An isothermal displacement calorimeter for positive excess enthalpies

Obbink, J.H.; Miltenburg, J.C. van; Berg, G.J.K. van den

doi:10.1016/0021-9614(78)90112-x

Cited by 7 publications

(1 citation statement)

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“…(1978) which are givcn in form of a Redlich-Kister correlation. The data taken in this work scatter by about 1 percent (1 J/mol) around the smoothed curve rcsulting from the data of Obdink et al (1978). The average derivation is about 0.05 percent (0.05 Jimol).…”

Section: Measurements On Reference Systemssupporting

confidence: 48%

Heat of Dilution in Aqueous and Methanolic Formaldehyde Solutions

Hasse

Maurer

1992

Ber Bunsenges Phys Chem

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83nodimedone is susceptible to self-condensation or hydrolysis reaction during work-up under macro-scale cpe conditions and this is responsible for the other scattered products observed.The third wave/peak of 4-CI-1-NHD (napp = 2 from microcoulometry) has been confirmed to be due to the cleavage of the carbon-chlorine bond of 4-chloro-1-naphthylamine formed as shown below since its Eli2 or E, values matched well with those of 4-chloro-1 -naphthylamine (Fig. 7):The third wave/peak of 1-NHD-4-S03H and 2-OH-1-NHD-4-S03H is attributed to a single electron, reversible reduction of the naphthylamine sulphonic acid (formed at the end of the second wave/peak) to the corresponding anion radical. Aromatic sulphones and sulphonate esters are known to be reversibly reduced to the corresponding radical anions in DMF at a mercury cathode, which have been detected by ESR [lS].4-Cl-1-NHD and 1-NHD-4-S0311 are reduced more easily and 2-OH-1-NHD-4-SO3H with more difficulty when compared to the reduction of 1-NHD [l, 31. This suggests that -I effect of -C1 in the case of 4-CI-l-NHD, -I and -M effects of -S03H in the case of 1-NHD-4-S03H and + M and steric effects of -OH in the case of 2-OH-1-NHD-4-SO3H are most predominant. References c1 I Formaldehyde Solutions J Heat of Dilution f ThermodynamicsAs part of an ongoing project dealing with thermodynamic properties of formaldehyde containing fluid mixtures, heats of dilution of formaldehyde, water, methanol and trioxane containing mixtures have been measured in a heat flow calorimeter at temperatures between 298 and 363 K. New mixing cells, allowing pressurization and avoiding vapor-space, were used to take over 300 data points covering binary, ternary and quarternary mixtures. The observed heats of dilution are generally small (less than 250 J/mol). They are correlated using a physico-chemical model. Physical effects are considered by the UNIFAC-group contribution method, reaction enthalpies are used for the description of the chemical contributions. The model allows a good representation of most of the binary data, extrapolations to multicomponent systems using binary data alone are, however, only qualitatively correct.*) Author to whom correspondence should be addressed.ical effects. While abundant data on vapor-liquid equilibria in formaldehyde containing systems is available (for a survey see Hasse 1990), up to now very little is known on caloric effects in these systems: Delepine (1897) and Walker (1933) have reported data on the heat of solution of formaldehyde gas in water and methanol, Iliceto (1951) gave results for the heat of dilution of an aqueous formaldehyde solution. The lack of data is an obstacle for modeling caloric prop-Ber. Bunsenges. Phys. Chem. 96 (1992) No. 1 0 VCH Verlagsgesellschaft mbH. W-6940 Weinheinr. lYYl ~~O O S -9 0 2~~9 2 j 0 l 0 l -W~3 $ 3.50 + ,2510

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Section: Measurements On Reference Systemssupporting

confidence: 48%