Aldehyde-amine condensation

Sour gas sweetening may also be carried out continuously in the flowline by continuous injection of H2S scavengers, such as amine-aldehyde condensates. Contact time between the scavenger and the sour gas is the most critical factor in the design of the scavenger treatment process. Contact times shorter than 30 sec can be accommodated with faster reacting and higher volatility formulations. The amine-aldehyde conden-... 

The advantages of amine-aldehyde condensates are water (or oil) soiu ble reaction products, lower operating temperatures, low eorrosivenL to, ind no reactivity with hydrocarbons... 

Hydroaminomethylation is hydroformylation coupled to amine-aldehyde condensation followed by hydrogenation. The hydroformylation reaction establishes... 

Amine compounds including primary amines and amine-aldehyde condensation products are commonly utilized as fuel sweetening applications. Primary amines will react with H2S to form amine sulfide compounds. These products are somewhat unstable and may tend to solubilize into water. 

Amine-aldehyde condensation compounds are believed to react with H2S to form more complex carbon-sulfur bonded products. 

Molecular self-assembly will not be considered here (see [9.2]) in fact, it is a special type of synthetic procedure where several reactions between several reagents occur in one experimental operation to yield the final covalent structure it is subject to control by the intramolecular conformational features of intermediates and by the stereochemistry of the reaction(s) the efficient assembly of a covalent structure may require that the connecting reaction(s) be reversible so as to allow searching for the final structure. Examples are found in the generation of macropolycyclic structures by multiple (amine-aldehyde) condensations (see Section 4.1) or of porphyrinogens, porphyrins and phthalocyanins (see also in [9.13a]. 

Amine-aldehyde condensations. Sometimes known as a Schiff base condensation, the reaction of dialdehydes with diamines has been used extensively in the preparation of macrocyciic ligands for metal cations. Reduction of the resulting imine (C = N) group with NaBH4 gives the corresponding aliphatic amine (Section 3.10.6). 

Amine-aldehyde condensate CASSOFIX American Hoechst... 

To date, no known bisindole alkaloid has been shown to be only an artefact. In addition, no experimental evidence exists which undermines the assumption that bisindole alkaloids are actually formed from the completed monomeric partners. Support for this idea is derived from the kind of reactions apparently necessary to effect such dimerisations which are known biogenetic processes amine-aldehyde condensations, Mannich reactions, Michael additions, Friedel-Craft type condensations, Diels-Alder type processes, radical coupling etc. The observation that the skeletal distribution amongst monomeric alkaloids is reflected throughout the dimeric series lends further support. 

Sitz et al. (2003) worked on amine-aldehyde condensates, and they concluded that these cou-densates are suitably used for hydrogen sulfide removal from the produced fluids to meet the sales specification for the maximum allowable hydrogen sulfide concentration in the gas of 4 ppm. But one of the drawbacks associated with the products is their expensiveness. 

They stressed further that nitrate solutions, acrolein, caustic scrubbing, formaldehyde, and amine-aldehyde condensates are best applied as scavengers (for sweetening purposes) in produced oil, water, and gas (Sitz et al. 2003). 

Specifically, the adhesives described by Briggs and Muschiatti employ chlorosulfonated polyethylene or mixtures of sulfonyl chlorides and chlorinated polymers as the toughening system. The toughener is dissolved in methyl methacrylate and an amine/aldehyde condensation product is used as the curative. These compositions are described as useful with or without the traditional hydroperoxide initiator. Compositions without hydroperoxide are noticeably slower to cure. 

Structural acrylic chemistry is very similar to anaerobic chemistry. The differences arise in the reactions that take place to initiate polymerization. The common initiator/curative redox couple in structural acrylic technology, hydroperoxide/amine-aldehyde condensate, reacts to generate alkoxy radicals. The exact fate of the DHP in the redox reaction is not known. However, a likely first step involves hydrogen abstraction as shown in Eq. (7). 

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