In the hydrolysis reaction of esters, it is better to use dilute sulfuric acid or NaOH solution as a

In the hydrolysis reaction of esters, it is better to use dilute sulfuric acid or NaOH solution as a catalyst

Chemical performance Colorless and transparent sodium-alkali liquid, one of the strong alkalis, easy to dissolve in water, can react with many organic and inorganic compounds, is very corrosive, can burn the human body, etc. Sodium hydroxide completely ionizes sodium ions and hydroxide ions in water and can be neutralized with any protonic acid. Take hydrochloric acid, for example:

NaOH + HCl NaCl + H2O sodium hydroxide is also a good catalyst for many organic reactions. The most typical of these is the hydrolysis reaction of esters: rcoor' + naoh → rcoona + r'The OH reaction proceeds both completely and rapidly.

This reaction also uses the principle of hydrolysis, and this type of ester hydrolysis catalyzed by NaOH is called saponification reaction. Uses Sodium hydroxide is widely used in various production processes. In chemical production, sodium hydroxide provides an alkaline environment or acts as a catalyst.

The dilute solution of NAOH can be used as a washing liquid at home. In food production, sodium hydroxide is sometimes used to process foods. Sodium hydroxide is even a necessary seasoning for a famous dish.

Note that the use of sodium hydroxide at this time is strictly controlled; Some unscrupulous traders will use excessive sodium hydroxide to make food more "beautiful", but such food can cause disease. Industrial production method Sodium hydroxide is a by-product of the chlorine production process in industry. Electrolysis of saturated salt water until all the chlorine elements are converted into chlorine gas and escaped, leaving only sodium hydroxide as a solute in the solution.

The reaction equation is: 2NaCl + H2O 2NaOH + Cl2 + H2 The main cause of copper rust is the result of the interaction of copper with oxygen and water in the air.

NaOH is used as a catalyst for complete hydrolysis, and sulfuric acid can only be partially hydrolyzed.

Answer]: Under alkali occlusion conditions, the acidity of carboxylic acids promotes the hydrolytic equilibrium of esters in the direction of alcohol and carboxylate; However, without the above-mentioned acid-alkali equilibrium, the acid-catalyzed esterification reaction of carboxylic acids and alcohols is more effective.

Dilute sulfuric acid can be used as a catalyst, mainly because it contains H+ (hydrogen ions). During acid catalysis, the carbonyl oxygen atom is protonated first, which enhances the positivity of the carbonyl carbon, thereby improving its ability to accept the attack of nucleophiles, and the water molecule attacks the carbonyl carbon, forming carboxylic acids and alcohols through addition-elimination. Carboxylic acids and alcohols can be recombined into esters, so acid-catalyzed ester hydrolysis cannot be carried out to the end.

In addition, esterification is a reversible reaction, and a large amount of water in dilute sulfuric acid can inhibit esterification and favor hydrolysis.

In the title, alcohol A can be oxidized into carboxylic acid B, and they can be reacted into esters, indicating that they each contain 3 carbon atoms, and because alcohol A can be oxidized to carboxylic acid B, it means that there is no isomer in A, that is, A and B are directly connected structures, in summary: A is CH3CH2CH2OH, B is CH3CH2COOH, and the original ester is CH3CH2COOCH2CH2CH3.

The oxidation of alcohol to acid does not change the number of carbon atoms, so the alcohols and acids obtained by hydrolysis of esters with the formula C6H12O2 contain 3 carbon atoms, namely propanol and propionic acid. There are two kinds of propanol, n-propanol and isopropanol, of which isopropanol cannot be oxidized into an acid with 3 carbon atoms, so a is n-propanol, b is n-propionic acid, and the original ester is ch3ch2cooch2ch2ch3

Because B can be obtained after the oxidation of A, the number of carbon atoms of A and B is equal, so the ester is: ch3ch2cooch2ch2ch3

Concentrated sulfuric acid in the esterification reaction is used as a dehydrating agent, because the esterification reaction will produce water if not dehydrated, the ester that has been produced will be hydrolyzed, according to this principle, the catalyst added should be able to absorb water, the following is what I found from the literature, I hope it will help you.

1. General acid catalysts This type of catalyst refers to phosphoric acid, boric acid, organic sulfonic acid, hydrochloride and sulfate. Generally, the catalytic yield of acid catalyst is low, and the reaction time is long, and the value is not large, while the prospect of using hydrochloride and sulfate as catalyst is very promising, and the catalyst after use still has a certain catalytic effect, but the activity is reduced.

2. Solid acid catalyst Solid acid catalyst refers to cation exchange resin, a variety of zeolite (including synthetic molecular sieves) and various modified zeolite and oxide catalysts, which can avoid the problems of sulfuric acid catalysts, and can be continuously esterified in the gas-solid phase reaction system, repeatedly used, with good stability and easy separation.

3. Heteropolyacid catalyst Heteropolyacid is a class of multi-nuclear complexes with a definite composition of oxygenated nuclei, as an acid-based catalyst, it not only has the remarkable characteristics of high activity, no corrosion of equipment, and reduced pollution, but also it has fast regeneration speed and high selectivity, which is an ideal esterification catalyst.

4. Solid super-acid catalyst Super-strong acid is an acid with stronger acid strength than 100% sulfuric acid, which makes many chemical reactions that are difficult to carry out under very mild conditions with its unusual acid strength, and has become a hot spot in the field of catalysts, known as "magic acid". Super acid generally has two forms of liquid and solid, respectively called liquid super acid and solid super acid, although the acid strength of liquid super acid is large, as a catalyst activity is also high, but similar to other liquid acid catalysts, the equipment is highly corrosive, can not be reused, or cause pollution to the environment. The solid super acid has its unique advantages, does not corrode the reactor, is easy to separate from the reactants, has high selectivity for some reactions, can be used repeatedly, is resistant to high temperature, and is easy to prepare.

Solid superacids can be divided into sulfuric acid-loaded solid superacids and metal oxide-supported solid superacids. According to the literature, the solid superacids supported by sulfuric acid have been synthesized as SO2-4 Fe2O3, SO2-4 TiO2, SO2-4 ZNO2, SO2-4 Fe2O3-SiO2, SO2-4 NiO-TiO2, and SO2-4 SNO2. Although the catalytic activity of the sulfuric acid supported by the solid super acid is equivalent to that of the concentrated H2SO4 liquid, the stability performance is good, the preparation method is simple, it is easy to separate from the product and can be used repeatedly for many times, it does not corrode the equipment and does not pollute the environment, but its cost is high, and it is easy to be reduced to make the sulfate ions fall off and lose the super acid properties

WO3 Zno2, MoO3 Zno2, etc., the catalyst showed high activity and selectivity for the reaction of methanol oxidation to formaldehyde, but the catalytic effect on the esterification reaction needs to be further studied.

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Which catalyst is used for esterification reaction? A: Strong acid B: Strong base C: Weak acid D: Weak base.

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Pro-affinity, esterification reaction uses strong acid as a catalyst. Commonly used esterification catalysts are: concentrated sulfuric acid, concentrated hydrochloric acid, p-toluenesulfonic acid, thionyl chloride, etc., so choose a I hope it can help you

The different causes of esterification hydrolysis catalysts may include the following:

1.Different reactants: Esterification and hydrolysis are two different chemical reactions that require different reactants to proceed.

For esterification reactions, acidic catalysts, such as sulfuric acid or benzoic acid, are usually required. For hydrolysis reactions, alkaline catalysts such as sodium hydroxide or potassium hydroxide are often used.

2.Characteristics of catalysts: Different catalysts have different characteristics, such as activity, selectivity, stability, etc.

For esterification reactions, the catalyst is usually required to have high acidity and good stability; For hydrolysis reactions, a catalyst with high alkalinity and good selectivity is usually required.

3.Different reaction conditions: Different reaction conditions will also affect the choice of esterification hydrolysis catalyst.

For example, in esterification reactions, it is often necessary to increase the reaction temperature and pressure to promote the reaction rate; In hydrolysis reactions, it is often necessary to control the reaction temperature and pressure to avoid excessive decomposition of the reaction products.

In summary, the different selection of esterification hydrolysis catalysts depends on the specific reaction conditions and requirements.