50-00-0 Usage
Uses
Used in Chemical Industry:
Formaldehyde is used as a chemical intermediate for the production of phenolic resins, cellulose esters, artificial silk, dyes, explosives, and organic chemicals. It is also used in the manufacture of urea, phenolic melamine, and acetale resins.
Used in Medical Laboratories and Embalming:
Formaldehyde is used as a preservative, disinfectant, and antiseptic in medical laboratories and embalming solutions. It is also used as a tissue fixative.
Used in Building Materials and Household Products:
Formaldehyde is used in the production of plastics and resins, such as urea-formaldehyde (UF) and phenol-formaldehyde (PF) resins, which are used in foam insulations, adhesives in the production of particle board and plywood, and in the treating of textiles.
Used in Agriculture:
Formaldehyde is used as a microbiocide, fungicide, and bactericide in agriculture. It is also used as a soil sterilent and as a pesticide intermediate.
Used in Textile Industry:
Formaldehyde is used to improve the fastness of dyes on fabrics, in tanning and preserving hides, and in mordanting and waterproofing fabrics.
Used in Cosmetics and Personal Care Products:
Formaldehyde is used as an astringent, disinfectant, and preservative in cosmetics, metal-working fluids, shampoos, and as an antiperspirant.
Used in Other Industries:
Formaldehyde is used in the production of pentaerythritol, hexamethylenetetramine, and lkbutanediol. It is also used in ceiling and wall insulation, resins used to wrinkle-proof fabrics, photography for hardening gelatin plates and papers, toning gelatin-chloride papers, and for chrome printing and developing.
Environmental and Health Considerations:
Formaldehyde is directly emitted into the air from vehicles and is released in trace amounts from pressed wood products, old buildings, and certain fabrics. It is also a toxic effluent gas emitted from burning wood and synthetic polymeric substances. Precautions and protections must be considered during its use due to links between formaldehyde and adverse health effects.
History
Formaldehyde is a by-product of combustion of organic compounds, metabolism, and
other natural processes. Formaldehyde results from wood combustion and elevated atmospheric
concentrations can result from forest fires, as well as from urban pollution sources
such as transportation. Formaldehyde has been identified as a significant indoor air pollutant.
Building materials such as particleboard, plywood, and paneling are major sources of formaldehyde
because they incorporate formaldehyde resins as bonding adhesives. Other sources of
formaldehyde in the home are carpets, upholstery, drapes, tobacco smoke, and indoor combustion
products. Formaldehyde may be emitted from building materials for several years after
installation. In the two decades of the 1960s and 1970s, a half million homes in the United
States used urea formaldehyde foam insulation, but health complaints led to its elimination
as an insulator in the early 1980s. People react differently to formaldehyde exposure, but it is
estimated that between 10% and 20% of the population will experience some reaction at concentrations
as low as 0.2 parts per million. Formaldehyde irritates the eyes, nose, and throats,
producing coughing, sneezing, runny nose, and burning eyes. More severe reactions result in insomnia, headaches, rashes, and breathing difficulties. Some states have established indoor air
quality standards ranging from 0.05 to 0.5 ppm.
Production Methods
The industrial preparation of formaldehyde has occurred since the late 1800s and involvesthe catalytic oxidation of methanol: 2CH3OH(g) + O2(g) → 2CH2O(g).the oxidationtakes place at temperatures between 400°C and 700°C in the presence of metal catalysts. Metalsinclude silver, copper, molybdenum, platinum, and alloys of these metals. Formaldehyde iscommonly used as an aqueous solution called formalin. Commercial formalin solutions varybetween 37% and 50% formaldehyde. When formalin is prepared, it must be heated anda methanol must be added to prevent polymerization; the final formalin solution containsbetween 5% and 15% alcohol.
Preparation
Formalin is adjusted to pH 8 and urea is added to give a urea to
formaldehyde ratio of about 1 :2.5 molar. The resulting solution is boiled
under reflux for 1 hour. Butanol (1.5-2.0 mole per mole of urea) is then added
together with a little xylene. The latter forms, with butanol and water, a
ternary azeotrope which on distillation yields a condensate separating into an
upper organic layer and a lower aqueous layer. By discarding the lower layer
and returning the upper layer to the reactor, water is progressively removed
from the system. After a substantial proportion of the water has been
removed, an acid catalyst (e.g. phosphoric acid or phthalic anhydride) is
added and heating is continued. When the required degree of reaction is
attained, the solution is neutralized and concentrated to the desired solids
content.
Air & Water Reactions
The solution gives up formaldehyde vapors readily. These vapors are flammable over a wide vapor-air concentration range. Water soluble.
Reactivity Profile
FORMALDEHYDE, SOLUTION, reacts violently with strong oxidizing agents (hydrogen peroxide, performic acid, perchloric acid in the presence of aniline, potassium permanganate, nitromethane). Reacts with bases (sodium hydroxide, potassium hydroxide, ammonia), and with nitrogen dioxide (explosive reaction around 180°C). Reacts with hydrochloric acid to form highly toxic bis(chloromethyl) ether. Polymerization reaction with phenol may develop sudden destructive pressure [Bretherick, 5th ed., 1995, p.168].
Hazard
Moderate fire risk. Explosive limits in air 7–
73%. Toxic by inhalation, strong irritant, a carcinogen. (Solution) Avoid breathing vapor and avoid
skin contact. Confirmed carcinogen.
Health Hazard
Formaldehyde is moderately toxic by skin contact and inhalation. Exposure to
formaldehyde gas can cause irritation of the eyes and respiratory tract, coughing, dry
throat, tightening of the chest, headache, a sensation of pressure in the head, and
palpitations of the heart. Exposure to 0.1 to 5 ppm causes irritation of the eyes, nose, and
throat; above 10 ppm severe lacrimation occurs, burning in the nose and throat is
experienced, and breathing becomes difficult. Acute exposure to concentrations above 25
ppm can cause serious injury, including fatal pulmonary edema. Formaldehyde has low
acute toxicity via the oral route. Ingestion can cause irritation of the mouth, throat, and
stomach, nausea, vomiting, convulsions, and coma. An oral dose of 30 to 100 mL of 37%
formalin can be fatal in humans. Formalin solutions can cause severe eye burns and loss
of vision. Eye contact may lead to delayed effects that are not appreciably eased by eye
washing.Formaldehyde is regulated by OSHA as a carcinogen (Standard 1910.1048) and is
listed in IARC Group 2A ("probable human carcinogen"). This substance is
classified as a "select carcinogen" under the criteria of the OSHA Laboratory
Standard. Prolonged or repeated exposure to formaldehyde can cause dermatitis and
sensitization of the skin and respiratory tract. Following skin contact, a symptom free period may occur in sensitized individuals. Subsequent exposures can then lead
to itching, redness, and the formation of blisters
Fire Hazard
Toxic vapors such as carbon dioxide and carbon monoxide are generated during combustion. Explosion hazard: when aqueous formaldehyde solutions are heated above their flash points, a potential for explosion hazard exists. High formaldehyde concentration or methanol content lowers flash point. Reacts with nitrogen oxides at about 180; the reaction becomes explosive. Also reacts violently with perchloric acid-aniline, performic acid, nitromethane, magnesium carbonate, and hydrogen peroxide. When heated, irritant formaldehyde gas evolved from solution. The main products of decomposition are carbon monoxide and hydrogen. Metals such as platinum, copper, chromia, and alumina also catalyze the formation of methanol, methylformate, formic acid, carbon dioxide, and methane. Reacts with peroxide, nitrogen oxide, and performic acid causing explosions. Can react with hydrogen chloride or other inorganic chlorides to form bis-chloromethylether (BCME), a known carcinogen. Very reactive, combines readily with many substances, 40% solution is powerful reducing agent. Incompatible with amines, azo compounds, dithiocarbamates, alkali and alkaline earth metals, nitrides, nitro compounds, unsaturated aliphatics and sulfides, organic peroxides, oxidizing agents, and reducing agents. Aqueous solutions are unstable. Commercial formaldehyde-alcohol solutions are stable. Gas is stable in absence of water. Avoid oxidizing and alkaline materials. Hazardous polymerization may occur. Compound will polymerize with active organic materials such as phenol. Will polymerize violently in the presence of caustics and nitrides; (amines) exothermic reaction, (Azo compound) exothermic reaction giving off nitrogen gas, (caustics) heat generation and violent polymerization, (dithiocarbamates) formation of flammable gases and toxic fumes, formation of carbon disulfide may result, (alkali and alkaline earth metals) heat generation and formation of a flammable hydrogen gas.
Flammability and Explosibility
Formaldehyde gas is extremely flammable; formalin solution is a combustible liquid (NFPA rating = 2 for 37% formaldehyde (15% methanol), NFPA rating = 4 for 37% formaldehyde (methanol free)). Toxic vapors may be given off in a fire. Carbon dioxide or dry chemical extinguishers should be used to fight formaldehyde fires.
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Trade name
DYNOFORM?; FANNOFORM?;
FORMALITH?; FORMOL?; FYDE?; HERCULES
37 M6-8?; HOCH?; IVALON?; KARSAN?;
LYSOFORM?; MAGNIFLOC 156C FLOCCULANT?;
MORBICID?; STERIFORM?; SUPERLYSOFORM?
Contact allergens
Sources and uses of formaldehyde are numerous. Exposed
people are mainly health workers, cleaners, painters, met alworkers, but also photographers (color developers) and
carbonless copy paper users. Formaldehyde can induce
contact urticaria. Formaldehyde may be the cause of sen sitization to formaldehyde releasers: benzylhemiformal,
bromonitrodioxane, bromonitropropanediol (?), chloroal lylhexaminium chloride or Quaternium-15, diazolidinylu rea, dimethylol urea, dimethyloldimethylhydantoin or
DMDM hydantoin, hexamethylenetetramine or methe namine, imidazolidinylurea, monomethyloldimethylhy dantoin or MDM hydantoin, N-methylolchloracetamide,
paraformaldehyde and trihydroxyethylhexahydrotriazine
or Grotan BK.
Formaldehyde is used for the synthesis of many resins.
Some of them, such as formaldehyde-urea and melamine formaldehyde resins, can be used in textiles and second arily release free formaldehyde (see Chap. 40).
Other resins, such as p-tert-butylphenol formalde hyde resin or tosylamine formaldehyde resin, do not
release formaldehyde.
Biochem/physiol Actions
Formaldehyde is the simplest aldehyde that denatures the bihelical regions of RNA and converts the polynucleotides into random coils. It is a genotoxic substance that significantly induces DNA-protein crosslinks (DPC), sister-chromatid exchanges, micronuclei formation and leads to cytotoxicity. It also induces tumors in the nasal epithelium of rats and supposed to be a human carcinogen.
Safety Profile
Confirmed carcinogen
with experimental carcinogenic,
tumorigenic, and teratogenic data. Human
poison by ingestion. Experimental poison by
ingestion, skin contact, inhalation,
intravenous, intraperitoneal, and
subcutaneous routes. Human systemic
effects by inhalation: lachqmation, olfactory
changes, aggression, and pulmonary changes. Experimental reproductive effects.
Human mutation data reported. A human
skin and eye irritant. If swallowed it causes
violent vomiting and darrhea that can lead
to collapse. Frequent or prolonged exposure
can cause hypersensitivity leading to contact
dermatitis, possibly of an eczematoid nature.
An air concentration of 20 ppm is quickly
irritating to eyes. A common air
contaminant.
Flammable liquid when exposed to heat or
flame; can react vigorously with oxidizers. A
moderate explosion hazard when exposed to
heat or flame. The gas is a more dangerous
fire hazard than the vapor. Should
formaldehyde be involved in a fire, irritating
gaseous formaldehyde may be evolved.
When aqueous formaldehyde solutions are
heated above their flash points, a potential
for an explosion hazard exists. High
formaldehyde concentration or methanol
content lowers the flash point. Reacts with
sodum hydroxide to yield formic acid and
hydrogen. Reacts with NOx at about 180';
the reaction becomes explosive. Also reacts
violently with perchloric acid + anhe,
performic acid, nitromethane, magnesium
carbonate, H2O2. Moderately dangerous
because of irritating vapor that may exist in
toxic concentrations locally if storage tank is
ruptured. To fight fire, stop flow of gas (for
pure form); alcohol foam for 37%
methanol-free form. When heated to
decomposition it emits acrid smoke and
fumes. See also ALDEHYDES.
Potential Exposure
Formaldehyde has found wide indus trial usage as a fungicide, germicide; and in disinfectants
and embalming fluids. It is also used in the manufacture of
artificial silk and textiles, latex, phenol, urea, thiourea and
melamine resins; dyes, and inks; cellulose esters and other
organic molecules; mirrors, and explosives. It is also used
in the paper, photographic, and furniture industries. It is an
intermediate in drug manufacture and is a pesticide
intermediate.
Carcinogenicity
Formaldehyde is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans and supporting data on mechanisms of carcinogenesis. Formaldehyde was first listed in the Second Annual Report on Carcinogens in 1981 as reasonably anticipated to be a human carcinogen based on sufficient evidence from studies in experimental animals. Since that time, additional cancer studies in humans have been published, and the listing status was changed to known to be a human carcinogen in the Twelfth Report on Carcinogens (2011).
Source
Formaldehyde naturally occurs in jimsonweed, pears, black currant, horsemint, sago
cycas seeds (1,640 to 2,200 ppm), oats, beets, and wild bergamot (Duke, 1992).
Formaldehyde was formed when acetaldehyde in the presence of oxygen was subjected to
continuous irradiation (λ >2200 ?) at room temperature (Johnston and Heicklen, 1964).
Schauer et al. (2001) measured organic compound emission rates for volatile organic
compounds, gas-phase semi-volatile organic compounds, and particle phase organic compounds
from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission
rates of formaldehyde were 1,165 mg/kg of pine burned, 759 mg/kg of oak burned, and 599 mg/kg
of eucalyptus burned.
Gas-phase tailpipe emission rates from California Phase II reformulated gasoline-powered
automobiles with and without catalytic converters were 8.69 and 884 mg/km, respectively
(Schauer et al., 2002).
Environmental Fate
Biological. Biodegradation products reported include formic acid and ethanol, each of which can further degrade to carbon dioxide (Verschueren, 1983).Photolytic. Major products reported from the photooxidation of formaldehyde with nitrogen oxides are carbon monoxide, carbon dioxide and hydrogen peroxide (Altshuller, 1983). In synthetic air, photolysis of formaldehyde gave hydrochloric acid andIrradiation of gaseous formaldehyde containing an excess of nitrogen dioxide over chlorine yielded ozone, carbon monoxide, nitrogen pentoxide, nitryl chloride, nitric acid and hydrochloric acid. Peroxynitric acid was the major photolysis product when chloChemical/Physical. Oxidizes in air to formic acid (Hartley and Kidd, 1987). Trioxymethylene may precipitate under cold temperatures (Sax, 1984). Polymerizes easily (Windholz et al., 1983). Anticipated products from the reaction of formaldehyde with ozone orhydroxyl radicals in air are carbon monoxide and carbon dioxide (Cupitt, 1980). Major products reported from the photooxidation of formaldehyde with nitrogen oxides are carbon monoxide, carbon dioxide and hydrogen peroxide (Altshuller, 1983).Reacts with hydrochloric acid in moist air forming bis(chloromethyl)ether. This compound may also form from an acidic solution containing chloride ion and formaldehyde (Frankel et al., 1974). In an aqueous solution at 25°C, nearly all the formaldehyde add
storage
work with formaldehyde should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles and impermeable gloves should be worn at all times to prevent eye and skin contact. Formaldehyde should be used only in areas free of ignition sources. Containers of formaldehyde should be stored in secondary containers in areas separate from oxidizers and bases.
Shipping
UN1198 Formaldehyde solutions, flammable,
Hazard Class: 3; Labels: 3-Flammable liquid, 8-Corrosive
material. Cylinders must be transported in a secure upright
position, in a well-ventilated truck. Protect cylinder and
labels from physical damage. The owner of the compressed
gas cylinder is the only entity allowed by federal law
(49CFR) to transport and refill them. It is a violation of
transportation regulations to refill compressed gas cylinders
without the express written permission of the owner.
UN2209 Formaldehyde solutions, with not<25% formal dehyde, Hazard class: 8; Labels: 8-Corrosive material.
UN3077 For solids containing varying amounts of formal dehyde : UN3077
Environmentally hazardous substances, solid, n.o.s., Hazard
class: 9; Labels: 9-Miscellaneous hazardous material,
Technical Name Required.
Purification Methods
It commonly contains added MeOH. Add KOH solution (1 mole KOH: 100 moles HCHO) to ~37% by weight aqueous formaldehyde solution (formalin), or evaporate to dryness, to give paraformaldehyde polymer which, after washing with water, is dried in a vacuum desiccator over P2O5 or H2SO4. Formaldehyde is regenerated by heating the paraformaldehyde to 120o under vacuum, or by decomposing it with barium peroxide. The monomer, a colourless flammable gas, is passed through a glass-wool filter cooled to -48o in a CaCl2/ice mixture to remove particles of polymer, then dried by passage over P2O5 and either condensed in a bulb immersed in liquid nitrogen or absorbed in ice-cold conductivity water. The gas or aqueous solutions have pungent suffocating odours, are LACHRYMATORY and suspected carcinogens, handle carefully. Formalin is a disinfectant and a preservative of dead animal and plant tissues. [Beilstein 1 IV 3017.]
Toxicity evaluation
The carbonyl atom is the electrophilic site of formaldehyde,
making it react easily with nucleophilic sites on cell membranes
and in body fluids and tissues such as the amino groups in
protein and DNA. Higher concentrations of formaldehyde
precipitate protein. It is probable that formaldehyde toxicity
occurs when intracellular levels saturate formaldehyde dehydrogenase
activity, allowing the unmetabolized intact molecule
to exert its effects locally. Formaldehyde is a very strong crosslinking
agent even in the low concentration range. The reaction
mechanism of this agent is the initial addition of formaldehyde
to a primary amine on either an amino acid residue or DNA
base to yield a hydroxymethyl intermediate. Then the hydroxymethyl
group condenses with a second primary amine to yield
a methylene bridge.
Incompatibilities
Pure formaldehyde may polymerize
unless properly inhibited (usually with methanol). May
form explosive mixture with air. Incompatible with strong
acids; amines, strong oxidizers; alkaline materials; nitrogen
dioxide; performic acid; phenols, urea. Reaction with
hydrochloric acid forms bis-chloromethyl ether, a carcino gen. Formalin is incompatible with strong oxidizers, alkalis,
acids, phenols, urea, oxides, isocyanates, caustics,
anhydrides.
Waste Disposal
Return refillable compressed
gas cylinders to supplier. Incineration in solution of combus tible solvent. Consult with environmental regulatory agen cies for guidance on acceptable disposal practices. Generators
of waste containing this contaminant (≥100 kg/mo)
must conform with EPA regulations governing storage, trans portation, treatment, and waste disposal.
Check Digit Verification of cas no
The CAS Registry Mumber 50-00-0 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 5 and 0 respectively; the second part has 2 digits, 0 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 50-00:
(4*5)+(3*0)+(2*0)+(1*0)=20
20 % 10 = 0
So 50-00-0 is a valid CAS Registry Number.
InChI:InChI=1/CH2O/c1-2/h1H2
50-00-0Relevant articles and documents
Oxidation of methane and ethylene in water at ambient conditions
Sorokin,Kudrik,Alvarez,Afanasiev,Millet,Bouchu
, p. 149 - 154 (2010)
Available spectroscopic, labelling and reactivity data show that stable μ-nitrido diiron phthalocyanine activates H2O2 to form a high-valent diiron oxo species. This species is a very powerful oxidant which oxidizes methane in pure water at 25-60 °C to methanol, formaldehyde and formic acid. The catalytic activity can significantly be increased in the presence of a diluted acid solution. Thus, a high turnover number of 209 was attained in 0.075 M H2SO4. Oxidation of ethylene resulted in the formation of formic acid as a major product and formaldehyde with high turnover numbers. Under optimal conditions, 426 mol HCOOH and 37 mol CH 2O per mole of catalyst were obtained in pure water. The practical and green features of this novel approach (H2O2 as the clean oxidant, water as the clean reaction medium, easily accessible solid catalyst) as well as the relevance to biological oxidation (binuclear structure of bio-inspired complex) are of great importance both from practical and fundamental points of view.
Partial Oxidation of Methane by Nitrous Oxide over Molybdenum Oxide supported on Silica
Liu, R.-S.,Iwamoto, M.,Lunsford, Jack H.
, p. 78 - 79 (1982)
Methanol and formaldehyde were formed as major products at a moderate conversion level (16percent) in the partial oxidation of methane by nitrous oxide in the presence of water over molybdenum oxide supported on silica.
Flash Photolysis Study of the CH3O2 + CH3O2 Reaction: Rate Constants and Branching Ratios from 248 to 573 K
Lightfoot, P. D.,Lesclaux, R.,Veyret, B.
, p. 700 - 707 (1990)
The reactions 2CH3O2 -> 2CH3O + O2 (1a), 2CH3O2 -> CH3OH + HCHO + O2 (1b), and 2CH3O2 -> CH3COOH + O2 (1c) have been studied at temperatures between 248 and 573 K.At temperature above 373 K, the resulting decay traces were distorted away from pure second order at short wavelenghts (around 210 nm), owing to the presence of the hydroperoxy radicals formed via the nonterminating pathway (1a) and the subsequent rapid step CH3O + O2 -> HCHO + HO2 (2).This distortion enabled the nonterminating/terminating branching ratio, β, to be determined.Combining the present resultswith previously published work on the branching ratios gave lnβ=3.80-1470/T.Thus, although reaction 1 acts as a termination reaction under atmospheric conditions, it largely serves to convert CH3O2 into HO2 under combustion conditions.The temperature dependence of β enabled the real constant for the reaction k1, to be obtained over the entire experimental temperature range, giving k1 = 1.3E-13exp(365/T)cm31/molecule1/s, with ?2A/cm6molecule-2s-2 = 2.00E-28, ?2E/R/K2 = 1712, and ?2AE/R/cm3molecule-1s-1 = -5.61E-13.Absolute uncertainties, including contributions from both the experimental measurements and the dependence of k1 on various analysis parameters, are estimated to be 22percent, independent of temperature.No dependence of either the branching ratio or k1 on the total pressure was found.The mechanism of the title reaction is discussed and the present results are compared with existing studies of alkylperoxy self-reactions.The implications for combustion and atmospheric modeling are also discussed.
Epidoxoform: A hydrolytically more stable anthracycline-formaldehyde conjugate toxic to resistant tumor cells
Taatjes, Dylan J.,Fenick, David J.,Koch, Tad H.
, p. 1306 - 1314 (1998)
The recent discovery that the formaldehyde conjugates of doxorubicin and daunorubicin, Doxoform and Daunoform, are cytotoxic to resistant human breast cancer cells prompted the search for hydrolytically more stable anthracycline-formaldehyde conjugates. Doxoform and Daunoform consist of two molecules of the parent drug bound together with three methylene groups, two forming oxazolidine rings and one binding the oxazolidines together at their 3'amino nitrogens. The 4'-epimer of doxorubicin, epidoxorubicin, reacts with formaldehyde at its amino alcohol functionality to produce a conjugate, Epidoxoform, in 59% yield whose structure consists of two molecules of epidoxorubicin bound together with three methylene groups in a 1,6-diaza- 4,9-dioxabicyclo[4.4.1]undecane ring system. The structure was established from spectroscopic data and is consistent with products from reaction of simpler vicinal trans-amino alcohols with formaldehyde. Epidoxoforrn hydrolyzes at pH 7.3 to an equilibrium mixture with dimeric and monomeric epidoxorubicin-formaldehyde conjugates without release of formaldehyde or epidoxorubicin. The hydrolysis follows the rate law (A mutually implies B) mutually implies C + D where A (Epidoxoform) is in rapid equilibrium with B, and B is in slow equilibrium with C and D. The forward rate constant for A/B going to C+D gives a half-life of approximately 2 h at 37 °C. At equilibrium the mixture is stable for at least 2 days. At pH 6.0, hydrolysis proceeds with first-order kinetics to epidoxorubicin and formaldehyde with a half- life of 15 min at 37 °C. Epidoxoform and epidoxorubicin plus formaldehyde react with the self-complementary DNA octamer (GC)4 to yield five drug-DNA adducts which have structures analogous to the doxorubicin-DNA adducts from reaction of Doxoform with (GC)4. Epidoxoform is 3-fold more toxic to MCF-7 human breast cancer cells and greater than 120-fold more toxic to MCF-7/ADR resistant cells than epidoxorubicin. Epidoxoform in equilibrium with its hydrolysis products is greater than 25-fold more toxic to resistant cells with respect to epidoxorubicin.
The rate of homolysis of adducts of peroxynitrite to the C=O double bond
Merenyi,Lind,Goldstein
, p. 40 - 48 (2002)
Nucleophilic addition of the peroxynitrite anion, ONOO-, to the two prototypical carbonyl compounds, acetaldehyde and acetone, was investigated in the pH interval 7.4-14. The process is initiated by fast equilibration between the reactants and the corresponding tetrahedral adduct anion, the equilibrium being strongly shifted to the reactant side. The adduct anion also undergoes fast protonation by water and added buffers. Consequently, the rate of the bimolecular reaction between ONOO- and the carbonyl is strongly dependent on the pH and on the concentration of the buffer. The pKa of the carbonyl-ONOO adduct was estimated to be 11.8 and 12.3 for acetone and acetaldehyde, respectively. It is shown that both the anionic and the neutral adducts suffer fast homolysis along the weak O-O bond to yield free alkoxyl and nitrogen dioxide radicals. The yield of free radicals was determined to be about 15% with both carbonyl compounds at low and high pH, while the remainder collapses to molecular products in the solvent cage. The rate constants for the homolysis of the adducts vary from ca. 3 x 105 to ca. 5 x 106 s-1, suggesting that they cannot act as oxidants in biological systems. This small variation around a mean value of about 106 s-1 suggests that the O-O bond in the adduct is rather insensitive to its protonation state and to the nature of its carbonyl precursor. An overall reaction scheme was proposed, and all the corresponding rate constants were evaluated. Finally, thermokinetic considerations were employed to argue that the formation of dioxirane as an intermediate in the reaction of ONOO- with acetone is an unlikely process.
Atmospheric sink of β-ocimene and camphene initiated by Cl atoms: Kinetics and products at NOx free-Air
Gaona-Colmán, Elizabeth,Blanco, María B.,Barnes, Ian,Wiesen, Peter,Teruel, Mariano A.
, p. 27054 - 27063 (2018)
Rate coefficients for the gas-phase reactions of Cl atoms with β-ocimene and camphene were determined to be (in units of 10-10 cm3 per molecule per s) 5.5 ± 0.7 and 3.3 ± 0.4, respectively. The experiments were performed by the relative technique in an environmental chamber with FTIR detection of the reactants at 298 K and 760 torr. Product identification experiments were carried out by gas chromatography with mass spectrometry detection (GC-MS) using the solid-phase microextraction (SPME) method employing on-fiber carbonyl compound derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. An analysis of the available rates of addition of Cl atoms and OH radicals to the double bond of alkenes and cyclic and acyclic terpenes with a conjugated double bond at 298 K is presented. The atmospheric persistence of these compounds was calculated taking into account the measured rate coefficients. In addition, tropospheric chemical mechanisms for the title reactions are postulated.
Kinetics of the Reaction of Vinyl Radical with Molecular Oxygen
Knyazev, Vadim D.,Slagle, Irene R.
, p. 2247 - 2249 (1995)
The kinetics of the reaction C2H3 + O2 -> products (reaction 1) has been studied at temperatures 299-1005 K and He densities (3-18)E16 molecule cm-3 using laser photolysis/photoionization mass spectrometry.Rate constants were determined in time-resolved experiments as a function of temperature and bath gas density.The overall rate constant of reaction 1 is independent of pressure within the experimental range and can be described by the Arrhenius expression k1 = (6.92 +/- 0.17)E-12 exp(120 +/- 12 K)/T) cm3 molecule-1 s-1.Experimental results are compared with theoretical predictions, and implications for the mechanism of reaction 1 are discussed.
O(1D) reaction with cyclopropane: Evidence of O atom insertion into the C-C bond
Shu, Jinian,Lin, Jim J.,Wang, Chia C.,Lee, Yuan T.,Yang, Xueming,Nguyen, Thanh Lam,Mebel, Alexander M.
, p. 7 - 10 (2001)
The reaction kinetics of O(1D) with cyclopropane was investigated using the universal crossed molecular beam method. The detailed dynamics of this reaction was explained from the analysis of time of flight spectra and angular distribution of th
Ab initio study on the unimolecular decomposition mechanisms and spectroscopic properties of CH3OF
Apeloig, Yitzhak,Albrecht, Karsten
, p. 9564 - 9569 (1995)
High-level ab initio calculations of the structure, vibrational frequencies, and NMR spectra of the recently isolated methyl hypofluorite, CH3OF, have been carried out. When electron correlation is included in the calculations (but not at the HF level), there is a very good agreement between the experimental and the theoretical IR and NMR spectra. Four different unimolecular decomposition pathways, all leading to CH2O and HF, were studied. Of these, two mechanisms, the synchronous single-step HF elimination and a two-step mechanism via the CH3O? and F? radicals, are predicted to be the most favorable, both having activation free energies of ca. 38 kcal mol-1 at GAUSSIAN 2. A theoretical analysis of the expected kinetic isotope effects between the competing pathways leads to a clear differentiation which can be used in experimental studies.
The Retardation of Methanol Oxidation at a Platinum Electrode in an Acid Solution
Matsui, Hiroshi
, p. 3295 - 3300 (1988)
The rate retardation of the oxidation of methanol at the potential range of about 0.65-0.8 V vs. a reversible hydrogen electrode on a platinum electrode in 0.5 mol dm-3 H2SO4 was studied.The rate retardation of the overall oxidation was caused by that of the oxidation, Reaction D, not via COad.From the relationship among the rate of Reaction D, the COad coverage, and the potentials, three types of rate retardation were found out: Type 1-Reaction D is not accelerated by the potential, and the rate of the reaction is determined by the COad coverage and the methanol concentration.Type 2- the rate of Reaction D decreases at stationary COad coverages as the oxidation is prolonged.Type 3- the rate decreases at COad coverages close to the limiting value.It is proposed that Types 1 and 2 of the rate retardations take place when the adsorption of methanol molecules is rate-determining, and when the formaldehyde and formic acid formed from methanol are accumulated in the vicinity of the electrode, respectively.Type 3 of the rate retardation has been explained in a preceding paper in terms of the aggregate damaging effect of COad.
