Separation and purification and stabilisation and use of additives (C07C47/09)

C   Chemistry; metallurgy(316576)
C07   Organic chemistry(61593)
C07C47        Compounds having ; cho groups(815)
C07C47/09                     Separation; purification; stabilisation; use of additives(2)

ethod of controlling process of removing permanganate reduced compounds using methanol carbonylation technique // 2493143
FIELD: chemistry.SUBSTANCE: invention relates to an improved method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction vessel containing water, methyl iodide and methyl acetate in the presence of a group VIII metal based carbonylation catalyst; separating products of said reaction into a volatile product phase containing acetic acid and a less volatile phase; distilling said volatile phase in a distillation apparatus to obtain a purified product of acetic acid and a first overhead fraction containing methyl iodide and acetaldehyde; condensing at least a portion of said overhead fraction; measuring density of said condensed first overhead fraction; determining relative concentration of methyl iodide, acetaldehyde or both in the first overhead fraction based on the measured density; and adjusting at least one process control parameter associated with distillation of said volatile phase as a response reaction to said relative concentration. The invention relates to a method of producing acetic acid comprising the following steps: reacting methanol with carbon monoxide in a reaction medium containing water and methyl iodide in the presence of a group VIII metal based carbonylation catalyst; performing vapour-liquid separation in said reaction medium to obtain a vapour phase containing acetic acid, methyl iodide, acetaldehyde and water, and a liquid phase; distilling said vapour phase in a distillation apparatus to obtain a purified acetic acid product and at least a first overhead fraction containing acetaldehyde and methyl iodide; condensing said first overhead fraction; extracting said first overhead fraction with water to obtain a raffinate containing methyl iodide and an aqueous extract; measuring density of at least one stream selected from a group consisting of said first overhead fraction, said raffinate and said aqueous extract; determining relative concentration of methyl iodide, acetaldehyde or both in at least said first overhead fraction, said raffinate and said aqueous extract based on the measured density; and adjusting at least one process control parameter associated with either distillation of said vapour phase or extraction of said first overhead fraction as a response reaction to said relative concentration.EFFECT: method of controlling the separation process in order to remove permanganate reduced compounds from a process stream during methanol carbonylation, involving steps of measuring density of a stream containing acetaldehyde and methyl iodide, and calculating relative concentration of acetaldehyde and methyl iodide in the stream enables to adjust parameters of the distillation or extraction process based on measured density or one or more relative concentrations calculated therefrom.12 cl, 5 dwg

ethod of controlling process of removing reduced permanganate compounds when using methanol carbonylation technology // 2376276
FIELD: chemistry.SUBSTANCE: first version of the method involves the following steps: distillation of a mixture which contains methyl iodide and acetaldehyde in a distillation apparatus in order to obtain an overhead fraction and a residue, measuring density of the said overhead fraction, determination of relative concentration of methyl iodide, acetaldehyde or both in the overhead fraction based on the measured density and regulation of at least one process variable, associated with the said distillation apparatus. As a response reaction to the said measured density or relative concentration calculated from the measured density, the said process variable is selected from heating intensity, column pressure, the composition fed, condensate composition and coefficient of flow reversal.EFFECT: effective reduction of amount and removal of acetaldehyde and methyl iodide from a carbonylation system.6 cl, 5 dwg
 
2550897.
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