Preparation of benzaldehyde
Preparation of benzaldehyde from benzal chloride
To a round bottom flask fitted with a reflux condenser 90 g of benzal chloride, 500 ml of distilled water and 150 g of precipitated CaCO3 are added. The reaction mixture is heated for 4 hours at 130° C. The contents of the flask are distilled with steam until no more oil passes over. Before the crude benzaldehyde is purified, the liquid remaining in the flask is filtered while hot and excess of concentrated hydrochloric acid added. On cooling, the benzoic acid, which is formed as a side-product, separates out in leafy crystals. Benzoic acid is filtered and recrystallized from hot water yielding product with melting point 121° C. The steam distillate is treated with a concentrated solution of NaHSO3 until, after long shaking, the greater part of the oil has passed into solution. If crystals of the hydroxy(phenyl)methanesulfonate (benzaldehyde sodium bisulfite) separate out, water is added until they are dissolved. The aqueous solution is separated by filtration from the undissolved oil, and the filtrate treated with anhydrous sodium carbonate until an alkaline reaction is obtained. The alkaline filtrate is then distilled with steam, when pure benzaldehyde passes over, and, after standing, is separated with separatory funnel. It is finally distilled, preferably in a stream of hydrogen. Benzaldehyde is colorless liquid, smelling of bitter almonds. It boils at 179° C, and has density 1.05 g/cm3. Benzaldehyde is slightly soluble in water.
The Synthetic Dyestuffs and the Intermediate Products from which They are Derived, by J. C. Cain, 210-211, 1905
Preparation of benzaldehyde by oxidation of benzyl chloride
The mixture of 50 g of benzyl chloride, 40 g of copper (II) nitrate in 500 ml of water is heated to boiling in a round flsk with reflux condenser for a 8-9 hours. A slow current of carbon dioxide is at the same time passed through the liquid to prevent oxidation of the benzaldehyde. During the process nitrous fumes are slowly evolved. When the reaction is complete, the contents of the flask are extracted with ether, and the yellow oil remaining, after distilling the ether, is well shaken with a saturated solution of sodium bisulfite and allowed to stand for a time. The colorless crystalline mass which separates is filtered, washed with a little alcohol and ether and filtered. The benzaldehyde is obtained by adding dilute sulfuric acid in excess and distilling in steam. The distillate is extracted with ether, dried over calcium chloride, decanted, and the ether distilled yielding 15 g of benzaldehyde.
A class-book of organic chemistry, by J. B. Cohen, 290, 1918
Preparation of benzaldehyde by oxidation of toluene
10 g of toluene and 30 g of chromyl chloride are each dissolved in anhydrous carbon disulphide, the former in 50 g and the latter in 120 g; the former solution is placed in a litre flask fitted with a thermometer and long reflux condenser, and the latter is added in 10 ml quantities, the reaction each time being allowed to moderate before further addition. Should no reaction occur on the first addition, the mixture is allowed to stand for 15 minutes before further addition. The reaction is very vigorous, and the flask must be cooled by immersing in a bath of ice-water, so that the temperature of the mixture never rises above 45° C. When addition is complete, the mixture is allowed to stand for 3 hours, the explosive intermediate compound which appears as a precipitate is filtered off, well washed with anhydrous carbon disulphide, dried by blowing air through, and decomposed by adding in small quantities to 1 litre of cold water. The chromic acid formed is reduced with gaseous sulphur dioxide, and the liquid steam distilled in a current of carbon dioxide to remove benzaldehyde, which is extracted from the distillate with ether. The extract is dried over calcium chloride, the ether removed on a water bath, and the residue .distilled in a current of carbon dioxide, the fraction 177-182° C being retained.
Systematic organic chemistry, by W. M. Cumming, 231-232, 1937.
Preparation of benzaldehyde by oxidation of toluene
30 g of toluene are heated to 60° C with 1500 g of sulphuric acid (d=1.5 g/ml) in a 2-l round-bottomed flask fitted with a reflux condenser and mechanical stirrer. 250 g of cerium dioxide are gradually added, and the temperature allowed to rise to 90° C. When no more cerium dioxide remains, the whole is steam distilled until no more benzaldehyde passes over which is extracted from the distillate with ether. The extract is dried over calcium chloride, the ether removed on a water bath, and the residue distilled in a current of carbon dioxide, the fraction 177-182° C being retained. Yield 70%.
Systematic organic chemistry, by W. M. Cumming, 232-233, 1937.
benzaldehyde, benzaldehyde, formyl-(14)C-labeled
benzaldehyde, Benzoic aldehyde, Benzenecarbonal, 100-52-7, Phenylmethanal, Artificial almond oil, Benzenemethylal, Benzenecarboxaldehyde, Benzaldehyde FFC, Benzene carbaldehyde, Oil Of bitter almond, benzanoaldehyde, Benzylaldehyde, Benzene carboxaldehyde, Benzoyl hydride, Almond artificial essential oil, Artificial essential oil of almond, Caswell No. 076, benzaldehyd, Synthetic oil of bitter almond, Benzadehyde, NCI-C56133, Phenylformaldehyde, Artificial bitter almond oil, Ethereal oil of bitter almonds, FEMA No. 2127, Benzoic acid aldehyde, Benzaldehyde (natural), NSC 7917, Bitter almond oil, synthetic, UNII-TA269SD04T, Phenylmethanone, CHEMBL15972, CCRIS 2376, HSDB 388, CHEBI:17169, HUMNYLRZRPPJDN-UHFFFAOYSA-N, Phenylmethanal benzenecarboxaldehyde, EINECS 202-860-4, UN1990, EPA Pesticide Chemical Code 008601, NCGC00091819-01, NCGC00091819-02, AI3-09931, DSSTox_CID_134, DSSTox_RID_79432, DSSTox_GSID_39241, CAS-100-52-7, benzaidehyde, benzaldehvde, Benzyaldehyde, Benzene methylal, Aromatic aldehyde, Ben zoyl hydride, (phenyl)methanone, HBX, Benzaldehyde (NF), Benzaldehyde [USAN], nchembio814-comp15, 2vj1, WLN: VHR, SCHEMBL573, AC1L18SM, AC1Q6PV7, B1334_ALDRICH, ACMC-1C91Y, ghl.PD_Mitscher_leg0.170, KSC176K2J, BIDD:ER0249, W212709_ALDRICH, W212717_ALDRICH, 418099_ALDRICH, B1334_SIAL, PENTADEOTERO BENZALDEHYDE, TA269SD04T, 09143_FLUKA, CTK0H6524, HMDB06115, Artifical essential oil of almond, NSC7917, Ald3-H_000012, LS-27, NSC-7917, Ald3.1-H_000160, Ald3.1-H_000479, Ald3.1-H_000798, Tox21_113069, Tox21_113244, Tox21_200634, ANW-14310, ZINC00895145, Benzaldehyde [UN1990] [Class 9], AKOS000119172, Benzaldehyde [UN1990] [Class 9], MCULE-7744113682, NA 1989, RP18863, NCGC00091819-03, NCGC00258188-01, AJ-24149, AK109012, DB-023673, KB-250682, TC-103055, B2379, FT-0622622, LT00939687, ST24030100, 5044-EP2269979A1, 5044-EP2269990A1, 5044-EP2272491A1, 5044-EP2272827A1, 5044-EP2275404A1, 5044-EP2275411A2, 5044-EP2275412A1, 5044-EP2277858A1, 5044-EP2277865A1, 5044-EP2277878A1, 5044-EP2281818A1, 5044-EP2284157A1, 5044-EP2286915A2, 5044-EP2287152A2, 5044-EP2287159A1, 5044-EP2289868A1, 5044-EP2292593A2, 5044-EP2295402A2, 5044-EP2295410A1, 5044-EP2295441A2, 5044-EP2298767A1, 5044-EP2298776A1, 5044-EP2301534A1, 5044-EP2301536A1, 5044-EP2301538A1, 5044-EP2305625A1, 5044-EP2305629A1, 5044-EP2305662A1, 5044-EP2305679A1, 5044-EP2305687A1, 5044-EP2305769A2, 5044-EP2305808A1, 5044-EP2308562A2, 5044-EP2311451A1, 5044-EP2311455A1, 5044-EP2311806A2, 5044-EP2311840A1, 5044-EP2314295A1, 5044-EP2314586A1, 5044-EP2314587A1, 5044-EP2314593A1, 5044-EP2316450A1, 5044-EP2316832A1, 5044-EP2316833A1, 5044-EP2371831A1, 5044-EP2374454A1, 5044-EP2374783A1, 5044-EP2377841A1, 5044-EP2380871A1, C00193, C00261, D02314, 53585-EP2305651A1, 53585-EP2308854A1, 125826-EP2287158A1, 125826-EP2295422A2, A800226, I01-1667, I14-7330, I14-90980, InChI=1/C7H6O/c8-6-7-4-2-1-3-5-7/h1-6
benzoic acid, benzoate, phenyl-methanone, CYCLOHEXANECARBOXALDEHYDE, CID240, Artificial Bitter Almond Oil, benzaldehyde, formyl-(14)C-labeled, c0279, C032175, 2043-61-0, BEZ