doi:10.1002/ejic.201800985engMonteagudo-Olivan, R.Paseta, L.Potier, G.López-Ram-de-Viu, P.Coronas, J.Solvent-Free Encapsulation at High Pressure with Carboxylate-Based MOFsART-2019-109079The solvent-free encapsulation of caffeine and kojic acid was carried out in different carboxylate-based MOFs [MIL-53(Al), UiO-66 and Mg-MOF-74] by high pressure (0.32 GPa) contact. This methodology enables fast and ecofriendly encapsulation and gives rise to additive@MOFs with physical and features equivalent to those of materials obtained by common liquid phase encapsulation processes. It could be applied to other host–guest systems, simplifying the procedures, reducing the use and waste of harmful chemicals, and approaching the conditions of interest in the industry. The characterization carried out by thermogravimetry, X-ray diffraction, N2 adsorption, and 13C NMR provided information about the presence and conformation of the additives in the MOFs. The highest encapsulation values for caffeine (37 %) and kojic acid (32 %) were obtained with MIL-53(Al).2019http://zaguan.unizar.es/record/8468910.1002/ejic.201800985http://zaguan.unizar.es/record/84689oai:zaguan.unizar.es:84689info:eu-repo/grantAgreement/ES/DGA-FSE/T43-17REuropean Journal of Inorganic Chemistry 2019, 1 (2019), 29-36All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/openAccess