Amine based processes

For example, if the BN bond were to break during the dehydrohalogenation process amine bases could be chosen that selectively capture a proton while the halogenated boron species remains uncoordinated due to steric hindrance. This concept is related to the recently published frustrated Lewis pair concept used for hydrogen activation by sterically demanding borane and amine species [104]. 

Decomposition to styrene and carbon dioxide has been observed upon heating the acid to temperatures in excess of 150°C. The decarboxylation process can be accelerated with the addition of a bicycHc amine base (9). 

This process is based on the very high reactivity of the isocyanate group toward hydrogen present ia hydroxyl groups, amines, water, etc, so that the chain extension reaction can proceed to 90% yield or better. Thus when a linear polymer is formed by chain extension of a polyester or polyether of molecular weight 1000—3000, the final polyurethane may have a molecular weight of 100,000 or higher (see Urethane polymers). 

In certain direct steam-contact process applications (such as in food and beverage processing or pharmaceutical preparations) the use of amine-based products in steam and condensate systems is subject to legal restrictions. Also, the use of ammonia or amines may be dependent on the materials of construction employed or technical limitations (such as the risk of copper alloy corrosion). 

Figure 4. Diagram of a conventional C02 capture process using amine-based chemical absorption.

The most important ruthenium-catalyzed domino process is based on a metathesis reaction. Nonetheless, a few other ruthenium-catalyzed processes have been employed for the synthesis of substituted 3,y-unsaturated ketones, as well as unsaturated y-lactams and allylic amines. 

Different variations of the hot carbonate process exist (e.g., Catacarb and Benfield) based on proprietary catalyst used to enhance the rate of reactions, for example, formaldehyde, arsenite, and hypochlorite. The activation by catalysts is apparently necessary to make the process economical compared with the amine-based processes. 

Cansolv A "flue-gas desulfurization process based on the selective absorption of sulfur dioxide in certain amine-based organic solvents. Developed by Union Carbide Corporation the first plant was planned for startup at Newburgh, IN, in 1994. See HS. 

Preparation of formamides from COz and a non-tertiary amine by homogeneous hydrogenation has been well studied and is extremely efficient (Eq. (12)). Essentially complete conversions and complete selectivity can be obtained (Table 17.3). This process seems more likely to be industrialized than the syntheses of formic acid or formate esters by C02 hydrogenation. The selectivity is excellent, in contrast to the case for alkyl formates, because the amine base which would stabilize the formic acid is used up in the synthesis of the formamide consequently little or no formic acid contaminates the product. The only byproducts that are likely to crop up in industrial application are the methylamines by overreduction of the formamide. This has been observed [96], but not with such high conversion that it could constitute a synthetic route to methylamines. 

In an attempt to further improve the yield and address the product color issue, the following process variables were studied the rate of addition of acetoxyacetyl chloride, the reaction temperature, and the effect of other amine bases. 

Although, from a historical standpoint the cinchona alkaloids also occupy a central position in the field owing to their use as catalysts for the alcoholative ASD of meso anhydrides (a Type II process, see Schane 2), the past few years have witnessed an explosion of interest in the development of other classes of iert-amine-based catalysts primarily for Type I processes. 

CANSOLV is an amine based regenerative scrubbing technology. It was originally developed by Union Carbide and acquired by Shell Global Solutions in 2008. The technology uses a unique amine to absorb SO. The process chemistry is outlined in Figure 16.10. 

The chiral enolate-imine addition methodology was examined in detail (Thiruvengadam et al., 1999). Enolate formation proceeds to completion within an hour at temperatures from — 30 to 0°C with either 1 equiv. TiCl4 or TiClaO-iPr (preformed or prepared in the presence of substrate by addition of TiCl4 and followed by a third of an equivalent Ti(0-iPr)4 and two equivalents of a tertiary amine base). Unlike the aldol process with the same titanium enolate, the nature of the tertiary amine base had no effect on the diaster-eoselectivity. The diastereoselectivity is maximized by careful control of the internal temperature to below — 20°C during the imine addition (2 equiv.) as well as during the acetic acid quench. The purity of the crude 2-amino carboxamide derivatives (17a or... 

Material accountability (the sum of recovered chloropinacolone, methyl pivaloyl acetate, and pinacolone) with the active Pd monophosphine and carbene complexes was in the range of 92-99% without accounting for impurities present in the starting chloropinacolone. A GC-MS examination of several product mixtures was undertaken to see if there were any additional, unanticipated by-products. The only additional material identified was a-methoxy pinacolone (l-methoxy-3,3-dimethyl-2-butanone). This compound was formed by methanolysis of the starting a-chloropinacolone and appears to be formed by a mixture of catalyzed and uncatalyzed processes Since this product was not anticipated, it was not quantified but represents the majority of, if not the only, remaining volatile product. No attempt was made to determine the presence of any quaternary ammonium salt formed by similar alkylation of the amine base by a-chloropinacolone. 

This problem is not common and is not expected. However, in a situation of gross overtreatment with an amine-based processing aid, interaction with a carboxylic acid based corrosion inhibitor is possible. In dilute solution within the fuel, it is unlikely that these compounds will react since only low levels, <5 ppm, of filmer or neutralizer will typically carry over into finished fuel. If the two do react, the product formed will provide corrosion protection, but not as effectively as the unreacted carboxylic acid based inhibitor. 

Evaluate the finished fuel for possible carryover of an amine-based processing additive into the final fuel blend. Many of the analytical techniques needed to... 

Ethyleneamine Processes. Present industrial processes are based on ethylene and ammonia. The sixly-year-old ediylcne dichloride (EDC) proeess is still the mosl widely practiced industrial route for producing ethylene amines. 

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