摘要:
Substantially spherical granules of phenacetin are prepared by spraying liquid phenacetin which has been melted without decomposition by means of rapid passage through a melting device in which superheating is minimized. The resultant melt-sprayed granules are superior to crystalline phenacetin in the formulation of pharmaceutical tablets.
摘要:
An apparatus for melt-spraying thermally sensitive material of low viscosity comprises a heatable multi-screw extruder having intermeshing, self-cleaning screws of specified clearance between the screws and between the screws and the extruder housing, a heatable pump for delivering molten material from the extruder to a heatable atomizer and a spray tank in which the atomizer is located for cooling and solidifying the melt-sprayed material.
摘要:
Particulate material is discharged continuously from fluidized bed reactors by passing the material emerging at the lowest point of the fluidized bed through a zone which is narrower than the fluidized bed and in which a gas stream flows counter-current to the material, the pressure of the gas stream being above the pressure of the fluidized zone.
摘要:
In the preparation of a cinnamic acid by reacting the corresponding benzaldehyde with ketene in the presence of a catalyst, the improvement which comprises using as the catalyst an iron and/or zinc salt of a mono- or di-carboxylic acid with 2 to 20 carbon atoms containing free carboxylic acid and/or anhydride, and then splitting the reaction product in the temperature range from 100.degree. to 250.degree. C. with an acid or basic catalyst.
摘要:
Aromatic hydroxycarboxylic acids are prepared by reacting an alkali metal salt of an aromatic hydroxy compound in solid phase with carbon dioxide, by reacting an alkali metal salt of an aromatic hydroxy compound in the form of granules in a fluidized bed with carbon dioxide, if desired under elevated pressure, at first at temperatures of 20.degree. to 130.degree. C. until at least 40% of the hydroxy compound has been converted into the corresponding carbonate, then completing the reaction at temperatures of 135.degree. to 300.degree. C., and then converting the reaction product obtained into the free acid.
摘要:
Aromatic hydroxycarboxylic acids are prepared by reacting alkali metal salts of aromatic hydroxy compounds in the solid phase with carbon dioxide in a process in which the alkali metal salt of the aromatic hydroxy compound is reacted at temperatures of 120.degree. to 300.degree. C., in the form of granules, in a fluidized bed with carbon dioxide, if appropriate under elevated pressure and, if appropriate, in the presence of the aromatic hydroxy compound in the form of vapor, with continuous removal, by means of excess carbon dioxide, of the aromatic hydroxy compound which is formed, until at least 40% of the hydroxy compound have been converted into the alkali metal salt of the corresponding hydroxycarboxylic acid, and, if appropriate, the resulting alkali metal salt of the hydroxycarboxylic acid is reacted further in a subsequent stage at temperatures of 150.degree. to 300.degree. C. and under elevated pressure, in the presence of carbon dioxide, with the aromatic hydroxy compound formed, and the resulting reaction product is then converted in a customary manner into the free acid.
摘要:
2,4,6-Trichloroaniline is prepared by reaction of aniline, which is optionally substituted by halogen, with a chlorinating agent in the presence of inert organic solvents and/or diluents at elevated temperatures.
摘要:
In a process for the preparation of oxalyl chloride from an oxalic acid compound of the formula ##STR1## wherein R.sup.1 and R.sup.2 are identical or different and represent hydrogen or a lower alkyl radical,and phosphorus pentachloride in the presence of phosphorus oxychloride, the improvement wherein the reaction is carried out in the presence of an amino compound of the formula ##STR2## wherein R.sup.3 represents alkyl, aralkyl, aryl or an acyl group, optionally substituted by amino or carboxamido andR.sup.4 and R.sup.5 are identical or different and represent hydrogen or alkyl, aralkyl, or aryl, optionally substituted by amino or carboxamido, orR.sup.4 and R.sup.5 are linked in an optionally substituted carbocyclic ring with 5 to 7 ring members, which optionally contains nitrogen, sulphur and/or oxygen and is optionally substituted by alkyl, aralkyl, aryl and/or amino groups, andR.sup.3 represents hydrogen or alkyl, which can be linked with R.sup.4 to form a carbocyclic ring, aralkyl or aryl, optionally substituted by an amino or carboxamido group, or optionally forms a double bond in one of the radials R.sup.4 or R.sup.5,and the oxalyl chloride formed is distilled off during the reaction.