Preparation of benzilic acid. CN102924264A 2022-10-15
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Benzilic acid is an aromatic carboxylic acid with the chemical formula C6H5CH(CO2H)2. It is a white crystalline solid that is soluble in water and organic solvents. Benzilic acid is an intermediate in the synthesis of a variety of chemicals and pharmaceuticals, and it is also used as a food and flavor additive.
There are several methods for preparing benzilic acid, each with its own advantages and disadvantages. One common method involves the base-catalyzed dehydration of benzil, which is an organic compound with the formula C6H5CO2C6H5. Benzil can be synthesized from benzaldehyde, which is an aromatic aldehyde with the formula C6H5CHO, through a process known as the benzoin condensation.
To prepare benzilic acid from benzil, the first step is to dissolve the benzil in a solvent such as ethanol or methanol. A strong base, such as sodium hydroxide or potassium hydroxide, is then added to the solution to catalyze the dehydration reaction. The base promotes the elimination of water from the benzil molecule, resulting in the formation of benzilic acid and the corresponding alcohol.
The yield of benzilic acid can be improved by adding a small amount of a dehydrating agent, such as sulfuric acid or phosphoric acid, to the reaction mixture. The dehydrating agent helps to remove the water by-product from the reaction, which can otherwise inhibit the formation of benzilic acid.
After the dehydration reaction is complete, the benzilic acid can be separated from the solvent and other reaction by-products by filtration or crystallization. The purity of the benzilic acid can be determined by various analytical techniques, such as spectroscopy or chromatography, to ensure that it meets the desired specifications.
In conclusion, benzilic acid is an important chemical intermediate that can be prepared through the base-catalyzed dehydration of benzil. The yield and purity of the final product can be optimized through the use of appropriate solvents, bases, and dehydrating agents, as well as by carefully controlling the reaction conditions.
US20100249451A1
A natural source of benzoic acid is gum benzoin, which comes from certain tree barks. In the first step alcohol group of benzoin is oxidized to ketone group forming benzil in presence of concentrated nitric acid. All results obtained have been included as well as a detailed analysis of what they represent alongside any improvements to the method used. A total of 750—800 cc. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.
By synthesid the mild oxidizing agent of nitiric acid, benzoin was oxidized to produce benzil through the mechanism in scheme 2. Dry the product thoroughly in a desiccator until the next laboratory period. Hubei ruikaixing Technology Co. The preparation method provided by the invention omits the step of oil separation in the existing preparation method, and material centrifugation is directly carried out after hydrochloric acid regulation to obtain the benzilic acid crude product, thereby simplifying the procedure and saving the cost; and after the benzilic acid crude product and ethanol react, the material centrifugation is carried out to obtain the benzilic acid finished product which has the advantages of high purity and high yield. It is aromatic because it has a benzene ring in its chemical structure.
There is then added, over a period of 10 minutes, 200 ml. More preferably, be 10 minutes the pitch time of every adjacent twice adding dibenzoyl. The moist benzoin 450—460 g. The IR and 1 H NMR sjnthesis displayed peaks that allowed for the distinction and identification of the different products that led to the ultimate synthesis of benzilic acid. The first step required HNO3 as an oxidizing agent and the second step required KOH and HCl. The initial reaction is conducted at a low temperature that is, at a temperature of about 20 C.
EXAMPLE I In a a 2. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. The reaction requires reflux temperature for complete conversion. Moreover, because of corrosive nature of base, and use of flammable solvent, the safety measures are needed during large scale production. Reactions which involve hydrophobic lipid loving or water hating conditions aacid might not otherwise be possible in an aqueous, biological environment. Wherein rearrangement of benzil is performed using a mixture of sodium hydroxide and sodium or potassium bromate in water as a medium.
The reaction can be performed either in water or in solvent free condition. Benzoic Acid Benzoic acid is an organic compound with the chemical formula C 6H 5CO 2H. A total of 750—800 cc. Preferably, in the 3rd step S3, benzilic acid crude product weight and alcohol volume ratio are 1:3. Synthesis of Benzoic Acid from Benzaldehyde In this experiment, you will design and perform an experiment to prepare benzoic acid from benzaldehyde. Moreover, the use of a mixture alcohol-water as a reaction medium also expensive and additional step is require to remove alcohol. The process comprises reacting a substituted benzene that is, a halobenzene such as bromobenzene or chlorobenzene or an alkoxybenzene, with glyoxylic acid or a derivative thereof and a halosulfonic acid such as, for example, chlorosulfonic acid or bromosulfonic acid or concentrated sulfuric acid or oleum to form a bis- phenyl or substituted phenyl -acetic acid compound.
After another 15 minutes there is added, accompanied by cooling and agitation, within 15 minutes, 345 g. Benzilic acid rearrangement — Wikipedia In deuterated watercarbonyl oxygen exchange occurs much faster than the rearrangement, indicating that the first equilibrium is not the rate-determining step. Description The present invention relates to an improved process for the preparation of substituted benzilic acid from substituted benzils in the presence of quaternary ammonium hydroxides as a non-metallic base. Therefore, the protection domain of patent of the present invention should be as the criterion with claims. Active Application number CN201210425770. Over a period of 40 minutes, 192 g.
The temperature ranging from 20° C. Introduction Acetylsalicylic acid aspirin is one of the most popular analgesic drugs on the market today. The aforesaid isopropyl 4,4'-dibromobezilate is also characterized by insecticidal activity against such insects as the Colorado beetle and is also suitable for the control of normally sensitive and resistant mites of the Parasitiformes, Tetrabodili, Trombidiformes and Sarcoptiformes types. Use a procedure that will oxidize the benzaldehyde to benzoic acid. Vogel, 5 th Edn; 1991. For achieving the above object, the invention provides a kind of preparation method of benzilic acid, it comprises: the first step, and dibenzoyl, sheet alkali and water carry out translocation reaction; Second step after the first step is finished, adds entry and hydrochloric acid again and carries out acid adjustment and react to obtain the benzilic acid crude product; In the 3rd step, benzilic acid crude product and the alcohol one that obtains in the second step is reacted, to obtain the benzilic acid finished product; Wherein, the concentration of alcohol is that benzilic acid crude product weight and alcohol volume ratio in the 50% ~ 80%, the 3rd step are 1:3. From above table data, the preparation method of benzilic acid of the present invention has saved point this step of oily matter in existing preparation method, but expects to obtain benzilic acid crude product by directly getting rid of after hydrochloric acid acid adjustment, has simplified operation, provides cost savings; And centrifugal drying material obtains benzilic acid finished product after benzilic acid crude product and alcohol reaction, and the purity of this benzilic acid finished product is high, and transmittance is good and productive rate is high.
The mixture is diluted with about 4 l. In addition to this, the reaction also requires higher temperature 80-100° C. Expired - Lifetime Application number US843844A Inventor Werner B Rothweiler Current Assignee The listed assignees may be inaccurate. Preferably, the concentration of alcohol is 50% ~ 80%, and highly preferred is 50%. It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention. It works by changing the internal PH of microorganisms to an acid state that is incompatible with their growth and survival. Description The preparation method of existing benzilic acid may further comprise the steps: the first step, and by dibenzoyl and sheet alkali generation translocation reaction, then oily matter is told in the acid adjustment layering, continues acid adjustment and gets the benzilic acid crude product; Second step is given birth to reaction with benzilic acid crude product and bitter almond oil camphor, potassium bromate, sheet alkali and steeping in water for reconstitution that the first step obtains, then adds dilute sulphuric acid and filters, and filtrate is continued acid adjustment and got the benzilic acid finished product.
