Alkanolamides amide ester

Significant quantities of amine and amide esters are formed by side reactions (9). In addition, with dialkanolamines, amide diesters, morpholines, and piperazines can be obtained, depending on the starting material. Reaction of dialkanolamines with fatty acids in a 2 1 ratio, at 140—160°C, produces a second major type of alkanolamide. These products, in contrast to the 1 1 alkanolamides, are water soluble they are complex mixtures of AJ-alkanolamides, amine esters, and diesters, and still contain a considerable amount of unreacted dialkanolamine, accounting for the water solubiUty of the product. Both the 1 1 and the 2 1 alkanolamides are of commercial importance in detergents. 

The reaction is a two-stage reaction with the initial formation of the alkanolamine soap followed by dehydration to form the alkanolamide. At the same time, significant quantities of amine esters and amide esters are formed by the side reaction. If a dialkanolamine is used as the starting material, smaller amounts of amine diester and amide diester are formed as well as some morpholine and piperazine derivatives. 

There are at least four types of alkanolamide commercially available. The first is formed by reacting monoalkanolamine or dialkanolamine with fatty acids in a 1 1 ratio at elevated temperatures of 140-160°C. Signihcant quantities of the byproducts—amine esters and amide esters—are also formed. 

These surfactants are produced by reacting fatty acids or fatty methyl esters with ethanolamine or diethanolamine. With fatty acids, conventional amides (sometimes called Kritchevsky alkanolamides) are obtained that consist of approximately 50% amide, 25% unreacted diethanolamine and 25% of various by-products (the amine ester the amide ester, and the amine soap). With methyl esters, higher-active (90% amide) alkanolamides are produced these are known as super amides . 

Figure 8.4 Alkanolamide synthesis by lipase-catalysed acylation of ethanolamine with a fatty acid. O-Acyl ester is formed as an intermediate product, which is immediately converted to the amide by acyl migration. When add Is In excess, the amide will react further with the acid, yielding the amide ester. The amide ester can be converted back into the amide through hydrolysis or aminoiysis in the latter case two moles of amide will be formed from one mole of amide ester.

Figure 8.5 Solvent-free synthesis of alkanolamide from lauric acid (0.5 mol) and monoethanolamine (0.5 mol) catalysed by Novozym 435 at 90°C. Water is removed throughout the reaction by vacuum. Half the molar amount ofethanolamine is added at the start of the reaction and the remaining amount is added in steps over a period of 4 hours, indicated by the dotted line. Symbols amide (0), amide ester (A) and lauric acid ( ).

Uses Intermediate for mfg. of detergents, amides, esters, alkanolamides, methyl ester sulfonates, rolling oils, low-volume soivs., metal working fluids Regulatory Not regulated for transport Canada DSL Australia Korea Japan ENCS Philippines China... 

Alkanolamides, a special subclass of substituted amides used as surfactants, are produced by three principal methods the reaction of fatty amides with formaldehyde, fatty acids with hydroxyalkylamines, and fatty esters with hydroxyalkylamines (37). A fatty amide and formalin can be heated in the presence of sodium hydroxide to yield 70—95% substituted alkanolamides (38,39). 

Sulfated Acids, Amides, and Esters. Reaction with sulfuric acid may be carried out on fatty acids, alkanolamides, and short-chain esters of fatty acids. The disodium salt of sulfated oleic acid is a textile additive and an effective lime soap dispersant. A typical sulfated alkanolamide stmcture is CiiH23C0NHCH2CH20S03Na. Others include the sulfates of mono and diethanolamides of fatty acids in the detergent range. The presence of... 

Superior to fatty acids as chemical intermediates in some applications. In the production of alkanolamides, esters can produce superamides, with more than 90% purity against fatty acids, which can only produce amides with a purity of 65-70% amides. 

Early experiments in the preparation of alkanolamides were begun by Kritchevs-ky (24, 25). It involves condensation reactions of fatty acids, triglycerides, esters, amides, anhydrides, and halides with an alkanolamine. The reaction was carried out at 100-300°C at atmospheric pressure. An important improvement was made by... 

Alkanolamides are the reaction products of mono- or dialkanolamines with fatty acids or their esters to form the respective secondary or tertiary amides, examples of which are depicted in Scheme 1.8. " Monoalkanolamides can be prepared by the reaction of monoalkanolamines with triglycerides such as coconut or palm kernel oil as well as from fatty acids or their methyl esters. The reaction of MEA with triglyceride at temperatures of 140-160°C liberates glycerin as a by-product, and because of the stability of the secondary amide formed, the reaction can be driven to a very low ester content with only a slightly super-stoichiometric amount of MEA. 

Alkanolamides based on DEA are tertiary amides and are not as stable as MEA amides such that a significant amount of esters can remain in equilibrium with the amide. The ester amines and esteramides of DEA have undesirable performance properties, but these components can be reduced by utilizing an excess of DEA to drive equilibrium toward the amide form. The most common version is prepared by the reaction of 2 moles of DEA with 1 mole of coconut fatty add or ester to give the Kritchevsky or Ninol-type DEA amide, which is liquid at room temperature. Products made with slightly more than a 1 1 molar ratio of DEA to fatty acid or ester are referred to as superamides and at reaction temperatures of 140-160°C, the mixture contains high level of ester components and free amine. However, with sufficient time at storage temperatures <50°C, the composition will increase in amide and decrease in ester and free-amine components and thus can be aged into specification for free DEA and ester content. 

Alkanolamides that are liquid at room temperature have been commercialized based on increased content of unsaturated C18 acids, use of branched alkanolamines such as monoisopropa-nolamine (MIPA), or propoxylation of MEA amides, as well as blends of all these with PEG esters to improve thickening performance of the products. The higher cost of the earlier-mentioned feedstocks... 

Early experiments in the preparation of alkanolamides were begun by Kritchevsky (20, 21). It involves condensation reactions of fatty acids, triglycerides, esters, amides, anhydrides, and halides with an alkanolamine. The reaction was carried out at 100-300°C at atmospheric pressure. An important improvement was made by Meade (22), who made use of an alkali metal alkoxide as a catalyst at 100°C at atmospheric and slightly above atmospheric pressure. Fmther refinement was made by Tesoro (23), who conducted the reaction at 55-75°C and a vacuum of 4—8 kPa. Schurman (24) patented a continuous process for making alkanolamide, which makes use of a thin film reactor. It is claimed the short contact time in the reactor produces a high-purity alkanolamide (25). 

Type 2 1 (or Kritchevsky alkanolamide) is a mixture of mono- or dialkanolamide and free mono- or dialkanolamine. It results from the reaction of a fatty acid or ester with mono- or dialkanolamine, this last component being combined at a 2 1 molar proportion. Reaction residues in type 2 1 surfactants are free alka-nolamine, unreacted fatty acid, and ester-amide. 

In both production routes, the two alkanolamides can also react to yield an ester-amide and the corresponding alkanolamine. Type 1 1 alkanolamides have poor water solubility at room temperature type 2 1 alkanolamides are much more soluble due to the presence of the free diethanolamine. 

The most common examples of this class are diesters of 2-ethylhexanol. However, there are commercial products which are monoesters, diesters, or mixtures of the two. The alcohol portion of the ester may be fatty alcohol, fatty acid alkanolamide, or ethoxylated fatty amine. They are typically synthesized by forming the ester or amide with maleic anhydride, followed by reaction of the alkyl fumarate with sodium bisulfite. The monoesters are often used in cosmetics and shampoos. 

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