4-chloropyridine hydrochloride (1:1)

4-Alkane to its carboxylic anhydride (1:1), is an important class of compounds in organic chemistry. The physical properties of the two have their own unique characteristics.
First of all, alkane. Alkane, one of the hydrocarbons, has a saturated carbon chain structure. Its molecules are maintained by weak van der Waals forces. Under normal temperature and pressure, alkanes with few carbon atoms, such as methane and ethane, are mostly gaseous, lightweight and flammable, and are often used as fuels. As the number of carbon atoms increases, such as propane and butane, although they are still gaseous, their boiling points gradually rise. To alkanes containing five to sixteen carbon atoms, such as pentane, hexane, etc., are liquid, have certain fluidity, are insoluble in water, have a lower density than water, and are often used as organic solvents. And higher alkanes containing more than sixteen carbon atoms are mostly solid at room temperature and have lower hardness.
As for carboxylic anhydrides (1:1), they are formed by the dehydration and condensation of two molecules of carboxylic acids. Because the molecule contains polar groups such as carbonyl groups, it is more polar than alkanes. Carboxylic anhydrides are mostly liquid or solid and have a special odor. Some lower carboxylic anhydrides, such as acetic anhydride, have relatively low boiling points, are highly volatile, and are corrosive. They can be slowly hydrolyzed in water to form corresponding carboxylic acids. Unlike alkanes, carboxylic anhydrides can participate in a variety of organic reactions, such as acylation reactions, and are widely used in the field of organic synthesis.
Overall, alkanes and carboxylic anhydrides (1:1) have significant differences in physical properties such as physical state, solubility, boiling point, etc. These differences also determine their use in different fields.

4-Hydroxynonenal and its ketones (1:1) are organic compounds with unique chemical properties. This compound is chemically active because it contains functional groups such as hydroxyl and carbonyl groups.
As far as nucleophilic addition reactions are concerned, its carbonyl groups can attract nucleophiles. Nucleophilic reagents such as alcohols can attack carbonyl carbon atoms to form hemiacetal or acetal structures. Taking ethanol as an example, under acid-catalyzed conditions, the lone pair electrons of the oxygen atom in ethanol will attack the carbonyl carbons of 4-hydroxynonenal and its ketones (1:1). After proton transfer, hemiacetal products are formed; if ethanol is excessive, it will further react to form acetals.
In addition, hydroxyl groups can also participate in the reaction. Hydroxyl groups are acidic to a certain extent, and under the action of alkali, they can lose protons to form oxygen negative ions. As a nucleophilic reagent, this oxygen negative ion can attack electrophilic reagents such as halogenated hydrocarbons, and a substitution reaction occurs. If reacted with bromoethane, oxygen negative ions will attack the carbon atoms of bromoethane, and bromine ions will leave to form ether compounds.
Because of its structure containing carbon-carbon double bonds, an addition reaction can occur. Common examples are addition to halogen elements, and bromine elements can be added to carbon-carbon double bonds to make the reddish brown of bromine fade away. During the reaction, the bromine molecule is first polarized, and the positively charged end is close to the carbon-carbon double bond to form a ternary cyclic bromide ion intermediate. Then the bromine negative ion attacks from the back surface to form a dibromo product.
In the redox reaction, the compound can be oxidized. The hydroxyl group can be oxidized to an aldehyde group, a carboxyl group, and a carbonyl group can be further oxidized. If a mild oxidizing agent is used, such as PCC (pyridinium chlorochromate salt), the hydroxyl group may be oxidized to an aldehyde group; if a strong oxidizing agent is used, such as potassium permanganate, the hydroxyl group and the carbonyl group may be further oxidized to a carboxyl group. At the same time, it can also be reduced under the action of a reducing agent. The carbonyl group can be reduced to For example, the use of reducing agents such as lithium aluminum hydride can reduce carbonyl groups to alcoholic hydroxyl groups.

The main use of 4-% oxidized acid (1:1) is to neutralize and reverse the water. When the two meet, the biochemical reaction is generated, and chlorinated water is generated. The equation is: NaOH + HCl → NaCl + H2O.
In the field of work, this reaction is often used for water treatment. If the water discharged from the work is acidic, the amount of 4-% oxidized solution can be added to neutralize the acid in the water to protect the discharge and avoid corrosion pollution caused by acidic water.
In the chemical room, this reaction is also a commonly used analysis method. For example, if you want to determine an acid or solution of unknown degree, you can use a titration of 4-% oxidized acid (1:1) of known degree. By means of inspection to indicate the transformation of the color of the body, the degree of the unknown solution can be estimated.
In terms of performance, it is also useful. There is a lot of stomach acid in humans, and it is not difficult to lead. The principle of the main component of some substances is similar to that of 4-% oxidized acid, which can neutralize the amount of stomach acid and solve the problem.
In addition, in the food processing industry, if the acidity is out of control during the food processing process, 4-% oxidized acid (1:1) can also be used to form to ensure the safety of food products. Therefore, 4-% oxidized acid (1:1) plays an indispensable role in many fields because it can effectively neutralize acid.

To prepare ethyl 4-hydroxybenzoate (1:1), the method is as follows:
First take p-hydroxybenzoic acid and ethanol as materials, which are the basis of the reaction. With concentrated sulfuric acid as the catalyst, this agent can promote the speed of the reaction and increase the amount of yield. Place the three in a round-bottomed flask in an appropriate ratio. The ratio is accurate, which is related to the effect of the reaction, and must not be ignored.
Then, connect a reflux condenser tube to the flask. This tube can condense the gasified reactants back to prevent their escape and preserve the amount of reactants. Heat in a water bath or an oil bath and control the temperature in a suitable area. If the temperature is too high, or side reactions are caused, the product is impure; if the temperature is too low, the reaction will be slow and take a long time. The temperature is within a certain range, depending on the specific situation.
During the reaction, the flask needs to be shaken frequently to fully blend the materials and make the reaction uniform. After a certain period of time, use thin-layer chromatography or other suitable methods to check the reaction process. When the reaction reaches the desired level, remove the heat source and allow the system to cool naturally.
After cooling, pour the reaction solution into the separation funnel and extract with an appropriate amount of water and an organic solvent. Water can dissolve unreacted acids and impurities such as sulfuric acid, and the organic solvent extracts the product. After separation, collect the organic phase and remove the water with a desiccant such as anhydrous sodium sulfate. < Br > After distillation, the organic solvent is removed first, and then distilled under reduced pressure to obtain pure ethyl 4-hydroxybenzoate. In this way, the compound is obtained. The whole process, each step is interlocked, and the operation needs to be careful to obtain satisfactory results.

4 - Oxidation (1:1) For storage and recovery, pay attention to the following things:
First storage environment. It should be placed in a dry, dry and well-ventilated place. This is because if the oxidation is affected by moisture, it is easy to absorb and cause polymerization, pollution, and its original characteristics. Therefore, the degree of oxidation must be controlled. Generally speaking, the degree of phase should be kept at 40% - 60%. And it is not allowed to be combined with acidic substances. Because of the oxidation nature, it is easy to react and destroy when exposed to acid.
It is difficult to be used, especially for packaging. It is properly wrapped in sealed and moisture-proof packaging materials, often such as plastic bags, external plate barrels or bags. In order to prevent the impact of external conditions on the way, the special purpose is to avoid the invasion of rain and water. It is also necessary to maintain dryness and cleanliness, and must not leave objects that may be oxidized and reversed.
Furthermore, if there is a problem or a problem, it must be a source of ignition and a high source. Oxidation itself burns, but under high temperatures, it may cause decomposition and reaction, and water will be released, which will affect its products. Usually, the storage degree should be maintained at 5 ° C - 35 ° C.
Operators also need to take precautions. Because if the powder is accidentally inhaled, it may irritate the respiratory tract; if it is connected to the skin or eyes, it may also cause damage. Therefore, the operation of the powder should be equipped with anti-mask, anti-mask and anti-glove for safety.