Process for forming alkyl vanadates using a catalyst

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is a process for forming alkyl vanadates.
2. Description of the Prior Art
Alkyl vanadates, which are useful as catalysts, can be formed by the reaction of vanadium pentoxide and an alkyl alcohol. A recent patent which describes this type of reaction is U.S. Pat. No. 3,987,074 to R. Haase. In such processes, by-product water is removed to help drive the reaction to completion, for example, by the incorporation of a suitable azeotroping solvent.
The prior art has suggested the use of certain catalysts in the above-described reaction, U.S. Pat. No. 3,652,617 to E. Termin et al. indicates that strongly acidic substances are useful as catalysts, whereas German Offenlegungschrift No. 1,816,386 also indicates the use of acidic substances as catalysts, including sulfuric and hydrochloric acids, phenyl sulfonic acid, and paramethyl sulfonic acid.
SUMMARY OF THE INVENTION
The present invention is an improved process for the production of alkyl vanadates by the reaction of vanadium pentoxide and an alkyl alcohol in the presence of an azeotroping solvent, wherein a catalytically effective amount of a basic nitrogenous compound is used.
DESCRIPTION OF PREFERRED EMBODIMENTS
The reactants that are used in practicing the present invention and vanadium pentoxide and an alkyl alcohol. The selection of the alkyl alcohol will depend upon the alkyl group desired in the alkyl vanadate product. Use of alkyl alcohols containing any of the C.sub.2 and C.sub.6 straight or branched alkyl groups is contemplated in accordance with the present invention. Branched chain alcohols are generally preferred, since they yield a vanadate product having improved thermal stability. Representative examples of such alkyl alcohols include ethanol, butanol, isobutanol, amyl alcohol, and isoamyl alcohol. The use of an excess amount of alcohol is preferred since it tends to increase the rate of reaction. Generally, the mole ratio of alkyl alcohol to vanadium pentoxide can vary from about 3:1 to 12:1.
In accordance with the present invention a suitable azeotroping agent is used to assist in the removal of by-product water from the reaction medium and thus held drive the reaction to completion. Examples of suitable aromatic solvents that have been proposed by various prior art investigators include toluene and benzene. It is, however, preferred to use an alkane azeotroping solvent, such as heptane, as described in U.S. application Ser. No. 245,868, filed Mar. 20, 1981, now U.S. Pat. No. 4,351,775 which is incorporated herein by reference.
In selecting the particular azeotroping agent, one should select one which insures that by-product water from the reaction will preferentially co-distill with the solvent at a high concentration of water. The boiling point of the alcohol should also be high enough to ensure that it is present to assist in the removal of the water when the reaction is taking place. Its boiling point should not be so high as to decompose the desired vanadate produce or to require the input of excessive amounts of heat energy to initiate and sustain the desired reaction. It is also preferred, in certain embodiments, that the solvent be less dense than water to produce water as the heavier phase in the separation apparatus to assist in its removal. Generally, the amount of azeotroping solvent to alcohol, for example, can range from about 0.05:1 to about 3:1 on a weight basis.
The present invention is specifically directed to catalysis of the aforementioned type of reaction by use of a catalytically effective amount of a basic nitrogenous compound. The basic nitrogenous compound is one which is capable of providing a basic nucleophilic entity to the reaction medium to catalyze the reaction. Compounds having a structure in which the electron pair on the nitrogen atom is readily available are preferred. Basic nitrogenous compounds having double bonds between the nitrogen atom or atoms and an adjacent carbon atom, or which have a carbonyl group on the adjacent carbon atom, are not preferred since they are less effective as catalysts. Also, the use of relatively insoluble basic nitrogenous compounds is not preferred for the same reason. In general terms, the amount of such catalyst can range from about 0.1% to about 25%, by weight, or more, of the vanadium pentoxide content. The upper limit is principally dictated by economic considerations and also by the possibility that at such higher concentrations, the compound may release excessive amounts of ammonia from the reaction.
Examples of some suitable basic nitrogenous compounds include ammonia; ammonium compounds, such as ammonium hydroxide, ammonium carbonate, ammonium phosphate (dibasic), and ammonium metavanadate; amine compounds, such as triethylamine; the dialkyl formamide compounds, such as dimethyl formamide; urea; pyridine; guanidine carbonate; and the like.
The reaction is conducted by admixing the desired quantities of vanadium pentoxide, alkyl alcohol, solvent, and catalyst in a reaction vessel and refluxing the contents of the reactor while preferably maintaining an inert gas blanket over the reaction mixture during the initial stages of the reaction. During the refluxing operation, the condensed liquid is passed through a trap where a hydrocarbon rich layer will form. Drawing off the water rich layer will remove a portion of the water of formation while the remaining liquid (a mixture of alcohol and solvent) is returned to the reactor. In order to achieve the highest yield in the shortest possible time, use of a packed column having a large diameter to encourage high throughputs of liquid is preferred. If it is desired to recover unused vanadium components (for example, vanadium pentoxide) from the reaction vessel, this can be readily accomplished by filtering the contents of the reactor after the reaction is performed. If desired, the filtrate containing alcohol, solvent and possibly some product can be distilled to remove alcohol and solvent from the product to achieve the highest yield desired.

The present invention is illustrated by the Examples which follow:
EXAMPLE 1
This Example comprises a series of runs which illustrate the improvement obtained by using the present invention.
Run A was a control run in which no catalyst was used.
Run B employed urea as a catalyst.
Run C used ammonium carbonate as a catalyst.
Run D employs both urea and ammonium carbonate as catalysts.
Runs A-C were conducted in a 1 liter flask equipped with a reflux condenser and DEAN-STARK trap, whereas Run D was conducted in a 5 liter flask equipped with reflux condenser, DEAN-STARK trap and packed distillation column. The reagents for the reaction, as described in the following Table, were added to the flask, and the agitator was turned on. Heat was applied so that refluxing began, and the reaction was run until no more water was formed. The resulting mixture was cooled to 25.degree. C., and the unreacted vanadium pentoxide was filtered to yield a filter cake. The filtrate was then recharged to the initial flask, and the n-heptane and isobutanol were distilled under vacuum, applying heat gradually to avoid foaming. The product in the flask was cooled to 25.degree. C. and (for Runs B to D) filtered to retrieve the unused catalyst. The remaining tri(isobutyl)vanadate endproduct was weighed, and the percent yield determined.
TABLE______________________________________ RUN A B C D______________________________________Vanadium pentoxide (gm.) 137.8 137.8 137.8 409.5Isobutyl alcohol (gm.) 507.6 507.6 507.6 1498.0n-heptane solvent (gm.) 84.6 84.6 84.6 675.0Urea catalyst (gm.) -- 6.9 -- 22.5Ammonium carbonate -- -- 6.9 20.0catalyst (gm.)Reflux temp. (.degree.C.) 96.5 95.5 95.0 91.0Reaction time (hrs.) 7.5 11.5 15.0 10.5End temp. (.degree.C.) 103.5 110 108.0 101.0H.sub.2 O collected (cc.) 21.1 32.6 42.0 127.9Filtration time (min.) 90 33 120 10Filter diameter (cm.) 7 7 7 15Filter cake Wt. (gm.) 103.9 59.1 24.3 70.6Distill. temp. (.degree.C.) 97 94 90 99Vacuum pressure (mm. Hg.) 14 13 15 18Catalyst recovered (gm.) -- 11.7 -- 16Product obtained (gm.) 217 307 371 1159% Yield of product 50.0 70.8 85.6 90.0______________________________________
In Run A, in which no catalyst was employed, the yield was 50% under the conditions employed. Use of urea in Run B gave two advantages: A higher yield (70.8%) and faster filtration rate for the unreacted vanadium pentoxide. The ammonium carbonate catalyst in Run C gave a very high yield (85.6%) but produced a slower filtration rate for the unreacted vanadium pentoxide. In Run D, a combined urea/ammonium carbonate catalyst and use of a distillation column gave the highest yield (90.0%) and the fastest filtration time for the unreacted vanadium pentoxide.
EXAMPLE 2
This Example illustrates the results obtained by using ammonium hydroxide as a catalyst. The procedure described in Example 1 was employed. The Table sets forth the data:
TABLE______________________________________Vanadium pentoxide (gm.) 137.8Isobutyl alcohol (gm.) 507.6n-heptane solvent (gm.) 84.6Ammonium hydroxide catalyst 2.6(gm.)Reflux temp. (.degree.C.) 95Reaction time (hrs.) 11.5End temp. (.degree.C.) 104.5H.sub.2 O collected (cc.) 31.1Filtration time (min.) 106Filter diameter (cm.) 7Filter cake Wt. (gm.) 65.7Distill temp. (.degree.C.) 89-97.degree.Vacuum press. (mm. Hg.) 14Catalyst recovered (gm.) NoneProduct obtained (gm.) 293.5% Yield of product 67.8______________________________________
The ammonium hydroxide was found to be approximately as effective a catalyst, under the conditions employed, as the urea catalyst used in Example 1, Run B, but a less effective one than the ammonium carbonate catalyst used in Example 1, Run C. The product formed by this reaction was of a blackish color. The filtration time in this Example was longer than for Run B of Example 1, but shorter than for Run C of Example 1.
EXAMPLE 3
In this Example, dimethyl formamide, pyridine, and ammonium carbonate were tested as catalysts using the procedure described in Example 1.
Run A employed dimethyl formamide, Run B, pyridine, and Run C, ammonium carbonate. The Table sets forth the data:
TABLE______________________________________ RUN A B C______________________________________Vanadium pentoxide (gm.) 137.8 137.8 137.8Isobutyl alcohol (gm.) 507.6 507.6 507.6n-heptane solvent (gm.) 84.6 84.6 84.6Dimethyl formamide 6.9 -- --catalyst (gm.)Pyridine catalyst (gm.) -- 6.9 --Ammonium carbonate -- -- 6.9catalyst (gm.)Reflux temp. (.degree.C.) 96.5 95.5 93.5Reaction time (hrs.) 6 6 9.1End temp. (.degree.C.) 102.5 102.5 107H.sub.2 O collected (cc.) >22.2 21.6 38.3Filtration time (min.) -- -- 71Filter diameter (cm.) -- -- 7Filter cake wt. (gm.) -- -- 40.8______________________________________
Dimethyl formamide and pyridine were less effective as catalysts than ammonium carbonate under the test conditions that were employed although they gave an improvement over the use of no catalyst (e.g., Example 1, Run A).
EXAMPLE 4
This Example shows a run using an ammonium carbonate catalyst utilizing the procedure shown in Example 1. The following data was obtained:
TABLE______________________________________Vanadium pentoxide (gm.) 137.8Isobutyl alcohol (gm.) 507.6n-heptane solvent (gm.) 84.6Ammonium carbonate 6.9catalyst (gm.)Reflux temp. (.degree.C.) 95Reaction time (hrs.) 15End temp. (.degree.C.) 108H.sub.2 O collected (cc.) 42.0Filtration time (min.) 120Filter diameter (cm.) 7Filter cake wt. (gm.) 24.3Distill temp. (.degree.C.) 90.degree.Vacuum press. (mm. Hg.) 15Catalyst recovered (gm.) NoneProduct obtained (gm.) 371.0% Yield of product 85.6______________________________________
EXAMPLE 5
This Example shows the use of ammonium metavanadate (Run A) and ammonium phosphate, dibasic (Run B) as catalysts. The following data was obtained:
TABLE______________________________________ RUN A B______________________________________Vanadium pentoxide (gm.) 137.8 137.8Isobutyl alcohol (gm.) 507.6 507.6n-heptane solvent (gm.) 84.6 84.6Ammonium metavanadate 6.9 --catalyst (gm.)Ammonium phosphate, dibasic -- 6.9catalyst (gm.)Reflux temp. (.degree.C.) 95 95Reaction time (hrs.) 11.5 3.9End temp. (.degree.C.) 105 102H.sub.2 O collected (cc.) 35.1 19.3Filtration time (min.) >150 --______________________________________
The amount of water collected in Run A amounted to 78% of theoretical. Run B was turned off at a relatively early point when the reaction began to slow down. If completed, it was estimated that the yield would be about 5-10% above the yield obtained using no catalyst.
EXAMPLE 6
This Example illustrates the catalytic effect for ammonium metavanadate (Run A) and ammonium carbonate (Run B) and illustrates (in Run C), for comparative reasons, that an acidic nitrogen catalyst, ammonium phosphate, monobasic [(NH.sub.4)H.sub.2 PO.sub.4 ], does not function as a catalyst. The procedure of Example 1 was used.
TABLE______________________________________ RUN A B C______________________________________Vanadium pentoxide (gm.) 137.8 137.8 137.8Isobutyl alcohol (gm.) 507.6 507.6 507.6n-heptane solvent (gm.) 84.6 84.6 84.6Ammonium metavanadate 17.23 -- --catalyst (gm.)Ammonium carbonate -- 2.76 --catalyst (gm.)Ammonium phosphate, -- -- 6.89monobasic (gm.)Reflux temp. (.degree.C.) 95 94.5 96Reaction time (hrs.) 8.2 8 3.sup.(1)End temp. (.degree.C.) 106 105 101H.sub.2 O collected (cc.) 35.5 34.6 12.9Filtration time (min.) 46* ** --Filter diameter (cm.) 7 ** --Filter cake wt. (gm.) 91* ** --______________________________________ .sup.(1) the reaction in Run C was terminated after only three hours because of a decrease in the rate of water that was observed leaving the reaction. This was indicative of a slowing of the reaction at this point. *an unknown amount of a filter aid (SOLKAFLOC) was used. The filter cake weight is higher due to use of this filter aid. **additional (2.76 gm.) of ammonium carbonate was added, and the reaction was continued 259 min. longer (102.5.degree. to 107.5.degree. C.). The total water collected was 40.3 cc. After the reaction was completed, the solvent was stripped without prior filtration. The remaining liquid was then filtered warm. Filtration time was 95 min. Product weight was 358.1 gm. representing a yield of 82.7%. The total filter cake was 28.6 gm. In Run C, the reaction was terminated without a filtration step when it became apparent that the amount of water collected was lower than the amount in a control run (e.g., see Example 1, Run A).
EXAMPLES 7-14
The procedure used in Example 1 was employed to test the effectiveness of a series of compounds as catalysts in accordance with the present invention. The Tables set forth below illustrate the results obtained.
______________________________________Example Tested Compound Weight______________________________________ 7 (Control) None -- 8 (Control) None -- 9 (Control) None --10 Urea 3.2 gm.11 Dicyandiamide 3.2 gm.12 Melamine 3.3 gm.13 Guanidine carbonate 3.1 gm.14 Triethylamine 3.2 gm.______________________________________
______________________________________ Heptane Isobutanol V.sub.2 O.sub.5 Time atExample (gm.) (gm.) (gm.) Reflux (hrs.)______________________________________ 7 (Control) 650 444 182 9.75 8 (Control) 650 444 182 8.5 9 (Control) 108 444 182 8.510 325 222 91 911 325 222 91 612 325 222 91 213 325 222 91 414 325 222 91 4.5______________________________________
______________________________________ Temp. (.degree.C.) H.sub.2 O Off Approx. YieldExample (Start-End) (wt.) TIBV (%)______________________________________ 7 (Control) 77-94 23.5 cc. 39.1 8 (Control) 88-98 * * 9 (Control) 94.5-102 20.7 gm. 35.910 88.5-97.5 17.8 gm. 61.911 89-94 10.25 cc. 34.1**12 89-92 5 cc. 16.6**13 87-94 12.5 cc. 41.614 88.5-93 13.25 cc. 44.1______________________________________ *the water byproduct was lost through the condenser. The calculated yield based on triisobutyl vanadate (TIBV) was 39.1%. **Dicyandiamide (Example 11) and melamine (Example 12) are not preferred catalysts for use in the present invention although both showed some effectiveness. Dicyandiamide exhibited a small effectiveness during the first three hours of the reaction and was only marginally better (about 1-2%) than the control for the next three hours, at which time the reaction was terminated. Melamine is a somewhat insoluble compound in water having double bonds between the nitrogen atom and an adjacent carbo atom. Melamine was an effective catalyst, in accordance with the present invention, during the first half hour of the reaction, but began to becom less effective, and it produced a lower yield than the control between th first and second hours, at the end of which time the reaction was terminated.
EXAMPLES 15-41
These Examples illustrate the present invention using the procedure described in Examples 7-14. In these runs, various reaction conditions and reagent combinations were changed.
______________________________________ Tested Catalyst WeightExample Compound (gm.)______________________________________15 Urea 3.216 Urea 1.617 Urea 3.218 Urea 0.519 Urea 3.220 Urea 3.2 p-Benzoquinone 1.021 Urea 3.222 Urea 3.223 Urea 3.224 Urea 3.225 (Control) None --26 Urea 3.227 (Control) None --28 Urea 4.829 Triethylamine 6.430 Urea 9.2431 Urea 7.6632 Urea 6.0833 Urea 6.0634 Urea 6.8935 Urea 6.8936 (Control) None --37 Ammonium hydroxide 2.638 Urea 6.8939 Dimethyl formamide 6.8940 Pyridine 6.8941 Ammonium carbonate 6.89______________________________________
______________________________________ Heptane Isobutanol V.sub.2 O.sub.5 Time atExample (gm.) (gm.) (gm.) Reflux (hrs.)______________________________________15 162.5 277.5 91 216 162.5 277.5 91 217 325 222 91 718 325 222 91 719 162.5 222 91 420 162.5 222 91 2.521 325 222 101.sup.(1) 5.2522 325 222 90.5.sup.(2) 8.523 325 222 95.4.sup.(3) 224 395 111 45.5 225 (Control) 325 222 109.6.sup.(4) 726 135.5 444 91.sup.(5) 1027.sup.(6) 325 222 91 4.528 232 333 91.sup.(7) 929 325 222 91 930.sup.(8) None 607.5 91 5.331 77 516 91 632 154 424.5 91 633 137 444 121.2 7.534.sup.(9) None 507.6 137.8 7.535 84.6 507.6 137.8 7.536 (Control) 84.6 507.6 137.8 7.537 84.6 507.6 137.8 11.538 84.6 507.6 137.8 11.539 84.6 507.6 137.8 640 84.6 507.6 137.8 641 84.6 507.6 137.8 9______________________________________ .sup.(1) includes 10 gm. of filter cake from Example 17. .sup.(2) includes 45 gm. added in increments during reaction. .sup.(3) includes 95.4 gm. wet cake (equivalent to about 73 gm. dry) of recovered V.sub.2 O.sub.5 from Examples 17, 18, 19, and 22. .sup.(4) includes 18.6 gm. wet V.sub.2 O.sub.5 recovered from another run .sup.(5) added in small increments during the reaction. .sup.(6) slow agitation (90-100 rpm.) used with blade raised about 0.64 cm. .sup.(7) addition of last 26 gm. made incrementally. .sup.(8) no heptane was added initially and no water was extracted. Hexan (40 gm.) was added 50 min. into the run. .sup.(9) Hexane (84.6 gm.) was used.
______________________________________ Filtra- tion Temp. (.degree.C.) H.sub.2 O Off Approx. Yield TimeExample (Start-End) (cc.) TIBV (%) (min.)______________________________________15 90-95 10.1 33.6 --16 90-95 10.4 34.6 --17 87-94.5 15.6 51.9.sup.(10) 518 87-94 15.5 51.6.sup.(10) 1119 88.5-95.5 11.2 37.3 620 88.5-95 9.9 32.9 --21 87-94 14.0 46.6 --22 88-95 17.75 59.4 5.2523 89.5-92.5 6.7 28 --24 87-93.5 7.0 46.6 --25 (Control) 88-93 11.15 37 --26 95-100 18.1 60.2 --27 (Control) 88.5-93.5 10.1 33.3 --28 90.97.5 20.15 67.0 5.2529 88.5-95.5 18.3 60.9.sup.(11) 15.530 96.5-102 16.0 53.2.sup.(12) --31 96.5-103 18.9 62.9.sup.(12) --32 92.5-99 18.8 62.6.sup.(12) --33 92.5-100.5 23.15 57.8.sup.(13) 14.7534 85-92 24.35 53.5.sup.(13) 18.535 95.5-105 30.3 66.6.sup.(13) 25.536 96.5-103.5 21.05 46.3 9037 95-104.5 31.1 68.3.sup. (14) 10638 95.5-104.5.sup.(15) 32.65 71.7.sup.(14) 3339 96.5-102.5 23 50.5 --40 95.5-102.5 21.6 47.5 --41 93.5-107 38.3 84.2 71______________________________________ .sup.(10) The product from Example 17 was of somewhat redder appearance than the product from Example 18. .sup.(11) The product from this Example was green and was greener than th product from any other run. .sup.(12) For Examples 30-32, the product was Example 30 was most green i color; from Example 32, was most red. .sup.(13) For Examples 33-35, the product from Example 34 was more red than the product from Example 33. The product from Example 35 was the mos green. .sup.(14) The product from Example 38 was more red than the product from Example 37. .sup.(15) The temperature reached 110.degree. C. for the last half hour.
EXAMPLES 42-65
These Examples illustrate additional testing of compounds as catalysts under a variety of reaction conditions in accordance with the present invention.
______________________________________Example Tested Catalyst Compound Weight (gm.)______________________________________42 Ammonium carbonate 6.8943 Ammonium vanadate 6.8944 Diammonium phosphate 6.89 45* Monoammonium phosphate 6.8946 Ammonium vanadate 17.2347 Ammonium carbonate 2.76 48* Potassium carbonate 6.8949 Ammonium carbonate 6.8950 Ammonium carbonate 13.7851 Ammonium carbonate 34.4552 Ammonium carbonate 31.053 Ammonium carbonate 6.8954 Ammonium carbonate 27.5655 Ammonium carbonate 6.8956 Ammonium carbonate 31.057 Ammonium carbonate 6.8958 Ammonium carbonate 4.5 Urea 5.059 Ammonium carbonate 4.560 Ammonium carbonate 6.8961 Ammonium carbonate 4.5 Urea 1.062 Ammonium carbonate 4.5 Urea 3.063 Ammonium carbonate 4.5 Urea 5.064 Ammonium carbonate 4.5 Urea 5.065 Ammonium carbonate 20.0 Urea 22.5______________________________________ *comparative run. Not part of the present invention. Monoammonium phosphate is acidic (Ex. 6).
______________________________________ Heptane Isobutanol V.sub.2 O.sub.5 Time atExample (gm.) (gm.) (gm.) Reflux (hrs.)______________________________________42 84.6 507.6 137.8 1543 84.6 507.6 137.8 11.544 84.6 507.6 137.8 445 84.6 507.6 137.8 346 84.6 507.6 137.8 847 84.6 507.6 137.8 848 84.6 507.6 137.8 449 84.6 507.6 137.8 9.550 84.6 507.6 137.8 9.551 423 2538 689 15.552 380.7 2284 620 753 84.6 507.6 137.8 8.554 676.8 2030.4 551.2 1555 232 333 91 6.556 380.7 2284 620.1 1157 232 333 91 4.558 232 333 91 6.559 232 333 91 6.060 None 333 91 9.561 232 333 91 5.562 232 333 91 5.563 116 333 91 5.7564 150 333 91 5.565 675 1498 409.5 10.5______________________________________
______________________________________ Temp. (.degree.C.) H.sub.2 O Off Approx. Yield FiltrationExample (Start-End) (cc.) TIBV (%) Time (min.)______________________________________42 95-108 42 93.3 120.sup.(1)43 95-105 35.1 78.0 >15044 95-102 19.3 --.sup.(2) --45 96-101 12.9 --.sup.(2) --46 95-106 35.5 78.9 46.sup.(1)47 94.5-105.sup.(3) 34.6 76.9.sup.(3) --.sup.(3)48 95-101.5 17.9 -- --49 95-105 33.1 73.6 125.sup.(4)50 94-106 36.5 81.1 3251 90-101 133.6 --.sup.(5) --.sup.(5)52 92-95.5 6 --.sup.(5) --.sup.(5)53 96-108.5 43.4 96.4.sup.(6) --54 93-102.5 170.7 93.8 --.sup.(7)55 91-98 29.2 98.3 >27056 97-107 185 91.4 Poor.sup.(8)57 91-96.5 22.8 76.8 --58 91-98 27.1 91.2 1059 91-98.sup.(9) 28.5 96.0 4160 82.88.5 29.8 100.sup.(10) --61 90-99.5 24.9 83.8 2562 90-98 26.0 87.5 1163 93.5-104.5 29.0 97.6 1264 91-101 26.5 89.2 1265 91-101 127.9 95.7 10______________________________________ .sup.(1) used SOLKAFLOC filter aid during the filtration step. .sup.(2) slow reaction. .sup.(3) added 2.76 gm. of additional catalyst after 8 hours. Continued refluxing for an additional 4.5 hours allowing the temperature to rise to 107.5.degree. C. A total of 40.3 cc. of H.sub.2 O came off indicating an 89.6% yield. The solvent was removed. The filtration time was 100 min. .sup.(4) used 1 gm. NUCHAR SN brand and 3 gm. SOLKAFLOC filter aid. .sup.(5) run discarded because of slower than anticipated reaction rates. .sup.(6) used a Vigreaux distillation column. .sup.(7) five different filtrations were conducted in an attempt to improve filtration time. .sup.(8) flocculating agents added. .sup.(9) 5 gm. of urea was added at the end of the reaction to attempt to improve filtration. .sup.(10) a slimy suspension resulted which was discarded.
EXAMPLES 66-72
The following Table illustrates a further series of reactions using the present invention. Example 66 utilized a Vigreaux column (30.48 cm. length; 2.54 cm. diameter). All other runs used a vacuum jacketed, Goodloe packed column (30.48 cm. length; 2.54 cm. diameter). The catalyst in Example 66 was 5 gm. ammonium carbonate and 4.5 gm. urea. In all other runs it was 20.25 gm. ammonium carbonate and 22.5 gm. urea. Examples 67-72 were on a five liter scale.
______________________________________ Isobutanol V.sub.2 O.sub.5Example Solvent Wt. (gm.) (gm.) (gm.)______________________________________66 Toluene 150 333 9167 Cyclohexane 675 1498.5 409.568 Toluene 675 1498.5 409.569 Heptane 740 Hexane 35 1498.5 409.570 Heptane 675 1498.5 409.571 Heptane 675 1498.5 409.572 Heptane 1915.6 1498.5 409.5______________________________________
______________________________________ Time at Temp. (.degree.C.) H.sub.2 O OffExample Reflux (hrs.) (Start-End) (cc.)______________________________________66 41/3 98-110 26.767 1.75 80-86 29.168 2 97.5-103 54.869 2 88-93.5 38.570 14.5 89-98.5 119.971 10 89-95 80.072 121/4 93-104 128.3______________________________________
______________________________________ Column VARIAC.sup.(1) Through-Put Approx. YieldExample Setting (cc/min.).sup.(2) (%)______________________________________66 94 -- 89.067 80 30 21.6.sup.(4)68 85 -- 40.6.sup.(4)69 80 -- 28.7.sup.(4)70 82.5 30 88.871 62.5 11 59.2.sup.(5)72.sup.(3) 82.5 30 95.0______________________________________ .sup.(1) numbers indicate relative settings on VARIAC apparatus which feeds electrical power to heating mantle. .sup.(2) the rate at which solvents pass through the column measured as the rate at which liquids return to the column from the DEANSTARK trap. A higher throughput generally results in a higher reaction rate. .sup.(3) very solw filtration time estimated as 2-4 hours. .sup.(4) the lower yield, compared to Example 66, is due to termination o the reaction after a shorter period of time at reflux. .sup.(5) the lower yield, compared to Example 66, is due to the lower column throughput.
EXAMPLE 73
This example illustrates a particularly preferred embodiment of the present invention utilizing a 378.53 liter reactor equipped with a glass-lined distillation column having a 15.24 cm. inner diameter and a height of 1.83 meters, which had been packed with a high performance stainless steel mesh.
The reactor was first charged with the following:
______________________________________INGREDIENT AMOUNT______________________________________Isobutanol 99.79 kg.n-heptane 45.36 kg.Vanadium pentoxide 27.22 kg.Urea catalyst 1.36 kg.Ammonium carbonate 1.59 kg.catalyst______________________________________
The resulting mixture was heated to reflux so that the heptane entrained the water of reaction as it forms. Vapor comprising isobutanol, heptane and water was condensed, and the water was further phase separated in a trap. The isobutanol and heptane were returned to the reaction vessel.
The reaction was allowed to continue for 32 hours until the rate of water removal fell to about 0.045 to 0.068 kg. per hour.
The temperatures (in .degree.C.) that were recorded during the reaction were as follows:
______________________________________ Start of During End ofTemperature Reflux Reaction Reaction______________________________________Reactor 92 102 104Vapor 88 90 88Jacket 125 140 140______________________________________
The reactor's contents were allowed to cool to 75.degree. C., and they were then filtered over a period of about 2 hours through a pressure filter. The unreacted vanadium pentoxide was washed with 4.54-6.8 kg. of heptane.
The filtrate was returned to the reactor, and the solvents were stripped at atmospheric pressure first, then at pressures down to 20 mm. Hg. vacuum. The resulting product was cooled to about 20.degree.-25.degree. C. so that all remaining catalyst crystallized. After filtration about 72.57 kg. of a clear, yellow triisobutyl vanadate liquid was obtained at a yield of about 84%. Approximately 1.81 kg. of wet cake remained in the filter.
The foregoing examples are merely illustrative of certain preferred embodiments of the present invention.
The scope of protection is set forth in the claims which follow.

Number	Name	Date
3652617	Termin et al.	Mar 1972
3657295	McCoy	Apr 1972
3772355	Merz	Nov 1973
3987074	Haas et al.	Oct 1976
4014911	Muntz et al.	Mar 1977
4014912	Muntz et al.	Mar 1977

Process for forming alkyl vanadates using a catalyst

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