How to identify the reaction mechanism between alkyls and aromatic rings
In terms of the reaction mechanism of alkyls, the chloridizing reaction of methane was an example. This was a free radical chain reaction, which was divided into three steps: chain initiation, chain growth, and chain termination. During the chain initiation stage, the Cl2 would be split into Cl-free radical under light or high temperature; During the chain growth, the combination of the CH4 and Cl-free radical would produce the methylethyl-free radical and the hydrogen chloride-free radical, and the methylethyl-free radical would combine with the Cl2 to produce the methylethyl-free radical and the Cl-free radical; During the chain termination stage, the combination of the methylethyl-free radical and the methylethyl-free radical would produce Cl2, and the combination of the methylethyl-free radical and the Cl-free radical would produce the methylethyl-free radical and the methylethyl-free radical would produce the methylethyl-free radical. This mechanism could also be used for the substitution of other alkyls. In the nitration reaction on the aromatic ring, concentrated sulfuric acid was protonated under the effect of concentrated sulfuric acid and then dehydrated to form a nitronium. The nitronium was used as an electrophile reagent to attack the aromatic ring to form a carbonium intermediate. When identifying the reaction mechanism of the alkyls and the aromatic ring, one could start from the reactions, reaction conditions, reaction intermediate, product, and so on. Alkane reactions mostly involved free radical intermediates, and the reaction conditions were often light or high temperature, such as the chloridizing reaction of methane. The reaction of the aromatic ring was mostly an electropathic substitution reaction. For example, in the nitration reaction, an electropathic reagent such as a nitronium would attack the aromatic ring to form a carbonium intermediate, and the reaction often required the participation of reagents such as concentrated sulfuric acid. Different reaction mechanisms would lead to different product structures and proportions, which could also be used for identification. Read more exciting novels for free
Explain the substitution reaction of alkyls
The substitution reaction of alkyls had the following phenomena and characteristics: 1. ** Reaction conditions ** - Requires light (no reaction in the dark at room temperature, but direct light cannot be used, otherwise it will explode). 2. ** Reactants ** - The reagent was a pure elemental gas, such as a gaseous mixture of sulfur and hydrogen. 3. ** Reaction progress ** - The reaction wouldn't stop at a single step. It would proceed step by step, and the final product would be a mixture of many substances. For example, if one hydrogen atom (1 mole of H) was replaced, one mole of Cl2 was needed. It was wrong to think that one Cl2 could replace two H atoms. For example, in the substitution reaction of methane, the atoms in the Cl3 could "seize" a hydrogen atom in the methane, and then compensate a Cl3 atom to the methane to form methachloromethanes. The reaction would continue, gradually forming various products such as methylethylane, methylethylane, and methachloromethanes. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is the state of the substitution reaction of alkyls?
Alkane substitution reaction was a chemical reaction process in which the active position of the organic group was replaced. For the common substitution reaction of alkyls (such as the reaction of methane and Cl2), the reaction condition is light (at room temperature, there is no reaction in the dark, but it cannot be directly illuminated by strong light, otherwise it will explode); The reagent is a pure halo elemental gas, for example, methane does not react when it is added to the bromic water; The reaction will not stop at a certain step, so the product is a mixture of various substances;1 mole of H is replaced, and 1 mole of Cl2 is needed. It is wrong to think that one Cl2 atom can replace two H atoms. From the reaction mechanism: 1. The substitution reaction was a substitution reaction that occurred in a water medium. An organic group in the alkyls reacted with water to form an ion form of the carbonates and the alkyls. Then, an organic substitution reaction occurred to form a new organic compound. 2. The substitution reaction referred to the substitution reaction that occurred under the effect of a catalyst. Commonly used catalyst included sulfuric acid derivative, organic sulfur, alcohol, basic metal oxides, and organic bases. Under the effect of the catalyst, the original acidic groups were replaced in the alkyls to form new organic substances. There were also situations such as electron substitution reactions. The chemical properties of cycloalkyls were similar to those of alkyls, and the substitution reactions were also similar. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
mechanism of the cycloaddition reaction
The cycloaddition reaction was a bimoleral reaction in which the carbon atoms of the end groups of two molecules in a Conjugated System joined together to form a ring. When forming a sigma-bond in the cycloaddition reaction, the carbon atoms of each pair of end groups could be in the same or different faces. If the polyene reagent has a substitution, then the product molecules may have different, recognizable structural characteristics. According to the principle of conservation of molecular orbit, the main way of cycloaddition reaction could be determined: when the sum of the number of carbon atoms in the two reaction molecules was an integral multiple of four, the thermochemical reaction was mainly carried out in the same face-different face or different face-same face way, and the photochemical reaction was mainly carried out in the same face-same face or different face-different face way. When the sum of the number of carbon atoms in the two reaction molecules is an even number that is not an integral multiple of four, the thermochemical reaction is mainly carried out in the same face-same face or different face-different face manner, and the biochemical reaction is mainly carried out in the same face-different face or different face-same face manner. For example, the sum of the number of carbon atoms in the Diels-Alder reaction was 6, which was an even number that was not an integral multiple of four. The thermochemical reaction was mainly carried out in the same face-same face or different face-different face manner. In addition, taking the "cycloaddition/ring-opening" reaction of bicyclo [1.1.0] butanes (BCPs) and triazinane reported by Peng Shiyong's research group of Wuyi University as an example, the cycloaddition followed a step-by-step (3 + 2 + 2) instead of (4 + 3) cycloaddition. It involved the SSN2-like addition of formaldimine and Lewis acid activated BCPs. The possible mechanism was: first, B(C6F5)3 activated 2a to form complex I; then, formaldimine (formed in place from triazinane 1a) and I carried out a N-like addition to form intermediate II; then, it reacted with another formaldimine to form intermediate III; finally, the molecular cycle released the B(C6F5)3 catalyst to form product 3a. Fantasy Realm is equally exciting. Everyone is welcome to click and read it!
The mechanism of the cycloaddition reaction
The cycloaddition reaction was a bimoleral reaction in which the carbon atoms of the end groups of two molecules in a Conjugated System joined together to form a ring. For the cycloaddition reaction, from the perspective of the molecular orbital symmetries conservation principle, when the sum of the number of carbon atoms in the two reaction molecules was an integral multiple of four, the thermochemical reaction was mainly carried out in the same face-different face or different face-same face mode, and the photochemical reaction was mainly carried out in the same face-same face or different face-different face mode. When the sum of the number of carbon atoms in the two reaction molecules is an even number other than four, the thermochemical reaction is mainly carried out in the same face-same face or different face-different face mode, and the biochemical reaction is mainly carried out in the same face-different face or different face-same face mode. The frontier orbital (FMO) theory believed that in a bimoleral photoreaction, both components were excited molecules with two single electrons. The Mo occupied by a single electron was also called SOMO. The cycloaddition method under illumination was: The two SOMOs with higher energy of the two components combined to form a single bond. However, this was only a part of the general bimoleral photoreaction. It was related to the cycloaddition reaction. The specific reaction mechanism was more complicated and different reagent systems might be different. Fantasy Realm is equally exciting. Everyone is welcome to click and read it!
The mechanism of the substitution reaction is
There were two mechanisms for the substitution reaction: 1. ** Bimoleral Nucleic Substitution Reaction (Sn2)**: - This was a bimoleral reaction, and the reaction rate depended on the concentration of the halon and the concentration of the nuclophile. - The reaction was completed in one step. During the reaction process, the central carbon atom of the cleaved carbon dioxide was attacked by the nuclophile and left by the leaving group at the same time, and it would go through a transition state. In the transition state, the nuclophile and the cleaved carbon dioxide were connected by a partial bond, and the leaving group and the cleaved carbon dioxide were also connected by a partial bond. - The reaction process was accompanied by a transformation of the configuration, known as the Walden transformation, which was an important sign of the Sn2 reaction. For example, R - 2 -Bromobutan would be converted to S - 2 -Butanol when 2 -Bromobutan was being digested. 2. ** Unimoleral Nucleophile Substitution Reaction (sn1)**: - The reaction was carried out in two steps. The first step was to undergo a slow reaction of heterocracking of the aromatic compounds to form the active intermediate carbon ions. This step was the step that determined the reaction rate. The second step was to combine the carbon ions with the nuclophile to form a product. - The product was racemized. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to write the reaction equation of alkyls and bromines?
Under the illumination, the substitution reaction between the alkyls and the bromines occurred. The reaction equation was: CnH2n +2 + Br2 → CnH2n +1Br2 (expressed by the general formula). For example, the reaction of methane and helium: CH4 + Br2 → CH3Br4. Moreover, the reaction could not stop at the first order substitution. It could carry out the second and third order substitution reactions. Under heating conditions, the Bromine vapor will undergo the same bromination reaction with the alkyls, such as: CH3CH2CH3 + Br2-heating → CH3CHBrCH3 + Brr, and the product is also a variety of bromated alkyls. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Reaction Mode of the Aromatic Ring and the Ethylene
Under the effect of the laser, it was a free radical reaction. First, a homolytic crack occurred between the aromatic ring and hydrogen, producing hydrogen free radical and aromatic free radical. The hydrogen free radical reacted with the ethene to form an ethvl free radical, which then combined with the aromatic free radical to form the ethlene. There was also an addition reaction. The double bond of ethene was opened, and one end was connected to the aromatic ring. Thus, a hydrogen was removed from the aromatic ring, and this hydrogen was connected to the other end of the ethene. From the reaction mechanism, the pi bond in the ethene molecules was broken, and the aromatic ring was added. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Reaction Sequence of the Halogenides in the Aromatic Ring
In the reaction of the aromatic and aromatic compounds with the elemental halo, the reaction sequence is as follows: If there is a catalyst (such as iron powder), the substitution reaction on the aromatic ring occurs; under illumination, the side chain substitution reaction occurs. Moreover, since there was no carbon-carbon double bond on the aromatic ring, the reaction between the aromatic ring and the aromatic ring would only result in a substitution reaction, not an addition reaction. In addition, when there are many positions on the aromatic ring that can be replaced, for the reaction of the reaction between the ether and the water, if the consumption and chemical reaction are discussed, only the substitution of the ortho-and para-hydrogen atoms of the hydrogen group is considered (because the substitution yield of the meta-hydrogen atom is low), and the addition reaction is not considered. If the discussion is about the substitution of the ether, it is necessary to consider the meta-substitution. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Reaction equation of ethene and aromatic ring
Under the effect of the laser, it was a free radical reaction. During the reaction, the ring and hydrogen would undergo homolytic cracking, producing hydrogen free radical and aromatic free radical. The hydrogen free radical would react with the ethene to form an ethvl free radical, which would then combine with the aromatic free radical to form the ethvl radical. The reaction equation was: aromatic ring (C H)+ ethene (CH Chi =CH Chi) → Sword ether (C H- CH Chi CH). The reaction phenomenon was not specifically mentioned in the information provided, so it was impossible to give an accurate answer. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Diels Alder reaction mechanism
The reaction mechanism of the Diels-Alder reaction was generally considered to be a cycloidal reaction through a circular transition state. During the reaction, the two reagents were close to each other and interacted with each other to form a ring-shaped transition state, and then gradually transformed into product molecules. That is, the breaking of the old bond and the formation of the new bond were coordinated and completed in the same step. There was no intermediate formation. From the perspective of orbital theory, when a dienophile with an electron donating group and a dienophile with an electron withdrawing group were reacting, the smaller the energy difference between the frontier orbitals (the HOMO of the diene and the LUMO of the dienophile), the more stable the interaction between the orbitals was, thus making the reaction easier to carry out (electron demanding type). Similarly, the reaction between a dienophile with an electron donating group and a dienophile with an electron withdrawing group was also easier to carry out (anti-electron demanding type). The reaction was carried out according to the cis-addition of the cooperative reaction, and the endo addition product was generated first (endo rule). However, in the Diels-Alder reaction, although the second-order orbital interaction could roughly explain this rule, the endo/exo selectively generated exo products were also affected by the size. In addition, the Diels-Alder reaction within the molecules was not completely applicable to the endo rule due to the fixed ring structure and the low degree of freedom of the configuration. According to the theory of organic electrons, the addition product of the Diels-Alder reaction was more likely to place the substitution group in the ortho-or para-position (ortho-and para-rules). The details could be explained by the frontier orbital theory, that is, the reaction points with large HOMO-LUMO coefficient were easy to overlap and add. The cyclo-transition state of the diene could be added when the s-cisoid structure, but the s-transoid structure could not undergo the Diels-Alder reaction. Fantasy Realm is equally exciting. Everyone is welcome to click and read it!