This invention discloses an approach for the separation of the close-boiling mixture of polyols. The raw material is ethylene glycol containing miscellaneous polyols (such as 1,2-propylene glycol and 1,2-butanediol). Over an acid catalyst, these miscellaneous polyols, through (1) a dehydration reaction, (2) pinacol rearrangement, and (3) acetalization or ketalization reaction, are converted into aldehydes (small amounts), acetals, and ketals (trace amount), which are simultaneously and readily separated via distillation. Meanwhile, after the reaction, the mixture is further separated to obtain an ethylene glycol product at a high purity. The invention provides a technique to remove the miscellaneous polyols from ethylene glycol via liquid-phase dehydration reactions under mild conditions, with low energy consumption. In particular, this approach is markedly effective for the removal of 1,2-butanediol that is difficult to be removed via conventional techniques. The purity of the resulting ethylene glycol product is high, and value-added acetals or ketals are co-produced.

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.

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.

The present disclosure describes compositions comprising substantially pure ribitol, pharmaceutical compositions of ribitol, and methods of making ribitol. The methods may include combining a reducing agent (e.g., borohydride) and ribose (e.g. D-ribose), optionally with stirring, to form a first reaction mixture; and contacting the first reaction mixture and an acidic quenching agent, optionally with stirring, to form a second reaction mixture, thereby forming ribitol.

The present disclosure describes compositions comprising substantially pure ribitol, pharmaceutical compositions of ribitol, and methods of making ribitol. The methods may include combining a reducing agent (e.g., borohydride) and ribose (e.g. D-ribose), optionally with stirring, to form a first reaction mixture; and contacting the first reaction mixture and an acidic quenching agent, optionally with stirring, to form a second reaction mixture, thereby forming ribitol.

The present disclosure describes compositions comprising substantially pure ribitol, pharmaceutical compositions of ribitol, and methods of making ribitol. The methods may include combining a reducing agent (e.g., borohydride) and ribose (e.g. D-ribose), optionally with stirring, to form a first reaction mixture; and contacting the first reaction mixture and an acidic quenching agent, optionally with stirring, to form a second reaction mixture, thereby forming ribitol.

This disclosure provides methods for the chemical modification of triglycerides that are highly enriched in specific fatty acids and subsequent use thereof for producing functionally versatile polymers.

This disclosure provides methods for the chemical modification of triglycerides that are highly enriched in specific fatty acids and subsequent use thereof for producing functionally versatile polymers.

The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.

The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.