Stationary phases cellulose, preparation

The Preparation of the Pirkle Stationary Phases The Preparation of Cellulose and Amylose Stationary Phases The Preparation of the Macrocyclic Glycopeptides Phases The Preparation of the Cyclodextrin Based Stationary Phases Column Packing Techniques... 

Of course, preparative or semipreparative separation of substances of clinical interest is realized not only on silica gels or impregnated silica gels, but favorable results are also obtained on different stationary phases (e.g., cellulose or ion exchangers). 

There is a wide variety of commercially available chiral stationary phases and mobile phase additives.32 34 Preparative scale separations have been performed on the gram scale.32 Many stationary phases are based on chiral polymers such as cellulose or methacrylate, proteins such as human serum albumin or acid glycoprotein, Pirkle-type phases (often based on amino acids), or cyclodextrins. A typical application of a Pirkle phase column was the use of a N-(3,5-dinitrobenzyl)-a-amino phosphonate to synthesize several functionalized chiral stationary phases to separate enantiomers of... 

Because of the similarities in the theory and practice of these two procedures, they will be considered together. Both are examples of partition chromatography. In paper chromatography, the cellulose support is extensively hydrated, so distribution of the solutes occurs between the immobilized water (stationary phase) and the mobile developing solvent. The initial stationary liquid phase in thin-layer chromatography (TLC) is the solvent used to prepare the thin layer of adsorbent. However, as developing solvent molecules move through the stationary phase, polar solvent molecules may bind to the immobilized support and become the stationary phase. 

For the preparation of the chiral stationary phase (3-methylbenzoyl cellulose) and of the analytical HPLC columns, see ref1421. The preparative column (glass column 5 cm i.d. x 75 cm Btichi AG, Flawil, Switzerland) was slurry-packed with a suspension of 3-methylbenzoyl-cellulose beads (550 g) in hexane/ iPrOH (9 l). The glass column was topped with a column of the same dimension as a reservoir. After decantation of the material in the column, the reservoir was taken away and the stationary phase washed by pumping the eluent through the column equipped with an inlet plunger, at a flow rate of 60 mL-min 1... 

Kubota, T., Yamamoto, C., and Okamoto, Y. (2003) Preparation of chiral stationary phase for HPLC based on immobilization of cellulose 3,5-dimethylphenylcarbamate derivatives on silica gel, Chirality 15, 77-82. 

L. Miller and R. Bergeron, Analytical and preparative resolution of enantiomers of verapamil and norverapamil using a cellulose-based chiral stationary phase in the reversed-phase mode, J. Chromatogr., 648 36(1993)... 

The majority of preparative separations undertaken at Ultrafine have used chiral stationary phases based on either cellulose or amylose derivatives. In one project 500 mg of salts of both the (R,R)- and (S,S)-Formoterol (6) enantiomers were prepared using an OJ column with a resulting ee of >97%.45 A loading of 200 mg/mL on a semipreparative column was achievable without loss of resolution or purity relative to the racemate. 

Advances in preparative enantioseparation by simulated moving bed (SMB) chromatography have occurred in the last 10 years. SMB was invented in the 1960s and was used by the petrochemical and sugar industries. Now with the improvements in stationary phases and hardware it is an option for the large-scale preparation of enantiomerically pure material. The majority of the latest published data are using either amylose- or cellulose-based phases because of their selectivity. There are now examples in the literature of the commercial separation on the multi-ton scale.8... 

Partition Chromatography. Unlike the other types of chromatography discussed thus far, this type is usually used for analytical (rather than preparative) applications. In addition, this type of chromatography is often performed in a thin-layer (rather than a column) format. The stationary phase in partition chromatography is usually a glass plate (rigid) or polyester sheet (flexible) coated with a very thin layer of the desired adsorbent. For most applications, the adsorbent is a cellulose, silica, polyamine, or aluminum oxide-based matrix. In... 

---