Benzal chloride benzaldehyde from

Place 45 g. (43 ml.) of benzal chloride (Section IV,22), 250 ml. of water and 75 g. of precipitated calcium carbonate (1) in a 500 ml. round-bottomed flask fltted with a reflux condenser, and heat the mixture for 4 hours in an oil bath maintained at 130°. It is advantageous to pass a current of carbon dioxide through the apparatus. Filter off the calcium salts, and distil the filtrate in steam (Fig. II, 40, 1) until no more oil passes over (2). Separate the benzaldehyde from the steam distillate by two extractions with small volumes of ether, distil off most of the ether on a water bath, and transfer the residual benzaldehyde to a wide-mouthed bottle or flask. Add excess of a concentrated solution of sodium bisulphite in portions with stirring or shaking stopper the vessel and shake vigorously until the odour of benzaldehyde can no longer be detected. Filter the paste of the benzaldehyde bisulphite compound at the pump... 

In the past benzal and benzyl chlorides were co-produced for the manufacture of benzaldehyde and benzyl alcohol, but today the vast majority of the benzaldehyde produced from benzal chloride is that which is made from recovered (by-product) material. For an historical article regarding the chlorination of toluene and the subsequent production of benzaldehyde, benzyl alcohol, and benzoic acid, see reference 4. 

Benzaldehyde is prepared by hydrolysis of benzal chloride, for example in acidic media in the presence of a catalyst such as ferric chloride, or in alkaline media with aqueous sodium carbonate. Part of the commercially available benzaldehyde originates from a technical process for phenol. In this process, benzaldehyde is a byproduct in the oxidation, with air, of toluene to benzoic acid. 

No studies were available on the disposition of benzotrichloride, benzal chloride or benzoyl chloride. Benzyl chloride is rapidly absorbed and distributed from the gastrointestinal tract. Excretion is mainly in urine as S -benzyl-A-acetylcysteine, benzyl alcohol and benzaldehyde. 

CHLOROCARBONSANDCHLOROHYDROCARBONS - BENZYL CM.ORIDE, BENZAL CHLORIDE AND BENZOTRICHLORIDE] (Vol 6) -from benzaldehyde [BENZALDEHYDE] (Vol 4)... 

Benzoic acid also can be obtained as a by-product of the manufacture of benzaldehyde from benzal chloride or benzyl chloride. 

Derivatives of Toluene Benzal Chloride and Benzaldehyde from Toluene (a) Benzol Chloride... 

Benzal chloride, used for the preparation of benzaldehyde, should be free from benzyl chloride. It should be fractionated carefully, therefore, removing the portion boiling below 180°. 

Benzaldehyde is prepared by the hydrolysis of (dichloromethyl)benzene (benzal chloride) in either aqueous acid or aqueous alkali and by the oxidation of toluene with chromium trioxide in acetic anhydride (Scheme 6.3). In the latter synthesis, as the benzaldehyde is formed, it is converted into its diacetate by the acetic anhydride, so preventing further oxidation subsequent hydrolysis generates the aldehyde group. The benzaldehyde has thus been protected from oxidation. Benzyl alcohol can... 

It may be synthesized also from benzal chloride and benzene by the Friedel-Craft reaction, or from benzaldehyde and benzene by heating with anhydrous zinc chloride to 2 o°-2jo°. 

Benzaldehyde from Benzal Chloride Using Hydrochloric Acid... 

Benzaldehyde from Benzal Chloride using Zinc Chloride... 

General Aniline Process for the Manufacture of Benzaldehyde or Substituted Benzaldehyde from the Corresponding Benzal Chloride 1962 GB 899,953... 

Benzaldehyde is a liquid with an agreeable odor, which boils at 179°, and has the specific gravity 1.0504 at 15°. It can be formed by oxidizing benzyl alcohol, or distilling calcium benzoate with calcium formate. It is manufactured by heating benzal chloride with milk of lime, or by oxidizing benzyl chloride with a solution of lead nitrate. It has been prepared from toluene directly by electrolytic oxidation or by oxidation with air in the presence of a catalyst. 

The reaction is used in the technical preparation of benzoyl chloride. The derivatives of benzaldehyde which contain a halogen atom in the ring, are prepared from substitution-products of benzal chloride —... 

Sulfur tetrafluoride [7783-60-0] SF, replaces halogen in haloalkanes, haloalkenes, and aryl chlorides, but is only effective (even at elevated temperatures) in the presence of a Lewis acid catalyst. The reagent is most often used in the replacement of carbonyl oxygen with fluorine (15,16). Aldehydes and ketones react readily, particularly if no alpha-hydrogen atoms are present (eg, benzal fluoride [455-31-2] from benzaldehyde), but acids, esters, acid chlorides, and anhydrides are very sluggish. However, these reactions can be catalyzed by Lewis acids (HP, BF, etc). 

Depending upon the conditions, the reaction of benzylmagnesium chloride with benzal-dehyde can yield benzylphenylmethanol, dibenzoylphenylmethane and 1,3-diphenyliso-chroman. The last product arises from the acid-catalyzed dehydration of the 1,5-diol (296), which is the predominant product when the Grignard reagent is added to benzaldehyde at room temperature (Scheme 81) (51 3163). There was no evidence for the formation of o-methylbenzhydrol, consistent with the lack of this type of product with citronellal and various simple aliphatic aldehydes (44JA354,51JA3237). 

---