Process for saparating a hydroxybenzonitrile-type compound
OwnerJean-Francis Spindler, Roland Jacquot +1inventors
InventorsJean-Francis Spindler, Roland Jacquot, Michel Alas
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Abstract
The invention concerns a method for separating a hydroxybenzonitrile-type compound obtained by an amination/dehydration process. More particularly, the invention concerns 2-hydroxybenzonitrile, also called 2-cyanophenol. The inventive method for separating a hydroxybenzonitrile compound from a reaction gas flow comprising it wholly or partly in the form of an ammonium salt is characterized in that it consists in displacing the ammonium ions, through a physical treatment carried out on the reaction gas flow derived from its preparation or from the solid previously recuperated from said flow or according to a chemical treatment carried out on the reaction gas flow, after liquefaction.
Claims47
A process for separating a hydroxybenzonitrile type compound from a gaseous reaction stream containing it either completely or partially in the form of an ammonium salt, characterized in that it consists, with the aim of obtaining a hydroxybenzonitrile type compound, of displacing the ammonium ions:
- by means of a physical treatment carried out on the gaseous reaction stream deriving from its preparation or by means of a physical treatment of the solid already recovered from the gaseous reaction stream after liquefaction, or of said same solid in solution;
- or by means of a chemical treatment carried out on the gaseous reaction stream after liquefaction.
A facility for separating 2-hydroxybenzonitrile from a gaseous reaction stream comprising 2-hydroxybenzonitrile, in the salt form, characterized in that it comprises:
- a first column (1) intended to bring the gaseous reaction stream and the solvent (water and/or organic solvent) into contact;
- a second column (2) the inlet to which is connected to the bottom of column (1), said column (2) being intended to produce a light fraction comprising ammonia, water and an alcohol (preferably methanol) from the column head and from the column bottom, a heavy fraction essentially comprising 2-hydroxybenzonitrile, the solvent (water and/or organic solvent), traces of ammonia and minor quantities of secondary products.
A facility for separating 2-hydroxybenzonitrile by physical treatment of ammonium cyanophenate comprising:
- a wash tower (11) provided with a system for admitting gas (F1) and a device for introducing water via a pump that can recover a liquid phase (F12) comprising water, crude ammonium cyanophenate and ammonia from the bottom;
- which mixture is transferred to reactor (12);
- a crystallization reactor (12) for the ammonium cyanophenate and provided with means for admitting the fraction (F12) and a withdrawal device to connect it to a separation device (13);
- said reactor being provided with agitation means and a temperature regulating means;
- a solid/liquid separation device (13), preferably an aspirator, agitated filter, filter-press, multi-tube filter to recover a solid essentially constituted by ammonium cyanophenate and an aqueous phase (F13) comprising the solvent, a little 2-hydroxybenzonitrile (less than 5% by weight) and by-products;
- drying means (14), preferably an agitated drier, in which it undergoes a temperature and pressure cycle to decompose the solid ammonium cyanophenate to 2-hydroxybenzonitrile, to recover 2-hydroxybenzonitrile in the form of a powder (P) while eliminating the solvent and remaining ammonia (F14).
A facility for separating 2-hydroxybenzonitrile by physical treatment of ammonium cyanophenate comprising:
- a wash tower (11) provided with a system for admitting gas (F1) and a device for introducing water via a pump that can recover a liquid phase (F12) comprising water, crude ammonium cyanophenate and ammonia from the bottom;
- which mixture is transferred to a reactor (12);
- a crystallization reactor (12) for the ammonium cyanophenate and provided with means for admitting the fraction (F12) and a withdrawal device to connect it to a separation device (13);
- said reactor being provided with agitation means and a temperature regulating means;
- a solid/liquid separation device (13), preferably an aspirator, agitated filter, filter-press, multi-tube filter to recover a solid essentially constituted by ammonium cyanophenate and an aqueous phase (F13) comprising the solvent, a little 2-hydroxybenzonitrile (less than 5% by weight) and by-products and provided with means for admitting a solvent (S2) to dissolve the ammonium cyanophenate;
- a reactor (16) provided with a device for admitting an organic solution of ammonium cyanophenate provided with agitation means, a temperature regulating device surmounted by a distillation column and provided with a reduced pressurization system to separate, by distillation, the organic solvent and/or remaining water (F16) and to carry out thermal decomposition of ammonium cyanophenate to 2-hydroxybenzonitrile.
A facility for separating 2-hydroxybenzonitrile by chemical treatment of a gaseous reaction stream comprising 2-hydroxybenzonitrile in the salt form, characterized in that it comprises:
- a wash tower (17) provided with a system for admitting gas (F1) and a device for introducing water via a pump that can recover a liquid phase (F18) comprising water, crude ammonium cyanophenate and ammonia from the bottom;
- which mixture is transferred to a reactor (18);
- a neutralization reactor (18) provided with agitation means, a temperature regulating device, a device for introducing reactant (acid) and a pH regulating device (electrode):
- the lower portion of said reactor comprising a withdrawal device that can connect it to a device (19);
- a liquid/liquid separation device (13), preferably a settler for separating an aqueous phase (F19) comprising excess acid and ammonium salts and an organic phase (F20) comprising 2-hydroxybenzonitrile.
Ammonium 2-cyanophenate with formula:
- a liquid/liquid separation device (8), preferably a settler, to separate an aqueous phase (F7) from an organic phase essentially constituted by 2-hydroxybenzonitrile (F8);
- a reactor (9) provided with means for admitting an organic phase and provided with agitation means, a temperature regulating means (hot/cold), a distillation column and provided with a reduced pressurization system to separate, by distillation (F9), the organic solvent and/or remaining water and to recover crude 2-hydroxybenzonitrile;
- and
- one or more refining devices, preferably of the draining sieve type to eliminate impurities (F10) and to recover a liquid fraction of 2-hydroxybenzonitrile (F11).
A facility for separating 2-hydroxybenzonitrile by physical treatment of ammonium cyanophenate comprising:
- a wash tower (11) provided with a system for admitting gas (F1) and a device for introducing water via a pump that can recover a liquid phase (F12) comprising water, crude ammonium cyanophenate and ammonia from the bottom;
- which mixture is transferred to reactor (12);
- a crystallization reactor (12) for the ammonium cyanophenate and provided with means for admitting the fraction (F12) and a withdrawal device to connect it to a separation device (13);
- said reactor being provided with agitation means and a temperature regulating means;
- a solid/liquid separation device (13), agitated filter, filter-press, multi-tube filter to recover a solid essentially constituted by ammonium cyanophenate and an aqueous
Dependencies are inferred from the claim text.