Name | m-cresol purple |
Synonyms | m-Cresolpurpl m-cresol purple M-CRESOL PURPLE M-CRESOLSULFONPHTHALEIN M-CRESOLSULFONEPHTHALEIN M-CRESOL PURPLE FREE ACID M-CRESOL PURPLE INDICATOR M-CRESOL PURPLE, INDICATOR GRADE 3,3-bis(4-hydroxy-2-methylphenyl)-2-benzofuran-1(3H)-one 4,4'-(1,1-Dioxido-3H-2,1-benzoxathiole-3,3-diyl)bis(3-methylphenol) Phenol, 4,4-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis3-methyl- phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[3-methyl- 2-[(Z)-(4-hydroxy-2-methylphenyl)(2-methyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]benzenesulfonic acid |
CAS | 2303-01-7 |
EINECS | 218-960-6 |
InChI | InChI=1/C22H18O4/c1-13-11-15(23)7-9-18(13)22(19-10-8-16(24)12-14(19)2)20-6-4-3-5-17(20)21(25)26-22/h3-12,23-24H,1-2H3 |
Molecular Formula | C21H18O5S |
Molar Mass | 382.43 |
Density | 1.404±0.06 g/cm3(Predicted) |
Melting Point | >250°C |
Boling Point | 577.5±50.0 °C(Predicted) |
Flash Point | 205.3°C |
Water Solubility | Soluble in water and sodium hydroxide solution. Slightly soluble in alcohol. |
Solubility | Solubility Very slightly soluble in water, ethanol; soluble in methanol |
Vapor Presure | 1.19E-13mmHg at 25°C |
Appearance | Dark green powder |
Color | Dark green |
Maximum wavelength(λmax) | ['579nm, 371nm'] |
Merck | 14,2577 |
BRN | 350314 |
pKa | 1.51, 8.32(at 25℃) |
Storage Condition | room temp |
Stability | Stable. Incompatible with strong oxidizing agents. |
Sensitive | Easily absorbing moisture |
Refractive Index | 1.668 |
MDL | MFCD00005871 |
Use | Used as acid-base indicator |
Safety Description | 24/25 - Avoid contact with skin and eyes. |
WGK Germany | WGK 2 water endanger |
TSCA | Yes |
HS Code | 2934 99 90 |
pH indicator color change ph range | 1.2 (red) - 2.8 (yellow) and 7.4 (yellow) - 9.0 (special) |
main applications | Fuel cells, sensors, display device, falsification-proof security paper, inks, correction fluid, paints, detection of electrophilic gases, lubricants, cement products, packaging system, adhesive, cosmetics, food storage, determining glucose in dialysis solution, screening of cat diseases, detecting carbohydrates, food, oral hygiene products |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
use | cresol purple is the main use of fresh tissue stains (such as tumor, nerve tissue, Nissl granule, blood in vivo staining, etc.) redox indicator. used as acid-base indicator acid-base indicator, pH1.2 (red) ~ 2.8 (yellow),pH7.4 (brown yellow) ~ 9.0 (purple). acid-base indicator, pH 1.2 (red) ~ 2.8 (yellow),pH 7.4 (yellow) ~ 9.0 (red purple) |
production method | 1. dry m-cresol and o-sulfonyl benzoyl anhydride are heated to 100~105 ℃ under stirring for 0.5~1h, heating is stopped, phosphorus oxychloride and anhydrous zinc chloride are slowly added in different times under continuous stirring, the temperature is strictly controlled, and condensation reaction is carried out at 90~100 ℃ for 6~8h: after the reaction, cool, add water to heat to 70~80 ℃, slowly add industrial sodium carbonate, keep the temperature for 5~6h, let it stand and filter. The filtrate is neutralized with hydrochloric acid to a ph value of 1~2. After standing, the lower viscous substance is heated to remove m-cresol. After drying, the finished m-cresol purple is obtained. |