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Chemical Industrycolumn函数的使用方法
1.Origins of the Chemical Industry
Although the u of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe u by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that the are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin’s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on rearch on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was bad on the discovery of new dyestuffs plus the development of both the contact process for sulp
吃完饭打嗝是什么原因huric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly incread demand for nitrogen-bad compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world war奋斗格言经典短句Ⅰin 1914. This initiated profound changes which continued during the inter-war years (1918-1939).
做人留一线Since 1940 the chemical industry has grown at a remarkable rate, although this has slowed significantly in recent years. The lion’s share of this growth has been in the organic chemicals ctor due to the development and growth of the petrochemicals area since 1950s. The explosives growth in petrochemicals in the 1960s and 1970s was largely due to the enormous increa in demand for synthetic polymers such as polyethylene, polypropylene, nylon, polyesters and epoxy resins.
The chemical industry today is a very diver ctor of manufacturing industry, within whi
ch it plays a central role. It makes thousands of different chemicals which the general public only usually encounter as end or consumer products. The products are purchad becau they have the required properties which make them suitable for some particular application, e.g. a non-stick coating for pans or a weedkiller. Thus chemicals are ultimately sold for the effects that they produce.
人的性格分类2. Definition of the Chemical Industry
中考什么时候At the turn of the century there would have been little difficulty in defining what constituted the chemical industry since only a very limited range of products was manufactured and the were clearly chemicals, e.g., alkali, sulphuric acid. At prent, however, many intermediates to products produced, from raw materials like crude oil through (in some cas) many intermediates to products which may be ud directly as consumer goods, or readily converted into them. The difficulty cones in deciding at which point in this quence the particular operation ceas to be part of the chemical industry’s sphere of activities. To consider a specific example to illustrate this dilemma, e
mulsion paints may contain poly (vinyl chloride) / poly (vinyl acetate). Clearly, synthesis of vinyl chloride (or acetate) and its polymerization are chemical activities. However, if formulation and mixing of the paint, including the polymer, is carried out by a branch of the multinational chemical company which manufactured the ingredients, is this still part of the chemical industry of does it mow belong in the decorating industry?
It is therefore apparent that, becau of its diversity of operations and clo links in many areas with other industries, there is no simple definition of the chemical industry. Instead each official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as the chemical industry. It is important to bear this in mind when comparing statistical information which is derived from veral sources.
3. The Need for Chemical Industry
The chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates and then into a tremendous variety of other chemicals.
The are then ud to produce consumer products, which make our lives more comfortable or, in some cas such as pharmaceutical produces, help to maintain our well-being or even life itlf. At each stage of the operations value is added to the produce and provided this added exceeds the raw material plus processing costs then a profit will be made on the operation. It is the aim of chemical industry to achieve this.空对空导弹打一成语是什么
It may em strange in textbook this one to po the question “do we need a chemical industry?” However trying to answer this question will provide(ⅰ) an indication of the range of the chemical industry’s activities, (ⅱ) its influence on our lives in everyday terms, and (ⅲ流苏是什么) how great is society’s need for a chemical industry. Our approach in answering the question will be to consider the industry’s contribution to meeting and satisfying our major needs. What are the? Clearly food (and drink) and health are paramount. Other which we shall consider in their turn are clothing and (briefly) shelter, leisure and transport.
(1)Food. The chemical industry makes a major contribution to food production in at least three ways. Firstly, by making available large quantities of artificial fertilizers which are us
ed to replace the elements (mainly nitrogen, phosphorus and potassium) which are removed as nutrients by the growing crops during modern intensive farming. Secondly, by manufacturing crop protection chemicals, i.e., pesticides, which markedly reduce the proportion of the crops consumed by pests. Thirdly, by producing veterinary products which protect livestock from dia or cure their infections.
