TOPS
a¥
22. ORGANIC CHEMISTRY
(Continued)
E. Industrial Products Plastic
T o sliov. The formation of a Bakelite-type plastic by the condensation reaction of formaldehyde and phenol. The reaction is
Imw + c a - w
-+ I
Compiled by HUBERT N. ALYEA Princeton University
Dem. 674-Ion-exchange
Resin:
Co^4
+ Ni+'
T o show: The selective adsorption of cobaltous and nickelous ions by resins. Materials: Organic cation ion-exchsinger, 10% CoCLaq; 1% NiCla-aq; C-2; two gas holders, SD-17-V; glass wool.
Dem. 672-Phenol-formaldehyde
OH
Tested Overhead Projection Series
OH
-cm-cH,-C,H.-cH,-
+
2 g phenol 5.5 lower Afaterzals: 2 5 g formalin glacial acetic acid, in a 4-02 wide-mouth (CARE: reaction is violently exothermic, do not use narrow neck bottle) squiire clear-glass unstoppered bottle; HC1 generator (cone. H 8 0 4 dripping into cone. HC1); cotton, towel.
Pwceclure: Project the bottle of solution. Insert HC1 delivery tube in the solution through open mouth of bottle Loosely protect mouth of bottle with cotton and a towel (CARE: solution may shoot out of bottle at end of reaction). Slowly bubble in HC1. After reaction, scrape out plastic, rinse well to remove acid, and pass around class. Observation: After about two min the solution suddenly grows pink, then reacts violent, forming a puffy pink solid.
Procedure: Insert inverted gas holders in C-2 with small plug of glass wool supporting half a tube-full of ion exchange resin, ( a ) Saturate the resin with Co++ by pouring CoCL-aq through it until pink Co++ runs through. Wash excess Go++ from both pis holders with water. Set in the two cells of C-2 and project. Run 10 ml water through the rosin in cell 1, and 10 ml 1% NiCli-aq into cell 2. To the 10 ml of effluent in both eases add one drop of IGFc(CN)'. Observations: Effluent of cell 1 is colorless; of cell 3, green. The I
