐Mn/H3PW12O40@TiO2 using molecular oxygen as a green oxidant

The oxidation of o‐xylene to phthalic anhydride over Co‐Mn/H3PW12O40@TiO2 was investigated. The experimental results demonstrated that the prepared catalyst effectively catalyzed the oxidation of o‐xylene to phthalic anhydride. Also, the synergistic effect between three metals plays vital roles in this reaction. From a green chemistry point of view, this method is environmentally friendly due to carrying out the oxidation in a fixed‐bed reactor under solvent‐free condition and using molecular oxygen as a green and cheap oxidizing agent. The resulting solid catalysts were characterized by FT‐IR, XRD, XPS, ICP‐OES, FESEM, TEM, EDX, DR‐UV spectroscopy, BET and thermogravimetric analysis. The oxidation of o‐xylene yields four products: o‐tolualdehyde, phthaldialdehyde, phthalide and finally phthalic anhydride as the main product. The reaction conditions for oxidation of o‐xylene were optimized by varying the temperature, weight hourly space velocity and oxygen flow rate (contact time). The optimum weight percentage of phosphotungstic acid (HPW) and Co/Mn for phthalic anhydride production were 15 wt % and 2 wt%, respectively. The best Co/Mn ratio was found to be 10/1. Oxygen flow rate was very important on the phthalic anhydride formation. The optimum conditions for oxidation of o‐xylene were T = 370 °C, WHSV = 0.5 h−1 and oxygen flow rate = 10 mL min−1. Under optimized conditions, a maximum of 88.2% conversion and 75.5% selectivity to phthalic anhydride was achieved with the fresh catalyst. Moreover, reusability of the catalyst was studied and catalytic activity remained unchanged after at least five cycles.

HYGIENIC EVALUATION OF THE IMPACT OF WORKING CONDITIONS ON THE HEALTH OF WORKERS OF THE COMPLEX FOR PRODUCTION OF PHTHALIC ANHYDRIDE AND FUMARIC ACID

In a priori assessment, the professional risk for workers in the production of phthalic anhydride is characterized by an average (class of labor conditions - 3.2), the main harmful chemical production factors: phthalic anhydride, fumaric acid, maleic aldehyde, dimethylbenzene (MPC for single dose (MPCsd) - up to 5.9). These factors are identified as priority ones in the development of adverse effects from the side of the hepatobiliary system. The impact of chemicals is intermittent in character during the shift, which requires control of the content of chemicals in the air in the working area in the form of average shift concentrations. In workers of the complex for the production of phthalic anhydride and fumaric acid, there is an accumulation of o-xylene, phthalic and fumaric acid, whose concentrations are significantly higher (p = 0.0001 - 0.03) if compared with the reference parameters of the comparison group (the excess multiplicity up to 7 times). Among the workers of the phthalic anhydride and fumaric acid production complex, there were no established statistically significant differences in the blood content of o-xylene, phthalic acid and fumaric acids when performing work under conditions of thermal loading of the environment and under conditions with acceptable microclimate parameters. The development of disorders of the hepatobiliary system was shown to begin with the intensification of free radical damage to cell membranes (manifested by an increase in the MDA content of blood relative to the age physiological norm and relative to the index of workers in the comparison group). With a work experience of up to 5 years, the accumulation of secondary products of lipid peroxidation (LPO) in workers is hampered by the activation of antioxidant protection processes. At the experience of more than 5 years, the development of adverse effects from the side of the liver has been established: significantly higher levels of aspartate aminotransferase (AST) (p = 0.027), in cases with an experience of more than 10 years - the level of total and direct bilirubin in blood serum is elevated by 1.4-1.5 times, p = 0.0001 - 0.002). There was found the statistically significant cause-and-effect relationship of the elevated total blood bilirubin content with labor conditions (RR = 2.86, 95% CI = 1.03-7.98, etiological proportion 65.08%)

A Comparative Study of Physical and Chemical Method for Separation of Benzoic Acid from Industrial Waste Stream

Phthalic anhydride is manufactured by the partial oxidation of ortho xylene in the presence of V2O5/TiO2 catalyst. In the residue, maleic acid, benzoic acid (BA), telluric acid and traces of other organic compounds are present in the by-product stream. There is almost 60% of (BA) in the residue sample, which compels to recover the tremendous amount of (BA), as it is of great importance. The waste stream is in the form of slurry at high temperature and is solidified at room temperature. Benzoic acid was selectively removed from the solid waste of Phthalic anhydride production industry by the processes associated with less intensive parameters as compare to the extraction techniques achieved by, pressurized hot water, supercritical CO2 extraction, where the required parameters are highly intensive. The separation has been performed by using physical and chemical techniques. In physical methods recrystallization (RE), liquid-liquid extraction (LLE) as well as recrystallization followed by liquidliquid extraction (RE, LLE) and liquid-liquid extraction followed by recrystallization (LLE, RE) have been studied. In another attempt chemical derivatization (CD) has been performed for the purification purposes. The operation has been performed at the atmospheric pressure with operating temperatures of 100°C and 25°C in physical processes (RE) and (LLE) respectively while in chemical derivatization it ranges from 72°C to 100°C. The characterization of the samples was accomplished by GCMS, FTIR and also its melting point was determined. Almost 99% of the purity was achieved by CD, LLE, RE followed LLE and LLE followed by RE.

Influence of Aromatic Hydrocarbons in Air on Spatial PEMFC Performance

The successful commercial deployment of proton exchange membrane fuel cells (PEMFCs) depends on the achievement of stringent performance and durability requirements. Currently, air is the most convenient oxidant for fuel cell applications, and its quality is an important consideration for operation because airborne contaminants can negatively affect fuel cell performance, cause premature degradation and decrease durability (1). Aromatic compounds are hazardous pollutants produced or used in many industrial processes. Benzene and naphthalene are the main representatives of aromatic hydrocarbons and are widely used as precursors for chemical syntheses. More than half of the entire benzene production is processed to styrene to manufacture polymers and plastics. Benzene is originated in the air from emissions of chemical plants, burning coal and oil, gasoline stations and vehicle exhausts. Naphthalene is used in the production of phthalic anhydride and as a pest control agent. Determination of the impact of C6H6 and C10H8 on PEMFC performance is critical to establish environmental requirements for fuel cell usage, define specifications for air filtration systems and support understanding of fundamental aspects of PEMFC operation and maintenance. A segmented cell and data acquisition system were used (2) with a commercially available 100 cm2 membrane/electrode assembly (MEA). Each electrode contained a Pt/C catalyst with a loading of 0.4 mgPt cm-2. A segmented SGL 25BC gas diffusion layer (GDL, 10 segments of 7.6 cm2) and a Teflon gasket were employed at the cathode whereas a single GDL piece was applied at the anode. The MEA was operated under galvanostatic control of the whole cell current. Other operating conditions were: 80°C, 48.3 kPagback pressure, 100/50% relative humidity and 2/2 stoichiometry for the anode and cathode respectively. The dry contaminant was injected into the humidified cathode air stream. The poisoning proceeded until the cell voltage reached a steady value. Subsequently, the contaminant injection was stopped to evaluate the cell self-recovery. Fig. 1 a) shows the voltage response and normalized current density for each segment at 1.0 A cm-2 under benzene contamination. For the first 18 hours, the cell was operated with pure air resulting in a cell voltage of 0.670 V. The injection of 2 ppm C6H6 decreased the voltage to a steady state of 0.560 V and caused a redistribution of local current densities. Operation with pure air fully recovered the initial cell performance. Effects of naphthalene are shown in Fig. 1 b). The introduction of 2.3 ppm C10H8to air stream led to a significant voltage drop within 10 h and a different current redistribution pattern. Voltage oscillations from 0.100 to 0.170 V were observed as soon as the cell reached 0.12 V. Recovery took 2 h and was accompanied by further redistribution of localized currents. Benzene and naphthalene have similar electrochemical properties (3, 4). Cathodic desorption of the adsorbed species on Pt occurs at hydrogen adsorption potentials (< 0.1 V) and is accompanied by partial hydrogenation, while electrooxidation takes place at 1.35 V with formation of CO2 as the main product. The strong adsorption of C6H6 and C10H8 occurs at 0.1-0.6 V without electrochemical reactions, and results in an in-plane adsorbate configuration due to the interaction between the aromatic ring and the Pt surface (5). Contaminant adsorption results in a decrease of the electrochemical area, suppression of O2 adsorption and shift the oxygen reduction from a 4-electron to a 2-electron mechanism, which negatively impact PEMFC performance. The data demonstrated that C10H8 has a severer effect on PEMFC than C6H6 which is most likely due to a higher adsorption energy and abilty to form multilayer adsorption (6, 7). A detailed discussion of the results and a poisoning mechanism will be presented. ACKNOWLEDGMENTS We gratefully acknowledge ONR (N00014-13-1-0463), DOE EERE (DE-EE0000467) and Hawaiian Electric Company. REFERENCES O.A. Baturina, Y. Garsany, B.D. Gould, K.E. Swider-Lyons, in: H. Wang, H. Li, X.-Z. Yuan (Eds.), PEM fuel cell failure mode analysis, CRC Press, 2011, p. 199.T.V. Reshetenko, G. Bender, K. Bethune, R. Rocheleau, Electrochim. Acta, 56, 8700 (2011).F. Montilla, F. Huerta, E. Morallon, J.L. Vazquez, Electrochim. Acta, 45, 4271 (2000).T. Löffler, E. Drbalkova, P. Janderka, P. Königshoven, H. Baltruschat, J. Electroanal. Chem., 550-551, 81 (2003).M.P. Soriaga, A.T. Hubbard, J. Am. Chem. Soc., 104, 2735 (1982).C. Morin, D. Simon, P. Sautet, J. Phys. Chem. B, 108, 12084 (2004).J.M. Gottfried, E.K. Vestergaard, P. Bera, C.T. Campbell, J. Phys. Chem. B, 110, 17539 (2006). Figure 1

Techno-economic assessment of the production of phthalic anhydride from corn stover

Phthalic anhydride is used worldwide for an extremely broad range of applications spanning from the plastics industry to the synthesis of resins, agricultural fungicides and amines. This work proposes a conceptual design of a process for the production of phthalic anhydride from an agricultural residue (i.e. corn stover), energy integration alternatives as well as water consumption and life cycle greenhouse emissions assessment. The techno-economic and financial appraisal of the flowsheet proposed is performed. Results show how the valorization of all the carbohydrate-rich fractions present in the biomass as well as energy savings and integration is crucial to obtain an economically viable process and that it is in principle possible to produce renewable phthalic anhydride in a cost-competitive fashion with a lower impact on climate change compared to the traditional synthetic route.

Phthalic anhydride production from hemicellulose solutions: Technoeconomic analysis and life cycle assessment

The process synthesis, technoeconomic analysis, and life cycle assessment (LCA) of a novel route for phthalic anhydride (PAN) production from hemicellulose solutions are presented. The production contains six steps including dehydration of xylose to furfural, reductive decarbonylation of furfural to furan, oxidation of furfural to maleic anhydride (MA), Diels‐Alder cycloaddition of furan, and MA to exo−4,10‐dioxa‐tricyclo[5.2.1.0]dec‐8‐ene‐3,5‐dione followed by dehydration to PAN in the presence of mixture of methanesulfonic acid and acetic anhydride (AAN) which is converted to acetyl methanesulfonate and acetic acid (AAD), and dehydration of AAD to AAN. The minimum selling price of PAN is determined to be $810/metric ton about half of oil‐based PAN. The coproduction of high‐value products is essential to improve the economics. Biomass feedstock contributes to the majority of cost. LCA results shows that biomass‐based PAN has advantages over oil‐based PAN to reduce climate change and fossil depletion however requires more water usage. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3708–3718, 2015

Simulation of V2O5/TiO2 catalyst activity by central composite design for optimal operating conditions and catalyst life in phthalic anhydride production

A simple central composite design was applied to estimate the activity of V2O5/TiO2 catalyst and catalyst life in phthalic anhydride production. Using 1–3 years of simulation data, it was found that the temperature profiles along the catalyst bed and the outlet flow rates of phthalic anhydride and maleic anhydride (main by-product) were less than 8% deviation compared with the plant data. In comparing the simulated optimal conditions to the normal operating conditions, the phthalic anhydride production increased by 1,600ton with the inlet o-xylene-air ratio (w/w) and the coolant temperature, while maleic anhydride decreased by approximately 340ton.

Estimation of kinetic parameters for the reactor model of the phthalic anhydride production by the design of experiments

Heterogeneous reactor model was developed to predict product, by-product and hot spot temperature in an industrial fixed bed reactor of phthalic anhydride production. This work modified the Calderbank's kinetic model by including the reaction from o-xylene to by-product maleic anhydride. The kinetic parameters appropriating to the catalyst in this study were estimated by the design of experiments. The reactor model was validated by comparing the simulated results with the production data in terms of the outlet molar flow rates of phthalic anhydride and maleic anhydride, and the hot spot temperature. The results were less than 1.8% deviated.

Renewable production of phthalic anhydride from biomass-derived furan and maleic anhydride

A route to renewable phthalic anhydride (2-benzofuran-1,3-dione) from biomass-derived furan and maleic anhydride (furan-2,5-dione) is investigated. Furan and maleic anhydride were converted to phthalic anhydride in two reaction steps: Diels–Alder cycloaddition followed by dehydration. Excellent yields for the Diels–Alder reaction between furan and maleic-anhydride were obtained at room temperature and solvent-free conditions (SFC) yielding 96% exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione (oxanorbornene dicarboxylic anhydride) after 4 h of reaction. It is shown that this reaction is resistant to thermal runaway because of its reversibility and exothermicity. The dehydration of the oxanorbornene was investigated using mixed-sulfonic carboxylic anhydrides in methanesulfonic acid (MSA). An 80% selectivity to phthalic anhydride (87% selectivity to phthalic anhydride and phthalic acid) was obtained after running the reaction for 2 h at 298 K to form a stable intermediate followed by 4 h at 353 K to drive the reaction to completion. The structure of the intermediate was determined. This result is much better than the 11% selectivity obtained in neat MSA using similar reaction conditions.