Temperature spontaneity

Flammability information Flash point Fire point Flammable limits (LEL, UEL) Ignition temperature Spontaneous heating Toxic thermal degradation products Vapour pressure Dielectric constant Electrical resistivity Electrical group Explosion properties of dust in a fire... 

Thermal insulation (or lagging) on plant equipment may become soaked or impregnated witli oils and otlier flanuiuible liquids. When the lagging gets hot, spontaneous combustion can occur. Lagging fires are affected by oil laiks, insulation material, and temperature. Spontaneous combustion occurs only when tlie oil is nonvolatile, since volatile oil evaporates more easily, tlius delaying tlie... 

Ignition temperature Spontaneous heating Toxic thermal degradation products... 

Figure 3 Landau free energy at different temperatures. Spontaneous symmetry breaking occurs fort < 0, giving rise to a second-order phase transition at t=0.

If a container with styrene monomer is subjected to a large heat flux, for example, fire or steam, the polymerization of the monomer causes the temperature to rise. At a certain elevated temperature, spontaneous decomposition of the styrene monomer and/or its polymer starts. This secondary decomposition process generates twice as much energy as the polymerization process itself. 

Polonium may be purified by various processes. Such purification methods include precipitation of polonium as sulfide and then decomposing the sulfide at elevated temperatures spontaneous decomposition of polonium onto a nickel or copper surface and electrolysis of nitric acid solutions of polonium-bismuth mixture. In electrolytic purification polonium is electrodeposited onto a platinum, gold, nickel, or carbon electrode. 

When the mixture ceases to maintain its temperature spontaneously at 95-100°, heat is applied cautiously until the temperature reaches 110°. About 13 cc. of nitromethane and 200 cc. of water distil over. Further distillation gives water which contains too little nitromethane to pay for recovery. At this point enough sodium chloride and sodium carbonate have separated to cause serious bumping. 

Crystallization of supercooled fat in topping powders may be studied by NMR afterreconstitution in heavy water. Below room temperature spontaneous fat crystallization takes place under isothermal conditions in the presence of effective emulsifier (PGMS) but not with ineffective emulsifiers or without emulsifiers (Figure 4). 

The dust from the hay collects in the bam. The dust reacts with oxygen. The reaction generates heat which raises the temperature to ignition temperature. Spontaneous combustion occurs. When a haystack catches fire outdoors, the heat is liberated well inside the haystack. The heat is generated by the action of bacteria that decompose the hay. The heat released by this starts a fire. 

A similar resolution has also been achieved on large scale <20040PD22>. The KR of racemic isoxazoline 312 catalyzed by enzymes was studied. The best result was obtained with lipase B from Candida antarctica (CALB), which hydrolyzed the ethyl ester of (—)-312 to the corresponding monoacid (—)-313. The reaction, which was run in 0.1 M phosphate buffer/acetone at room temperature, spontaneously stopped at 50% conversion to yield monoacid (—)-313 and the residual ester (- -)-312 with ees higher than 99% <2004TA3079>. The C-5 epimer of 312 underwent enantioselective hydrolysis (>99% ee) of the methyl ester linked to C-5 in the presence of the protease proleather (subtilisin Carlsberg), whereas CALB and other lipases were not able to resolve it (Equation 53). 

Analogous oxidation of selenoglycosides has been used to directly synthesize glycals due to the low temperature spontaneous sy -elimination of seienoxides [161,162]. 

INTRODUCTION PRESSURE AND TEMPERATURE SPONTANEOUS STRAIN Experimental methods Fitting high-pressure lattice parameters Calculating strains ELASTICITY OTHER TECHNIQUES ACKNOWLEDGMENTS APPENDIX... 

Oximes and oxime ethers exist as a mixture of E and Z isomers with a relatively low difference of AG° and a moderate energy barrier to isomerization (<10 kcal mol-1) [28]. They show some similarities with imines and may interconvert at room temperature, spontaneously, by an acid- or base-catalyzed isomerization involving a nitronium ion, and photochemically [29,30]. Oxime ethers have been employed as amide surrogates in peptides where they display a marked Z-E isomerism which is mainly controlled by the formation of H-bonds, which stabilize a given isomer. As an example, the structure of pseudopeptide 6 was investigated by Fourier transform infrared spectroscopy (FTIR) and NMR spectroscopy which both showed that Z-6 is folded in a /Mike conformation by a strong bifurcate hydrogen bond whereas the E isomer adopts an extended conformation (Fig. 13.5) [31]. 

Addition of 95% ethyl acetimidate (94 g, 1.02 mol) to 2-methylisourea hydrochloride (37.8 g, 341 mmol) caused a moderately exothermic reaction the temperature spontaneously rose to the bp in 10 min. The mixture was held at a gentle reflux by cooling and, after the reaction had subsided, was allowed to cool unaided for 1.5 h. Crystalline acetimidamide hydrochloride (25 g, mp 165-170 °C) was separated by filtration and the filtrate was fractionally distilled. After a forerun of 2,4,6-trimethyl l,3,5-triazine [yield 12.3 g (10%)]. the title compound was obtained (— 80°C/ 3 Torr) yield 34.6 g (73%) mp 43.5 C. The distillation residue (8 g) was nearly pure acetimidamide hydrochloride. 

Exchange studies have shown, among other things, that the 3-chloropropyl-alanes are unstable even at room temperature. Spontaneous decomposition occurs to give cyclopropane and the aluminum halide ... 

Fig. 8. Room-temperature spontaneous magnetization values ( saturation intrinsic induction ) of transition metal-rich RE-TM(-B) compounds of interest for permanent magnets.

QN3 MP,-45°C BP, 15°C Room temperature Spontaneous explosions at room temperature 335,336... 

When a supersaturated aqueous solution of this compound was left to stand at room temperature, spontaneous resolution took place... 

---