Лако-красочные материалы — производство

In many reactions involved in industrial organic chemistry, continu­ous, vigorous stirring of the reaction mixture is absolutely essential for good results. This is especially true if some of the reactants are not in solution in the reaction medium, but are only suspended, in either solid or liquid form. Also, when a precipitate is formed during […]

At one time, the school laboratories of industrial chemistry sought to train students to use the most primitive sorts of apparatus, put to­gether by themselves from the simplest parts. The modem viewpoint is to use not the simplest, but the most suitable, equipment — that which conserves time and effort. To be sure, the simpler […]

It is imperative for the technical chemist to keep an accurate record of all his experiments, and the student should become accustomed to recording all of the work he performs in his laboratory notebook. He should not write up the directions he followed, but should describe the procedure he actually used in sufficient detail so […]

In the organic industrial laboratory the work is almost always done with molecular quantities. Calculations are thus greatly simplified. One — tenth of a gram molecule, or with large molecules one-twentieth, is the commonly used unit in the preparation of end products. This quantity gives enough of the product for the first tests of a […]

General It cannot be overemphasized to the beginner in organic industrial work that absolute cleanliness of work is the first requirement for success, not only in analytical and research laboratories, but also in the industrial laboratory. This applies both to the apparatus and con­tainers and to the materials employed. Keeping the apparatus dean is often […]

Halogen atoms, usually chlorine or bromine (rarely iodine or fluorine1) are generally introduced by the action of the elementary halogen on the compound to be substituted. It is often necessary to use a catalyst; otherwise chlorine adds instead of substitutes (replacing hydrogen). The catalyst most commonly employed is iron (ferric chloride), sometimes iron with a […]

Many methods have been evolved for oxidizing organic compounds. Oxidation may be brought about by: (1) Air, often in the presence of a catalyst. Examples of this method are the preparation of phthalic anhydride from naphthalene by air and vanadium oxide (Wohl’s method, page 171), and the analogous oxida­tion of anthracene to anthraquinone. In the […]

The introduction of amino and alkoxy groups into aromatic mole­cules is frequently accomplished by methods analogous to those used for introducing the hydroxyl group. Thus, for example, nitrochloro- benzene and anthraquinone derivatives in many cases can be trans­formed into amino or alkoxy compounds. The sulfonic acid group can be replaced by an amino group, as […]

The hydroxyl group can be introduced into a molecule in various ways. (1) Fusion of a sulfonic acid with sodium hydroxide. This method is often referred to as “potash fusion,” a term applied when potassium hydroxide was used almost exclusively. The cheaper sodium hydroxide is now almost always used. Dilute or concentrated hydroxide is employed, […]

The reduction most frequently encountered by the dye chemist is the transformation of a nitro compound into an amine, but numerous other reductions play an important role in dye chemistry. The following methods are employed. (1) Reduction with iron and water, with the addition of small amounts of acid (hydrochloric, sulfuric, or acetic acid, and […]