Oxidatively-heating liquid

As commented in Section 7.1, there exist four kinds of gas-permeable oxidatively-heating substances i.e., (1) moisture-containing gas-permeable oxidatively-heating substances, (2) almost dry gas-permeable oxidatively-heating substances, (3) almost dry oxidatively-heating liquids and (4) gas-permeable oxidatively-heating substances, which are each almost dry but include some self-heating component such as hydroperoxide. 

As stated in Preface, whenever the adiabatie oxidatively-heating test is performed for an oxidatively-heating liquid, such as unsaturated fatty acid, the liquid is tested, in principle, in the form of oil-soaked adsorbent cotton at relatively low temperatures, or in the form of oil-soaked glass wool at relatively high temperatures. And, the Tc for a heap of the oil-soaked adsorbent cotton, or that of the oil-soaked glass wool, having some one of the several specific shapes and an arbitrary size, placed in the atmosphere under isothermal conditions, is also calculated in the same manner as applied to the calculation of the 71 for a heap of a gas-permeable oxidatively-heating substance. 

L of an oxidatively-heating liquid is added, by means of a microsyringe, onto about 500 mg of ethyl ether placed in a small beaker. 50 mg of adsorbent cotton is next immersed in the ethyl ether solution to soak up the solution. The solution-soaked adsorbent cotton is allowed to stand at room temperature until ethyl ether has evaporated almost completely. 

For the above reasons, both gas-permeable oxidatively-heating substances and oxidatively-heating liquids are dealt with as gas-permeable oxidatively-heating substances all together herein. 

Heat of combustion is the heat liberated or absorbed when one gram mole of the substance is completely oxidized to liquid water and CO2 gas at one atmosphere and 20°C or 25°C. (Cj-C hydrocarbons and cyclohexane at 25°C, others at 20°C). The gross heating value in Btu/ft could be calculated as follows ... 

The violent or explosive reactions exhibited by glycerol in contact with many solid oxidants are due to its unique properties of having three centres of reactivity, of being a liquid which ensures good contact, and of high boiling point and viscosity which prevents dissipation of oxidative heat. The difunctional, less viscous liquid glycols show similar but less extreme behaviour. 

Puri and collaborators (3d, 59) found that the amount of CO2 given off on heating to 1200° was always equivalent to the Ba(OH)2 or NaOH neutralization. Evolution of COj was complete between 750 and 900°. Samples oxidized in liquid medium evolved more COg in relation to CO on heating than did samples treated with oxygen (3d, 55). Puri and Bansal (59) suggested that the neutralization of alkali was caused by carbon dioxide chemisorbed on the carbon surface ( COg complex ). If carboxyl groups were responsible, 1 mole of COg should be formed for each equivalent of alkali consumed. The author of this article thinks, as will be shown below, that very likely carboxyl groups of different environment are responsible for bicarbonate and carbonate neutralization as well as COg evolution. 

In dynamic flash combustion, the tin-encapsulated sample is dropped into the preheated furnace shortly after the flow of a 50 vol% O2/50 vol% He mixture is started (Figure 27-8). The Sn capsule melts at 235°C and is instantly oxidized to Sn02, thereby liberating 594 kJ/mol, and heating the sample to 1 700°-l 800°C. If the sample is dropped in before very much Oz is present, decomposition (cracking) occurs prior to oxidation, which minimizes the formation of nitrogen oxides. (Flammable liquid samples would be admitted prior to any 02 to prevent explosions.)... 

SAFETY PROFILE Poison by intraperitoneal route. Flammable liquid and very dangerous fire hazard when exposed to powerful oxidizers, heat or open flame. When heated to decomposition it emits toxic fumes of NOx. See also AMINES. 

For the heat generation data of a chemical of the TD type, irrespective of liquid and powdery, including every gas-permeable oxidatively-heating substance, refer to Sections 2.4. 

For the heat transfer data of an arbitrary volume of a liquid charged in an arbitrary container and placed in the atmosphere under isothermal conditions, refer to Subsection 5.3.2. For the heat transfer data of a powdery chemical of the TD type, including every gas-permeable oxidatively-heating substance, having an arbitrary shape and an arbitrary size, placed in the atmosphere under isothermal conditions, refer to Section 6.2. 

When a small-scale chemical of the TD type, irrespective of liquid and solid, including every small-scale gas-permeable oxidatively-heating substance, the diameter of which is of the order of, say, 10 mm, is charged, or confined, in some one of the open-cup, the draft or the closed cell, in accordance with the self-heating property of the chemical, and subjected to either of the above-mentioned two kinds of adiabatic tests, the spatially uniform distribution of temperature is effected necessarily in the chemical so it is done, while the selfheating process is, in particular, in the early stages. 

An air bath is adopted instead of a liquid bath, considering that the heat capacity of the former is much smaller than that of the latter. That the heat capacity of the bath is small means that it is possible to heat the atmosphere in the adiabatic jacket, which is set in the air bath, at a rate high enough to follow a rapid increase in temperature of 2 cm of a chemical of the TD type, including every gas-permeable oxidatively-heating substance, in the two kinds of adiabatic tests. 

As a matter of fact, however, the experimental procedure explained in the present section is, in principle, in common with (1) the procedure for 2 cm of a non-volatile liquid or powdery chemical of the TD type charged in the open-cup cell, which is explained in Section 5.4, and (2) the procedure for 2 cm of a gas-permeable oxidatively-heating substance charged in the draft cell, which is explained in Section 7.4 and in Subsection 8.4.1, as well as (3) the procedure... 

In order to compare the values of Tc calculated each for the ten organic liquid peroxides charged each in the container and placed each in the atmosphere under isothermal conditions with one another, however, it is required to calculate the individual values of T assuming that these peroxides are each placed under the same conditions of shape and size. The same is true of powdery chemicals of the TD type and of gas-permeable oxidatively-heating substances. 

The draft cell and the touch-flow cell, in the four kinds of cells, are used exclusively in the adiabatic oxidatively-heating test. In this regard, the open-cup cell, one of the three kinds of open cells, is used only in the adiabatic selfheating test performed for a non-volatile liquid chemical, or powdery chemical, of the TD type at atmospheric pressure. 

In Chapter 3, a classification of self-heating chemicals, except gas-permeable oxidatively-heating substances, is introduced. Treatments of gas-permeable oxidatively-heating substances are made in Chapters 7 and 8. Self-heating chemicals are divided into two large groups, i.e., the thermal decomposition or TD type and the autocatalytic reaction or AC type. The TD type is subdivided into liquid chemicals, for each of which the Semenov equation is applied to calculate the Tc, and, solid (powdery, in reality) chemicals, for each of which the F-K equation is applied to calculate the Tc. On the other hand, the AC type is subdivided into high explosives of the true AC type and powdery chemicals of the quasi-AC type. 

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