What is the main pathway for double bond activation, and what is the main pathway for C C double bon

Hello. c = c double bond coupling reaction which ones.

Ullmann coupling reaction example: terminal alkene bond coupling of iodobenzene surface c-c coupling ahaha, specific chachama literature, proline cuprous iodide as catalyst.

Can a compound with a c=n double bond be a fluorescent probe, it can be simply judged from the classification of the compounds, and the hydrocarbon compounds can be simply divided into three parts: saturated alkanes, alkenes, and alkynes, and the bonds in alkanes are all carbon-carbon single bonds, for example: ethane, ch3-ch3, and alkenes contain c=c double bonds in addition to carbon-carbon single bonds, for example.

The general formula of single-stranded olefin molecule is CNH2N, and C2-C4 is gas at room temperature, which is a non-polar molecule, insoluble or slightly soluble in water. The double bond group is a functional group in the olefin molecule, which is reactive, and can undergo addition reactions such as hydrogenation, halogenation, hydration, halohydrogenation, hypohalogenation, sulfate, epoxidation, polymerization, etc., and can also oxidize the cleavage of double bonds to generate aldehydes, carboxylic acids, etc.

Olefins generally use unsaturation to undergo addition reactions, and there is the above H substitution reaction, which is generally replaced by halogens.

Asymmetric olefins refer to olefins with different groups connected by two carbon atoms with double bonds of olefins.

Ethylene is a symmetric olefin, and all other olefins that contain a carbon-carbon double bond and are at the top of the carbon-carbon single bond are not asymmetric olefins.

For olefins of type with the general formula cxhy-ch=ch2, when n is an odd number, they are all asymmetric olefins. When x is an even number, there is an isomer that is a symmetric olefin, e.g., CX 2H(Y+1) 2-CH=CH-CX 2H(Y+1) 2

Olefins are hydrocarbons that contain C=C bonds (carbon-carbon double bonds) (alkene bonds). It is an unsaturated hydrocarbon, which is divided into chain olefins and cyclic olefins. According to the number of double bonds, they are called monoolefins, diolefins, etc. One of the double bonds is easy to break, so an addition reaction occurs.

The molecular structure is not symmetrical in terms of spatial geometry. For example, propylene, the carbon atoms on both sides of the double bond are more on one side and less on the other, which is an asymmetric olefin. And 1,4-dibutene is symmetrical.

Its essence is due to the oxidative rancidity of substances containing unsaturated bonds (fats, fatty acids, fat-soluble vitamins and other fat-soluble substances). Lipid oxidative rancidity is divided into automatic oxidative rancidity and microbial oxidative rancidity.

1. Automatic oxidation of grease.

The completely spontaneous oxidation reaction of the compound and the oxygen in the air at room temperature, without any direct light, without any catalyst, etc., proceeds with the reaction, and its intermediate state and primary products can accelerate its reaction speed.

The automatic oxidation of lipids is a chain reaction of free radicals, and its rancidity process can be divided into four stages: induction stage, propagation stage, termination stage and formation of secondary products.

2. Microbial oxidation of oils and fats.

Microbial oxidation is catalyzed by microbial enzymes. Lipoxidase, which is present in plant feed or lipoxidase produced by microorganisms, is the most susceptible to the oxidation of unsaturated fatty acids. Microorganisms such as fluorescein bacilli, aspergillus and penicillium have a strong ability to break down fats.

1. Influencing factors.

The most important factors affecting the rate of lipid oxidation are the degree of unsaturation of antioxidants, metals and lipids themselves, followed by moisture and its storage conditions (e.g. temperature and light). Linoleic acid and other polyunsaturated fatty acids oxidize much faster than oleic acid because the double bonds on both sides of the methylene are greatly activated.

Antioxidants are the most important factors affecting the oxidation rate of oils, and the amount of antioxidants contained in oils and fats is the determining factor for the stability of oils. In general, the optimal concentration of phenolic antioxidants is that if they are too low, the oil will not be sufficiently stabilized.

However, when the concentration exceeds a certain level, the stability of the oil increases very slowly, and when the concentration of some antioxidants is too high, the stability of the oil decreases. For quinone antioxidants, when their concentrations are high, the oxidative stability of oils and fats has an upward trend.

The physical properties of olefins can be compared with alkanes. The physical state is determined by the mass of the molecule. In standard or room temperature, ethylene, propylene, and butene are gases in simple olefins, linear olefins containing 5 to 18 carbon atoms are liquids, and higher olefins are waxy solids.

Under standard conditions or at room temperature, C2 and C4 olefins are gases; C5 and C18 are volatile liquids; C19 or above solids. In n-olefins, the boiling point increases as the relative molecular weight increases. The boiling point of n-olefins with the same carbon number is higher than that of alkenes with branched chains.

For the alkenes of the same carbon frame, the double bond moves from the end of the chain to the middle of the chain, and the boiling point and melting point are increased.