1-[(2-Methylphenyl)azo]naphthalin-2-amin

Deep red crystals from alcohol. Also reported as bright yellow needles

Orange or yellow powder

Soluble in alcohol, ether, benzene, carbon tetrachloride, vegetable oils, glacial acetic acid.

Practically insoluble in water

125-126 °C

MP: 122-125 °C

Warning

H351: Suspected of causing cancer [Warning Carcinogenicity]

P203, P280, P318, P405, and P501 (click each P-code to see the statement)

Chemical: 2-Naphthalenamine, 1-[(2-methylphenyl)azo]-

2-Naphthalenamine, 1-(2-methylphenyl)azo-: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

(a) Ext. D&C Yellow Nos. 9 and 10. These colors cannot be produced with any assurance that they do not contain beta-naphthylamine as an impurity. While it has been asserted that the two colors can be produced without the impurity named, no method of analysis has been suggested to establish the fact. beta-Naphthylamine is a known carcinogen; therefore, there is no scientific evidence that will support a safe tolerance for these colors in products to be used in contact with the skin. The Commissioner of Food and Drugs, having concluded that such action is necessary to protect the public health, hereby terminated the provisional listing of Ext. D&C Yellow No. 9 and Ext. D&C Yellow No. 10.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

LC50; Species: Oryzias latipes (Medaka) length 2 cm, weight 0.2 g; Conditions: freshwater, static, 25 °C; Concentration: 600 ug/L for 24 hr /formulation/

LC50; Species: Oryzias latipes (Medaka) length 2 cm, weight 0.2 g; Conditions: freshwater, static, 25 °C; Concentration: 400 ug/L for 48 hr /formulation/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1.1X10+5(SRC), determined from a structure estimation method(2), indicates that FD&C Yellow No. 4 is expected to be immobile mobility in soil(SRC). Volatilization of FD&C Yellow No. 4 from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.6X10-10 atm-cu m/mole(SRC), using a fragment constant estimation method(3). FD&C Yellow No. 4 is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.9X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(4). Biodegradation data in soil were not available(SRC, 2011).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1.1X10+5(SRC), determined from a structure estimation method(2), indicates that FD&C Yellow No. 4 is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 5.6X10-10 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 10(SRC), from an estimated log Kow of 5.32(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data in water were not available(SRC, 2011). However, azo dyes are hydrophobic compounds, suggesting they will partition strongly to bottom sediments where reductive cleavage of the azo linkage may occur. This transformation process could result in the release of potentially hazardous aromatic amines to the water column(8).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), FD&C Yellow No. 4, which has an estimated vapor pressure of 1.9X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase FD&C Yellow No. 4 is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2.5 hours(SRC), calculated from its rate constant of 5.0X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase FD&C Yellow No. 4 may be removed from the air by wet or dry deposition(SRC). FD&C Yellow No. 4 contains chromophores that absorb at wavelengths >290 nm(4), and therefore may be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of FD&C Yellow No. 4 can be estimated to be 1.1X10+5(SRC). According to a classification scheme(2), this estimated Koc value suggests that FD&C Yellow No. 4 is expected to be immobile in soil.

/HUMAN EXPOSURE STUDIES/ Skin tests with certain certified food dyes such as disodium salt of 1-pseudocumylazo-2-naphthol-3,6-disulfonic-acid, trisodium salt of 1-(4-sulfo-1-naphthylazo)-2-naphthol-3,6-disulfonic acid, trisodium salt of 1-(4-sulfo-1-naphthylazo)-2-naphthol-3,6-disulfonic acid 1-phenylazo-2-naphthylamine, 1-o-tolylazo-2-naphthylamine (131793), trisodium salt of 3-carboxy-5-hydroxy-1-p-sulfophenyl-4-p-sulfophenylazopyrazole, disodium salt of 1-p-sulfophenylazo-2-naphthol-6-sulfonic-acid (2783940), monosodium salt of 4-p-sulfophenylazo-1-naphthol, and 1-o-tolylazo-2-naphthol (2646175), in patients sensitive to paraphenylenediamine (106503) suggest that eczematous hypersensitivity to paraphenylenediamine may not only cross over to azo-dyes used for the dyeing of leather and fabrics, or in ointments, but also to certain azo-dyes certified by the Food, Drug and Cosmetic Act of 1938 for use in foods, drugs, and cosmetics.

ANAEROBIC: Azo dyes are hydrophobic compounds, suggesting they will partition strongly to bottom sediments where reductive cleavage of the azo linkage may occur. This transformation process could result in the release of potentially hazardous aromatic amines to the water column(1), in this case, ortho-toluidine and 1,2-naphthylamine(SRC).

Yellow OB

Group 3: Not classifiable as to its carcinogenicity to humans

Volume 8: (1975) Some Aromatic Azo Compounds

1987

1987

An estimated BCF of 10 was calculated in fish for FD&C Yellow No. 4(SRC), using an estimated log Kow of 5.32(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for FD&C Yellow No. 4 is estimated as 5.6X10-10 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that FD&C Yellow No. 4 is expected to be essentially nonvolatile from water surfaces(2). FD&C Yellow No. 4 is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.9X10-7 mm Hg(SRC), determined from a fragment constant method(3).

/LABORATORY ANIMALS: Acute Exposure/ Yellow OB is lethal to rabbits after its sc, oral or ip administration in doses of 1 g/kg bw; doses of 250 mg/kg bw are tolerated.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Dietary levels of 15,000 or 30,000 mg yellow OB per kg of diet caused changes in the liver, thymus, adrenal gland, pancreas and kidney. Levels of 2500 mg/kg of diet caused anemia, edema, hypertrophy of the heart and changes in the liver, spleen, bone marrow, and testis, growth inhibition and 100% mortality within 12 months, compared with 4% mortality for controls; levels of 500 mg/kg diet had no toxic effects. Rats fed diets containing 40,000 mg yellow OB per kg of diet lived only for a few months.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ The experimental studies ... determine the effects of the oral administration of Oil Yellow-AB and Oil Yellow-OB on growth, food consumption, food efficiency, blood values, and on the pathology of a number of the organs. FD-and-C-Yellow-No-3 and FD-and-C-Yellow-No-4 were fed to rats in differing dosages and over differing times. Male and female rats were distinguished for purposes of measurement and some, but not all, of the effects appeared to be sex-linked. The effect on hemoglobin was marked, and significant weight changes in a number of organs were found. Tissue histology of those rats surviving for 65 weeks showed differences in the effects of FD-and-C-Yellow-No-3 and FD-and-C-Yellow-No-4.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ The results of two-year oral toxicity studies with rats at feeding levels of 2500, 1000, and 500 ppm for ... Yellow AB or Yellow OB has been presented. ... Yellow AB and Yellow OB at 2500 ppm of the diet of rats produced high mortality and growth inhibition. Anemia was sometimes present. One or more of subcutaneous edema, hydrothorax, or ascites were seen frequently. In the heart, right-sided hypertrophy, dilatation of the ventricle and atrium, and thrombi were observed. Changes were also observed in the liver, spleen, bone marrow, and testis. Slight but definite effects were caused at the 1000 ppm feeding level, whereas the 500 ppm level produced no demonstrable effects.

For more Non-Human Toxicity Excerpts (Complete) data for FD&C Yellow No. 4 (11 total), please visit the HSDB record page.

The rate constant for the vapor-phase reaction of FD&C Yellow No. 4 with photochemically-produced hydroxyl radicals has been estimated as 5.0X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.5 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). FD&C Yellow No. 4 is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). FD&C Yellow No. 4 contains chromophores that absorb at wavelengths >290 nm(2), and therefore may be susceptible to direct photolysis by sunlight(SRC).

(a) Ext. D&C Yellow Nos. 9 and 10. These colors cannot be produced with any assurance that they do not contain beta-naphthylamine as an impurity. While it has been asserted that the two colors can be produced without the impurity named, no method of analysis has been suggested to establish the fact. beta-Naphthylamine is a known carcinogen; therefore, there is no scientific evidence that will support a safe tolerance for these colors in products to be used in contact with the skin. The Commissioner of Food and Drugs, having concluded that such action is necessary to protect the public health, hereby terminated the provisional listing of Ext. D&C Yellow No. 9 and Ext. D&C Yellow No. 10.

Yellow OB is converted to an imidazole derivative by reaction with aldehydes in the stomachs of rats and rabbits.

1-(ortho-Tolylazo)-6-hydroxy-2-sulphonaminonaphthalene-O-glucuronide and 1(ortho-toylazo)-2-sulphonaminonaphthalene were also present in the urine of /rats and rabbits/.

Bile contained 1-(ortho-tolylazo)-6-hydroxy-2-naphthylamine-O-hydrogen sulfate N-glucuronide, 1-(ortho-tolylazo)-6-hydroxy-2-susulphonamino-naphthalene-O-glucuronide, 1-(ortho-tolylazo)-6-hydroxy-2-naphthylamine-N-glucuronide and 1-(ortho-tolylazo)-2-sulphonaminonaphtalene.

As a part of studies on the participation of intestinal flora in the metabolism of food additives, some properites of azo- and nitro-reductase systems of intestinal bacteria and liver microsomes were compared. The bacterial reductase was prepared from the lyophilized cells of Escherichia coli by ultrasonic disruption. Most of azo- and nitro-reductase activity which required FMN and NADP was found in the ... (male Hartley guinea pig) liver microsomes in the reduction of water-soluble sulfonated azo dyes and p-nitrobenzoic acid. However, fat-soluble azo dyes, such as Oil Yellow AB and OB, were not reduced by either of the enzyme systems. Some difference in the substrate specificity for azo dyes was observed between the 2 enzyme systems and there was a remarkable difference in the inhibitory effect by CO, KCN, O2 and chelating agents.

Studies with (14)C-labelled color indicated that almost all of the yellow OB was eliminated in 48 hours: the feces contained 82% and urine 18% of the radioactivity.

/Yellow OB/ accumulates in fatty tissues of the body after its sc injection and is eliminated slowly...

Biological stain

Formerly used in the US for coloring oleomargarine

From 1940 until 1959 /Yellow AB (1-phenylazo-2-naphtylamine) and Yellow OB (1-o-tolylazo-2-naphtylamine)/ were certifiable as FD&C Yellow No. 3 and FD&C Yellow No. 4, respectively. In 1959 they were removed from the list of colors suitable for general use in foods, drugs, and cosmetics, and became certifiable provisionally as Ext. D&C Yellow No. 9 and Ext. D&C Yellow No. 10, respectively. On December 1, 1960, this provisional listing was terminated.

Color additives were initially regulated in the United States under the U.S. Department of Agriculture's (USDA) Bureau of Chemistry. In 1906, the Food and Drugs Act was passed by Congress, which prohibited the use of poisonous or deleterious colors in confectionery and the coloring or staining of food to conceal damage or inferiority. In 1927, responsibility of the Food and Drugs Act was transferred to FDA. Increasing government oversight, the Federal Food, Drug, and Cosmetic Act (FFDCA) was passed in 1938 and established the three following categories for colors: FD&C: colors used in foods, drugs and cosmetics; D&C: colors used in drugs and cosmetics when in contact with mucous membranes or ingested; and Ext. D&C: colors used in products applied externally.