Continuous-flow in-line solvent-swap crystallization of vitamin D(3)

A continuous tandem in-line evaporation–crystallization is presented. The process includes an in-line solvent-swap step, suitable to be coupled to a capillary based cooler. As a proof of concept, this setup is tested in a direct in-line acetonitrile mediated crystallization of Vitamin D₃. This configuration is suitable to be coupled to a new end-to-end continuous microflow synthesis of Vitamin D₃. By this procedure, vitamin particles can be crystallized in continuous flow and isolated using an in-line continuous filtration step. In one run in just 1 min of cooling time, ∼50% (w/w) crystals of Vitamin D₃ are directly obtained. Furthermore, the polymorphic form as well as crystals shape and size properties are described in this paper.Marc Escribà-Gelonch, Volker Hessel, Manuel C. Maier, Timothy Noël, Maria Fernanda Neira d’Angelo and Heidrun Gruber-Woelfle

Tailored Stationary Phases for Continuous Electro-Chromatographic Separation of APIs

Highly purified organic materials are essential in various fields, including the fine-chemical, pharmaceutical and food industry. [...

Effect of Acetonitrile-based crystallization conditions on the crystal quality of vitamin D3

To design an integrated continuous crystallization setup that is directly coupled to a photochemical synthesis in flow, the crystallization of vitamin D3 was studied in detail. Because of the high solubility of the vitamin in the reaction solvent tert-butylmethyl ether, a solvent swap to acetonitrile was necessary. While other methods use a multistep procedure, with the proposed approach, crystalline vitamin D3 can be obtained within one crystallization step. The influence of crystallization parameters, such as the initial concentration of vitamin D3, stirring as well as cooling temperature, rate, and time, on the obtained results in terms of yield, crystal shape, polymorphism, and particle size distribution are discussed in detail

UV-induced immobilization of tethered zirconocenes on H-terminated silicon surfaces

A tethered ethylenebis(indenyl) zirconocene was covalently immobilized on H-terminated Si(111) surfaces using UV-mediated alkene hydrosilylation, thus making possible the development of structured catalytic surfaces with highly controlled propertie

Effect of Acetonitrile-based crystallization conditions on the crystal quality of vitamin D\u3csub\u3e3\u3c/sub\u3e

\u3cp\u3eTo design an integrated continuous crystallization setup that is directly coupled to a photochemical synthesis in flow, the crystallization of vitamin D\u3csub\u3e3\u3c/sub\u3e was studied in detail. Because of the high solubility of the vitamin in the reaction solvent tert-butylmethyl ether, a solvent swap to acetonitrile was necessary. While other methods use a multistep procedure, with the proposed approach, crystalline vitamin D\u3csub\u3e3\u3c/sub\u3e can be obtained within one crystallization step. The influence of crystallization parameters, such as the initial concentration of vitamin D\u3csub\u3e3\u3c/sub\u3e, stirring as well as cooling temperature, rate, and time, on the obtained results in terms of yield, crystal shape, polymorphism, and particle size distribution are discussed in detail.\u3c/p\u3

Continuous-Flow In-Line Solvent-Swap Crystallization of Vitamin D\u3csub\u3e3\u3c/sub\u3e

\u3cp\u3eA continuous tandem in-line evaporation-crystallization is presented. The process includes an in-line solvent-swap step, suitable to be coupled to a capillary based cooler. As a proof of concept, this setup is tested in a direct in-line acetonitrile mediated crystallization of Vitamin D\u3csub\u3e3\u3c/sub\u3e. This configuration is suitable to be coupled to a new end-to-end continuous microflow synthesis of Vitamin D\u3csub\u3e3\u3c/sub\u3e. By this procedure, vitamin particles can be crystallized in continuous flow and isolated using an in-line continuous filtration step. In one run in just 1 min of cooling time, ∼50% (w/w) crystals of Vitamin D\u3csub\u3e3\u3c/sub\u3e are directly obtained. Furthermore, the polymorphic form as well as crystals shape and size properties are described in this paper.\u3c/p\u3