Catalyst

“ The tactful hostess, the salon leader, is a social catalyst. The trouble with catalysts, either human or metallic, is that they are rare and that sometimes they get sulky and won't work if the ingredients they are supposed to mix are unsuitable.
But the uranium, osmium, platinum or whatever metal is used as a catalyzing agent is expensive and although it is not used up it is easily "poisoned," as the chemists say, by impurities in the gases. The nitrogen and the hydrogen for the Haber process must then be prepared and purified before trying to combine them into ammonia. ”

“ At the same time it acquires an odor—familiar to us when we are curing a cold—that neither of the original gases had. The agent that effects the transformation in this case is not the electric spark—for this would tend to work the reaction backwards—but uranium, a rare metal, which has the peculiar property of helping along a reaction while seeming to take no part in it. Such a substance is called a catalyst. The action of a catalyst is rather mysterious and whenever we have a mystery we need an analogy. We may, then, compare the catalyst to what is known as "a good mixer" in society. ”

“ After a moment: "Naturally, this combination decreases the total volume of gas; so the pump has to pull in more hydrogen from outside to satisfy its barystat, and more nitrogen is welling from below all the time. We've been operating quite an efficient little ammonia factory down there, though it should reach equilibrium as to pressure and yield pretty soon.
"The Haber process catalyst, incidentally, is spongy iron with certain promoters—potassium and aluminum oxides are excellent ones. ”

“ Considering that the catalyst to the chemical reaction only effects the rate of reaction and yield by participating in the reaction while remaining as it is after the reaction and does not contribute to the chemical composition of the target material, the unity of the technical composition of the manufacturing method invention as well as the consistency of the sequential organic relationship when producing a particular target material by adding a reactant to an initial material is not lost when adding the catalyst in the invention to the manufacturing method of the chemical material. ”

“ For that reason the catalyst is referred to as "a chemical parson." Finely divided metals have a strong catalytic action. Platinum sponge is excellent but too expensive. So in this case nickel is used. A nickel salt mixed with charcoal or pumice is reduced to the metallic state by heating in a current of hydrogen. Then it is dropped into the tank of oil and hydrogen gas is blown through. The hydrogen may be obtained by splitting water into its two components, hydrogen and [Pg 205] oxygen, by means of the electrical current, or by passing steam over spongy iron which takes out the oxygen. ”

“ Subsequent work has shown that other organisms act by the enzymes they contain, so that it is now recognized that there is no essential difference between the living or organized ferment and the non-living or unorganized ferment. All ferments probably act as catalysators or catalysts. Catalysis is the process by which reactions are either initiated or accelerated by the mere presence of certain substances which remain unchanged during the process ”

“ A catalyzer is a substance which changes the velocity of a reaction, but does not change its products.
Examples of Catalysis. We have already had several instances of such action. Oxygen and hydrogen combine with each other at ordinary temperatures in the presence of platinum powder, while if no catalytic agent is present they do not combine in appreciable quantities until a rather high temperature is reached. Potassium chlorate, when heated with manganese dioxide, gives up its oxygen at a much lower temperature than when heated alone. ”

“ We must content ourselves with saying that most modern producers are of the form of a tower in which a thick bed of fuel is partially burnt and partly gasified under the action of a blast of air mixed with steam. The chemical actions that take place are complicated, but the final result is the production of a gas containing from 2 to 8 or 10 per cent. of carbonic acid, 10 to 20 per cent. of hydrogen, 8 to 25 per cent. of carbonic oxide (CO) , 1 to 3 per cent. methane (CH4) , and 45 to 60 per cent. of nitrogen, with varying quantities of moisture, tarry matter, and ammonia. ”

“ In wood, coal, oil, tallow, and spirits of wine; in everything in short that we call combustibles, because the name of combustion has been given to this marriage of oxygen with other bodies, hydrogen and carbon keep themselves shut up very discreetly and very quietly; like two children playing at hide-and-seek. You have sometimes played at hide-and-seek yourself, no doubt? ”

“ Thus, if we regard a mixture of hydrogen oxygen, and vapor of water as an ideal gas-mixture, for a mixture containing any given quantities of these three gases at any given temperature there will be a certain volume at which the mixture will be in a state of dissipated energy. In such a state no such phenomenon as explosion will be possible, and no formation of water by the action of platinum. (If the mass should be expanded beyond this volume, the only possible action of a catalytic agent would be to resolve the water into its components.) ”

“ Acids and bases appear to act catalytically upon all reactions involving consumption or liberation of water, and indeed that action is proportional to the concentration of the hydrogen or hydroxyl-ions. Further, the decomposition of hydrogen peroxide is “catalysed” by iodine-ions, the condensation of two molecules of benzaldehyde to benzoin by cyanogen-ions. One of the earliest known and technically most important instances of catalysis is that of the oxidation of sulphur dioxide to sulphuric acid by oxygen in the presence of oxides of nitrogen. ”

“ A catalyzer is a stimulus which excites a transformation of energy. The catalyzer plays the same rôle in a chemical transformation as does the minimal exciting force which sets free the accumulation of potential energy previous to its transformation into kinetic energy. A catalyzer is the friction of the match which sets free the chemical energy of the powder magazine. ”

“ The effect of a catalytic agent on the diagram is to obliterate the ridge between two depressions representing different states of equilibrium on the free energy surface. This means that a system disturbed by a catalytic agent may pass from a higher to a lower minimum of free energy, but never from a lower to a higher unless acted upon by external forces of considerable magnitude. ”

“ Just as the mechanical skill of the engineer enables him to construct an engine out of the raw material iron, which is extracted from its ore, and converted into steel by chemical processes, so the skill of the chemist enables him to build up complex colouring-matters, &c., out of the raw materials furnished by tar, which is obtained from coal by chemical decomposition.
The illuminating gas which is obtained from coal by destructive distillation consists chiefly of hydrogen and gaseous hydrocarbons, the most abundant of the latter being marsh gas. ”

“ Physical research has proved to us that all bodies have peculiar powers, by which they condense with varying degrees of force gases and vapours upon their surfaces; every body in nature may, indeed, be regarded as forming its own peculiar atmosphere. To this power, in all probability, does catalysis belong. Different views have, however, prevailed on this subject, and Dr. Lyon Playfair [207] argues that the catalytic force is merely a modified form of chemical affinity, exerted under peculiar conditions. ”

“ Of other theories of catalysis the most important is that of Ostwald himself, summed up in his famous definition: A catalytic agent is one which modifies the velocity of a chemical reaction without appearing in its final process. This statement introduces two new ideas, the notion of infinite swiftness and infinite slowness in chemical change and the fact that catalytic change may be brought about by a series of intermediate reactions. ”

“ For fuel a pound of coal is about equal to two pounds of wood, and a pound of gasoline to three pounds of wood in heating value, so there would be a great loss in efficiency and economy if the world had to go back to a wood basis. But when that time shall come, as, of course, it must come some time, the wood will doubtless not be burned in its natural state but will be converted into hydrogen and carbon monoxide in a gas producer or will be distilled in closed ovens giving charcoal and gas and saving the by-products, the tar and acid liquors. ”

“ A few examples will be sufficient. By the combustion [xxv] of metals, iron for instance, we obtain a fixed product, and in the present case an oxide of iron; by the combustion of antimony and arsenic, the antimonic and arsenic acids; by the combustion of charcoal, we have carbonic acid gas, a gaseous product; by the combustion of potassium or sodium, we obtain a fixed alkali, depending however on the quantity of oxygen; by the combustion of sulphur, phosphorus, &c. acids; and when metals are burnt in chlorine gas, chlorides are produced. ”

“ This is catalysis, and Gibbs's definition of a catalytic agent—one capable of reducing a substance to a phase of dissipated energy without limitation as to their relative proportions—is characteristic of the mathematician. A chemical system at constant temperature has several states of equilibrium corresponding to different minima of its isothermal potentials, and on the solid diagrams of Gibbs these minima are valleys at the bottoms of sloping curves. ”

“ Illuminating gas is obtained by the dry distillation of coal. The products of distillation are subjected on the gasworks to several purifying processes, such as condensation in coolers, moist and dry purifying, from which valuable bye-products (such as tar, ammonia, cyanogen compounds) are obtained. The purified gas is stored in gas holders containing on an average 49 per cent. hydrogen, 34 per cent. methane, 8 per cent. carbonic oxide, 1 per cent. carbon dioxide, 4 per cent. nitrogen, and about 4 per cent. ”

“ We may also mention the interesting work of Dixon and Baker, which led to the discovery that a large number of gas-reactions, e.g. the combustion of carbon monoxide, the dissociation of sal-ammoniac vapour, and the action of sulphuretted hydrogen upon the salts of heavy metals, cease when water-vapour is absent, or at least proceed with greatly diminished velocity.
“Negative catalysis,” i.e. the retardation of a reaction by addition of some substance, which is occasionally observed, appears to depend upon the destruction of a “positive catalyte” by the body added. ”

“ But when an inventor devised a machine on runners to move on lubricated rails, a great step was gained, though the invention was not a success, and when, after this, liquid carbonic acid, or carbonic acid ice expanding again to a gas was employed as a motive power, another advance was made. Then the greatest lift of all was given. The solidification of oxygen and hydrogen by an easy process was discovered and mankind presented with a new motive power. ”

“ The gases with their oil content instead of being blown out into the air and burned are conducted through pipes to an intricate apparatus where coal tar, ammonium sulphate, a valuable fertilizing agent, ammonia, and benzol, an important base for high explosives and dyes and also usable as fuel for motor cars, as well as other products are extracted, and the gas itself is made available for use in motor engines54 or in illuminating. More than one city to-day lights its street with the gas from by-product coke plants. ”

“ The discovery of catalytic agents is, as a rule, the result of accident. I do not think that any guide exists which would enable us to predict that any particular substance would cause an acceleration or a retardation of any particular reaction. But catalytic agents are generally those which themselves, by their power of combining with or parting with oxygen, or some other element, cause the transfer of that element to other compounds to take place with increased or diminished velocity. ”

“ In no department of applied science is this truth more forcibly illustrated than in the branch of technology of which I have here attempted to give a popular account. The pure theory of chemical structure—the guiding spirit of the modern science—has been advanced enormously by means of the materials supplied by and resulting from the coal-tar industry. The fundamental notion of the structure of the benzene molecule marks an epoch in the history of chemical theory of which the importance cannot be too highly estimated. ”

“ Ellisen, of the Paris gas-works, have shown that the gases rich in carbon, such as defiant and acetylene, are developed chiefly during an interval of time, beginning half an hour after the commencement and terminating at half the whole period of distillation, while during the remainder of the time, marsh gas and hydrogen are chiefly developed, which, while possessing little illuminating power, are most advantageous for heating purposes. ”

“ A true theory of catalysis will enable us to solve the problem of the transmutation of the elements, of which we have already had examples in the substances derived from radium, and the recent derivation of tellurium from copper by Sir William Ramsay. The action of animal and vegetable protoplasm is probably catalytic and the chemist can now make some vegetable substances, such as indigo or alizarine, more cheaply and purely than the plants themselves do. ”

“ Fairbanks-Morse Producer Plant and Engine, Connected for Operation.
In practical work, the natural fuels are coal, mineral oils, natural gas, and wood, which are compounds of the elements carbon and hydrogen. When these fuels are burned to their lowest forms the products of combustion consist of carbon dioxide and water, the first being the result of the oxydization of carbon, and the latter a compound of oxygen and hydrogen. ”