PROCESS AND METHOD FOR TREATING ALKYLAMINES
FIELD OF THE INVENTION The present invention relates to treatment of alkylamines to reduce impurities. More specifically, the present invention relates to a process and/or method for combining a catalyst with the alkylamine under specific conditions, to produce an improved alkylamine product.
BACKGROUND OF THE INVENTION Alkylamines, particularly monoalkylmethyl amines and dialkylmethyl amines, are known for use in many applications such as being a precursor for surfactants, such as amine oxide, and softeners, such as quaternary amines. Such alkylamines may be produced by a number of known processes including direct amination which will directly add an alcohol to an amine with at least one replaceable hydrogen present, in the presence of a catalyst, temperature, and pressure. Alkylamines are also made from the conversion of an alcohol to an alcohol sulfate or alkyl halide, which then reacts with an amine that has at least one replaceable hydrogen present. Alkylamines are also made from olefins, which are converted to an alkyl halide via the anti-Markonikoff reaction. The alkyl halide is then reacted with an amine that has at least one replaceable hydrogen present to form the final alkylamine. However, the known production processes for alkylamines often produce unwanted by-products such as flocculant precipitate (commonly known as "floe"). Floe may occur in alkylamine products as either a grey or blue haze or a solid precipitate. It is believed that the two of the components of floe are monoalkyltrimethylammonium halide (MAQ) and diallyldimethylammonium halide (DAQ). It is believed that DAQ is formed by the reaction of residual alkyl halide, particularly alkyl bromide, with the alkyldimethylamine product. MAQ is believed to be formed by a two-step process where DAQ thermally degrades forming dialkylamine and methyl bromide. The methyl bromide then reacts with the alkyldimethyl amine product to form MAQ.
After manufacture of the alkylamine, floe may or may not be visibly present. The solid floe precipitate normally occurs in product samples which have been stored for a few days or longer after production. It is also common for the presence of floe to increase with longer storage. Floe can be filtered out, but will come back in storage again if the alkyl halide reactant is not removed. Other undesirable by-products from alkylamine production include color-body precursors. Color-body precursors, although not problematic in the alkylamine product itself, can cause undesirable discoloration to occur in products that are made from or incorporate such alkylamines, such as quaternary amines. Color-body precursors are presumed to be formed by trace amounts of aldehydes, ketones, esters, fats, and residual olefins in alkylamines. Although processes are known for reducing the amount of floe or color-body precursors present in alkylamines, there is still a need for further improvements, especially those that reduce both floe and color body precursors in an efficient, time- saving, and or cost-saving manner.
SUMMARY OF THE INVENTION It has now surprisingly been discovered that a treatment of an alkylamine with a catalyst that is an alkali metal alkoxide, alkaline earth metal alkoxide, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal hydride, alkaline earth metal hydride, alkali metal, alkaline earth carbonate, alkaline earth phosphate, alkaline earth silicate, or a mixture thereof can generate an alkylamine having low color-body precursors and low floe. The present invention therefore relates to processes and/or methods for treating alkylamines to reduce floe and/or color body pre-cursors, the process including the sequential steps of: a) combining an alkylamine with a catalyst that is selected from alkali metal alkoxides, alkaline earth metal alkoxides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrides, alkaline earth metal hydrides, alkali metals, alkaline earth carbonate, alkaline earth phosphate, alkaline earth silicate and mixtures thereof to form a base slurry;
b) reacting the catalyst with the alkylamine by heating the base slurry to a temperature of from about 80°C to about 200°C to form a reaction slurry; c) separating the reaction slurry at a pressure of about 10mm Hg or below and at a temperature of from about 100°C to about 200°C to form a top cut comprising an amine and a bottom cut comprising undesirable by-products; and d) removing the top cut to form an amine product.
The present invention further relates to the above process and/or method wherem an "alkylamine" refers to compounds having the formula: R2 Ri N
R3
wherein each of Ri , R2, and R is independently selected from hydrogen, alkyl chains having from 1 to 24 carbon atoms, and mixtures thereof. The present invention further relates to the above process and/or method wherein Ri is selected from alkyl chains having from about 8 to about 18 carbon atoms. The present invention further relates to the above process and/or method wherein R2 and R3 are independently selected from alkyl chains having from about 1 to about 4 carbon atoms. The present invention further relates to the above process and/or method wherein the catalyst is an alkaline earth metal alkoxide. The present invention further relates to the above process and or method wherein the alkaline earth metal alkoxide is sodium methoxide. The present invention further relates to the above process and or method wherein the alkylamine is selected from N, N-dimethyl 1-Decaneamine; N, N-dimethyl 1- Dodecaneamine; N, N-dimethyl, 1-Tetradecaneamine; N, N-dimethyl 1- Hexadecaneamine; and mixtures thereof.
The present invention further relates to the above process and/or method wherem the alkylamine is a alcohol or olefm-based amine that contains alkyl halide, olefms, and or carbonyl-containing compounds (aldehydes/ketones). The present invention further relates to the above process and/or method wherein the base slurry comprises from about 0.1% to about 10%) sodium methoxide. The present invention further relates to the above process and/or method wherein the base slurry comprises from about 0.1% to about 10% potassium carbonate. The present invention further relates to the above process and/or method wherein the separation of the reaction slurry is performed by use of a vacuum. The present invention further relates to the above process and/or method wherein the amine product is substantially free of floe and/or color body pre-cursors after 6 weeks period of time. The present invention further relates to the above process and/or method wherein the base slurry comprises from about 0.1%> to about 10%, by weight of the base slurry, of the catalyst.
BRIEF DESCRIPTION OF THE DRAWING The Figure sets forth a schematic of an embodiment of the features detailed herein, in block form, comprising the addition, reaction, and separation steps.
DETAILED DESCRIPTION OF THE INVENTION While the specification concludes with the claims particularly pointing and distinctly claiming the invention, it is believed that the present invention will be better understood from the following description. All percentages and ratios used herein are by weight of the total composition and all measurements made are at 25 °C, unless otherwise designated. Undesirable byproducts of alkylamine production include floe and color-body precursors. It is believed that the two components of floe are monoalkyltrimethylammonium bromide (MAQ) and dialkyldimethylammonium bromide (DAQ). It is believed that DAQ is formed by the reaction of residual alkylbromide with the alkyldimethylamine product. MAQ is believed to be formed by a two step process
where DAQ thermally degrades forming dialkylamine and methyl bromide. The methyl bromide then reacts with the alkyldimethyl amine product to form MAQ. Without being limited by theory, it is believed that the catalysts useful herein catalyze the dehydrobromination of alkyl bromide, resulting in olefϊn and hydrogen bromide (HBr). The removal of alkylbromide prevents or reduces the formation of floe. Furthermore, it is believed that the color-body precursors are formed by trace amounts of aldehydes, ketones, esters, fats, and olefins present in alkylamines. Without being limited by theory, it is believed that aldehydes with a hydrogen atom on the alpha carbon undergo aldol condensation followed by dehydration. Aldol condensation is either acid or base catalyzed. When it occurs multiple times, it can be viewed as an oligomerization or polymerization. Subsequent dehydration is catalyzed by acid, base or I2 and results in a conjugated, unsaturated structure, thus color. Without being limited by theory, it is believed that the catalysts useful herein presumably catalyzes the polymerization reaction. The conjugated, unsaturated structures are removed in the bottoms of the distillation column. Olefins, ketones, fats, and esters follow a similar polymerization base-catalyzed chemistry that is also removed in the bottom of the separation step. The top cut from the distillation can be a virtually colorless amine with the majority of the color body precursors removed. Thus, the present invention provides advantages over the current practice. The present invention relates to a process or method for the treating of alkylamines to reduce and/or eliminate floe and/or color body pre-cursors. The processes and methods herein may also include a wide variety of other variations. The processes and methods of the present invention are described in detail hereinafter. The steps of such process are as follows:
I. Combining an alkylamine with a catalyst that is an alkali metal alkoxide, alkaline earth metal alkoxide, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal hydride, alkaline earth metal hydride, alkali metal, alkaline earth carbonate, alkaline earth phosphate, alkaline earth silicate or a mixture thereof to form a base slurry. ,
The base slurry includes an alkylamine and a catalyst. In one embodiment, the base slurry contains from about 90% to about 99.1%>, by weight of the base slurry, of the amine. In another embodiment, the base slurry contains from about 95.0%> to about 99.8%, by weight of the base slurry, of the amine, alternatively, from about 97.5%> to about 99.7%), alternatively, from about 99.5%> to about 99.6%, of the amine. In one embodiment, the base slurry contains from about 0.1% to about 10%), by weight of the base slurry, of the catalyst. In another embodiment, the base slurry contains from about 0.2%» to about 5.0%>, by weight of the base slurry, of the catalyst; alternatively, from about 0.3% to about 2.5%>, alternatively from about 0.40%> to about 0.50%, by weight of the base slurry, of the catalyst. The amount of catalyst used should be approximately, but not limited to, a molar equivalent of the amount of alkyl halide present. As used herein, an "alkylamine" refers to compounds having the formula: R2 Ri N
R3 wherein each of Ri ,R2, and R3 is independently selected from hydrogen or an alkyl chain having from about 1 to about 24 carbon atoms. In one embodiment, Ri is selected from longer alkyl chains having from about 8 to about 18 carbon atoms. In one embodiment, R2 and R3 are independently selected from shorter alkyl chains having from about 1 to about 4 carbon atoms, alternatively are methyl groups. Alkylamines to be used with the treatment process herein include, but are not limited to, single chain lengths of alkyldimethyl amines (having from about 8 to about 18 carbons); or blends of multiple chain lengths. In one embodiment, the alkylamine is selected from N, N-dimethyl 1-Decaneamine; N, N-dimethyl 1-Dodecaneanιine; N, N- dimethyl, 1-Tetradecaneamine; N, N-dimethyl 1-Hexadecaneamine; and mixtures thereof. In another embodiment the alkylamine is an alkyl halide derived alkylamine. Alkylamines to be used with the treatment process can include undistilled or distilled amines from the amination process.
Catalysts that may be used with the treatment process herein include alkali metal alkoxides, alkaline earth metal alkoxides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrides, alkaline earth metal hydrides, alkali metals, alkaline earth carbonate, alkaline earth phosphate, alkaline earth silicate, and mixtures thereof. In one embodiment, the catalyst is selected from alkali earth metal alkoxides. In another embodiment, the catalyst is sodium methoxide. In another embodiment, the catalyst is potassium carbonate. Alkaline earth carbonates useful herein include potassium carbonate, sodium carbonate, calcium carbonate, and combinations thereof. Alkaline earth phosphates useful herein include trisodium phosphate, tripotassium phosphate, and combinations thereof. Alkaline earth silicates useful herein include sodium metasilicate. The combining of the alkylamine and the catalyst may be completed at temperatures in the range of from about 25°C to about 180°C, preferably from about 25°C to about 100°C. The combining of the alkylamine and the catalyst may be completed at atmospheric pressure or under vacuum.
II. Reacting the catalyst with the alkylamine by heating the base slurry to a temperature of from about 80°C to about 200°C to form a reaction slurry.
A reaction slurry is formed by reacting the catalyst with the alkylamine at a temperature from about 80°C to about 200°C with adequate agitation. In one embodiment, the reaction slurry may be formed by reacting the catalyst with the alkylamine at a temperature from about 80°C to about 200°C, alternatively at a temperature from about 80°C to about 180°C, alternatively at a temperature from about 80°C to about 160°C. The reaction slurry is formed at atmospheric pressures or under vacuum. Heating, where necessary, can be performed by any means known in the art. In one embodiment, the base slurry and/or reaction slurry is heated by external electric tracing and in another embodiment, internal heating coils are used. Adequate mixing, where necessaiy, can be performed by any means known in the art. In one embodiment, the base slurry is mixed by a motorized impellar.
III. Separating the reaction slurry at a pressure of about 10 mm He or below and at a temperature from about 100°C to about 200°C to form a top cut comprising an amine and a bottom cut comprising undesirable by-products.
The reaction slurry is separated at 10 rnmHg or less. In one embodiment, the separation occurs at a pressure of less than 5 nxtnHg, alternatively less than 3mmHg. The reaction slurry is separation at a temperature of from about 100°C to about 200°C to form a top cut comprising an amine and a bottom cut comprising undesirable by-products. In one embodiment the separation is performed at a temperature of from about 110°C to about 190°C, alternatively from about 120°C to about 170°C. In one embodiment, the undesirable by-products include floe and/or color-body precursors. Separation of the undesirable by-products and the amine by vacuum and temperature can be performed by any means known in the art. In one embodiment, the separation of the reaction slurry is performed by vacuum distillation. Distillation operations are usually carried out in vertical, cylindrical columns or towers in which devices such as plates or packing elements are placed. The vapor and liquid streams normally flow counter-currently and the devices serve to provide the contacting and development of interfacial surface through which mass transfer takes place. Sieve trays, bubble cap trays, structured packing, and loose packing such as rings or saddles are examples of column internals that may be used herein. Preferred operating conditions for the column are a pressure of from about 1 mmHg to 5 mmHg and a bottoms temperature of from about 110°C to about 170°C. As used herein, "tops" refers to the vapor or relatively more volatile stream that is separated from the relatively less-volatile or "bottom" stream in distillation columns. The "tops" is also sometimes referred to as "overhead" in the art. The tops composition is nearly pure amine.
IV. Removing the top distillation cut to form an amine product.
The top distillation cut contains the amine product. By removing the top distillation cut from the bottom distillation cut, the final amine product is formed. In one embodiment, the amine product is substantially free of floe. As used herein, "substantially free of floe" means that the product contains less visible floe then the untreated amine. Alternatively, the amine product contains less visible floe than the untreated amine after storage at 25°C after 6 weeks. Turbidity measurements can be completed to quantify floe removal. Untreated amine will have less then 20 NTU (Turbidity measurement) after production initially, while treated amine should have less then 10 NTU. In one embodiment, the amine product is substantially free of color-body precursors. As used herein, "substantially free of color-body precursors" means that the derivatives of the amine product contains less than 50 Pt/Co Color (according to the known APHA Color method). Combination of the amine and catalyst, reaction, and separation of the treated amine can occur in a batch or continuous process.
EXAMPLES
Example 1 - AT-1295 (a 1-dodecyl dimethylamine of minimum 95%> purity)
A sample of 1-dodecyl dimethylamine (C12 ADMA) production is post treated with sodium methoxide powder (approximately 98% active) followed by a separation step using vacuum distillation. A 1-dodecyl dimethylamine or tertiary amine is produced by the reaction of an olefin with a hydrohalogen, and the product of that reaction is then reacted with dimethylamine to form a tertiary amine or simply an amine. The sample of amine is about one week old and forms a significant level of floe. The following materials are added to a one liter 3 -neck round bottom reaction flask (with a thermometer well) in the following order: 529.3 grams of the amine; 7.4 grams of sodium methoxide powder; and 1.5 grams of inert boiling chips. The flask is then placed
in a heating mantle. A shaft-mounted agitator is put into the flask at the middle neck. A condenser (fed with chilled water) is fitted to one of the side necks and the other side neck is stoppered. The mixture is then heated to allow the reaction of the amines and amine impurities with the sodium methoxide to take place. The reaction is carried out for approximately 30 minutes at temperatures from about 80°C to about 89°C. The agitator speed is set to allow the agitator to form a vortex of about 1.5 to 2 inches. After about 30 minutes the agitator and the condenser are removed from the flask and the openings stoppered. One of the side necks of the flask is then fitted with a Vigreux distillation column, followed by a condenser and a collection vessel. This system is then evacuated to about 3 to 4 mm of pressure and heated to, and maintained at, about 109°C to about 110°C. The distillate is collected and the still bottoms separated. The yield of distillate is about 95% of the starting amine. Several batches are prepared following this procedure and the treated amines from each batch are combined into a composite. Aliquots from the composite are placed into glass jars, the headspace purged with nitrogen gas and sealed. Samples are placed into storage at 80°F and 100°F for twelve weeks and are monitored weekly for the appearance of floe regeneration. Un-treated amines are placed into storage under the same conditions to be used as baseline samples for floe growth. Samples of the amine treated using the methoxide process remain essentially free of floe for six weeks at both storage conditions. The un-treated amines develop additional floe and are graded as having "heavy" levels of floe (orders of magnitude higher than treated samples). Pt/Co (APHA) color data is also taken on the treated and un-treated amines. The un-treated amines require filtration to remove the floe prior to color evaluation.
Example 2 - AT-1495 (a 1-tetradecyl dimethylamine of minimum 95% purity)
A sample of 1-tetradecyl dimethylamine (C1 ADMA) production is post treated in a as in Example 1, and separation is completed using vacuum distillation. The 1-tetradecyl dimethylamine or tertiary amine is produced by the reaction of an olefin with a hydrohalogen, and the product of that reaction is then reacted with dimethylamine to form a tertiary amine or simply an amine. The sample of amine in this example is about one to two weeks old and has formed a significant level of floe. The following materials are added to a one liter 3-neck round bottom reaction flask (with a thermometer well) in the following order: 544.9 grams of the amine; 7.6 grams of sodium methoxide powder; and 1.5 grams of inert boiling chips. The flask is placed in a heating mantle. A shaft mounted agitator is put into the flask at the middle neck. A condenser (fed with chilled water) is fitted to one of the side necks and the other side neck is stoppered.
The mixture is heated to allow the reaction of the amines and the amine impurities with the sodium methoxide to take place. The reaction is carried on for 30 minutes at temperatures from 80°C to about 88°C. The agitator speed is set to allow the agitator to form a vortex of about 1.5 to 2 inches. After 30 minutes the agitator and condenser are removed from the flask. One of the side necks of the flask is fitted with a Vigreux distillation column, followed by a condenser and a collection vessel. This system is then evacuated to about 3 to 4 mm of pressure and heated to, and maintained at, 136°C to 138°C. The distillate is collected and the still bottoms separated. The yield of distillate is about 95% of the starting amine. Several batches are prepared following this procedure and the treated amines from each batch are combined into a composite. Aliquots from the composite are placed into glass jars, the headspace is purged with nitrogen gas and sealed. Samples are placed into storage at 80°F and 100°F for twelve weeks and are monitored weekly for the appearance
of floe regeneration. Un-treated amines are placed into storage under the same conditions to be used as baseline samples for floe growth. Samples of amines treated using the methoxide process remain essentially free of floe for six weeks at both storage conditions. The un-treated amines develop additional floe and are graded as having "heavy" levels of floe (orders of magnitude higher than the un-treated amines). Pt/Co (APHA) color data is also taken on the treated and un-treated amines. The un-treated amines required filtration to remove the floe prior to color evaluation.
Example 3 - AT-1695L (1-hexadecyl dimethylamine of minimum 95% purity)
A sample of 1-hexadecyl dimethylamine (C16 ADMA) production is post treated as in Example 1, and separation is completed using vacuum distillation. The 1-hexadecyl dimethylamine or tertiary amine is produced by the reaction of a fatty alcohol with an inorganic chloride compound to form an alkyl chloride, and the product of that reaction is then reacted with dimethylamine to form a tertiary amine or simply an amine. The sample of amine in this example is about two weeks old and has formed a layer of precipitate on the bottom of the container. The following materials are added to a one liter
3-neck round bottom reaction flask (with a thermometer well) in the following order: 533.2 grams of the amine; 7.6 grams of sodium methoxide powder; and 1.5 grams of inert
boiling chips. The flask is placed in a heating mantle. A shaft mounted agitator is put into the flask at the middle neck. A condenser (fed with chilled water) is fitted to one of the side necks and the other side neck is stoppered. The mixture is heated to allow the reaction of the amines and the amine impurities with the sodium methoxide to take place. The reaction is carried on for 30 minutes at temperatures from 85°C to 94°C. The agitator speed is set to allow the agitator to form a vortex of about 1.5 to 2 inches. After 30 minutes the agitator and the condenser are removed from the flask and the openings are stoppered. One of the side necks of the flask is fitted with a Vigreux distillation column, followed by a condenser and a collection vessel. This system is then evacuated to about 3 to about 4 mm of pressure and heated to, and maintained at, 161°C to 167°C. The distillate is collected and the still bottoms are separated. The yield of distillate is about 95% of the starting amine. Several batches are prepared following this procedure and the treated amines from each batch are combined into a composite. Aliquots from the composite are placed into glass jars, the headspace purged with nitrogen gas and sealed. Samples are placed into storage at 80°F and 100°F for twelve weeks and monitored weekly for the appearance of precipitate regeneration. Un-treated amines were placed into storage under the same conditions for use as baseline samples for precipitate measurement. Samples of the amines treated using the methoxide process remain essentially free of precipitate for six weeks at both storage conditions. Pt/Co (APHA) color data is also taken on the treated and un-treated amines. The un-treated amines require filtration to remove the floe prior to color evaluation.
All documents cited in the Detailed Description of the Invention are, are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
Example 4 - AT-1295 (a 1-dodecyl dimethylamine of minimum 95%> purity)
A sample of 1-dodecyl dimethylamine (Cπ ADMA) production is post treated with potassium carbonate powder (approximately 98% active) followed by a separation step using vacuum distillation. A 1-dodecyl dimethylamine or tertiary amine is produced by the reaction of an olefin with a hydrohalogen, and the product of that reaction is then reacted with dimethylamine to form a tertiary amine or simply an amine. The sample of amine is about one week old and forms a significant level of floe. The following materials are added to a one liter 3-neck round bottom reaction flask (with a thermometer well) in the following order: 529.3 grams of the amine; 7.4 grams of potassium carbonate powder; and 1.5 grams of inert boiling chips. The flask is then placed in a heating mantle. A shaft-mounted agitator is put into the flask at the middle neck. A condenser (fed with chilled water) is fitted to one of the side necks and the other side neck is stoppered. The mixture is then heated to allow the reaction of the amines and amine impurities with the sodium methoxide to take place. The reaction is carried out for approximately 30 minutes at temperatures from about 80°C to about 89°C. The agitator speed is set to allow the agitator to form a vortex of about 1.5 to 2 inches. After about 30
minutes the agitator and the condenser are removed from the flask and the openings stoppered. One of the side necks of the flask is then fitted with a Vigreux distillation column, followed by a condenser and a collection vessel. This system is then evacuated to about 3 to 4 mm of pressure and heated to, and maintained at, about 109°C to about 110°C. The distillate is collected and the still bottoms separated. The yield of distillate is about 95%) of the starting amine. Several batches are prepared following this procedure and the treated amines from each batch are combined into a composite. Aliquots from the composite are placed into glass jars, the headspace purged with nitrogen gas and sealed. Samples are placed into storage at 80°F and 100°F for twelve weeks and are monitored weekly for the appearance of floe regeneration. Un-treated amines are placed into storage under the same conditions to be used as baseline samples for floe growth. Samples of the amine treated using the methoxide process remain essentially free of floe for six weeks at both storage conditions. The un-treated amines develop additional floe and are graded as having "heavy" levels of floe (orders of magnitude higher than treated samples). Pt/Co (APHA) color data is also taken on the treated and un-treated amines. The un-treated amines require filtration to remove the floe prior to color evaluation.
Example 5 -AT-1295 (a 1-dodecyl dimethylamine of minimum 95%> purity)
A sample of 1-dodecyl dimethylamine (C12 ADMA) production is post treated with trisodium phosphate powder (approximately 98%> active) followed by a separation step using vacuum distillation. A 1-dodecyl dimethylamine or tertiary amine is produced by the reaction of an olefin with a hydrohalogen, and the product of that reaction is then reacted with dimethylamine to form a tertiary amine or simply an amine. The sample of amine is about one week old and forms a significant level of floe. The following materials are added to a one liter 3-neck round bottom reaction flask (with a thermometer well) in the following order: 529.3 grams of the amine; 7.4 grams of trisodium phosphate powder; and 1.5 grams of inert boiling chips. The flask is then placed in a heating mantle. A shaft-mounted agitator is put into the flask at the middle neck. A condenser (fed with chilled water) is fitted to one of the side necks and the other side neck is stoppered. The mixture is then heated to allow the reaction of the amines and amine impurities with the sodium methoxide to take place. The reaction is carried out for approximately 30 minutes at temperatures from about 80°C to about 89°C. The agitator speed is set to allow the agitator to form a vortex of about 1.5 to 2 inches. After about 30 minutes the agitator and the condenser are removed from the flask and the openings stoppered. One of the side necks of the flask is then fitted with a Vigreux distillation column, followed by a condenser and a collection vessel. This system is then evacuated to about 3 to 4 mm of pressure and heated to, and maintained at, about 109°C to about 110°C. The distillate is collected and the still bottoms separated. The yield of distillate is about 95% of the starting amine. Several batches are prepared following this procedure and the treated amines from each batch are combined into a composite. Aliquots from the composite are placed into glass jars, the headspace purged with nitrogen gas and sealed. Samples are placed into storage at 80°F and 100°F for twelve weeks and are monitored weekly for the appearance of floe regeneration. Un-treated amines are placed into storage under the same conditions
to be used as baseline samples for floe growth. Samples of the amine treated using the methoxide process remain essentially free of floe for six weeks at both storage conditions. The un-treated amines develop additional floe and are graded as having "heavy" levels of floe (orders of magnitude higher than treated samples). Pt/Co (APHA) color data is also taken on the treated and un-treated amines. The un-treated amines require filtration to remove the floe prior to color evaluation.