TY - CONF A1 - Kulla, Hannes T1 - Cocrystals of Pyrazinamide with Dicarboxylic acids T2 - COST-School CY - Berlin, Germany DA - 2015-11-23 PY - 2015 AN - OPUS4-35257 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes T1 - In situ investigation of mechanochemical reactions with PXRD and Raman spectroscopy - cocrystals of pyrazinamide with dicarboxylic acids N2 - - Cocrystal formation of pyrazinamide with dicarboxylic acids proceeds either directly or via a crystalline intermediate. - Two new crystal structures were discovered by in situ investigations. T2 - ICS 2016 CY - Granada, Spain DA - 30.05.2016 KW - In situ KW - Mechanochemie KW - XRD KW - Cocrystal PY - 2016 AN - OPUS4-36620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes T1 - In situ investigations of a mechanochemical cocrystal formation by X-ray diffraction for two different milling jar materials N2 - Mechanochemistry has become a valuable method for the synthesis of new materials, especially for pharmaceutical cocrystals. The Advantages of fast reactions in high purity and yield face a lack of understanding the underlying mechanism. Therefore, in situ setups to study mechanochemical reactions have been established. Herein, we present an in situ investigation of the mechanochemical cocrystal formation of pyrazinamide (PZA) with pimelic acid (PM) using synchrotron XRD. Two new polymorphs of PZA:PM (1:1) were synthesized by milling the starting materials in milling jars of different materials. While Form I is only obtained using a steel jar, Form II can be obtained purely in jars made of Perspex. In situ XRD experiments reveal a direct formation of Form II in Perspex and an intermediate formation of Form II in steel jars converting to Form I upon further grinding. Heating experiments and DFT calculations predict that Form II is the thermodynamically more stable polymorph. Therefore, the reaction progress in the steel jar contradicts Ostwald’s rules of stages as the more stable Form II converts into the metastable Form I. Hence, mechanochemistry offers the possibility to synthesize new materials that cannot be obtained using conventional methods. T2 - Adlershofer Forschungsforum 2017 CY - HU-Berlin, Erwin-Schrödinger Zentrum, Germany DA - 10.11.2017 KW - Cocrystal KW - Mechanochemistry KW - Polymorph KW - In situ KW - Milling PY - 2017 AN - OPUS4-42956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes T1 - In situ investigations of a mechanochemical cocrystal formation by X-ray diffraction in two different milling jars N2 - We present an in situ PXRD investigation of the mechanochemical cocrystal formation of pyrazinamide with pimelic acid in two milling jar materials. DFT calculations of the two synthesized polymorphs suggest that the relative stability is based on a conformation change of pyrazinamide in the cocrystal. T2 - 3. BAM-BfR Workshop CY - Berlin, Adlershof, Germany DA - 15.02.2018 KW - Mechanochemistry KW - Cocrystal KW - Polymorph KW - In situ XRD KW - DFT PY - 2018 AN - OPUS4-44315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes T1 - In situ PXRD monitoring of a mechanochemical cocrystal formation in milling jars of different material N2 - We present an in situ PXRD investigation of the mechanochemical cocrystal formation of pyrazinamide with pimelic acid in two milling jar materials. In the steel jar a polymorph transformation presenting an exception of Ostwald’s rule of stages is observed. T2 - BESSY User Meeting 2017 CY - Bessy II (HZB), Berlin, Germany DA - 14.12.2017 KW - In situ KW - XRD KW - Polymorph KW - Cocrystal KW - Milling PY - 2017 AN - OPUS4-43502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Haferkamp, Sebastian A1 - Akhmetova, Irina A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Rademann, Klaus A1 - Emmerling, Franziska T1 - In situ investigations of mechanochemical one-pot syntheses N2 - We present an in situ triple coupling of synchrotron X-ray diffraction with Raman spectroscopy, and thermography to study milling reactions in real time. This combination of methods allows a correlation of the structural evolution with temperature information. The temperature information is crucial for understanding both the thermodynamics and reaction kinetics. The reaction mechanisms of three prototypical mechanochemical syntheses, a cocrystal formation, a C@C bond formation (Knoevenagel condensation), and the formation of a manganese-phosphonate, were elucidated. Trends in the temperature development during milling are identified. The heat of reaction and latent heat of crystallization of the product contribute to the overall temperature increase. A decrease in temperature occurs via release of, for example, water as a byproduct. Solid and liquid intermediates are detected. The influence of the mechanical impact could be separated from temperature effects caused by the reaction. KW - In situ studies KW - Mechanochemistry KW - Raman spectroscopy KW - Thermography KW - X-ray diffraction PY - 2018 DO - https://doi.org/10.1002/anie.201800147 SN - 1433-7851 SN - 1521-3773 VL - 57 IS - 20 SP - 5930 EP - 5933 PB - Wiley-VCH CY - Weinheim AN - OPUS4-44946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Wilke, Manuel A1 - Fischer, Franziska A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Emmerling, Franziska T1 - Warming up for mechanosynthesis – temperature development in ball mills during synthesis N2 - We present a first direct measurement of the temperature during milling combined with in situ Raman spectroscopy monitoring. The data reveal a low temperature increase due to the mechanical impact and clear temperature increases as a consequence of the reaction heat. Based on the data, temperature rises as postulated in the magma plasma and hot spot theory can be excluded for soft matter milling syntheses. KW - Thermography KW - Milling KW - Mechanochemistry KW - Soft matter PY - 2017 DO - https://doi.org/10.1039/c6cc08950j SN - 1364-548X SN - 1359-7345 SN - 0009-241X VL - 53 IS - 10 SP - 1664 EP - 1667 AN - OPUS4-39251 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Fischer, Franziska A1 - Benemann, Sigrid A1 - Rademann, K. A1 - Emmerling, Franziska T1 - The effect of the ball to reactant ratio on mechanochemical reaction times studied by in situ PXRD N2 - The effect of the reactant powder mass on reaction times for the mechanochemical formation of a soft matter model system was studied by in situ PXRD. The syntheses were performed at a constant ball mass in a shaker mill with and without glassy SiO2 as an inert additive. Reaction times decreased with the increase of the ball to reactant ratio (BRR). The kinetic influence of the SiO2 powder was excluded. The decrease in the reaction time with decreasing mass of reactants was related to the rise in the stress energy transferred to the powder by a higher ball impact. The BRR had no effect on the induction time. But the product conversion was accelerated by raising the BRR. While a certain temperature is needed for the activation of reactants in the induction phase, the conversion of soft matter reactants is rather controlled by impact than temperature. KW - XRD KW - Mechanochemistry PY - 2017 UR - http://pubs.rsc.org/en/content/articlehtml/2017/ce/c7ce00502d DO - https://doi.org/10.1039/c7ce00502d VL - 19 IS - 28 SP - 3902 EP - 3907 AN - OPUS4-41197 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Greiser, Sebastian A1 - Benemann, Sigrid A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Knowing When To Stop-Trapping Metastable Polymorphs in Mechanochemical Reactions N2 - The cocrystal formation of pyrazinamide (PZA) with malonic acid (MA) was studied in situ. The mechanochemical reaction proceeds via conversion of a crystalline intermediate (PZA:MA II) into the thermodynamically more stable form (PZA:MA I) upon further grinding. The information derived from in situ powder X-ray diffraction (PXRD) enabled the isolation of this new metastable polymorph. On the basis of the PXRD data, the crystal structure of the 1:1 cocrystal PZA:MA II was solved. The polymorphs were further characterized and compared by Raman spectroscopy, solid-state NMR spectroscopy, differential thermal analysis/thermogravimetric analysis, and scanning electron microscopy. Our study demonstrates how monitoring mechanochemical reactions by in situ PXRD can direct the discovery and isolation of even short-lived intermediates not yet accessed by conventional methods. KW - Mechanochemistry KW - Polymorphs KW - Metastable KW - In situ PXRD KW - Cocrystal KW - Pyrazinamide PY - 2017 DO - https://doi.org/10.1021/acs.cgd.6b01572 SN - 1528-7483 SN - 1528-7505 VL - 17 IS - 3 SP - 1190 EP - 1196 AN - OPUS4-39420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Greiser, Sebastian A1 - Benemann, Sigrid A1 - Rademann, K. A1 - Emmerling, Franziska T1 - In Situ Investigation of a Self-Accelerated Cocrystal Formation by Grinding Pyrazinamide with Oxalic Acid N2 - A new cocrystal of pyrazinamide with oxalic acid was prepared mechanochemically and characterized by PXRD, Raman spectroscopy, solid-state NMR spectroscopy, DTA-TG, and SEM. Based on powder X-ray diffraction data the structure was solved. The formation pathway of the reaction was studied in situ using combined synchrotron PXRD and Raman spectroscopy. Using oxalic acid dihydrate the initially neat grinding turned into a rapid self-accelerated liquid-assisted grinding process by the release of crystallization water. Under these conditions, the cocrystal was formed directly within two minutes. KW - in situ KW - cocrystal KW - mechanochemistry KW - pyrazinamide KW - hydrate PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372357 DO - https://doi.org/10.3390/molecules21070917 SN - 1420-3049 VL - 21 IS - 7 SP - Article 917, 1 EP - 9 AN - OPUS4-37235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -