Argon flash

Initiation by Light. Neither Deb (quoted in Ref 19, p 111) nor the writer (Ref 47) could produce detonation of PETN exposed to high-intensity light. The writer used PETN cores at 0.8 to 1.5g/cc, with and without small additions of graphite (in attempts to increase light absorbency), in 1 /4 inch ID plastic holders, and exposed them up to around 25microsec to the radiation of Argon flash bombs (T=29000°K). 

The production of NOz, with NO as a possible precursor to NOz, has been observed when synthetic air or 02/N2 mixtures are photolyzed using a deuterium lamp, an argon flash lamp, or a 185-nm mercury line (Zipf and Prasad, 1998a). They proposed that this occurs from the reaction of electronically excited 02(B%) with N2, or photodissociation of 02 N2 dimer, and that the rate of NOx production from this process could be comparable to that from reaction (13b) (Zipf and Prasad, 1998a Prasad, 1998). If this proves to be the case, there must be some unidentified NOx sinks to be consistent with the measured NOx concentrations in the upper atmosphere. 

Recovery of Argon Flash Vapors. Argon like helium is a highly expensive industrial gas. Its cost is about 3.00 per 100 SCF to large consumers and much higher to moderate and smaller consumers. 

Fiber-Optic Pins. In one version of the fiber-optic pin (Benjamin et al., 1984), a small microballoon, 0.25 mm in diameter, filled with a noble gas such as argon or xenon is attached to the end of an optical fiber. When the pin is impacted, the shock heats the gas in the microballoon producing a flash which is channeled to a recording system via optical fibers. Some of the useful features of this pin are... 

A solution of 3.7I g (0.013 mol) of tributyltin hydride in 10 mL benzene is added dropwise to a solution of 3.09 g (0.011 mol) of S-[(S)-4-(benzyloxy)-3-pentenyl] 5-methyl carbonodithioate in 25 mL of degassed, anhyd benzene under an atmosphere of argon, followed by 5 mg of AIBN. The mixture is heated under reflux for 2.5 h and then is concentrated under reduced pressure. Flash chromatography of the residue using ht,0/petroIeum ether 1 50 containing 1 % triethylamine as eluant gives a colorless oil yield 3.87 g (78%) [a] - 26 (e = 1. CHCl3). 

A flame-dried flask under argon containing a 0.08 M THF solution of 317 mg (1.0 mmol) of the 2-(l- or 2-naphthyl)-substituted 4,5-dihydrooxazole is cooled to a temperature of between — 80 and 0 CC (see ref 7) and is treated with 1.5-2.0 equiv of the alkyllithium. The solution becomes deep red over 2-4 h and is quenched by the dropwise addition of 1.5 equiv of the electrophile (either neat or as a THF solution). The temperature is maintained for 1 h and then the solution is warmed gradually to 0 JC. The solution is diluted with 100 mL of diethyl ether and washed with 5 mL of sat. NH4C1, followed by 3 mL of sat. aq NaCI. The combined aqueous layers are back-extracted with 10 mL of CII2C12, and the combined extracts are dried over Na2S04. Concentration of the filtrate in vacuo provides a yellow oil, which is flash chromatographed over silica gel (1 -10% ethyl acetate in hexane) to yield the desired adducts. The diastereomeric ratios are determined by HPLC (Zorbax Sil column, Du Pont). 

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