Naphthalene vapors

Toxicology. The acute oral and dermal toxicity of naphthalene is low with LD q values for rats from 1780—2500 mg/kg orally (41) and greater than 2000 mg/kg dermally. The inhalation of naphthalene vapors may cause headache, nausea, confusion, and profuse perspiration, and if exposure is severe, vomiting, optic neuritis, and hematuria may occur (28). Chronic exposure studies conducted by the NTP ia mice for two years showed that naphthalene caused irritation to the nasal passages, but no other overt toxicity was noted. Rabbits that received 1—2 g/d of naphthalene either orally or hypodermically developed changes ia the lens of the eye after a few days, foUowed by definite opacity of the lens after several days (41). Rare cases of such corneal epithelium damage ia humans have been reported (28). Naphthalene can be irritating to the skin, and hypersensitivity does occur. 

Because naphthalene vapors can cause eye irritation at concentrations of 15 ppm in air and because continued exposure may result in adverse effects to the eye, a threshold limit value of 10 ppm (50 mg/m ) has been set by the ACGIH (45). This amount is about 30% of the air-saturation value at 27°C. 

Naphthalene sodium, 22 764 preparation of, 22 778 Naphthalene sulfonates, 17 83-84 24 146 Naphthalene vapors, inhalation of,... 

Figure 3. Slow dissociation of naphthalene-dg ions resolved by TRPD. Naphthalene ions were generated by multiphoton ionization of naphthalene vapor at 193 nm. After thermalization for about 5 s at 3 x 10 torr, they were photoexcited by two photons at 355 nm, using an 8-ns pulse from the Nd YAG laser. The plots show the extent of fragment ion signal observed at several delay times following the laser pulse and the competitive slow fragmentation to give the C,oD7, CioDj, and CgDj products.

In the case of dimethylaniline, which possesses the lowest Ip (7.14 e.v.), there are at a photon energy of 11.0 e.v. four maxima on the distribution curve. For naphthalene vapor at a photon energy of 11.2 e.v., five maxima on the distribution curve are present. 

As in Section IV for naphthalene vapor, the kinetic spectra of solids are presented by plotting on the abscissa axis the quantity Ep = (hv — incident photon,

work function of the solid (energy of electron abstraction). Ekin is the photoelectron kinetic energy, which is lower than the theoretical upper energy limit of kinetic energy because of internal energy... 

Compressed air and o-xylene or naphthalene vapor are mixed in an approximately 20 1 ratio and oxidized at 400°C. The product phthalic anhydride is recovered by condensation and purified by vacuum distillation. Maleic anhydride, a byproduct in both oxidations may be recovered from the waste gases in the form of maleic acid after water scrubbing. 

Fig. 6. The fluorescence spectrum of naphthalene vapor reported by Watts...

Naphthalene.—Wilde2 also investigated the behavior of naphthalene vapor under reduced pressure when subjected to-the action of the induction spark. He obtained a gas mixture containing acetylene. 

In the naphthalene vapor spectrum, the combination of extensive sequence structure, extending for the Si Bgw) system more than 200 cm-1 to the red of... 

Assumptions 1 The low mass flux conditions exist so that the Chilton-Colburn analogy between heat and mass transfer is applicable (v/ill be verified). 2 Both air and naphthalene vapor are ideal gases. 

Mice exposed to naphthalene vapor at concentrations as high as 30 ppm in air for 6 h a day, 5 day a week for 104 weeks developed nose and lung lesions. These lesions were described as nose inflammation accompanied by metaplasia and hyperplasia of the olfactory and respiratory epitheliums. 

Example Estimate the low-pressue thermal conductivity of naphthalene vapor at 500 K. 

The pink coloration, produced on silica-alumina in the presence of naphthalene vapor at 20°C, is due to a broad band with sharp maxima... 

Patent claims have been made for the formation of benzene and maleic anhydride with benzoquinone as a by-product by the oxidation of naphthalene.2 For the formation of benzene an example is given in which a mixture of air and naphthalene vapor are passed over a vanadium oxide catalyst at 400° C., the reaction products cooled to 380° C. and then passed over a catalyst containing the oxides of cadmium and aluminum. For the formation of maleic anhydride a mixture of air and naphthalene vapor... 

Figure 57 shows a general layout for the phthalic anhydride process. Air compressed to 30 or 40 pounds per square inch gage is filtered and preheated, mid then passed through the naphthalene vaporizer. The naphthalene vaporizer consists of a steam-jacketed pot fitted with baffle plates, a distributor for admitting the necessary air, and an outlet for the naplitlialcne-air mixture. No attempt is made to saturate the air with naphthalene at the temperature of the saturator, but steady conditions are maintained and secondary air is admitted to the stream before it enters the... 

Air at the rate of 35 to 40 thousand cubic feet (room temperature) per hour and carrying the correct amount of naphthalene vapor from the vaporizer enters the catalytic converter from the top and passes downward through the thousand or more individual catalyst tubes. The entering air-vapor mixture first becomes preheated in passing through the empty upper portion of the tubes by the condensing mercury vapors until a temperature... 

In the B6C3Fj mouse studies, animals were exposed to naphthalene vapors at 0, 10, or 30 ppm 6 hr/day, 5 days/wk for 2 yr, and an increased incidence of alveolar/bronchiolar adenoma was observed in the 30-ppm group of female mice (NTP, 1992, Abdo et al, 1992). 

Abdo, K.M., S. Grumbein, B.J. Chou, and R. Herbert. 2001. Toxicity and carcinogenicity study in F344 rats following 2 years of whole-body exposure to naphthalene vapors. Inhal. Toxicol. 13(10) 931-950. 

Figure 1. Excitation energy dependence of dispersed fluorescence in naphthalene vapor. (From ref. [6] with permission.)... 

Figure 12. Relative quantum yield of sensitized phosphorescence of biacetyl (top), and nonradiative decay rate of naphthalene vapor (bottom), as a function of the excess vibrational energy in Sl naphthalene. (From ref. [40] with permission.)...

EXPLOSION and FIRE CONCERNS combustible NFPA rating Health 0, Flammability 2, Reactivity 0 flammable liquid when exposed to heat or flame reacts violently with chromic anhydride and naphthalene vapor is explosive when exposed to heat or flame or ehro-mium (III) oxide burning may increase hazardous vapor levels incompatible with potassium permanganate salts of any kind should not be added to camphor water use dry chemical, foam, or carbon dioxide for firefighting purposes. 

The hydrocarbon naphthalene was frequently used in mothballs until recently, when it was discovered that human inhalation of naphthalene vapors can lead to hemolytic anemia. Naphthalene is 93.71% carbon by mass, and a 0.256-mol sample of naphthalene has a mass of 32.8 g. What is the molecular formula of naphthalene This compound works as a pesticide in mothballs by sublimation of the solid so that it fumigates enclosed spaces with its vapors according to the equation... 

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