Introduction to Modern Therapeutics

Introduction to Modern Therapeutics

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...united by double and single affinities, while others have proposed connections between atoms on opposite sides of the ring. Benzene. H H H C C C POSITION IN BENZENE COMPOUNDS. 89 We must bear in mind that this ring is simply hypothetical, but it gives us a convenient means both of representing aromatic substances and of studying their relationship. Whatever the real nature of the connection may be, it appears that the benzene nucleus is symmetrical; and that if we replace an atom of hydrogen in it by hydroxyl, chlorine, methyl, or any other radical, the product is the same whichever atom of hydrogeD be replaced. 6 oa ocl (Monochlor-benzene.) But if we replace a second atom the case is different, for the fact that one atom in the original nucleus has been already replaced has rendered the nucleus unsymmetrical. If the second replacement occurs on a carbon atom-next to the first' it is represented in a formula by the figures i: 2, and is said to be in the ortho position. CI CI Clr or jfTsd (Ortho-dichlor-benzene.) If on the next atom but one it is represented in a formula by 1: 3, and is said to be in the meta position. Cl Q (Meta-dichlor-benzene.) And if in the next but two it is represented as 1: 4, and is said to be in the para position. Cl Effect of Position of Radicals on Chemical Behaviour. The position of radicals replacing hydrogen in the benzene nucleus affects the chemical behaviour of the compound very considerably. Thus if an alkyl, such as methyl, be attached to one carbon atom, the attachment of a second negative radical, such as hydroxyl, in the ortho position to the nucleus prevents its oxidation in acid solutions, but hastens it in alkaline ones, and there can be little doubt that the relative position of the radicals attached to...show more

Product details

  • Paperback | 62 pages
  • 189 x 246 x 3mm | 127g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236581598
  • 9781236581594