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The reaction conducted in two steps beginning with the conversion of DMT to the diester dimethyl 1,4-cyclohexanedicarboxylate (DMCD): C 6 H 4 (CO 2 CH 3) 2 + 3 H 2 → C 6 H 10 (CO 2 CH 3) 2. In the second step DMCD is further hydrogenated to CHDM: C 6 H 10 (CO 2 CH 3) 2 + 4 H 2 → C 6 H 10 (CH 2 OH) 2 + 2 CH 3 OH. A copper chromite catalyst ...
In this molecule, the two methyl groups are in opposing positions of the ring (1,4-), and their cis stereochemistry projects both of these groups toward the same side of the ring. Hence, if forced into the higher energy boat form, these methyl groups are in steric contact, repel one another, and drive the equilibrium toward the chair conformation.
These groups can be cis or trans. Other isomers of cyclohexanedicarboxylic acid are known, but the 1,4- isomers are of greatest interest, perhaps because they are obtainable from a commodity chemical. Specifically, hydrogenation of terephthalic acid affords the title compound: [1] C 6 H 4 (CO 2 H) 2 + 3 H 2 → C 6 H 10 (CO 2 H) 2.
The silver salt 1 reacts with bromine to form the acyl hypohalite intermediate 2. Formation of the diradical pair 3 allows for radical decarboxylation to form the diradical pair 4, which recombines to form the organic halide 5. The trend in the yield of the resulting halide is primary > secondary > tertiary. [2] [3]
The anion reacts with bromine in an α-substitution reaction to give an N-bromoamide. Base abstraction of the remaining amide proton gives a bromoamide anion. The bromoamide anion rearranges as the R group attached to the carbonyl carbon migrates to nitrogen at the same time the bromide ion leaves, giving an isocyanate.
[1] The general chemical formula of the halogen addition reaction is: C=C + X 2 → X−C−C−X (X represents the halogens bromine or chlorine, and in this case, a solvent could be CH 2 Cl 2 or CCl 4). The product is a vicinal dihalide. This type of reaction is a halogenation and an electrophilic addition.
These compounds usually form the -1, +1, +3 and +5 oxidation states. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger ...
Compared with its isomer cyclohexa-1,4-diene, cyclohexa-1,3-diene is about 1.6 kJ/mol more stable. [5] Cyclohexadiene and its derivatives form (diene)iron tricarbonyl complexes. Illustrative is [(C 6 H 8)Fe(CO) 3], an orange liquid. This complex reacts with hydride-abstracting reagents to give the cyclohexadienyl derivative [(C 6 H 7)Fe(CO) 3 ...