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Cyclododecatrienes are cyclic trienes with the formula C 12 H 18.Four isomers are known for 1,5,9-cyclododecatriene. The trans,trans,cis-isomer is a precursor in the production of nylon-12.
A mixture of cis-decalin and CXB can simultaneously match optical index and density of PMMA. [1] Due to the moderate dielectric constant of CXB (ε = 7.9 [2]), PMMA acquires charges that can be screened by the addition of salt (e.g. tetrabutyl ammonium bromide), leading to a very good approximation of colloidal hard sphere. [3]
The reaction is highly stereospecific in the sense that the double bond stereochemistry is generally transferred to the relative configuration of the epoxide with essentially perfect fidelity, so that a trans-olefin leads to the stereoselective formation of the trans-2,3-substituted epoxide only, as illustrated by the example above, while a cis ...
Multiple double bonds take the form -diene, -triene, etc., with the size prefix of the chain taking an extra "a": CH 2 =CHCH=CH 2 is buta-1,3-diene. Simple cis and trans isomers may be indicated with a prefixed cis-or trans-: cis-but-2-ene, trans-but-2-ene. However, cis-and trans-are relative descriptors.
With cycloheptene, the cis-isomer is always assumed but the trans-isomer does also exist. One procedure for the organic synthesis of trans-cycloheptene is by singlet photosensitization of cis-cycloheptene with methyl benzoate and ultraviolet light at −35 °C. [2] The double bond in the trans isomer is very strained. [3]
cis is a mathematical notation defined by cis x = cos x + i sin x, [nb 1] where cos is the cosine function, i is the imaginary unit and sin is the sine function. x is the argument of the complex number (angle between line to point and x-axis in polar form ).
On the right side, E k (k = 1, 2, ..., M) is the energy of conformer k, R is the molar ideal gas constant (approximately equal to 8.314 J/(mol·K) or 1.987 cal/(mol·K)), and T is the absolute temperature. The denominator of the right side is the partition function.
Enoyl-CoA-(∆) isomerase (EC 5.3.3.8, also known as dodecenoyl-CoA-(∆) isomerase, 3,2-trans-enoyl-CoA isomerase, ∆3(cis),∆2(trans)-enoyl-CoA isomerase, or acetylene-allene isomerase, [1] is an enzyme that catalyzes the conversion of cis- or trans-double bonds of coenzyme A (CoA) bound fatty acids at gamma-carbon (position 3) to trans double bonds at beta-carbon (position 2) as below: