Phenylhydrazin

Nitrogen Compounds -> Hydrazines

Flammable agents - 2nd degree

log Kow= 1.25

1.25

1.0978 (USCG, 1999) - Denser than water; will sink

1.0978 at 20 °C/4 °C

Relative density (water = 1): 1.1

1.1

1.0978 @ 20°C

1.10

Monoclinic prisms or oil

Colorless to pale yellow liquid or solid (below 67 degrees F).

Slight (NIOSH, 2024)

Sparingly sol petroleum ether, sol in dil acids. Miscible in alcohol, ether, chloroform, and benzene

Soluble in oxygenated, chlorinated, and aromatic solvents.

Very soluble in acetone.

In water, 1.27X10+5 mg/L at 25 °C

Solubility in water, g/100ml at 25 °C: 14.5

190 °F (USCG, 1999)

88 °C

190 °F, 88 °C (closed cup)

88 °C c.c.

190 °F

190 °F

471 °F at 760 mmHg (with decomposition) (USCG, 1999)

243.5 °C, decomp (760 mm Hg); 173.5 °C at 100 mm Hg; 148.2 °C at 40 mm Hg; 131.5 °C at 20 mm Hg; 115.8 °C at 10 mm Hg; 101.6 °C at 5 mm Hg; 71.8 °C at 1 mm Hg

470 °F (decomposes)

243.5 °C @760 [mm Hg]

470 °F (Decomposes)

When heated to decomposition it emits highly toxic fumes of /nitrogen oxides/.

243.5 °C

68 °F (USCG, 1999)

19.5 °C

MP: 243-6 °C, decomposes; molecular wt 144.60 /Phenylhydrazine hydrochloride/

Liquid Molar Volume= 0.098820 cu m/kmol; IG Heat of Formation= 2.0350X10+8 J/kmol; Heat of Fusion at the Melting Point= 1.6429X10+7 J/kmol.

19.5 °C

67 °F

3.7 (air= 1)

Relative vapor density (air = 1): 3.7

Danger

H301: Toxic if swallowed [Danger Acute toxicity, oral]

P203, P260, P261, P262, P264, P264+P265, P270, P271, P272, P273, P280, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P318, P319, P321, P330, P332+P317, P333+P317, P337+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Danger

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

P203, P260, P261, P262, P264, P264+P265, P270, P271, P272, P273, P280, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P318, P319, P321, P330, P332+P317, P333+P317, P337+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Chemical: Hydrazine, phenyl-

Hydrazine, phenyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Hydrazine, phenyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 01-04-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/14149

Phenylhydrazine: HSNO Approval: HSR003056 Approved with controls

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Special Hazards of Combustion Products: Irritating vapors and toxic gases, such as nitrogen oxides and carbon monoxide, may be formed when involved in fire.

· Combustible material: may burn but does not ignite readily.

Combustible. Gives off irritating or toxic fumes (or gases) in a fire. Above 88 °C explosive vapour/air mixtures may be formed.

Material is corrosive to tissue. Exposure can cause vomiting, diarrhea, fatigue, headache, and irritation and itchiness of the eyes and skin. (USCG, 1999)

· TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death.

Hemolytic anemia has been observed in workers after inhalation and dermal exposures. [ACGIH] Phenylhydrazine is a potent skin sensitizer and can cause hemolytic anemia by all routes of exposure. Toxic effects were observed in patients treated for polycythemia with doses of 0.2 G/day for 3 or 4 doses, then 0.1 G/day. Adverse effects included hemolytic anemia, liver injury, and methemoglobinemia. [HSDB] Can cause hemolytic anemia and skin sensitization; [ICSC] Causes first-degree burns on short exposure and second-degree burns on prolonged exposure; [CHRIS]

2572 153

2572 153

Excerpt from ERG Guide 153 [Substances - Toxic and/or Corrosive (Combustible)]:

Use water spray, alcohol-resistant foam, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Give a slurry of activated charcoal in water to drink. Refer for medical attention .

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

Excerpt from NIOSH Pocket Guide for Phenylhydrazine:

General First Aid:

(General first aid procedures)

Keep well closed and protected from light

Since they are strong reducing agents, they are hypergolic when in contact with strong oxidizers ... /Hydrazine derivatives/

All hydrazines should be stored at temperatures well below their boiling points. Hydrazines that are ignitable shall be stored in electrically grounded containers and isolated from ignition sources and oxidants. All containers of hydrazines shall be kept tightly closed when not in use and stored in a cool ventilated room or sheltered outside space. In the containers, a blanket of nitrogen or other inert gas should be placed over the hydrazines.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure 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, aquatic, and plant life; and conformance with environmental and public health regulations.

Evacuate danger area! Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT let this chemical enter the environment. If liquid: collect leaking liquid in sealable containers. Absorb remaining liquid in sand or inert absorbent. If solid: sweep spilled substance into containers. Carefully collect remainder. Then store and dispose of according to local regulations.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

... Should be used only in well ventilated premises and cumulative action of repeated small doses should be avoided.

Inhalation of salt dusts should be avoided. /Hydrazine & derivatives/

For more Preventive Measures (Complete) data for PHENYLHYDRAZINE (9 total), please visit the HSDB record page.

Excerpt from ERG Guide 153 [Substances - Toxic and/or Corrosive (Combustible)]:

Immediate precautionary measure

Erythrocytes (RBC) from phenylhydrazine treated mice are protective when injected into syngenic mice before x-ray irradiation. Evidence suggested that repair of hemopoietic stem cells was enhanced in mice injected with phenylhydrazine red blood cells before x-ray irradiation.

The protective effect of phenylhydrazine hydrochloride (PHCL) against acute deaths resulting from whole body irradiation was examined in mice. Male (C3H/C57Bl)F1 mice received sc 1 mg PHCL in 0.1 mL water for 3 days. Controls received injections of water. Mice were injected ip with (59)iron as citrate 1 to 10 days after 3rd PHCL injection. Some mice were exposed to 800 roentgens at various intervals after 3rd injection. During the 1st five days, PHCL caused increases in spleen wt and (59)iron uptake in erthyrocytes and spleen, but a reduction in (59)iron uptake in femurs. All values returned to those of controls by 10 days after 3rd injection. Thirty-day survival of water injected control was 10%. Pretreatment with PHCL improved 30-day survival to almost 100% when mice were irradiated between 4 and 8 days after 3rd injection. Apparently the improved survival resulted from an increase in the number of hemopoietic stem cells at time of irradiation. /Phenylhydrazine hydrochloride/

The peroxidation induced by phenylhydrazine in rats chronically exposed to lead was evaluated. Wistar-rats were exposed to lead in-utero and up to four months after birth via administration of distilled drinking water containing ...lead-acetate. The animals were then maintained in a closed desiccator system for analysis of exhaled hydrocarbons before or immediately after injection of phenylhydrazine. The effect of chronic lead pretreatment was assessed by measuring the production of the four main volatile hydrocarbons: ethane and pentane as indices of lipid peroxidation; propane as a marker of protein peroxidation; and ethylene as an index of both lipid and protein peroxidations. Lead alone did not increase the physiological formation of alkanes. After phenylhydrazine injection, lipid peroxidation markers were not modified except for pentane in male lead treated rats. Ethylene and propane exhalation, on the other hand, were increased 45 minutes after phenylhydrazine injection in lead treated rats, indicating lead induced potentiation of the oxidative effect of phenylhydrazine.

LC50 Brachydanio rerio (Zebrafish) 0.16-0.26 mg/L/96 hr /Conditions of bioassay not specified in source examined/

EC50 Daphnia sp. (Water flea; intoxication, immobilization) <1200 ug/L 24 hr; static

LC50 Oryzias latipes (Medaka) 21,400 ug/L/24 hr, 15,700 ug/L/48 hr; static

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 110(SRC), determined from a measured log Kow of 1.25(2) and a recommended regression-derived equation(3), indicates that phenylhydrazine will have high mobility in soil(SRC). Phenylhydrazine is a weak base with a pKa of 5.21(4), suggesting it will partially exist as a cation in moist soil, and the cationic form may adsorb to soil more than the free base(SRC). Phenylhydrazine is not expected to volatilize from moist soil surfaces(SRC)because cations do not volatilize and the Henry's Law constant of the free base is estimated as 2.9X10-8 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure, 0.026 mm Hg(5), and water solubility, 1.27X10+5 mg/L(6). In the Zahn-Wellens aqueous screening test, 85% of this compound was biodegraded in 9-13 days(7). Phenylhydrazine may be susceptible to photolysis upon exposure to sunlight on soil surfaces as it strongly absorbs UV light in the environmentally significant range (wavelengths >290 nm)(8).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 110(SRC), determined from a measured log Kow of 1.25(2) and a recommended regression-derived equation(3), indicates that phenylhydrazine should not adsorb to suspended solids and sediment in water(SRC). Phenylhydrazine is a weak base with a pKa of 5.21(4), suggesting it will partially exist as a cation in water, and the cationic form may adsorb to sediment more than the free base(SRC). Phenylhydrazine is not expected to volatilize from water surfaces(3)because cations do not volatilize and the Henry's Law constant of the free base is estimated as 2.9X10-8 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure, 0.026 mm Hg(5), and water solubility, 1.27X10+5 mg/L(6). According to a classification scheme(7), an estimated BCF value of 2(SRC), from a measured log Kow(2) and regression derived equation(8), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Based on limited data, phenylhydrazine may biodegrade under aerobic conditions in natural water environments(SRC). In the Zahn-Wellens aqueous screening test, 85% of this compound was biodegraded in 9-13 days(9). Phenylhydrazine is not expected to undergo hydrolysis as it lacks hydrolyzable functional groups, but may be susceptible to photolysis upon exposure to sunlight in natural waters because it strongly absorbs UV light in the environmental UV spectrum (wavelengths >290 nm)(10).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), phenylhydrazine, which has a measured vapor pressure of 0.026 mm Hg at 25 °C(2), will exist solely as a vapor in the ambient atmosphere. Vapor-phase phenylhydrazine 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 about 9 hours(SRC), calculated from its rate constant of 4.3X10-11 cu cm/molecule-sec at 25 °C(SRC) estimated with a structure estimation method(3).

The substance can be absorbed into the body by inhalation of its aerosol, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

IDENTIFICATION: Phenylhydrazine exists as yellow to brown crystals or as a yellowish oily liquid. This chemical is used world wide mainly as a chemical intermediate in the pharmaceutical, agrochemical and chemical industries. HUMAN EXPOSURE: The number of persons potentially exposed to phenylhydrazine or its hydrochloride salt is unknown, but is expected to be small. No personal exposure data were available. There is evidence that phenylhydrazine has skin sensitizing properties in humans. There are no adequate data available regarding the reproductive or developmental effects, hence, it is not possible to evaluate the risk to human health for these endpoints. The level of risk in occupational settings is uncertain; as a result, there is a continuing requirement to reduce exposure levels with the technology currently available. The lack of available data to serve as a basis for estimation of indirect exposure of individuals to phenylhydrazine from the general environment precludes the characterization of potential cancer risks for the general population. ANIMAL/PLANT STUDIES: The limited data on the toxicokinetics indicate that phenylhydrazine is well absorbed by inhalation, oral and dermal routes and binds readily with hemoglobin in red blood cells. Metabolism seems to occur via ring hydroxylation and conjugation, probably with glucuronic acid. Excretion is primarily via the urine. Phenylhydrazine is toxic by single exposure via the oral route (LD50 80-188 mg/kg body weight) and is expected to be toxic by inhalation and dermal routes (data from these routes are less clear). Phenylhydrazine has potential for skin and eye irritation. Exposure to this chemical may cause damage to red blood cells, potentially resulting in anemia and consequential secondary involvement of other tissues such as the spleen and liver. Phenylhydrazine is mutagenic in vitro, and there is some evidence to indicate that it may express genotoxic activity in vivo. The substance is clearly carcinogenic in mice following oral dosing, inducing tumors of the vascular system. Phenylhydrazine is readily biodegradable. Phenylhydrazine is toxic to aquatic organisms, with the lowest reported no observed effect concentration (NOEC) in standard acute fish tests at 0.01 mg/l; fish are generally more sensitive than either daphnids or bacteria. A NOEC of 0.49 ug/l has been reported for embryo larval stages of the zebra fish (Brachydanio rerio).

/AQUATIC SPECIES/ The toxicities of hydrazine and phenylhydrazine to embryos and larvae of zebrafish, Brachydanio rerio, were studied under standardized conditions. Exposures to the chemicals started at the blastula stage and the effect on hatching and survival were monitored for 15 days. The results showed that toxicities of phenylhydrazine to both embryos and larvae were more than those of hydrazine. The Lowest Observed Effect Concentration for hatching was 0.049 mg/L for hydrazine and 0.0078 mg/L for phenylhydrazine, the Lowest Observed Effects Concentration for survival of larvae was 0.0035 mg/L for hydrazine and 0.00098 mg/L for phenylhydrazine, respectively. The No Observed Effect Concentration for hatching was 0.0245 mg/L for hydrazine and 0.0039 mg/L for phenylhydrazine and the No Observed Effect Concentration for survival of larvae was 0.00175 mg/L for hydrazine and 0.00049 mg/L for phenylhydrazine, respectively.

/AQUATIC SPECIES/ In a study on the goldfish (Carassius auratus), 40% of fish died when exposed to phenylhydrazine at a nominal concentration of 1 mg/L for 48 h. Signs of toxicity included erratic swimming, sinking to the bottom of the test tank, and slowed and erratic respiration. No gross lesions were found following dissection, although all viscera showed focal hemorrhaging.

/AQUATIC SPECIES/ Effects on blood cells and the hematopoietic system, comparable to those found in mammals, were seen in fish injected with phenylhydrazine. Chinook salmon (Oncorhynchus tshawytscha) juveniles were injected with 12.5 mg phenylhydrazine/kg body weight. Red cell count, hemoglobin, and hematocrit fell to 1-5% of their normal values within 10 days of treatment; a slight improvement was reported 15 days following injection, and values had returned to normal 95 days after treatment.

Cough. Sore throat. Weakness. Dizziness.

MAY BE ABSORBED! Dry skin. Redness. Pain.

Redness. Pain. Blurred vision.

Abdominal pain. Diarrhoea. Dizziness. Nausea. Vomiting. Weakness.

Skin sensitization, hemolytic anemia, dyspnea (breathing difficulty), cyanosis; jaundice; kidney damage; vascular thrombosis; [potential occupational carcinogen]

... Situations in which air concentration ... approach 5 ppm and particularly where there is additional possibility of skin contact, workers should be under careful medical observation.

It is essential that alcoholics or persons suffering from liver ailments or blood disorders are ... /protected/ from work with phenylhydrazine. Complete periodic medical exam should including blood tests, as well as biochemical tests (glycemia, cholesterolemia, bilirubinemia). Urine should be exam ... for the degradation products of phenylhydrazine.

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Phenylhydrazine is included on this list.

Superoxide anion was unimportant in phenylhydrazine induced hemolysis and destruction of human oxyhemoglobin. Phenyldiazene, presumably produced by 2-electron oxidation of phenylhydrazine by oxyhemoglobin, hemolyzed red cells rapidly and converted oxyhemoglobin into methemoglobin, hemichromes, and other hemoglobin breakdown products. Induction of hemolysis by phenyldiazene requires the presence of oxygen. The hemolysis produced in presence of phenyldiazene and oxygen was related to lipid peroxidation. It is concluded that the active hemolytic agent produced by phenylhydrazine in red cells is a phenyldiazene-derived free radical produced by reaction of phenyldiazene with oxygen, and is most probably the phenyl free radical.

The enzyme systems in rat liver and lung responsible for the oxidative metabolism of hydrazine derivatives were studied to determine whether these enzymes, cytochrome p450 and monoamine oxidase, were responsible for metabolically activating hydrazines to carcinogenic/toxic metabolites. Cytochrome p450 preferentially oxidized the nitrogen to nitrogen bond of 1,2-disubstituted hydrazines and hydrazides, while monoamine oxidase oxidized the nitrogen to nitrogen bond of all the classes of hydrazine derivatives that were tested. Oxidation of the nitrogen to nitrogen bond led to the formation of stable azo intemediates in the case of 1,2-disubstituted hydrazines and to unstable monoazo (diazene) metabolites in the case of monosubstituted hydrazines and hydrazides. /Substituted hydrazines/

The mechanism of action has been postulated to include indirect alkylation of DNA, an observation which is also closely connected to the toxic endpoint.

Iron transfer from duodenum to blood was increased significantly /in rats/ 5 days after treatment with phenylhydrazine. Autoradiography showed that most brush border iron uptake occurred at the upper villus region and the maximal rate was increased fourfold by phenylhydrazine; Duodenal villus length was increased in phenylhydrazine-treated rats. Phenylhydrazine treatment did not influence mucosal reducing activity but Vm, measured using duodenal sheets, increased from -50 to -57 mV (p<0.001) and this was due to a reduced brush border sodium permeability. Thus, an expanded absorptive surface and an enhanced electrical driving force for iron uptake across the duodenal brush border are important adaptations for increased iron absorption in phenylhydrazine-induced hemolytic anemia.

Inhibition of electron transport system by phenylhydrazine was studied with mitochondria and submitochondrial particles of rat liver and beef heart. The inhibition of the electron transport system required oxygen and depended on temperature and occurred at a site between cytochrome b and cytochrome c1.

In rabbits, ...urinary metabolites, p-hydroxyphenylhydrazine and the phenylhydrazines of pyruvic and oxoglutaric acid, were excreted for 10 days following /oral/ dosing.

Phenylhydrazine is extensively metabolized following oral administration, although the complete metabolic pathway has not been characterized. The main reactions identified in this study were hydroxylation of the aromatic ring to p-hydroxyphenylhydrazine, followed by conjugation, probably with glucuronic acid, and production of phenylhydrazones, by reaction with natural keto acids.

Evidence from a number of studies in vitro and in vivo suggests that phenylhydrazine interacts with hemoglobin and cytochrome P-450 in an oxidation reaction, resulting in the generation of destructive free radicals, which are responsible for subsequent hemolysis.

Evidence from toxicokinetic and toxicity studies and from human experience indicates that phenylhydrazine is well absorbed by the inhalation, oral, and dermal routes in animals and humans.

In rabbits, 30-60% of an oral dose of phenylhydrazine was excreted in the urine in 48 hr and (40-60% in 4 days). 5-10% of the radioactivity was found in erythrocytes 4 days postdosing.

Used in the synthesis of dyes and pharmaceuticals; [ACGIH]

Manufacture dyes, antipyrine, nitron (a stabilizer for explosives); reagent for sugars, aldehydes, ketones.

Reducing agent /Phenylhydrazine hydrochloride/

Used as a chemical intermediate for the synthesis of 3-amino-1-phenyl-5-pyrazolone; chloridazon; 4,4-dimethyl-1-phenyl-3-pyrazolidinone; ethyl 1-phenylpyrazolone-3-carboxylate; 2-methylindole; 3-methyl-1-phenyl-5-pyrazolone; N-methyl-2-p-tolylindole; 2-phenylindole; 1-phenyl-3-pyrazolidone; sulfaphenazole; triazophos; L-tryptophan.

Organic synthesis (intermediates, dyestuffs, pharmaceuticals)

(1972) 3.02X10+8 G (PRINCPL CUSTMS DISTS)

(1975) 1.70X10+8 G

2023: 20,282 lb

(1972) PROBABLY GREATER THAN 4.54X10+5 G

(1975) PROBABLY GREATER THAN 4.54X10+5 G

Prepared by diazotizing aniline with sodium nitrite and hydrochloric acid, then treating solution with sodium sulfite followed by sodium hydroxide.

Benzenediazonium chloride (reduction)

A general synthesis for arylhydrazines is via diazotization of aromatic amines, followed by reduction of the resulting diazonium salt. In the industrial synthesis of phenylhydrazine, the reducing agent is sodium bisulfite.

Pesticide, Fertilizer, and Other Agricultural Chemical Manufacturing

Hydrazine, phenyl-: ACTIVE