Patent GB-786223-A (GB)
Title: Improvements in and relating to the manufacture of organic chemical compounds
IPC: C07D231/52
Filed: 1955-06-09
Abstract: <PICT:0786223/IV (b)/1> In a chemical process, which may be used for condensation, addition or halogenation reactions, at least two reactants of different volatilities are reacted in a column packed to provide a multiplicity of tortuous, constricted paths and the product is collected from the lower end of the column.  The process is characterized in that a liquid comprising the two reactants or the reactant of lower volatility flows downwards through said column while the vapour of a solvent for said two reactants or the vapour, in excess, of the reactant of higher volatility respectively flows upwards through said column, the temperature being adjusted so that the two reactants or said reactant of lower volatility and the product remain substantially in the liquid state and said solvent or said reactant of higher volatility remains substantially in the vapour state while passing through said column, and the proportions of the two reactants flowing through the column being adjusted so that they react substantially completely to form the desired chemical compound. The process wherein a normally solid material is melted and flows downwardly while vapours of another reactant are passed upwardly in countercurrent to the downflowing melt may be used to form acid chlorides of solid fatty acids, e.g. those containing up to 18 carbon atoms such as palmitic, oleic and stearic, from the acid and thionyl chloride vapours.  The process wherein two normally liquid materials of different volatility are used as counterflowing reactants may be utilized to chlorinate normally liquid unsubstituted or substituted lower fatty acids by upflowing thionyl chloride vapours.  Into a vertical column 10, filled with packing material 11, a liquid reactant is introduced at inlet 25 and a gaseous reactant vaporized in the vessel 17 is introduced at inlet 12.  Reaction products are withdrawn into vessel 28 and the unchanged vapour is condensed and separated from the other gases by condenser 16 to be returned to vessel 17 for re-vaporizing and re-cycling.  In examples apparatus of this type is used (1) to chlorinate a solution of 2 : 4-di-tert.-amylphenoxy-acetic acid in its chloride with thionyl chloride containing a trace of quinoline; (2) to produce (21 : 41 - di - tert - amyl - phenoxy)acet - (2 - hydroxy - 3 : 5 - dichloro - 4 - methyl) anilide by introduction of a mixture of 2 : 4-ditert - amyl - phenoxyacetyl chloride, 2 - amino4 : 6 - dichloro - 5 - methyl phenol hydrochloride, dimethylaniline, acetone and water at the top of a column through which acetone vapours are cycled, the initial reaction produced being acidified with concentrated hydrochloric acid; (3) to form palmitoyl chloride from palmitic acid and thionyl chloride; and (4) to produce 1 - [21 : 41 : 61 - trichlorophenyl] - 3-[m - (211 : 411 - di - tert - amyl - phenoxyacetamido)benzamido] - 5 - pyrazolone by introduction of a mixture of 1-(21 : 41 : 61-trichloropheny) - 3 - m - aminobenzamido - 5 - pyrazolone, 2 : 4-di-tert-amyl-phenoxyacetyl chloride and acetic acid at the top of a column through which acetic acid vapours are cycled.ALSO:<PICT:0786223/III/1> Into a vertical column 10, filled with inert packing material 11, a liquid reactant is introduced at inlet 25 and a gaseous reactant vaporized in vessel 17 is introduced at inlet 12.  Reaction products are withdrawn into vessel 28 and the unchanged vapour is condensed and separated from other gases by condenser 16 to be returned to vessel 17 for revaporizing and recycling.