Potassium-40 heat source

Cyanate. Potassium cyanate, [CAS 590-28-3], KCNO, white solid, soluble, formed along with lead metal by reaction of potassium cyanide and lead monoxide solids upon heating. Source of cyanate. 

B. Azetidine. A stirred mixture of 38 g. (0.68 mole) of potassium hydroxide pellets in 100 ml. of white mineral oil (Note 8) is heated to 140-150° in a four-necked 500-ml. round-bottomed flask, fitted with an air-driven Hershberg stirrer, a thermometer, a dropping funnel, and a 6-in. Vigreux column fitted with a vacuum-distillation head. The flask is removed from the heat source, and 50 g. (0.32 mole) of purified l-(2-carbethoxyethyl)azetidine is added dropwise at a rate sufficient to maintain the reaction temperature at 150° (Note 9). After addition is complete, the reaction mixture is heated to 200° at 50 mm. to remove all traces of ethanol (Note 10). The flask is fitted with a distillation head and a nitrogen bubbler, and the distillation is resumed at atmospheric pressure until azetidine distills (210° maximum pot temperature) (Note 11). The resulting product (19.6 g., 85% purity) is dried over potassium hydroxide and redistilled through a short Vigreux column to furnish 14.5-15.8 g. (80-87%) of purified azetidine, b.p. 62-63° (Note 12). 

CHAPTER 21 THE PREPARATION OF NITRO PARAFFINS AND THEIR DERIVATIVES potassium salt will begin to precipitate. After the heating process, remove the heat source, and allow the reaction mixtureto cool to room temperature. Then, pi ace the reaction mixture into an ice water bath for 30 to 50 minutes. After which time, filter-off the potassium salt, and then vacuum dry or air-dry the product. The result will be about 12gramsof relatively pure potassium nitroform. 

As a possible radiogenic heat source in the Earth, the presence of an appreciable amount of potassium in the core was suggested over 30 years ago (Lewis, 1971 Hall and Murthy, 1971). The estimated concentration of potassium in the mantle is 240 ppm (McDonough and Sun, 1995). If the concentration of potassium in the core is at a comparable level, the present-day heat production due to would be on the order of 10 W, enough to drive the geodynamo. Radiogenic heat production due to also has direct implications for convection in the outer core, heat flux at the CMB, and the dynamics of the lower mantle. Recent studies of plume dynamics and considerations of the age of the inner core have inspired a renewed interest in the potassium content of the core (Murthy et ai, 2003, and references therein see Chapter 2.15). 

Murthy R., van Westrenen W., and Fei Y. (2003) Experimental evidence that potassium is a substantial radioactive heat source in planetary cores. Nature. 423, 163-165. 

Sanders, Robert. Radioactive Potassium May Be Major Heat Source in Earth s Core. Available online. URL berkeley.edu/ news/media/releases/2003/12/10 heat.shtml. Accessed on August 5, 2009. This press release from the University of California, Berkeley, describes an experiment that has simulated conditions deep beneath Earth s crust and tested a geodynamo model involving potassium 40. 

Use a balance to measure the mass of 1.0 g of potassium nitrate CKNO3). Add the KNO3 to Test Tube 1. WARNING Keep all chemicals used in this lab away from heat sources. 

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