Benzaldehyde

Abstract

Benzaldehyde, C 6 H 5 CHO, is the simplest and possibly the most industrially useful member of the family of aromatic aldehydes. Benzaldehyde exists in nature, primarily in combined forms such as a glycoside in almond, apricot, cherry, and peach seeds. The characteristic benzaldehyde odor of oil of bitter almond occurs because of trace amounts of free benzaldehyde formed by hydrolysis of the glycoside amygdalin. Benzaldehyde is a versatile intermediate because of its reactive aldehyde hydrogen, its carbonyl group, and the benzene ring. The only industrially important processes for the manufacturing of synthetic benzaldehyde involve the hydrolysis of benzal chloride and the air oxidation of toluene. The hydrolysis of benzal chloride is no longer utilized in the United States. Benzaldehyde is produced in the United States by Kalama Chemical Incorporated, Kalama, Washington. Benzaldehyde is sold as technical grade or as meeting the specifications of the National Formulary (NF), the Food Chemicals Codex (FCC), or the British Pharmacopeia (BP). The oral LD 50 for benzaldehyde is reported as 1300 mg/kg in rats and as 1000 mg/kg in guinea pigs. Based upon these values, benzaldehyde is considered a moderately toxic substance when ingested. Overexposure to benzaldehyde vapors is irritating to the upper respiratory tract and produces central nervous system depression, with respiratory failure possible. The low autoignition temperature of benzaldehyde (192°) presents safety problems. Benzaldehyde may also spontaneously ignite when soaked into rags or clothing or adsorbed onto activated carbon. Bulk storage of benzaldehyde should be made under a nitrogen blanket. Benzaldehyde is a synthetic flavoring substance, sanctioned by the U.S. Food and Drug Administration (FDA) to be generally recognized as safe (GRAS) for foods. Both “pure almond extract” and “imitation almond extract” are offered for sale; each contains 2.0–2.5 wt % benzaldehyde. Benzaldehyde is also recognized as safe for use as a bee repellant in the harvesting of honey. Benzaldehyde's most important use is in organic synthesis, where it is the raw material utilized to produce various aldehydes.

The solubilities of benzene polycarboxylic acids in water

“…Along with their various ester derivatives are used as intermediates in the preparations of resins, plasticizers, dyes, inks, adhesives, alkaloidal solutions, pharmaceutical (antifungal) aids and in the preservation of foods, fats, and fruit juices [1][2][3][4][5]. Ultra-pure benzoic acid serves as a standard in titrimetric and calorimetric experiments.…”

Association thermodynamic parameters for nano Cu(NO3)2·2.5H2O with ligands at different temperatures

“…Then the solution of the ligand; 4,6-diacetylresorcinol was added to the copper( ii ) nitrate hemi pentahydrate solution step by step and the conductivity was measured after each addition of the ligand. 49–55 The pervious steps are repeated for each molar ratio of DMF-water mixed solvents at 293.15, 303.15, 313.15 and 323.15 K. The same method was used in case of another ligand; 4,6-bis(1-hydrazonoethyl)benzene-1,3-diol. The specific conductance ( K s ) of solutions was measured by using a conductivity bridge of type (JENCO – 3173 COND), which has cell constant equal to one.…”

In situ decomposition of bromine-substituted catechol to increase the activity of titanium dioxide catalyst for visible-light-induced aerobic conversion of toluene to benzaldehyde

“…[1][2][3][4][5][6][7] Benzaldehyde, which is one of the most important chemicals used as a raw material for the synthesis of other chemicals, is currently synthesized under high-temperature conditions using molecular oxygen in the presence of solid catalysts. 8 Therefore, it is desirable from a cost point of view to carry out this transformation under light irradiation at ambient temperature and pressure. 9,10 Many research groups have been developing visible-light-driven selective oxidation of toluene to benzaldehyde using photocatalysts, including narrow bandgap semiconductors as BiVO 4 .…”