Can carboxylic acids be reduced to alcohols

Yes. Metal hydrides such as lithium aluminum hydride, borane, sodium borohydride.

Potassium) is a commonly used reducing agent in the laboratory to reduce carboxylic acids to the corresponding primary alcohols. Lithium aluminum hydride is the most commonly used reagent for reducing carboxylic acids. Borane is an excellent reagent for selectively reducing carboxylic acids to alcohols, with mild conditions and fast reaction speed, and does not affect the nitro, halogen and other groups present in the molecule.

For the reduction of carboxylic acids by lithium aluminum hydride, the reaction can be carried out under very mild conditions and usually does not stop at the aldehyde stage. Even acids with large steric hindrance have good yields, so they are widely used. This type of reaction releases hydrogen, so the reaction should be carried out in a well-ventilated fume hood.

All carboxylic acids can be reduced to primary alcohols, and there are many ways to reduce them, such as:

First, nickel-metal-catalyzed hydrogenation; Second, it reacts with lialh4.

CH3COOH plus reducing H can be reduced to ethanol, not the so-called H2, but LialH4

The reaction conditions that are not available in secondary school are the reduction of the high-temperature and high-pressure catalyst (copper-zinc, nickel chromite) to the primary alcohol equation under the action of the reducing agent LiALH4: CH3COOH + LiALH4 = (absolute ethanol, hydrolysis) CH3CH2OH

Certain alcohols can be oxidized to aldehydes, which in turn continue to oxidize to carboxylic acids. But carboxylic acids cannot be reduced to aldehydes and alcohols. All can be hydrogenated and reduced to alcohol.

The functional group of alcohol is hydroxy-OH, aldehyde is aldehyde-cho, and acid is carboxy-cooh. The alcohols are oxidized to obtain aldehyde groups, and the carboxyl groups of aldehyde groups are oxidized. The oxidation process can be considered as a dehydrogenation process.

The catalytic oxidation reaction of alcohol can generate aldehydes, for example, under the catalytic action of metallic copper, ethanol oxidation reaction occurs, and the reaction equation is:

2ch₃ch₂oh ＋ o₂ →2ch₃cho ＋ 2h₂o

Conversely, the reduction reaction of aldehydes can produce alcohols, e.g., under the condition of nickel powder as a catalyst and heating, the reaction equation is:

ch₃cho ＋ h₂ →ch₃ch₂oh。

The oxidation reaction of aldehydes can produce carboxylic acids, for example, in the presence of a catalyst, the reaction equation is:

2ch₃cho ＋ o₂→ 2ch₃cooh

However, it is generally not through the direct reduction of carboxylic acids (carboxylic acids are unstable and easy to decarboxylated when heated), but by the reduction of carboxylic acid derivatives (such as acid chlorides, esters, amides, etc.) to obtain aldehydes.

1. Catalytic hydrogenation, rosenmund reaction (reduction of acid chloride, that is, a derivative of carboxylic acids, to aldehydes):

h2rcocl*****====rcho

pd/baso4

2. Carboxylic acids and their derivatives can also be reduced by metal hydrides to primary alcohols, aldehydes or amines (amides are reduced). Commonly used metal hydrides are lithium aluminum hydride (LiALH4) and sodium borohydride (NaBH4). The former has too strong reducing ability, and can directly reduce carboxylic acids, acid chlorides, esters and anhydrides to primary alcohols.

The latter has a slightly inferior reducing capacity and reduces acyl chloride to aldehydes in the dimethylamide (DMF) axis in the presence of pyridine or cadmium dichloride

nabh4rcocl*****====rcho

dmf/thf

ch3cooh

The addition of reducing H can be reduced to ethanol, not the so-called H2, but LialH4

The reaction conditions that are not available in secondary school are the reduction of the high-temperature and high-pressure catalyst (copper-zinc, nickel chromite) to the primary alcohol equation under the action of the reducing agent LiALH4: CH3COOH + LiALH4 = (absolute ethanol, hydrolysis) CH3CH2OH