The product from the reaction is subjected to solvent extraction with chloroform and then followed by purification with n-hexane, ethanol and acetonitrile via recrystalization method. Such an oleylamide is preferred for application as a mould release agent, slip agent in plastic film production, water repellent and as a raw material for cosmetics production.
More particularly, the present invention relates to a process for the production of fatty acid amides, particularly oleylamide, which utilises microwave irradiation as the heating element for the reaction between fatty acids and gaseous ammonia liberated by urea in the presence of a Lewis catalyst at atmospheric pressure and high temperature. These reactions can be accomplished with or without catalyst at elevated temperature and at very high pressure as described in U.
Accordingly, catalytic procedures have been developed whereby the reaction of the fatty acids with ammonia can be achieved by substantially reduced pressures and, in some cases, even at atmospheric pressure. The major drawback -for such process is that it typically requires very long reaction time that may be 48 or more hours to achieve acceptable levels of conversion and consequently some of the amide is dehydrated to the corresponding nitrile.
One of the competing reactions in amidation of carboxylic acids to amide is the dehydration of amide to nitrile, and this is promoted by long reaction time, therefore short reaction time is preferred in order to achieve higher yield of amide. Processes requiring shorter reaction time and employing reaction condition, which minimise undesirable by-product formation, have been developed.
According to U. The catalysts used in this process are from the Group IVb or Vb metal, preferably a compound of titanium, zirconium or tantalum. Furthermore, in U. Other than that, U. This process requires high. In view of starting materials for the synthesis of fatty acid amide, most commonly used raw material is the fatty acid itself, but British Patent No. GB discloses the use of long carbon chain fatty esters C12 to C30 as the feed stock and reacting it with gaseous ammonia under high pressure and temperature.
Non patent literature Cravatt et al revealed the use of acid halide typically the one with chlorine atom, which is more reactive compare to fatty acid and esters when react with ammonia. On the other hand, most of the prior art use gaseous ammonia as starting material to react with the fatty moiety to give the desired amide. Other than that, the U. In general, it can be said that the usual methods have at least one of three serious drawbacks.
Either the methods require long reaction time of at least 11 hours as disclosed in U. Accordingly, it is an object of this invention to provide such a method of synthesis for normal amide of fatty acids. It is a further object of this invention to provide such a method of synthesis that will give high percentage yield of amide with a short reaction time.
Allowing even minor amounts of oxygen to enter the reaction vessel will cause significant color. Thus, it is preferred that all possible measures be taken excluded oxygen. Elevated temperature is greatly preferred for complete reaction. In the preferred embodiment wherein the amine is diethylenetriamine, the product is a diakylamidoethylimidazoline of the formula STR2 wherein each R2 represents the residue of the particular fatty acid used in the reaction.
The hypophosphorous acid and the hindered phenol compound are each present in a synergistic mixture. By "synergistic mixture" is meant that each is present, relative to the other, in an amount such that the mixture is more effective at reducing color in the product than an equivalent weight of either component alone. Further, the hypophosphorous acid and the hindered phenol compound are used together in a color stabilizing amount.
By "color stabilizing amount" is meant an amount of the mixture, in relation to the reactants and product, which is sufficient to render the product less colored than if the hypophsophorous acid and hindered phenol compound were not present.
Following the above requirements, the hypophosphorous acid is desirably at 0. The hindered phenol is desirably present at 0. The color of the amides produced by the process of the invention is very low, and remains relatively low during storage. The storage stability can be further increased by a post-reaction addition of the hindered phenol, but such post reaction addition is not as important when the preferred high molecular weight hindered phenols are used in the initial reactor charge.
If a post treatment is used it is used in a post treatment color stabilizing amount. By "post treatment color color stabilizing amount" is meant an amount of the hindered phenol which, when added subsequent to the reaction, will render the amide more color stable than if it were not added. The hindered phenol is thusly present as a post treatment in an amount of 0. The invention will be further illustrated by the following examples. In the examples, all parts and percentages are by weight unless otherwise specified.
The vessel is charged with 1 equivalent tallow acid, 0. The vessel is flushed with nitrogen to remove all oxgyen and 1 equivalent diethylene triamine is added. The amides of ricinoleic acid and oleic acid were also produced for comparison. The hydroxy FA were transformed at comparable rates to that of oleic acid.
The rate of amide formation was greater for the longerchain lesquerolic acid than for ricinoleic acid. Other peaks present are consistent with cleavage on either side of the hydroxyl position. The mass spectra, together with 1H and 13C NMR data, suggest that the products of lipase-catalyzed direct amidation of ricinoleic acid and lesquerolic acid are hydroxy-9 Z -octadecenamide and hydroxy Z -eicosenamide, respectively.
Preview Unable to display preview. Download preview PDF. References 1. Hayes, D. Oil Chem. Google Scholar 2. Biermann, U. Friedt, S. This is consistent with the statistical analysis wherein further increase of the molar ratio gives a negative and significant effect of However the influence of the interaction between molar ratio and enzyme amount gives a positive and a significant effect of 6.
It is possible because increasing in enzyme amount which is followed by the increase of the substrate molar ratio allows the high enzyme substrate complex . At this condition, the amide conversion can be reached up to From the contour response in Fig.
At this range of temperature level, more likely an increase in lipase activity in the amidification reaction. Under this condition, the increasing substrate molar ratio increases the oleic acid conversion.
However, further increase in the substrate molar ratio would likely result in a sharp decrease in oleic acid conversion. It is due to the barrier product where the enzyme active space binds to the substrate has full, thus the enzyme no longer able to synthesize the substrate.
From the contour response in Fig. However, consumer uses for fatty amides such as fabric softeners require low color, and high color fatty amides are not saleable in such applications. Allowing even minor amounts of oxygen to enter the reaction vessel will cause significant color. A first component of the invention is a C4 to C22 carboxylic acid.
It is a still further object of this invention to provide such a method of synthesis that does not require the use of expensive intermediate compounds. Friedt, S. As a result, the reaction time is very short and the yield of desired product is considerably high. Preview Unable to display preview. Furthermore, in U. Under this condition, amine groups are protonated and then cannot be reacted with the acyl enzyme.
While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention. A nitrogen flow of about 0. The rate of amide formation was greater for the longerchain lesquerolic acid than for ricinoleic acid.
EXAMPLE 4 The same experiment was repeated by using tetra-n-ethyl titanate as the Lewis acid catalyst, while the other reaction parameters remained the same as Example 1. One problem unaddressed by these solutions is that after decolorization, the fatty materials will tend to become colored during storage. It is possible because increasing in enzyme amount which is followed by the increase of the substrate molar ratio allows the high enzyme substrate complex . Bilyk, and S. Further increase of the molar ratio decreases the conversion because when the molar ratio of substrate exceeded the optimum then the active space of the reaction is reduced so that reducing the possibility of particle collisions.
Hou, C. It is possible because increasing in enzyme amount which is followed by the increase of the substrate molar ratio allows the high enzyme substrate complex . If triglicerides are used, glicerine, rather than water, will be removed during the reaction. It is another object of this invention to provide such a method of synthesis that does not require high pressure to give high percentage yield of fatty amide. The vessel is charged with 1 equivalent tallow acid, 0. It has been reported that fatty amide can be produced from the reaction between fatty acid and ammonia without the present of a catalyst but the yield of fatty amide is considerably low.
The ammonia gas may come from nitrogenous compounds that can liberate gaseous ammonia upon heating such as urea and thiourea. The observations are in line with Zhang and associates , which concluded that the addition of base through increased amine ratio to the reaction mixture would increase the yield of amidification. Yet another approach is the use of liquefied hydrocarbon gases such as propane to extract colored components. The results are in line with the results of analysis of variance where the influence of substrate molar ratio is more dominant than the effect of temperature and enzyme amount.
While it is not necessary to dry the urea or reactant s , excessive amounts of water should not generally be present therein. Under this condition, amine groups are protonated and then cannot be reacted with the acyl enzyme. On the other hand, if the ratio amine and oleic acid is greater than one, the media reaction is alkaline and amidification reaction is more dominant because there is more reactive amine group.
The storage stability can be further increased by a post-reaction addition of the hindered phenol, but such post reaction addition is not as important when the preferred high molecular weight hindered phenols are used in the initial reactor charge. The analysis of variance shows that there is limitation of enzyme amount to be added into reaction. McLafferty, F.
References Zhang, J. Accordingly, catalytic procedures have been developed whereby the reaction of the fatty acids with ammonia can be achieved by substantially reduced pressures and, in some cases, even at atmospheric pressure.