50-79-3 Usage
Chemical Properties
Needle crystals or white crystalline powder. Soluble in ethanol and ether, soluble in hot water. Some volatilize in the vapor.
Uses
2,5-Dichlorobenzoic acid was used as calibration standard to investigate the gas-phase OH reaction products of biphenyl, monochlorobiphenyl and dichlorophenyl
Application
2,5-Dichlorobenzoic acid is used in organic synthesis and pesticide intermediates. It is used to synthesize herbicides chloramben, 2,5-Dichloro-3-nitrobenzoic acid, etc. The pesticide has less phytotoxicity and is not affected by rainy days.
Preparation
2,5-Dichlorobenzoic acid is obtained by reacting p-dichlorobenzene with phosgene to obtain 2,5-dichlorobenzoyl chloride, which is then hydrolyzed.
Definition
ChEBI: 2,5-dichlorobenzoic acid is a chlorobenzoic acid that is benzoic acid in which the ring hydrogens at positions 2 and 5 are substituted by chloro groups. It is a chlorobenzoic acid and a dichlorobenzene.
General Description
Needles (from water) or white powder.
Air & Water Reactions
Insoluble in water.
Reactivity Profile
Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in 2,5-Dichlorobenzoic acid to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions.
Fire Hazard
Flash point data for 2,5-Dichlorobenzoic acid are not available; however, 2,5-Dichlorobenzoic acid is probably combustible.
Purification Methods
Crystallise the acid from water. [Beilstein 9 IV 1005.] Aromatic acid impurities (to <0.05%) can be removed via the (±)--methylbenzylamine salt as described for 2,4-dichlorobenzoic acid [Ley & Yates Organic Process Research & Development 12 120 2008.]
Check Digit Verification of cas no
The CAS Registry Mumber 50-79-3 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 5 and 0 respectively; the second part has 2 digits, 7 and 9 respectively.
Calculate Digit Verification of CAS Registry Number 50-79:
(4*5)+(3*0)+(2*7)+(1*9)=43
43 % 10 = 3
So 50-79-3 is a valid CAS Registry Number.
InChI:InChI=1/C7H4Cl2O2/c8-4-1-2-6(9)5(3-4)7(10)11/h1-3H,(H,10,11)
50-79-3Relevant articles and documents
Preparation method of 5-chloro-2-aminobenzoic acid intermediate
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Paragraph 0017-0020, (2021/08/11)
The invention discloses a preparation method of 5-chloro-2-aminobenzoic acid, and belongs to the technical field of organic synthesis, the preparation method specifically comprises the following steps: dissolving 2, 5-dichlorotoluene in a solvent, adding an oxidant while stirring, heating to 50-80 DEG C, carrying out heat preservation reaction for 3-6 hours, recovering the organic solvent after the reaction is finished, adding water, filtering while hot, and adjusting the pH value of the filtrate to 2 by using hydrochloric acid, obtaining 2, 5-dichlorobenzoic acid through cooling, crystallization and filtering, adding 2, 5-dichlorobenzoic acid into an organic solvent to be dissolved, addign a metal catalyst, alkali and an ammonia source, heating the mixture to 70-150 DEG C and then performing a heat preservation reaction for 8-15 h, performing reduced pressure distillation after the reaction is finished, and obtaining 5-chloro-2-aminobenzoic acid. A new path for synthesizing 5-chloro-2-aminobenzoic acid is designed, the preparation method is simple, easy to operate, low in cost and environmentally friendly, and N, N-dimethylglycine is added in the ammoniation reaction process, so that the temperature of the ammoniation reaction can be reduced, the reaction time can be shortened, and the reaction yield can be increased.
Pharmaceutical intermediate 2,5-dichlorobenzoic acid synthesis method
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Paragraph 0006; 0009-0014, (2018/07/30)
The invention relates to a pharmaceutical intermediate 2,5-dichlorobenzoic acid synthesis method, which mainly comprises: adding 2 mol 2,5-dichloro-6-aminobenzoic acid and 3-5 mol diisobutyl adipate solution to a reaction container, increasing the solution temperature to 70-78 DEG C, controlling the stirring speed at 130-160 rpm, adding 3-4 mol cobalt naphthenate in 3-5 times every 30-40 min, continuously carrying out the reaction for 90-120 min, adding 1200 ml of a potassium chloride solution, layering the solution, reducing the solution temperature to 10-15 DEG C, adding an oxalic acid solution, adjusting the pH value to 4-5, washing with a potassium sulfate solution, washing with a methyl tert-butyl ether solution, washing with a 2-methyl tetrahydrofuran solution, carrying out pressurereducing distillation, collecting the distillate at a temperature of 110-120 DEG C, and dehydrating with a dehydrating agent to obtain the finished product 2,5-dichlorobenzoic acid.
Flow carbonylation of sterically hindered ortho-substituted iodoarenes
Mallia, Carl J.,Walter, Gary C.,Baxendale, Ian R.
supporting information, p. 1503 - 1511 (2016/08/02)
The flow synthesis of ortho-substituted carboxylic acids, using carbon monoxide gas, has been studied for a number of substrates. The optimised conditions make use of a simple catalyst system compromising of triphenylphosphine as the ligand and palladium acetate as the pre-catalyst. Carbon monoxide was introduced via a reverse "tube-in-tube" flow reactor at elevated pressures to give yields of carboxylated products that are much higher than those obtained under normal batch conditions.
