摘要:
Verfahren zur Herstellung von 24-Dichlor- bzw. 2-Methyl-4-chlorphenoxyessigsäure oder alpha-2,4-Dichlor- bzw. alpha-2-Methyl-4-chlorphenoxypropionsäure durch Umsetzung von Phenoxyessigsäure bzw. 2-Methylphenoxyessigsäure oder alpha-Phenoxypropionsäure bzw. alpha-2-Methylphenoxypropionsäure mit Chlor in Wasser, indem man Phenoxyessigsäure aus ihrer wäßrigen Lösung ausfällt, in die so erhaltene Suspension von Phenoxyessigsäure bzw. 2-Methylphenoxyessigsäure oder alpha-Phenoxypropionsäure bzw. alpha-2-Methylphenoxy- propionsäure in Wasser Chlorgas bei einer Temperatur von 30 bis 70°C höchstens in der Menge und Geschwindigkeit, in der es von der Suspension verbraucht wird, einleitet, bis 100 bis 110 % der theoretisch erforderlichen Menge an Chlorgas von der Suspension aufgenommen worden sind, und die 2,4-Dichlor- bzw. 2-Methyl-4-chlorphenoxyessigsäure oder alpha-2,4-Dichlor- bzw. alpha-2-Methyl-4-chlorphenoxy- propionsäure von der Suspension abtrennt.
摘要:
The present invention pertains to a process for the chlorination of acetic acid to form monochloroacetic acid comprising the following steps a. reacting acetic acid with chlorine using acetic anhydride and/or acetyl chloride as catalyst to form a liquid phase, and a gaseous phase, - the liquid phase comprising at least monochloroacetic acid, acid chlorides, acid anhydrides and optionally un reacted acetic acid, and - the gaseous phase comprising HCI, acetic acid, monochloroacetic acid and acid chlorides, b. stripping said liquid phase at a temperature of between 120 and 180°C and a pressure between 1 and 7 bara with gaseous HCI to form a gaseous HCI stream comprising acetic acid, acid chlorides and optionally acid anhydrides and monochloroacetic acid, and a liquid stream comprising monochloroacetic acid and dichloroacetic acid; c. cooling the gaseous HCI stream comprising acetic acid, acid chlorides, acid anhydrides and optionally monochloroacetic acid to a temperature of between 10 and 60°C (preferably around 35°C), and d. feeding the cooled gaseous HCI to an absorber with acetic acid as absorber, absorbing the acetic acid, acid chlorides and optionally monochloroacetic acid forming a stream comprising acetic acid and acid chlorides.
摘要:
Process for producing polyhydroxyalkanoates or PHA from volatile fatty acid (VFA) molecules, termed precursors, produced by anaerobic fermentation from fermentable biomass, characterized in that it comprises at least the following steps: - a) extracting the volatile fatty acid (VFA) molecules, without interrupting the fermentation, using an extraction means chosen from means which are, at least, insoluble in the fermentation medium, - b) collecting, outside the fermentation reactor, the volatile fatty acid (VFA) molecules once extracted, - c) synthesizing a given α‑halogenated acid by halogenation from a type of volatile fatty acid (VFA) chosen from the volatile fatty acids collected in step b) and defined according to the type of PHA desired, - d) synthesizing, from this α‑halogenated acid, molecules of a given α‑hydroxy acid by reaction with a base, - e) polymerizing a defined polyhydroxyalkanoate (PHA) from the α‑hydroxy acid obtained.
摘要:
Provided is a method of preparing and recovering 2-methyl-5-iodobenzoic acid. The method utilizes o-methylbenzoic acid as raw material, iodinating via iodine/potassium persulfate in a mixed acid solvent to obtain a mixture of 2-methyl-5-iodobenzoic acid, 2-methyl-3-iodobenzoic acid, and 2-methyl-3, 5-diiodobenzoic acid; refining to obtain 2-methyl-5-iodobenzoic acid and recoverable mother liquor, the recoverable mother liquor being a mixture of 2-methyl-5-iodobenzoic acid, 2-methyl-3-iodobenzoic acid, and 2-methyl-3, 5-diiodobenzoic acid; conducting catalytic hydrogenation and deiodination to recover o-methylbenzoic acid and iodide ions; and oxidating the iodide ions to recover iodine. The whole process is recycled. The preparation and recovery method has cheap and easily available raw materials, and is easy of operation, has low requirements for equipment, and is suitable for large-scale industrial production.
摘要:
The present invention relates to a method for preparing a carboxylic acid ester, wherein a carboxylic acid and/or a salt thereof is reacted with an alcohol in the presence of hydrogen chloride (HCl) and water to form the carboxylic acid ester, wherein the reaction is carried out using a starting reaction system wherein the molar ratio of HCl to carboxylic acid is at least 0.075 : 1 and the molar ratio of water to carboxylic acid is at least 0.25 : 1.