Benzohydroxamic acid Property

Melting point:

126-130 °C(lit.)

Boiling point:

251.96°C (rough estimate)

Density 

1.2528 (rough estimate)

refractive index 

1.5030 (estimate)

storage temp. 

2-8°C

solubility 

Soluble in alcohol. Slightly soluble in ether. Insoluble in benzene.

pka

pK1: 8.89(0) (20°C)

form 

Solid

color 

Rhombic tablets

Water Solubility 

22 g/L (6 ºC)

BRN 

1907585

Stability:

Moisture and Temperature Sensitive

InChIKey

VDEUYMSGMPQMIK-UHFFFAOYSA-N

CAS DataBase Reference

495-18-1(CAS DataBase Reference)

NIST Chemistry Reference

Benzamide, n-hydroxy-(495-18-1)

EPA Substance Registry System

Benzohydroxamic acid (495-18-1)

Safety

Hazard Codes 

Xn

Risk Statements 

68-40-20/21/22

Safety Statements 

45-36/37-36-22

WGK Germany 

3

RTECS 

DF9650000

TSCA 

Yes

HS Code 

29280090

Toxicity

LD orl-rat: >500 mg/kg NCNSA6 5,26,53

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

H341Suspected of causing genetic defects

Precautionary statements

P201Obtain special instructions before use.

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P405Store locked up.

Benzohydroxamic acid Chemical Properties,Usage,Production

Chemical Properties

Crystalline Solid

Uses

Benzhydroxamic acid is used as precursor in the synthesis of novel mono-anionic and di-anionic hydroxamato complexes by reacting with BiPh3 and Bi(O(t)Bu)3, which has anti-bacterial activity against helicobacter pylori. It is used in the photometric determination of trace amounts of vanadium in alloy steels by making mixed-ligand vanadium chelates with ammonium thiocyanate. It is also involved in the palladium catalyzed synthesis of benzisoxazolones.

Uses

Benzhydroxamic acid may be employed for the Pd-catalyzed synthesis of benzisoxazolones.

Preparation

To a rapidly stirred suspension of 19.6 gm (0.35 mole) of powdered anhydrous potassium hydroxide in 120 ml of pyridine, maintained at 0-5°C, is a added a solution of 13.9 gm (0.2 mole) of hydroxylamine hy­drochloride in 100 ml of pyridine.
While maintaining the reaction temperature at 0-5°C, 15 gm (0.1 mole) of ethyl benzoate is added. Vigorous stirring is continued at room tempera­ture for 6 hr. Then the solids are filtered off. The solids are washed with cold water to remove inorganic coproducts. The remainder, recrystallized from aqueous ethanol, represents a 94% yield of potassium benzohy­droxamate.
This salt is triturated with cold 0.01 TV hydrochloric acid. From this mixture, by the usual procedures, 12.5 gm (91% overall) of benzohydrox­amic acid is isolated, m.p. 131°C (from aqueous alcohol).

Synthesis Reference(s)

Tetrahedron Letters, 33, p. 5055, 1992 DOI: 10.1016/S0040-4039(00)61187-5

General Description

Rhombic crystals or light beige solid.

Air & Water Reactions

Slightly soluble in water.

Reactivity Profile

Benzohydroxamic acid is an amide. Amides/imides react with azo and diazo compounds to generate toxic gases. Flammable gases are formed by the reaction of organic amides/imides with strong reducing agents. Amides are very weak bases (weaker than water). Imides are less basic yet and in fact react with strong bases to form salts. That is, they can react as acids. Mixing amides with dehydrating agents such as P2O5 or SOCl2 generates the corresponding nitrile. The combustion of these compounds generates mixed oxides of nitrogen (NOx).

Health Hazard

ACUTE/CHRONIC HAZARDS: When heated to decomposition Benzohydroxamic acid emits toxic fumes of nitrogen oxides.

Fire Hazard

Flash point data for Benzohydroxamic acid are not available; however, Benzohydroxamic acid is probably combustible.

Safety Profile

Moderately toxic by ingestion.Mutation data reported. When heated to decomposition itemits toxic fumes of NOx.