Why can sodium carbonate be used to remove grease? And ethyl acetate is not hydrolyzed in sodium car

Sodium carbonate. The principle that can be used to remove grease is that sodium carbonate reacts with some components of the grease to form surfactants with detergency.

Sodium carbonate is alkaline. When fats and fats contain carboxylic acids (e.g., animal fats and fats often contain stearic acid.

C17H35COOH), carboxylic acids can react with sodium carbonate:

r-cooh

co32-r-coo-

HCO3- anion of carboxylic acids generated.

r-coo-), one end is a non-polar chain alkyl group.

r, one end is charged-coo-, such that such a molecule is hydrophilic at one end and lipophilic at the other. In water, when these "amphiphilic" molecules encounter oil, the lipophilic end will be close to the oil, and the hydrophilic end will extend into the aqueous solution, so that a spherical shape is formed, which wraps the oil and plays the role of a surfactant, so that the oil can exist in the aqueous phase in the form of small droplets (otherwise oil and water are immiscible with each other).

At this point, the object to be washed is properly scrubbed and the grease leaves the surface. Then change the water to rinse, and the purpose of washing will be achieved.

Ethyl acetate. Hydrolysis can occur in aqueous or alcohol solutions of strong bases (e.g., NaOH) and heating (often 80 °C). Ethyl acetate is also not completely hydrolyzable in sodium carbonate. However, because (1) the alkalinity of sodium carbonate is still significantly weaker than that of NaOH

2) The washing process is generally at 20°C to 50°C (too high to be hot), so the reaction rate.

It is very low, and for a short period of time (the washing process is generally a few minutes to 1 hour), the degree of hydrolysis of ethyl acetate is negligible.

Why can sodium carbonate be used to remove grease?

Sodium carbonate is a strong alkali and weak salt, which is hydrolyzed in water, so that the concentration of oh- in the water rises, the solution is alkaline, and the alkaline solution and oil (fatty acid) produce a saponification reaction, which converts the fatty acids that are not dissolved in water into sodium fatty acids dissolved in water. Thus the grease can be washed away.

Ethyl acetate is also hydrolyzed slowly in sodium carbonate solution and faster than in water. The reason why ethyl acetate is collected and prepared with sodium carbonate saturated solution is to reduce the solubility of ethyl acetate in water, remove the acetic acid mixed in ethyl acetate, Na2CO3 can react with the volatile acetic acid to generate odorless sodium acetate, which is convenient for smelling the fragrance of ethyl acetate, and water can dissolve ethanol mixed in ethyl acetate.

Due to the accelerated hydrolysis of ethyl acetate in alkaline solution, it cannot be collected with NaOH solution, and Na2CO3 is selected because it can neutralize the entrained reactant acetic acid, and the alkalinity is not too strong, so it has limited contribution to promoting the hydrolysis of ethyl acetate.

Ethyl acetate is insoluble in saturated sodium carbonate, and the reason for using saturated sodium carbonate is to reduce the hydrolysis of ethyl acetate.

First of all, it is necessary to clarify why ethyl acetate is soluble in water, it is due to the similar density that it will be integrated, not the hydrophilicity of "R-OH" and "R-Cooh", these two guys have been converted into "R-COO", and this thing is insoluble in inorganic solvents.

So if you want to reduce its solubility, you can use sodium carbonate (because it can also neutralize incomplete acetic acid or ethanol), and when sodium carbonate is added, it will produce delamination and facilitate separation.

The most important reason is that although sodium carbonate is a basic compound, the concentration of hydroxide from its ionization is not high, and it cannot cause the reaction to move in reverse.

The part of ethyl acetate contained in water is largely based on the hydrogen bonds formed by the oxygen in it and the hydrogen in the water. Once sodium carbonate is abundantly dissolved in water,"Occupation"A part of the hydrogen, due to the saturation of hydrogen bonds, naturally affects the solubility of ethyl acetate, which is already slightly soluble in oil.

The density of ethyl acetate and water is not much different, so miscibility occurs and treatment is required. When sodium carbonate is added, the density of water will increase, and sodium dicarbonate is insoluble in ethyl acetate, resulting in the density of the aqueous layer being greater than that of ethyl acetate solution, and delamination will occur, which is convenient for separation. However, the alkaline environment produced by the hydrolysis of sodium carbonate is not enough to hydrolyze ethyl acetate, and the alkalinity is relatively weak.

In high school chemistry, the principle of "similar dissolution" is used to explain the reason: ethyl acetate is very polar and difficult to dissolve in a saturated sodium carbonate solution with strong polarity.

The reason why sodium carbonate (Na2CO3) can reduce the solubility of ethyl acetate is because it can undergo acid-base neutralization reaction with ethyl acetate.

Ethyl acetate is an organic compound that partially dissociates into acetate ions (CH3COO-) and acetate ions in water, increasing the solubility of ethyl acetate in water. Sodium carbonate is an alkaline compound that can be neutralized with acetate ions in ethyl acetate.

The alkalinity of sodium carbonate can cause it to dissolve in water to release hydroxide ions (OH-), and acetate ions react with hydroxide ions to form water (H2O), and this reaction can be expressed as:

ch3coo-+oh-→ch3cooh+oh-

This reaction converts acetate ions from solution to acetic acid (CH3COOH), which has a lower solubility than ethyl acetate, so the solubility of ethyl acetate is reduced.

In conclusion, sodium carbonate converts acetate ions into acetic acid by an acid-base neutralization reaction with acetate ions in ethyl acetate, thereby reducing the solubility of ethyl acetate. <>

Sodium carbonate (Na2CO3) can reduce the solubility of ethyl acetate (sock skin ethylacetate) due to the alkaline nature of sodium carbonate and the reaction that occurs with ethyl acetate.

Sodium carbonate decomposes into sodium ions (Na+) and carbonate ions (CO32-) in water. Whereas, ethyl acetate molecule contains an ester group (-coo-ch2-ch3). Under alkaline conditions, carbonate ions combine with hydrogen ions in the acetic acid group to form acetate ions (CH3COO-).

This reaction is an acid-base neutralization reaction, and the acetate ions formed have a lower solubility. The formation of acetate ions reduces the solubility of ethyl acetate molecules, causing ethyl acetate to precipitate or agglomerate into small particles in a solution containing sodium carbonate, thereby reducing its solubility in solution.

As a result, sodium carbonate reduces the solubility of ethyl acetate and allows it to precipitate out of solution. This phenomenon is often used to separate mixtures of organic solvents such as ethyl acetate and water. <>

First, the question was raised, and when reading the materials, the person who put forward the pen found that "the common misunderstanding of organic separation and purification in high school" (2 Yi) 9 No. 7 "Middle School Chemistry Teaching Reference") There is such a paragraph in the article: Concentrated sulfuric acid can not be used to remove acetic acid and ethanol mixed in acetic acid and vinegar, because this reaction is a reversible reaction, and the correct method should be: acetic acid and acetic acid are insoluble in water, ethanol and acetic acid are easily soluble in water, so saturated sodium carbonate can be added to the original mixture, and then separated by a separating funnel.

This statement is widely circulated among middle school teachers, and it is generally believed that there are three functions of saturated sodium carbonate solution: ruler letter removes acid, dissolves alcohol, and reduces the solubility of vinegar. Alcohol is soluble in water, but isn't alcohol also soluble in cool?

Whether the sodium carbonate solution can remove ethanol, I decided to verify the authenticity through experiments. 2. Reagents used in experimental verification: distilled water, absolute ethanol (AR), ethyl acetate (AR), saturated sodium carbonate solution, saturated calcium chloride solution.

Instruments used: burette and 10 ml graduated cylinder. Experiment l:

Mix 3 ml of water with 3 ml of ethanol, and find that the volume is less than 6 m to about ml, which indicates that there is a gap between molecules), and then add 3 ml of human ethyl acetate vinegar, and the total volume after shaking is gmij, without stratification. Experiment 2: Mix 3 ml of ethanol with 3 ml of ethyl acetate vinegar and find that the volume becomes larger (about ml).,6,

Others can also be used, sodium carbonate has a good effect.

The purity of sodium carbonate chemicals is mostly above, and the classification belongs to salt, not alkali. Also known as soda or soda ash in international **. It is an important organic chemical raw material, mainly used in the production of flat glass, glass products and ceramic glaze.

It is also widely used in household washing, acid neutralization, and food processing.

Before the artificial synthesis of soda ash, the burned ash contains alkalis, and the brown lye solution can be obtained by leaching and filtering the branch chain with hot water for washing.

Because saturated sodium carbonate contains sodium ions, (CO3)2- ions, (HCO3)- ions, and ethyl acetate will generate a small amount of acetate in water, acetic acid will combine with hydrogen ions to form slow biacetic acid, but because (CO3)2-ions, (HCO3)- ions will combine with hydrogen ions, and (CO3)2- is much more acidic than acetic acid, it will first combine with hydrogen ions and inhibit the decomposition of ethyl acetate.

Ethyl acetate belongs to the ester group, but it does not mean that it is oil. Esters can be hydrolyzed by acids or bases, but sodium carbonate is salt, so no.