Acrolein addition reaction

Since the principal hazard of contamination of acrolein is base-catalyzed polymerization, a "buffer" solution to shortstop such a polymerization is often employed for emergency addition to a reacting tank. A typical composition of this solution is 78% acetic acid, 15% water, and 7% hydroquinone. The acetic acid is the primary active ingredient. Water is added to depress the freezing point and to increase the solubiUty of hydroquinone. Hydroquinone (HQ) prevents free-radical polymerization. Such polymerization is not expected to be a safety hazard, but there is no reason to exclude HQ from the formulation. Sodium acetate may be included as well to stop polymerization by very strong acids. There is, however, a temperature rise when it is added to acrolein due to catalysis of the acetic acid-acrolein addition reaction. 

Also, Michael addition reactions occur between Ai-acylaminomalonic acid esters and unsaturated compounds, ie, acrolein [107-02-8] acrylonitrile [107-13-1y, acryhc acid esters, and amino acids result from hydrolysis of the addition products. 

Bicyclic alcohols with angular methyl groups (11, 10-11). The reaction of 2,5-dimethylmethylenecyclopentane (1) with acrolein (1 equiv.) and (CH3)2A1C1 involves two sequential ene reactions to give the expected bicyclic alcohol 2 (69%) and in addition the corresponding ketone 3 (12% yield), even in the absence of an oxidant.6 In the presence of 2 equiv. of acrolein, the reaction results in 3 in 60% yield and only 1% of 2. Apparently, the alkoxide precursor to 2 undergoes... 

This reaction is the acid-catalyzed counterpart of a 1,4-addition reaction to an a,l3-unsaturated carbonyl compound. Chloride ion, without an acid present, will not add to acrolein. That is, chloride ion is not a strong enough nucleophile to drive the reaction to the right. However, if the carbonyl is protonated, the intermediate cation is a stronger electrophile and will react with chloride ion. 

The addition of trialkyl phosphites to acrolein was first investigated in dioxane solution. However, despite a rather effective control of the conditions, isolation of a pure product was difficult. The reaction generally furnishes the conjugated addition product in low yields in the enol ether form. Among a number of factors that may affect the completion of such a conjugate addition reaction, the dealkylation of the zwitterionic adduct is crucial to the success of the reaction to exclude the inter- and intramolecular competition that can lead to production of mixtures of products, including acetals, enol ethers, and simple carbonyl compounds. - ... 

It is curious to note that fV-CBA-inactivated MAO continues to produce acrolein at pH 7, but at pH 9 incorporates up to 40 equivalents of acrolein into the protein in a time-dependent manner. The increased incorporation at higher pH is consistent with the ionization of nucleophilic groups that partake in Michael addition reactions with the liberated acrolein. The continued production of acrolein after complete inactivation results from reactivation-inactivation cycling of the enzyme by the iV-CBA inhibitor (103). However, with 7Y-(l-methyl)cyclopropyIbenzylamine, the inactivated and reduced enzyme does... 

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