Volume 1

Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors.

Date:
1888-1894
Catalogue details

Licence: Public Domain Mark

Credit: Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    aqueous hydrochloric acid, and treating this compound with sodium ethylate: C.,H40 f C,H60 + HC1 = H,0 + C4H9C10 ; and C,HUC10 + C2H5ONa = NaCl + C6HH02 (Wurtz a. Frapolli, C. B. 47, 418 ; A. 108, 223). 2. By treating aldehyde with PBr5, whereby it is converted into ethylidene bromide, and acting on this compound with sodium ethylate : CHMeBr2 + 2NaOEt = 2NaBr + CHMe(OEt)2 (W. a. P.). Properties.—Colourless liquid, less mobile than ether, having a peculiar agreeable odour and refreshing taste, with an after-taste like that of hazel-nuts. Separated from aqueous solution by calcium chloride and other soluble salts. Miscible with ether or alcohol. Reactions.—1. Not altered by mere exposure to air, but quickly oxidised in contact with pla- tinum-black to aldehyde and acetic acid. Oxi- dised also by nitric and by chromic acid.—2. Not decomposed by caustic alkalis if air is excluded. 3. Forms substitution-products with chlorine. 4. Strong sulphuric and hydrochloric acids dis- solve and decompose it, the mixture turning- black.—5. Dilute acids, even in the cold, split up acetal into alcohol and aldehyde.—6. A solution of acetal does not give the iodoform reaction, unless it be first acidified (Grodzki, B. 16, 512). 7. PC15 forms CH3.CHC1.0Et, EtCl and POCl3 (Buchanan, A. 218, 38).—8. Heated with glacial HOAc it forms acetic ether, thus : CH3.CH(OEt), + 2AcOH = CH3CHO + H20 + 2AcOEt. 9. Does not reduce AgNO,Aq.—10. Chromic mixture forms acetic acid.—11. Heated with MeOH it is almost completely converted into EtOH and CH3CH(OMe),.—12. Heated with PrOH it is mostly unchanged, but some CH3.CH(OEt)(OPr) and some CH3CH(OPr)2 are formed.—13. Heated with iso-amyl alcolwl it behaves as in 12. Beferences.—Homologues of acetal are de- scribed under the aldehydes, to which they cor- respond. Bromo- and chloro-acetals are described under bromo- and chloro-acetic aldehyde. For oxy-acetal v. glyeollic aldehyde. ACETALDEHYDE v. Aldehyde. ACETAMIDE C,H5NO i.e. NH.Ac or CH3.CO.NH — Amide of acetic acid. M.w. 59. [83°] (Hofmann, B. 14, 2729) (222° cor.). S.G. 4 1-159 (Schroder, B. 12, 562). 24-35 in a 34-p.c. aqueous solution (Kanonnikoff, J. pr. [2] 31, 347). Discovered by Dumas, Malaguti, and Leblanc in 1847 (C. B. 25, 657). Formation.—-1. By heating ethyl acetate with strong aqueous ammonia at 120° AcOEt + NH3 = AcNH, + HOEt. 2. By action of ammonia on acetic anhydride : Ac,0 + 2NH3 = NH2Ac + AeONH4. 3. By distillation of ammonic acetate : AcONH4 = AeNH2 + H20 (Kundig, A. 105, 277). 4. When dry NaOAc (580 g.) is distilled with NH4C1 (225 g.) very little acetamide (70 g.) is got: the distillate is chiefly NH, and acid am- monic acetate, which boils at 145°. Preparation.—1. Acetic ether and aqueous ammonia are left in a closed vessel until the ether has disappeared. The product is distilled.— 2. Glacial acetic acid (1 kilo.) is saturated with dry NH3 and the product distilled in a current of dry NH3. Above 190° acetamide (460 g.) comes over; the first distillate (below 190°) is treated in the same way: it gives more acetamide (170 g.). A third repetition of this operation gives more acetamide (110 g.). Total yield : 740 g. (Keller, J. pr. [2] 31, 364).—3. Ammonic chloride and sodic acetate are heated in an enamelled iron digester for six hours at 230D. The product is distilled (Hofmann, B. 15, 981).—4. A mixture of ammonic acetate (20 g.) and acetic anhydride (26 g.) yields on distillation 96 p.c. (12 g.) of acetamide (Schulze, J. pr. [2] 27, 512).—5. Am- monic sulphocyanide (1 mol.) is boiled for four days with glacial acetic acid (2^ mols.): NH.CNS + 2AcOH = 2AcNH2 + COS + H20 (S.). Purification.—Acetamide can be freed from ammonic acetate by drying over lime (Menschut- kin, J. B. 17, 259). Properties.—White hexagonal scales, smell- ing like excrement of mice. Deliquescent. V. e. sol. water. Conducts electricity and is easily electrolysed. Beactions.—1. Resolved by distillation with P205 into water and acetonitrile, C2H3N.—2. With P,S5 it also yields acetonitrile, giving off H,S, and leaving a blackish tumefied residue.—3. Heated in dry HCl-gas it yields: a. A liquid distillate consisting of acetic acid with a small quantity of acetyl chloride ; b. A crystalline distillate of (C2H5N0)2HC1, and a compound of acetamide and diacetamide C2H5NO.C,H7N02, the latter of which may be dissolved out by ether ; c. A non- volatile residue of acetamidine hydrochloride mixed with sal-ammoniac: 2C2H5N0 + HC1 = C,H6N„.HC1 + C„H402 (Strecker, A. 103, 328).—4. Acetamide heated in sealed tubes with saturated hydriodic acid yields ammonia, acetic acid, and ethane : 2C,H5N0 + 3H, = C,H,02 + 2NH3 + C.,H6 (Berthelot, Bl. [2] 9, 183).—5. With CS, at about 210° it gives off H2S, COS, CO, and pro- bably ethane, leaving ammonium sulphocyanide mixed with undecomposed acetamide: 2GH5NO + CS2 = NH4.SCN + COS + CO + Oft (Ladenburg, Z. [2] 4, 651). V. Aldehydes.— 6. Nascent hydrogen (copper-zinc couple or sodium-amalgam) forms some alcohol and alde- hyde (Essner, Bl. [2] 42, 98).—7. Heated with NaOEt at 1803 it forms ethylamine (Seifert, B. 18, 1357).—8. With ethyl orthoformate at 180° acetamide yields ethyl alcohol and diacetyl- formamidine: 2NH„Ac + CH(OEt)3 = 3EtOH + N2(CH)Ac2H. Another reaction, however, takes place at the same time, producing alcohol, ethyl acetate, and formamidine: 2NH,Ac + CH(OEt)3 = EtOH + 2EtOAc + N2(CH)H3 (Wichelhaus, B. 3, 2).—9. Acetamide heated in sealed tubes with bemaldehyde is converted into benzylidene-diacetamide: 2NH2Ac + PhCOH = H20 + PhCH(NHAc).,. With aldehyde in like manner, it yields MeCH(NHAc)2 in large prisms [169°], partly de- composed by distillation, and giving off aldehyde when treated with acids (Tawiklarow, B. 5, 477). With anisaldehyde the compound C^H^NjO.; is formed in nodular groups of needles [180°], sol- uble in water, insoluble in alcohol and ether, decomposed by HC1, not altered by boiling with potash (Schuster, Z. [2] 6, 681). With salicylic aldehyde a yellow neutral body is formed (Cred-
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