What is a Synthesis Reaction?

Synthetic reaction refers to a reaction process and a reaction method in which multiple substances produce only one chemical product through chemical reactions. Drug synthesis reactions refer to organic synthesis reactions commonly used in drug synthesis. Such as: halogenation, nitration, sulfonation, diazotization, oxidation, reduction, elimination, hydrocarbonation, acylation, condensation, cyclization and rearrangement reactions.

Synthetic reaction refers to a reaction process and a reaction method in which multiple substances produce only one chemical product through chemical reactions. Drug synthesis reactions refer to organic synthesis reactions commonly used in drug synthesis. Such as: halogenation, nitration, sulfonation, diazotization, oxidation, reduction, elimination, hydrocarbonation, acylation, condensation, cyclization and rearrangement reactions, etc. ^[1]

First, the halogenation reaction

Halogenation reaction refers to the reaction of establishing carbon-halogen bonds in organic molecules. The introduction of halogen atoms often increases the activity of organic molecules and is easily replaced, which makes them widely used in drug synthesis and drug modification. According to the type of reaction, it can be divided into addition reaction and substitution reaction.

Second, the alkylation reaction

The hydrocarbonation reaction refers to the rapid cracking of ethylene and a small amount of propylene and butene in the dry gas to alkylate with benzene at a certain temperature and the presence of a catalyst to produce ethylbenzene and a small amount of propylbenzene and butylbenzene. However, the alkylation reaction does not stop at the stage of generating ethylbenzene, propylbenzene and styrene-butadiene. The alkylation reaction will continue, and theoretically a series of polyalkylbenzenes such as diethylbenzene, triethylbenzene, Tetraethylbenzene, pentaethylbenzene, hexaethylbenzene, ethylpropylbenzene, ethylbutylbenzene, etc., but this continuous reaction step gradually slows down as the steric hindrance on the alkyl-substituted benzene ring increases, Moreover, the diffusion resistance of macromolecules in the catalyst continues to increase, restricting them to reach the active center of the catalyst to participate in the reaction. At the same time, the catalyst for the role of sieving molecules is used in the hydrocarbonization reaction process. A small amount. Maintaining too much benzene during the hydrocarbonation reaction can obtain higher ethylene conversion and better ethylbenzene selectivity. The hydrocarbonation reaction is a strongly exothermic reaction, and the heat released by the reaction is taken away by the circulating benzene.

Third, the acylation reaction

Acylation

Chemical synthesis reactions, especially organic synthesis reactions, are generally more complex, and there are more factors affecting the reaction. Therefore, different reactions need to be adopted according to the reaction conditions such as reaction temperature, reaction time, method and order of material input, and whether the reaction requires stirring. Different devices. Common experimental devices used in chemical synthesis experiments include reflux, distillation, suction filtration, gas absorption and stirring.

Instrument assembly method and general requirements:

Whether the instrument is assembled correctly or not has a great bearing on the success or failure of the experiment. First, the glass instruments and accessories used should be very clean. If the reaction requires anhydrous conditions, the glass instruments and accessories should be sufficiently dry. The volume of the instrument should be appropriate. For example, the reaction volume of the round bottom flask should be about 1/2 of its volume, and it should not exceed 2/3 at most. Glass instruments are generally fixed on the iron frame with iron clips. The double clips of the iron clips should be affixed with soft materials such as rubber or flannel. If the iron clamp directly clamps the glass instrument, the clamp is not tight, and the instrument is easily damaged.

When assembling the instrument, first determine the height of the main instrument (usually a round-bottomed flask) with the height of the heat source, and then assemble the instruments one by one in order from bottom to top and from left to right. The device is required to be strict, correct, neat and secure.

A reaction in which two or more new substances are generated from the reaction of one substance is called a decomposition reaction. Some of these reactions are redox reactions and some are non-redox reactions. According to different classification criteria, decomposition reactions can be divided into different categories. In addition, only compounds can undergo decomposition reactions.