| 1. |
- Lilja, J., et al.
(författare)
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Esterification of propanoic acid with ethanol, 1-propanol and butanol over a heterogeneous fiber catalyst
- 2005
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 115:02-jan, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Esterification kinetics of propanoic acid with ethanol, 1-propanol and butanol over a fibrous polymer-supported sulphonic acid catalyst (Smopex-101) was studied. Experiments were carried out in a batch reactor operating isothermally at three different temperatures: 60, 70 and 75 degrees C (80 degrees C for butanol) and with different initial molar ratios of propanoic acid and alcohol (1:1, 1:2 and 2:1). The fiber catalyst was active and stable in all the experiments. The experimental results were modeled according to a Langmuir-Hinshelwood model and with an advanced adsorption-based model. The activity coefficients were calculated according to the UNIFAC model. The activation energy of esterification of propanoic acid with ethanol was found to be 52.6 kJ/mol, 49.9 kJ/mol with 1-propanol and 47.3 kJ/mol with butanol. The kinetic model, which includes the adsorption of carboxylic acid and water combined with the activities of the species, explained the experimentally recorded concentrations well.
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| 2. |
- Nyman, Ulf, et al.
(författare)
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Preventing contrast medium-induced acute kidney injury: Side-by-side comparison of Swedish-ESUR guidelines
- 2018
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Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 28:12, s. 5384-5395
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Tidskriftsartikel (refereegranskat)abstract
- A side-by-side comparison of updated guidelines regarding contrast medium-induced acute kidney injury (CI-AKI) from the Swedish Society of Uroradiology (SSUR) and the European Society of Urogenital Radiology (ESUR) is presented. The major discrepancies include a higher glomerular filtration rate (GFR) threshold as a risk factor for CI-AKI and for discontinuation of metformin by SSUR, i.e., < 45 ml/min versus < 30 ml/min/1.73 m(2) by ESUR, when intravenous or intra-arterial contrast media (CM) with second-pass renal exposure is administered. SSUR also continues to recommend consideration of traditional non-renal risk factors such as diabetes and congestive heart failure, while ESUR considers these factors as non-specific for CI-AKI and does not recommend anyconsideration. Contrary to ESUR, SSUR also recommends discontinuation of NSAID and nephrotoxic medication if possible. Insufficient evidence at the present time motivates the more cautionary attitude taken by SSUR. Furthermore, SSUR expresses GFR thresholds in absolute values in ml/min as recommended by the National Kidney Foundation for drugs excreted by glomerular filtration, while ESUR uses the relative GFR normalised to body surface area in ml/min/1.73 m(2). CM dose/GFR ratio thresholds established for coronary angiography/interventions are also applied as recommendations for CM-enhanced CT by SSUR, since SSUR regards coronary procedures as a second-pass renal exposure of CM with no obvious difference in the incidence of AKI compared withIV CM administration. Finally, SSUR recommends reducing the gram-iodine dose/GFR ratio from < 1.0 in patients not at risk to < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation.Key Points center dot The more cautionary attitude taken by SSUR compared with that of ESUR is motivated by insufficient evidence regarding risk for contrast medium-induced acute kidney injuries (CI-AKI).center dot SSUR recommends that absolute and not relative GFR should be used when dosing drugs eliminated by the kidneys such as contrast media.center dot According to SSUR the gram-iodine dose/GFR ratio should be < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation.
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