Heats of Dilution, Solvation, Solution
The Dortmund Data Bank contains heats of mixing for quite some time. These mixing enthalpies describe the mixing of two or more pure components.
The MHSDDDB contains the enthalpy data where pure components or mixtures are added to existing mixtures. Data sets may contain initial and final concentrations, the thermal effect, temperatures, and pressures.
The MHSDDB is not an independent database although data may be purchased independently. It is part of the XDDB (DDB "Extended Data") where quite some data types are stored which haven't been assigned to DDBST's standard data banks.