Initially, to evaluate the catalytic activity of Feist's acid for the Michel addition reaction
, indole 4 and [beta]-nitrostyrene 2a have been chosen as model substrates.
Although chiral ethers-crown are more resistant to decomposition and have been used successfully, for example, in asymmetric Michael addition reactions
, their high cost makes impracticable their use in industrial scale .
Alkenes in general are also known to undergo addition reactions
at lower temperatures.
After the Michael addition reaction
was complete as demonstrated by NMR, polyesterification was performed by increasing the reaction temperature to 120[degrees]C, adding 0.3 wt% titanium butoxide catalyst and applying reduced pressure (ca.
Table-2: Addition reaction
of 2-Mercapto-5-Methyl- [1, 3, 4] thiadiazde with oleic acid in the presence of catalyst
Recently, we have developed a mechanistic model that adequately predicted the Michael addition polymerization of BMI with BTA in the temperature range 383-423 K with the aid of adding sufficient HQ to completely suppress the free radical polymerization (5), This approach is capable of decoupling the rather complicated competitive Michael addition reaction
and free radical polymerization mechanisms, thereby leading to the true key kinetic parameters such as the reaction rate constants and activation energy for the Michael addition reaction
In the case of less bulky and especially bisphosphine chelating ligands, different types of 14-electron Pd[L.sub.2] complexes have been postulated as active catalysts, and corresponding products of the oxidative addition reactions
to such complexes have been characterised [37-40].
The three new adhesive types are two-component, colorless and transparent silicone gels that crosslink via a platinum-catalyzed addition reaction
to form soft, highly flexible materials with an elastic, gel-like consistency.
It is miscible in xylene with the PDMS containing vinyl group of 10 mol% and the HSO to prepare easily the CHM by silicon-hydrogen addition reaction
at room temperature by means of casting solution method.
Caption: FIGURE 1: Free energy profile for the [3 + 2] and [2 + 2] addition reaction
between CpCo[(NO).sub.2] and ethylene.
Ammonium chloride which is inexpensive and readily available reagent catalyzes the thia-michael addition reaction
of thiols in water efficiently.
With the reactive bismaleimide groups (two terminal -C=C-groups), BMI can polymerize with active hydrogen atom-containing species such as polyamines via the Michael addition reaction