Abstract: A process is provided for the preparation of pure cyclosporin which is purified chromatographically from a mixture of different cyclosporin forms and other substances prepared by fermentation. The process comprises feeding a mixture containing a desired form of cyclosporin with an eluent consisting of high pressure carbon dioxide and an adjuvant, into a chromatography column being packed with particles prepared of silica, and recovering from the eluent flow coming out of the chromatography column a fraction which contains the desired cyclosporin form in adequately pure form.

Abstract: A method is provided for supplying the desired optical isomer of a derivative of epoxypropionic acid from a racemix mixture. A representative derivative of epoxypropionic acid is an ester of (p-methoxyphenyl)epoxypropionic acid. The racemic mixture initially is dissolved in carbon dioxide and the resulting solution is passed through a chromatographic column. The desired isomer is subsequently separated from the resulting eluant. In a preferred embodiment the chromatographic column is packed with microcrystallized cellulosetriacetate, cellulose-tris-(3,5-dimethylphenylcarbamate), or cellulose-tris-(p-methylphenylcarbamate).

Abstract: A method for producing fire-retarded blend fibers having a fire resistance LOl-value of at least 21% O.sub.2, made from cellulose and chlorine containing polymer. Chlorine containing polymer having a chlorine content of 30-75% by weight, is blended, either as such or dissolved in a solvent, with a DMSO/formaldehyde solution of cellulose so that the obtained blend has 10-70% by weight of chlorine containing polymers, based on the total amount of cellulose and said polymers. Fibers are produced of the obtained mixture by bringing it into contact with an aqueous or alcoholic solution.

Abstract: A process for producing regenerated cellulosic articles from cellulose which has been dissolved in a mixture of dimethyl sulfoxide (DMSO) and formaldehyde, and for recovering the solvent chemicals. The DMSO/formaldehyde solution of cellulose is brought into contact with an aqueous solution, the pH of which is at least 9 and the adjustment of pH has been carried out by means of a base or an alkaline salt which does not react with formaldehyde and the content of which is at most 0.1% by weight, so that the product is coagulated and regenerated in the desired form, such as fibres, films or shaped articles. The coagulation solution is evaporated in one stage or plurality of stages so that the DMSO and formaldehyde of the cellulose solution remain in the evaporation residue. The evaporation residue is recycled for the production of cellulose solution, purified, if so required.