Sodium hydroxide with propanoic acid

Scheme 9.100. A representation of the Kolbe electrolysis of the sodium salt of propanoic acid. The voltage for the electrolysis must be greater than that required for the reduction of water to hydroxide anion (OH") and hydrogen (H2) which occurs at the cathode. It is generally accepted that one electron is lost by the carboxylate anion at the anode to generate a carboxyl radical. The arrows shown on the carboxyl radical (with half-heads) are drawn to account for the apparent movement of one electron (in contrast to the usual cartoons showing two electron arrows) at a time to produce carbon dioxide (CO2) and the ethyl radical (CH3CH2 ).The latter dimerizes to butane or loses a hydrogen to a second radical, producing ethane and ethene.

A mixture of 4,4 parts of 1-chloro-3-(1-naphthoxy)-2-propano and 16 parts of isopropylamine is heated in a sealed vessel at 70° B0°C for 10 hours. The vessel is cooled and to the contents there are added 50 parts of water. The mixture is acidified with 2N hydrochloric acid, and washed with 50 parts of ether. The aqueous phase Is decolorized with carbon, and then added to 50 parts of 2N sodium hydroxide solution at 0°C, The mixture is filtered. The solid residue is washed with water, dried, and crystallized from cyclohexane. There is thus obtained 1-isopropylamino-3-(1-naphthoxy)-2-propanol, MP 96°C. 

Propanoic acid, HC3H3O2, is a weak acid. When propanoic acid completely reacts with sodium hydroxide, the final solution has a pH slightly greater than 7. Why are the products of this neutralization reaction not neutral Use the net ionic equation to help in your explanation. 

Both phenols and carboxylic acids are neutralized by the strong base sodium hydroxide. Since both are water soluble, there would be no obvious visible difference with this reagent, even if there were a difference in extent of reaction. However, phenols are a lot less acidic than carboxylic acids and will not react with the weak base sodium bicarbonate. If one adds sodium bicarbonate to aqueous solutions of these compounds, bubbles of carbon dioxide will be visible as the bicarbonate and propanoic acid neutralize one another. Since the phenol does not react, no CO2 evolution will be observed. 

At 1()0 "C, 0.8 g of the Raney nickel is soaked in the modifying solution of 1 g (6.7 mmol) of (R.R)-tartaric acid and 10 g (0.1 mol) of sodium bromide in 100 mL of deionized water, the pH of which is adjusted to 3.2 with 1N sodium hydroxide. After 1 h with occasional shaking, the solution is removed by decantation and the residue is washed wilh 10 mL of deionized water. The water suspending the catalyst is replaced by two 50-mL portions of Cl],OH and then by 25 mL of methyl propanoate. 

Like all acids, carboxyhc acids react with strong bases via neutralization reactions. For example, propanoic acid reacts with sodium hydroxide to form sodium propanoate and water. 

Write the balanced chemical equation for the neutralization of propanoic acid with sodium hydroxide. 

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