Crystal violet lactone

Chemical Properties

Light yellow solid

Uses

Crystal Violet lactone is an important functional dye for the production of pressure sensitive materials. It is a chemical intermediate , intermediates for thermal/carbonless Paper, used in medicine and biochemical research, a leuco dye..

Definition

ChEBI: Crystal violet lactone is a member of benzofurans.

General Description

Blue-green crystals or pale green powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Crystal violet lactone may be sensitive to excessive light and heat.

Health Hazard

SYMPTOMS: Symptoms of exposure to Crystal violet lactone may include irritation.

Fire Hazard

Flash point data for Crystal violet lactone are not available; however, Crystal violet lactone is probably combustible.

Flammability and Explosibility

Non flammable

Synthesis

Example 1: 21.5 g (97.0% purity) of 2-[4,4'-bis(dimethylamino)diphenylmethyl]-5-dimethylaminobenzoic acid was added to a 500 mL three-necked flask, followed by 250 mL of deionized water. The resulting suspension was stirred with the addition of 21.5 g of activated carbon (Model: SHIRASAGI-C, manufactured by Takeda Chemical Industries) and 2.0 g of 49% NaOH aqueous solution. The reaction system was heated to 90-95°C and maintained in this temperature range. During the reaction, air was passed into the reaction system at a rate of 400 mL/min for 9 hours. Upon completion of the reaction, the reaction mixture was filtered while hot, the filter cake was collected and re-slurried with deionized water. 19.5 g of 36% HCl aqueous solution was slowly added to the slurried solution until the solid was completely dissolved. Subsequently, the activated carbon was removed by filtration. The pH of the filtrate was adjusted to 7.0 with 49% NaOH aqueous solution and crystals of the target product were precipitated. The crystals were collected by filtration, washed with cold water and dried under vacuum to give 20.1 g of 3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide in 95.4% yield. Analyzed by HPLC, the by-product generation rate was 1.5% and the reaction selectivity was 98.4%.

References

[1] Patent: US5973168, 1999, A
[2] Journal of Organic Chemistry USSR (English Translation), 1986, vol. 22, # 10, p. 2012 - 2014
[3] Zhurnal Organicheskoi Khimii, 1986, vol. 22, # 10, p. 2240 - 2241
[4] Patent: US4595768, 1986, A
[5] Patent: US4271075, 1981, A