ALDEHYDES. KETONES. 495 



Sulphur derivatives. A comparison of such inorganic compounds 

 as H 2 S, CS 2 , NH 4 SH, with H 2 O, CO 2 , NH 4 OH, shows that sulphur 

 often replaces oxygen. Correspondingly, sulphur frequently replaces 

 oxygen in organic compounds. When this replacement takes place 

 in alcohols compounds are formed, called mercaptans, mlpho-alcohols, 

 or thio-alcohoh; when it takes place in aldehydes sulph-aldehydes are 

 formed. These bodies, as a general rule, are ill-smelling compounds, 

 some of which are the result of putrefaction in proteids. 



When mercaptans are treated with oxidizing agents three atoms of oxygen 

 e taken up and compounds are formed which are called sulphonic acids, 



na 



are 

 thus: 



C 2 H 5 SH -f 30 = C 2 H 5 .S0 2 OH. 



Ethyl Ethyl sulphonic 



mercaptan. acid. 



Sulphonic acids correspond to sulphurous acid in which a hydrogen atom 

 has been replaced by a hydrocarbon radical. 



Ketones form condensation products with both alcohols and mercaptans 

 thus: 



CH 3 \ m HO.C 2 H 5 CH 3 \ p /OC 2 H 

 CH 3 X CO + HO.C 2 H 5 5 " 



Acetone. Ethyl Ketol. 



alcohol. 



Acetone. Ethyl Mercaptol. 



mercaptan. 



By oxidizing mercaptol with potassium permanganate it takes up oxygen 

 (similar to mercaptans), with the result that a compound is formed containing 

 sulphonic acid : 



CH 3 \ r /SC 2 H 5 CH 3 \ r /S0 2 C 2 H 5 



C + ' = CH 3 / C \S0 2 C 2 H 6 ' 



Mercaptol. Diethylsulphon- 



dimethyl-methane. 



This compound is used medicinally under the name of sulphonal. 



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

 considered in this chapter, may be shown graphically thus : 



H\ p /Cl H\ n /I H\ C /COH 



H/\H C1X C \C1 I/ C \I H/\H 



Methane. Chloroform. lodoform. Aldehyde. 



Cl\ r /COH ^p/CH,, CH 3 \ r /S0 2 C 2 H 6 



Cl/Sd / C \CH 3 CH 3 X\S0 2 C 2 H 6 



Chloral. Acetone. Hul phonal. 



Sulphonmethane, Sulphonmethanum, Sulphonal, (CH 3 ) 2 C- 

 (C 2 H 5 SO 2 ) 2 = 226.55 (Diethylsulphon-dimethyl-methane). Sulphonal 

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



