Moderate Pressure Research Articles

Impact of chloride salts on TBAB/Methane and TBAB/Carbon dioxide semiclathrate hydrates: Application to desalination

As water consumption increases due to industrialization and global population growth, climate change and urbanization exacerbate the limited available freshwater resources. To counter the challenge water desalination has been used to provide potable water that is ready for human consumption. However, most of the existing water desalination techniques have persistent drawbacks despite decades of development. Thus, a need for efficient and sustainable techniques is urgent. One of the emerging water desalination techniques is hydrate-based desalination. While clathrate has been a nuisance in the oil and gas industry, it has been investigated in several applications including water desalination. This work investigates thermodynamic effectiveness of two hydrate formers in the presence of chloride salts. Methane or carbon dioxide with Tetra n‑butyl ammonium bromide have been used as formers. While the presence of salts depresses the pressure effect on semiclathrate equilibrium on the tested range, it does not have a clear effect at low TBAB concentration. Thus, based on this study using a low concentration of TBAB (20 wt%) with low to moderate pressure of carbon dioxide would yield the most favorable thermodynamic conditions for hydrate-based desalination.

Superconductivity of thulium substituted clathrate hexahydrides at moderate pressure

Due to the BCS theory, hydrogen, the lightest element, would be the prospect of room-temperature superconductor after metallization, but because of the difficulty of the hydrogen metallization, the theory about hydrogen pre-compression was proposed that the hydrogen-rich compounds could be a great option for the high Tc superconductors. The superior properties of TmH6, YbH6 and LuH6 indicated the magnificent potential of heavy rare earth elements for low-pressure stability. Here, we designed XTmH12 (X = Y, Yb, Lu, and La) to obtain higher Tc while maintaining low pressure stability. Most prominently, YbTmH12 can stabilize at a pressure of 60 GPa. Compared with binary TmH6 hydride, its Tc was increased to 48 K. The results provide an effective method for the rational design of moderate pressure stabilized hydride superconductors.

Long‐time high‐pressure processing of a patatin‐rich potato proteins isolate: impact on aggregation and surface properties

SummaryIn this study, a 4% (w/w) dispersion of a commercial patatin‐rich potato protein isolate (Po‐PI) was pressurised at 400 MPa up to 48 h at 20 °C. Protein aggregation induced by high‐pressure processing (HHP) was followed by dynamic light scattering, intrinsic fluorescence (in‐situ or ex‐situ) or SAXS analysis. Surface properties (surface hydrophobicity and interfacial properties) of the HHP‐induced aggregates were also investigated. A gradual dimer dissociation/protein unfolding was observed under pressure. Po‐PI exhibited a slow relaxation time under pressure. Long‐time HHP (>4 h) induced significant modification of the Po‐PI protein structure with partial non‐reversible unfolding. After 48 h of pressurisation at 400 MPa, large aggregates (160 nm) were obtained and a monomodal distribution in intensity and in number frequency was observed indicating a controlled aggregation. Up to 24 h of pressurisation at 400 MPa, intermediate states were obtained after high‐pressure release. SDS‐PAGE profiles showed that HHP‐induced aggregation of Po‐PI was driven by non‐covalent interactions. All high‐pressure processed dispersions displayed a higher surface hydrophobicity as compared to non‐treated Po‐PI. Po‐PI dispersion treated for 8 h at 400 MPa presented the lowest adsorption rate, the highest final surface tension and formed the most rigid interfacial film. Po‐PI showed resistance to moderate pressure levels (400 MPa) and long pressure application times were required to induce significant protein denaturation/aggregation (≥24 h) and to optimally modify its interfacial properties (8 h).

Superior Superconducting Properties Realized in Quaternary La-Y-Ce Hydrides at Moderate Pressures.

The recent revolution in the superconductivity field stems from hydride superconductors. Multicomponent hydrides provide a crucial platform for tracking high-temperature superconductors. Besides high superconducting transition temperature (Tc), achieving both giant upper critical magnetic field [μ0Hc2(0)] and high critical current density [Jc(0)] is also key to the latent potential of the application for hydride superconductors. In this work, we have successfully synthesized quaternary La-Y-Ce hydrides with excellent properties under moderate pressure by using the concept of "entropy engineering." The obtained temperature dependence of the resistance provides evidence for the superconductivity of Fm3m-(La,Y,Ce)H10, with the maximum Tc ∼ 190 K (at 112 GPa). Notably, Fm3m-(La,Y,Ce)H10 boasts exceptional properties: μ0Hc2(0) reaching 292 T and Jc(0) surpassing 4.61 × 107 A/cm2. Compared with the binary LaH10/YH10, we find that the Fm3m structure in (La,Y,Ce)H10 can be stable at relatively low pressures (112 GPa). These results indicate that multicomponent hydrides can significantly enhance the superconducting properties and regulate stabilizing pressure through the application of "entropy engineering." This work stimulates the experimental exploration of multihydride superconductors and also provides a reference for the search of room-temperature superconductors in more diversified hydride materials in the future.

LES investigations of turbulent heat transfer structures with exponential power escalation

The BORAX-type accident is a key scenario in the safety design of pool-type experimental nuclear reactors. It considers a reactivity insertion large enough to initiate an exponential power escalation with a period as small as tens of milliseconds, necessitating effective heat removal by the coolant system. This study presents a computational analysis of single-phase transient heat transfer under thermal-hydraulic conditions relevant to such reactors, focusing on turbulent channel flow between planar fuel plates with highly subcooled water. Our investigation uses Large Eddy Simulation (LES) performed with TrioCFD, the open-source CFD code developed by the French Atomic Energy Commission (CEA). Several modeling options are tested: incompressible flow with temperature as a passive scalar, incompressible flow with varying viscosity, and quasicompressible flow with temperature-dependent viscosity and mass density. To evaluate the accuracy of our physical models, all simulations were performed under uniform conditions, using the same experimental parameters, mesh, and numerical strategies. The specific examined scenario involves a highly subcooled turbulent channel flow at moderate pressure, experiencing an exponential power increase. We ensure detailed turbulence resolution at the Batchelor scale in the wall normal direction close to the heating wall. This communication presents a comparative study of LES simulations of the single-phase flow under exponential power excursion at the wall. Subsequent analyses focused on the impact of different velocity-temperature couplings on the prediction of wall heat transfer, incorporating comparisons with experimental infrared thermometry measurements. Early in the transient phase, temperature peaks are confined within turbulent streaks, as reported in the existing literature. However, as the exponential power transient unfolds, the viscous layer and streak structures destabilize, leading to a more dispersed distribution of hot spots. Preliminary findings suggest a transition in heat transfer modes from turbulence-driven to conduction during the final stages of the single-phase transient.

TEN YEAR FOLLOW-UP OF PATIENTS WITH RESISTANT HYPERTENSION RANDOMIZED TO RENAL DENERVATION OR ANTIHYPERTENSIVE DRUG TREATMENT

Objective: Renal denervation (RDN) is a treatment option in resistant hypertension. The procedure is considered safe, although randomized trials only demonstrate a moderate blood pressure (BP) lowering effect, when considering medication adherence. Some observational studies describe reduction in BP several years after the procedure. The aim of the study was to describe long-term safety and potential benefits of RDN after ten years, compared to optimized drug treatment, measuring serum concentration of antihypertensive drugs to ensure adherence. Design and method: We report data from ten year follow-up of patients randomized to RDN (n=9) or drug adjustment (n=10). Initially the patients had treatment-resistant hypertension, defined as daytime systolic ambulatory BP >= 135 mmHg after witnessed intake (directly observed therapy, DOT) of >= 3 antihypertensive drugs including a diuretic and therefore considered as adherent. One year after RDN or drug adjustment, we optimized antihypertensive medication for all patients. Thereafter, patients received appropriate antihypertensive treatment in primary or secondary care, according to their BPs. Patients were informed of serum concentration measurements performed at the 7-year visit. At the 10-year visit, serum drug measurements before DOT and ambulatory BP measurement (ABPM) were used for evaluation of adherence. Antihypertensive agents were registered, glomerular filtration rate (eGFR) was estimated by the CKD-EPI formula using creatinine and Cystatin C, and renal arteries were examined by CT or MRI. Results: All living patients (n=18) attended the 10-year visit, now mean age 69 years, using 4±2 antihypertensive agents, with no difference between groups. Serum concentrations confirmed that all patients were adherent to reported medication. There were significant and similar BP reductions in both groups compared to baseline; daytime ABPM -22±15/9±8 mmHg in the RDN group, and -20±15/13±7 mmHg in the control group (figure). No patients developed renal artery stenosis. The decrease in eGFR was similar in both groups. Conclusions: To our knowledge this is the RCT with the longest follow-up supporting long-term safety of RDN in patients with resistant hypertension. Daytime ABPM improved during 10 years of follow-up, not explained by RDN, but due to adjustments in antihypertensive regimens and probably better adherence to medication.

The copper size effect of CuZn/CeO2 catalyst in CO2 hydrogenation to methanol

The escalating emission of CO2 has caused a significant environmental impact. Hydrogenation of CO2 to methanol stands as the primary objective in the liquid sunlight vision, aiming to mitigate CO2 emissions. CuZn-based transition metal catalysts, known for their cost-effectiveness, demonstrate commendable catalytic performance at moderate temperatures and pressures, showcasing considerable potential in industrial applications. Consequently, a series of catalysts, composed of CuZn-based species supported on CeO2 with strategically introduced appropriate oxygen vacancies, were meticulously prepared. It worth to noting that the size of Cu was precisely tuned, along with the enhanced ability to the adsorption and activation of CO2 and H2. As a result, the optimal CuZn/CeO2 catalyst exhibits high methanol formation rate, recording at 433.4 gMeOH kgcat−1 h−1 with selectivity of 68.5% at 260 °C and 3 MPa. Simultaneously, the reaction path and the evolution of intermediates in CO2 hydrogenation was thoroughly delineated.

Bonding properties and superconductivity of electride Be6C under moderate pressure

Superconducting electrides are characterized by the emergence of electrons occupying the interstitial region of lattice and exhibit coexistence of distinctive electride state and superconductivity, which have attracted wide attention. However, the underlying crucial factors governing the superconductivity and influencing the structural stability by electride states remain elusive. Here, we performed structure searches in conjunction with first-principles calculations to identify a dynamically stable electride Be6C at 40 GPa, which exhibits p-orbital type electride states and demonstrates superconductivity with a Tc of 22.4 K. Furthermore, it remains dynamically stable even down to ambient conditions while maintaining a Tc of 18.9 K. Further analyses unveiled that the dual p-hybridized electrons within the orbitals of p-orbital electride states and Be-2p mainly composed of a van Hove singularity near the Fermi level and participate in electron–phonon interaction to form Cooper pairs leading to the high-Tc. The preservation of dynamic stability for Be6C at low pressure is primarily attributed to the presence of electride states that effectively form both covalent and ionic bonding properties to bind neighbor Be cations to lower enthalpy of system and subsequently, in turn, lowering the required pressure. Our findings not only explained the underlying factors affecting superconductivity but also revealed the crucial role of electride states in determining the dynamic stability of structure, providing valuable insights for subsequent research on superconducting electrides at low pressures.

Operando Monitoring of Homolytic Cleavage of H2 into Surface Hydrides on Defective Cerium Dioxide Nanoparticles

AbstractThe use of ceria as catalyst in hydrogenation reactions is a recent trend, as they were uncovered to be active on a number of substrates, including alkynes, alkenes, and enones. While some studies focused on the use of well‐defined shapes, others emphasized the interest of defective structures. Overall, the meeting point of these studies is the need to characterize the surface reactivity vs. H2, by considering a number of interesting textures (films, nanopowders with various grain size or porosity), using monitoring techniques that preserve the original features of the materials. A key question is in particular to assess the possibility to form surface hydride through homolytic H2 splitting at cerium sites rather than at the oxygen one, a route recently highlighted as plausible. To address this question on small crystallites of CeO2, we designed a low‐temperature synthetic route for nanorods with an average grain size of 10 nm. Then, we employed near‐ambient‐pressure X‐ray photoelectron spectroscopy as an operando tool to monitor the cerium surface oxidation state during the initial annealing of the nanopowders, followed by exposure to a moderate pressure of H2 (0.52 mbar). We demonstrate that H2 homolytic splitting at cerium sites is the main activation process on this surface at 100 °C, leading to the oxidation of ca. 30 % of the surface cerium atoms from Ce3+ to Ce4+. The surface hydride species were however not stable at 250 °C, H2 was released, and cerium reduced back to Ce3+. A similar mechanism was observed on a defective ceria material obtained by calcination of CeO(OH)2, with comparable intensities. Overall, we report here CeO2 nanorods, exposing predominantly {100} and {110} facets, as showing an interesting surface reactivity for potential application in hydrogenation reactions, and we expose a straight operando methodology to delineate suitable temperatures to be used.

Combined blood pressure and heart rate trajectories are associated with prognosis in critically ill patients with acute aortic dissection: A group-based multi-trajectory analysis

BackgroundManaging systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) is pivotal in acute aortic dissection (AAD) care. However, no prior studies have jointly analyzed the trajectories of these parameters. This research aimed to characterize their joint longitudinal trajectories and investigate the influence on AAD prognosis. MethodsWe included AAD patients from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Using group-based multi-trajectory modeling (GBMTM), we identified combined trajectories of SBP, DBP, and HR within the initial 24 h of intensive care unit (ICU) admission. Cox proportional hazard regression, log-binomial regression, and logistic regression were employed to assess the association between trajectory groups and mortality outcomes. ResultsData from 337 patients were analyzed. GBMTM identified five combined trajectory groups. Group 1 featured rapidly declining SBP and DBP with high pulse pressure and low HR; Group 2 showed high to moderate SBP with slight rebound and persistently low HR; Group 3 displayed persistently moderate BP and HR; Group 4 was characterized by moderate blood pressure with persistently high HR; and Group 5 had high to moderate SBP with slight rebound, high but gradually declining DBP, and slightly high HR. Group 3 demonstrated a lower risk of mortality, with an adjusted hazard ratio of 0.32 (95 % CI, 0.14–0.74), and the adjusted relative risks for in-hospital, 30-day, and 1-year mortalities were 0.37 (95 % CI, 0.15–0.87), 0.25 (95 % CI, 0.10–0.62), and 0.41 (95 % CI, 0.22–0.79), respectively. The time-independent C-index curve demonstrated that the multi-trajectory groups had higher C-index values than any univariate trajectory groups or admission values of SBP, DBP, and HR. ConclusionsUtilization of GBMTM can yield data-driven insights to identify distinct subphenotypes in AAD patients. The combined trajectories of SBP, DBP, and HR within 24 h of ICU admission significantly influenced the mortality rate.

Insights into hydrogen and methane storage capacities: Grand canonical Monte Carlo simulations of SIGSUA.

In the pursuit of sustainable energy solutions, the development of materials with efficient hydrogen and methane storage capacities is imperative, particularly for advancing hydrogen-powered vehicles. Metal-organic frameworks (MOFs) have emerged as promising candidates to meet the stringent targets set by the Department of Energy for both hydrogen and methane storage. This study employs Grand Canonical Monte Carlo simulations to investigate the usable hydrogen and methane gravimetric and volumetric storage capacities of the recently synthesized SIGSUA. A comparative analysis encompasses the selected MOFs with similar metal compositions, those with comparable density and average pore radius, and classical benchmarks, such as IRMOF-15 and IRMOF-20, all evaluated at room temperature and moderate pressures ranging from 25 to 35 MPa. The results reveal that SIGSUA demonstrates noteworthy gravimetric and volumetric storage capacities for both hydrogen and methane, rivaling or surpassing those of the selected MOFs for analysis. These findings underscore the potential of SIGSUA in advancing clean energy storage technologies.

Power measurement analysis of moderate pressure capacitively coupled discharges

This study examines the transition of 13.56 MHz, capacitively coupled plasmas (CCP) from low to intermediate pressure regimes. Here, we investigate power deposition/plasma production in argon, nitrogen, and oxygen discharges as a function of pressure. These three feed gases were chosen as they provide a set of electropositive and electronegative gases and they are widely discussed in the existing literature. Experiments were conducted for all combinations of pressures: 0.5, 1.5, and 2.5 Torr, and nominal power density between 0.1 and 0.7 W/cm2 for each feed gas at a fixed electrode gap of 24 mm, a commonly employed gap in many industrial processes. Our study shows that increasing pressure results in an increase in current at a given electrode bias in argon and oxygen discharges, while there is no discernible pressure-induced change in nitrogen discharges. We attribute this increase to an increase in plasma density, which might result from a change in power deposition or ionization processes. It is likely that heating via secondary electrons becomes more important at intermediate pressures, resulting in increased plasma density and current. Specifically, based on our measurements, it appears that the mechanisms through which power is deposited into the plasma change with increasing pressure for both argon and oxygen discharges but not for nitrogen discharges. Our experimental results align with the outcomes of our simulations and the simulation results of CCP discharges conducted by other researchers under similar conditions.

Dynamic Model Validation and Simulation of Acetone-Toluene and Benzene-Toluene Systems for Industrial Volatile Organic Compound (VOC) Abatement.

Environmental impact mitigation is one of the grand challenges for industries globally. Volatile organic compounds (VOCs) are solvents whose emissions are potentially toxic to human health and ecosystems yet indispensable for the manufacturing of life-saving medicine. Adsorption with activated carbon columns is an established countermeasure for end-of-pipe emission control, whose efficiency, however, is impeded by irregular bed saturation due to the complex nature of its inputs. This work presents the application of a validated nonisothermal adsorption model to examine multicomponent trace mixtures of acetone-toluene and benzene-toluene on activated carbon. Our results indicate preferential adsorption of toluene over both acetone and benzene for all concentrations examined, which is in agreement with experimental data. Moreover, moderate temperature variations and pressure drops are revealed. Finally, Glueckauf's hodograph theory is employed for maximum outlet concentration prediction and compared with simulation results and experimental data, thus providing valuable insights into nonisothermal VOC abatement, which paves the way for industrial operation optimization.

MACROZOOBENTHOS COMMUNITY STRUCTURE IN THE INTERTIDAL ZONE OF MUARA AIR HAJI VILLAGE PESISIR SELATAN REGENCY WEST SUMATERA PROVINCE

Muara Air Haji Village is a coastal area with various anthropogenic activities that can disrupt the aquatic ecology, especially in the intertidal zone. Biological indicators such as macrozoobenthos are needed to provide a correct and sustainable picture of water quality. This research uses a survey method to determine macrozoobenthos' type, abundance, diversity, uniformity, dominance, and distribution pattern in the intertidal zone. Sampling was carried out using three stations, and each station consisted of three transects and three subzones comprised of the upper, middle, and lower intertidal zones using a quadrant plot measuring 1 x 1 m. The results of this research found three classes of macrozoobenthos with five species. Abundance values ​​at each station ranged from 0.89–4.56 ind/m2, while abundance in the intertidal subzone ranged from 1.11–3.56 ind/m2. The diversity index (H') at stations I and III is 1.93 and 1.17, which means it is included in the medium diversity category, while the diversity index (H') at station II is 0.84, which means it is included in the low category, moderate distribution of individuals or non-uniform number of individuals, moderate ecological pressure and moderately polluted water stability. The uniformity index value ranges from 0.65–0.99, which means the uniformity category is balanced. At station II, macrozoobenton dominates with an index value of 0.62, while stations I and III have no dominant species with index values ​​of 0.30 and 0.45. The distribution pattern (Id) of macrozoobenthos is clustered with a value of 3.45–4.18

Spatio-temporal analysis of power deposition and vibrational excitation in pulsed N2 microwave discharges from 1D fluid modelling and experiments

Vibrational excitation of N2 beyond thermodynamic equilibrium enhances the reactivity of this molecule and the production of radicals. Experimentally measured temporal and spatial profiles of gas and vibrational temperature show that strong vibrational non-equilibrium is found in a pulsed microwave discharges at moderate pressure (25 mbar) in pure N2 outside the plasma core and as an effect of power pulsing. A one dimensional radial time-resolved self-consistent fluid model has been developed to study the mechanism of formation of vibrationally excited N2. In addition to the temperature maps, time-resolved measurements of spontaneous optical emission, electron density and electron temperature are used to validate the model and the choice of input power density. The model reveals two regions in the plasma: a core where chemistry is dominated by power deposition and where vibrational excitation starts within the first ∼10 µs and an outer region reliant on radial transport, where vibrational excitation is activated slowly during the whole length of the pulse (200 µs). The two regions are separated by a sharp gradient in the estimated deposited power density, which is revealed to be wider than the emission intensity profile used to estimate the plasma size. The low concentration of excited species outside the core prevents the gas from heating and the reduced quenching rates prevent the destruction of vibrationally excited N2, thereby maintaining the observed high non-equilibrium.

Depositional Architecture of a Neoproterozoic Clastic Shelf: Clue from the Owk Shale Formation, Kurnool Group, India

Abstract Process-based facies and facies association analysis from the Neoproterozoic Owk Shale Formation, Kurnool Group allowed identification of seven facies types, grouped under four facies associations viz. (i) Greenish grey shale without sand interbed, (ii) Grey shale with thin fine sandstone/siltstone interbeds (iii) Grey shale interbedded with HCS-bearing sheet sandstone (iv) Coarsegrained sandstone interbedded with reddish brown shale. A shallow-marine setting ranging from outer shoreface to distal shelf set-up is interpreted. From facies succession analysis, a steady progradation is documented in course of Owk shale depositional history whereby distal shelf shale is successively overlain by the mid, inner shelf shale and finally by outer shoreface succession. Stacked decimeter-thick progradational depositional cycles (demarcated by mid to inner shelf transitions) constitute the progradational depositional motif. The Owk shelf was storm influenced, though from restriction of storm features within the inner shelf deposit, it is argued that no large-scale coastal set-up occurred at the Owk coastline in course of storm events. Instead, a low to moderate offshore-ward pressure gradient is inferred with coriolis effect that possibly hindered active sediment transport in the distal part of the Owk shelf.

Analysis Adherence Of Hypertension Controlling Blood Pressure In Patients At Puskesmas Pegandon

Hypertension is persistent blood pressure where systolic blood pressure ≥140 mmHg and diastolic blood pressure ≥90 mmHg. Obedience comes from the rude word obey which means discipline and obedience. The purpose of this research is to determine the relationship between compliance of hypertensive patients in controlling blood pressure in patients at the Brangsong I Health Center. This type of research is quantitative research with a cross sectional approach. Measurement of the level of relationship with compliance using the chi square statistical test with α = 0.05. The relationship between medication adherence rates using the Morisky Medication Adherance Scale (MMAS-8) questionnaire. Based on the results of measuring the level of compliance from 50 respondents, there were 36 respondents (72%) had a level of compliance, 14 respondents (28%) had a level of compliance that was less compliant. The relationship between blood pressure control from 50 respondents was 14 respondents (28%) had mild blood pressure, 25 respondents (50%) had moderate blood pressure while 11 respondents (22%) had severe blood pressure. The relationship between adherence to taking medication in controlling the blood pressure of patients at the Brangsong I Health Center is the relationship between adherence to taking medication and blood pressure. There is a relationship between compliance of hypertensive patients in controlling blood pressure in patients at Brangsong I Health Center

The Influence of Independence, Competence and Time Budget Pressure on Audit Quality with Auditor Ethics as a Moderating Variable at Big Ten Public Accounting Firms

This study aims to determine "the influence of independence, competence and time budget pressure on audit quality with auditor ethics as a moderating variable". The method in this research is quantitative with primary data sources. The population in this study are auditors who work at Public Accounting Firms in the DKI Jakarta area who are members of the Big Ten and are registered as IAPI members. Sampling was carried out using probability sampling so that the minimum sample used in this research was 83 respondents. The data analysis used in the research is SEM PLS data analysis version 4.0 Based on the results of research using hypothesis testing, it shows that Independence, Competence and Time Budget Pressure have a significant effect on Audit Quality. Auditor Ethics are able to moderate Independence, Competence and Time Budget Pressure.

Low temperature fabrication of highly dense α‐Si3N4 ceramics

AbstractHighly dense α‐silicon nitride (Si3N4) ceramics were densified at a lower temperature of 1450°C under a moderate mechanical pressure of 50 MPa from commercial α‐Si3N4 powder and with conventional Al2O3–Y2O3 sintering additives. The fabricated α‐Si3N4 ceramics exhibited a hardness of 19 GPa, which is higher than that of the β‐Si3N4 ceramics usually obtained. The effect of sintering temperature and sintering pressure in the liquid phase sintering of the α‐Si3N4 ceramics is studied. The role of the dissolution–reprecipitation process and the particle rearrangement during densification of the α‐Si3N4 ceramics is discussed.

Copper(I) iodide catalyzed redistribution of aromatic carboxylic acids

Copper(I) iodide catalyzes the disproportionation of aromatic and heteroaromatic carboxylic acids to give dicarboxylic acids. Potassium furoate heated to 280 – 300 °C in the presence of 10 mol % CuI under carbon dioxide (40 bar) forms dipotassium 2,5-furandicarboxylate (2,5-FDCK), which is isolated as pure 2,5-dicarboxylic acid (2,5-FDCA) in up to 75 % isolated yield and in excellent selectivity over the regioisomeric 2,4-furandicarboxylate (92 % selectivity). Starting materials are recovered in experiments lacking CuI or with pressurized N2 replacing CO2, whereas high conversion and low yields of 2,5-FDCA are obtained with moderate CO2 pressures, suggesting several roles for carbon dioxide in the transformation. Similarly, potassium benzoate heated to 320 – 350 °C in the presence of 10 mol % CuI under carbon dioxide (40 bar) produces terephthalic acid after workup in up to 60 % yield.