ALDEHYDES. HALOID DERIVATIVES. 321 



nearly insoluble in water and acids, soluble in alcohol, ether, fatty 

 and essential oils. It contains 96.7 per cent, of iodine. 



lodoform digested with an alcoholic solution of potassium hy- 

 droxide imparts, after acidulation with nitric acid, a blue color to 

 starch solution. 



Experiment 45. Dissolve 4 grammes of crystallized sodium carbonate in 6 

 c.c. of water : add to this solution 1 c.c. of alcohol ; heat to about 70 C. (158 

 F.), and add gradually 1 gramme of iodine. A yellow crystalline deposit of 

 iodoform separates. 



Ethyl bromide, C.,H 5 Br (Hydrobromic ether}. Obtained by the simultaneous 

 action of phosphorus and bromine on ethyl alcohol. It is a colorless, ethereal 

 liquid, which boils at 40 C. (104 F.) and has a sp. gr. of 1.473. 



Sulphonal, (CH 3 ) 2 C(C 2 H 5 S0 2 ) 2 , Dimethyl-diethylsulphonyl-methane. It has 

 been stated before that mercaptans are alcohols in which the oxygen is replaced 

 by sulphur. Alcohol treated with oxidizing agents are converted into acids by 

 exchanging two atoms of hydrogen for one atom of oxygen. Mercaptans 

 behave differently ; they combine directly with three atoms of oxygen, forming 

 compounds known as sulphonic adds. Thus, ethyl mercaptan, C 2 H 5 HS, when 

 treated with nitric acid, is converted into ethyl-sulphonic acid, C 2 H 5 HSO 3 . 

 The radical of this acid, known as ethylsulphonyl, C 2 H 5 S0 2 , may, by indirect 

 process, be caused to replace hydrogen in methane, CH 4 , twice, while the two 

 remaining methane hydrogen atoms can be replaced by methyl. The compound 

 thus obtained is the dimethyl-diethylsulphonyl-methane, or sulphonal. The 

 relations between methane and some of its derivatives, which have been con- 

 sidered in this chapter, may be shown graphically thus : 



H Cl I 



H C-H H C Cl H C I 



I I I 



H - Cl I 



Methane. Chloroform. lodoform. 



COH COH CH 3 



I I I 



H C H Cl C Cl CH 3 C C 2 H 5 SO 2 



H Cl C 2 H 5 SO 2 . 



Aldehyde. Chloral. Sulphonal. 



Sulphonal is a white crystalline substance, having neither odor nor taste ; it 

 is soluble in 15 parts of boiling and 500 parts of cold water, soluble with diffi- 

 culty in alcohol ; it fuses at 130 C. (266 F.), and volatilizes at about 300* C. 

 (572 F.), with partial decomposition. A mixture of sulphonal with either 

 wood charcoal or with potassium cyanide evolves, on heating, the characteristic 

 odor of mercaptan. 



QUESTIONS. 411. What is an aldehyde, and what are its. relations to alco- 

 hols and acids? 412. State the composition of acetic aldehyde. 413. Explain 

 the action of chlorine upon alcohol. 414. Give the composition and properties 



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