The present invention provides a chromatography medium comprising one or more electrospun polymer nanofibers which form a stationary phase comprising a plurality of pores through which a mobile phase can permeate and use of the same in chromatography, such as the isolation of recombinant proteins, monoclonal antibodies, viral vaccines and plasmid DNA. The invention further provides for the use of the chromatographic medium in a simulated moving bed system.

The invention related to a method for purifying a first fatty acid, preferably polyunsaturated, using an initial mixture further comprising at least one second fatty acid, optionally a third fatty acid and optionally a fourth fatty acid, with the method comprising: a first step of chromatographic separation in liquid phase, using the initial mixture, carried out in a first unit for chromatographic separation, making it possible to recover on the one hand a first flow enriched with a first fatty acid and on the other hand a flow enriched with a second fatty acid, optionally, a second step of chromatographic separation in liquid phase, using the first flow enriched with a first fatty acid, carried out in a second chromatographic separation unit, making it possible to recover on the one hand a second flow enriched with a first fatty acid and on the other hand a flow enriched with a third fatty acid; optionally, a third step of chromatographic separation in liquid phase, using the third flow enriched with a first fatty acid, carried out in a third chromatographic separation unit, making it possible to recover on the one hand a third flow enriched with a first fatty acid and on the other hand a flow enriched with a fourth fatty acid; at least one among the first unit for chromatographic separation, the second unit for chromatographic separation and the third unit for chromatographic separation being a static bed chromatographic separation unit with a single column with recycling in stationary state.

The invention relates to a method for purifying a first fatty acid, in particular a first polyunsaturated fatty acid, using an initial mixture further comprising at least one second fatty acid and a third fatty acid, with the method comprising at least: a first step of chromatographic separation in liquid phase, using the initial mixture, making it possible to recover on the one hand a first flow enriched with a first fatty acid and on the other hand a flow enriched with a second fatty acid; a second step of chromatographic separation in liquid phase, using the first flow enriched with a first fatty acid, making it possible to recover on the one hand a second flow enriched with a first fatty acid and on the other hand a flow enriched with a third fatty acid, with the second step of chromatographic separation being carried out in a static bed chromatographic separation unit.

The invention relates to an adsorbent comprising a zeolite-based phase and a non-zeolite-based phase, said adsorbent having: an outer surface area of less than or equal to 30 m.sup.2.Math.g.sup.−1, preferably less than or equal to 20 m.sup.2.Math.g.sup.−1, a zeolite-based phase comprising at least one zeolite of FAU structure of X type, and a pore diameter distribution, determined by mercury intrusion according to standard ASTM D 4284-83 and expressed by the volume distribution dV/d log DHg, in which DHg is the apparent pore diameter and V is the pore volume, the mode of which is between 100 nm and 250 nm, limits inclusive.

The invention also relates to a process for preparing the said adsorbent and to the uses thereof, especially for separating xylene isomers.

Processes for separating a di-carboxylic acid or salt thereof from a mixture containing the di-carboxylic acid or salt thereof and one or more other components are provided. Also separation media useful for these separation processes is provided. In particular, processes for preparing an aldaric acid are described, such as glucaric acid from glucose, which includes separating the aldaric acid from the reaction product. Also, various glucaric acid products are described.

A process for producing paraxylene is provided. The process includes separating a first mixture of C.sub.8 aromatic hydrocarbons in a simulated moving bed apparatus using a desorbent to produce (i) an extract comprising ≧50.0 wt % of the paraxylene in the first mixture; (ii) a desorbent-rich raffinate comprising ≧75 wt % of the desorbent withdrawn, and (iii) an desorbent-lean raffinate comprising ≦25 wt % of the desorbent withdrawn in the desorbent-rich and desorbent-lean raffinates. The desorbent-lean raffinate can then, without an intervening separation step, be passed to a refinery process or a vapor phase isomerization reaction to produce an effluent comprising paraxylene in a greater concentration than the desorbent-lean raffinate. The desorbent-rich raffinate can be passed to a liquid phase isomerization reaction to produce an effluent comprising paraxylene in a greater concentration than the desorbent-rich raffinate.

The present invention relates to spherical agglomerates based on zeolite(s) and clay(s), having controlled size and morphology, in particular a size of less than or equal to 600 μm, very good sphericity, and a high content of zeolitic material, to the process for the production thereof. These agglomerates are particularly suitable for uses in gas-phase and/or liquid-phase adsorption processes.

The present invention relates to a zeolite absorbent comprising at least one FAU zeolite with hierarchical porosity and comprising barium or barium and potassium, and the external surface area of which is greater than 20 m.sup.2.Math.g.sup.−1, and the non-zeolite phase content being between 6% and 12% by weight with respect to the total weight of the absorbent. The present invention also relates to the use of such a zeolite absorbent as an adsorption agent, as well as the method for separation of para-xylene from aromatic isomer fractions with 8 carbon atoms.

The present invention describes a novel configuration for simulated moving bed separation processes characterized by using two adsorbers each containing 12 beds, these two adsorbers functioning in parallel. This novel configuration can be used to optimize para-xylene production.

A simulated moving-bed type chromatographic separation method separating a weakly adsorptive component, a strongly adsorptive component, and an intermediately adsorptive component, with eluents by using a circulation system in which a plurality of unit packed columns packed with an adsorbent are connected in series and in an endless form via pipes in which a feed solution supply port F, two or more eluent supply ports D corresponding to the eluents, an extraction port A of a fraction containing the weakly adsorptive component, an extraction port B of a fraction containing the intermediately adsorptive component, and an extraction port C of a fraction containing the strongly adsorptive component are provided in the pipes of the circulation system, and positions of the ports F, A, B, and C are set to have a specified relationship.