Catalyst for aldol condensations

Aldol condensation catalysts have been prepared by interacting stoichiometric amounts of a water soluble salt of a Group II metal and a water soluble aluminum salt with a stoichiometric amount of an alkaline metal or alkaline earth metal, water soluble hydroxide and doping the washed slurry which precipitates with a water soluble lithium or zinc salt.

BACKGROUND OF THE INVENTION 
This invention pertains to aldol condensations and more particularly to the 
heterogeneous catalyst used for said aldol condensations. 
The aldol condensation of active hydrogen containing organic carbonyl 
compounds has been widely used in industry for synthesize compounds. Base 
catalyst such as alkali metal hydroxides have been used for producing 
2-ethylhexanediol-1,3, 2-ethylhexanol-1, diacetone alcohol, isophorone, 
mesityl oxide, methyl isoamyl ketone, methyl isobutyl ketone, and the 
like. 
Myriad methods have been disclosed for converting, for example, acetone by 
aldol condensation into a variety of products particularly isophorone and 
mesityl oxide which are used in industrial solvents and as chemical 
intermediates for resins, dyes, insecticides and the like. By-products 
which arise from the general reaction include diacetone alcohol, 
4,4-dimethyl-hepta-2,6-dione, 4,6-dimethyl-hepta-3,5-diene-2-one, 
3,5,5-trimethylcyclohex-3-ene-one, mesitylene, 2,2,6,6-tetramethyl, 
tetrahydropyran-4-one, xylitones, and isoxylitones, as well as various 
unidentified high boilers and tars. Needless to say, the specificity of 
the reaction must be controlled for commercial success in order to direct 
the conversion of acetone to the desired end products. 
It is an object of this invention to control the condensation of acetone to 
produce chiefly mesityl oxide and isophorone and in addition to limit the 
molar ratio of mesityl oxide:isophorone produced to a low value 
(preferably less than 1) to conform to the commercial demand for these 2 
products. 
It is another object of the invention to provide a catalyst for this 
control condensation of acetone having the following properties: 
High and constant activity 
Reproducible activity 
Long Catalyst Life 
Ability to regenerate readily 
Consistent in selective production of mainly mesityl oxide and isophorone 
Cheap and available 
Examples of typical catalysts used for the conversion of acetone to 
isophorone and mesityl oxide are: alkali metal hydroxides, such as, 
sodium, potassium, and lithium hydroxide; alkaline earth hydroxides, such 
as, calcium, magnesium, strontium and barium hydroxide; calcium aluminate, 
sodium aluminate, calcium borate, potassium zincate, magnesium plumbate, 
barium aluminate, lithium plumbate, sodium borate, strontium stannate, 
potassium stannate, calcium borate, magnesium antimonate, sodium 
antimonate, calcium arsenate, sodium arsenate, potassium titanate, calcium 
zincate, magnesium aluminate, beryllium aluminate, cesium borate, rubidium 
arsonate, lithium phosphate, magnesium oxide, and the like. 
It is another object of this invention to provide a catalyst and method for 
the aldol condensation of active hydrogen containing organic carbonyl 
compounds in general. 
SUMMARY OF THE INVENTION 
An improved catalyst for the aldol condensation of active hydrogen 
containing organic carbonyl compounds has been developed by the steps of: 
(a) interacting stoichiometric amounts of a water-soluble salt of a metal 
of Group II of the Deming Periodic Table and a water-soluble aluminum salt 
with a stoichiometric amount of an alkali metal or alkaline earth metal, 
water-soluble hydroxide in water to precipitate a water-insoluble slurry 
of mixed hydroxides with the proviso that the ratio of gram atoms of Group 
II metal to aluminum metal is in the range of about 0.02 to about 0.3; 
(b) washing the slurry from step (s) with water until substantially free of 
water-soluble salts; 
(c) contacting the washed slurry from step (b) with a dilute aqueous 
solution of a lithium or zinc salt at ambient temperatures; and 
(d) recovering and drying the product of step (c) at a temperature below 
about 400.degree. C. 
A catalyst which is unusually active and selective in the ratio of 
condensation products obtained has been developed in a series of steps 
comprising: 
(a) interacting a stoichiometric amount of a water-soluble salt of a metal 
of Group II of the Deming Periodic Table with a stoichiometric amount of 
an inorganic water-soluble hydroxide in water to precipitate a 
water-insoluble slurry; 
(b) mixing 100 parts by weight on a dry basis of the slurry of step (a) 
with about 1 to about 20 parts by weight, of a water-soluble salt of a 
metal of Group II of the Deming Periodic Table dissolved in water to 
produce a second slurry; 
(c) mixing 100 parts by weight on a dry basis of the slurry of step (b) 
with about 2 to about 40 parts by weight on a dry basis of an alkali metal 
aluminate to afford a third slurry; 
(d) washing the slurry of step (c) with water until substantially free of 
the water-soluble salts; 
(e) contacting the washed slurry of step (d) with a dilute aqueous solution 
of a lithium or zinc salt at ambient temperatures; and 
(f) recovering and drying the product of step (e) at a temperature below 
about 400.degree. C. 
Exemplary water-soluble salts of metals of Group II of the Deming Periodic 
Table include nitrates, halides, acetates, and the like, of beryllium, 
magnesium, calcium, strontium, barium, zinc and cadmium. 
Representative inorganic water-soluble hydroxides which can be used 
include: alkali metal hydroxides, such as, sodium hydroxide, potassium 
hydroxide, lithium hydroxide, rubidium hydroxide and caesium hydroxide; 
alkaline earth metal hydroxides, as for example, calcium hydroxide, 
strontium hydroxide, barium hydroxide, and the like. 
Suitable lithium and zinc salts which can be used for doping the slurry 
obtained in step (d) above include halides (i.e., the fluorides, 
chlorides, bromides and iodides), the nitrates, sulfates, perchlorates, 
acetates, and the like. The term "dilute aqueous solutions" of the 
above-mentioned salts is meant to mean salt concentrations between about 
0.1 and about 100 grams of salt per liter of water. 
It is preferred that sufficient "dilute aqueous solution" be used in step 
(e) to afford recovering a slurry from step (e) wherein 100 parts by 
weight of said slurry contains about 1.0 to about 0.001 parts by weight of 
lithium or zinc ion. 
It is preferred that the mole ratio of the Group II metal salt, in step 
(b), to the alkali metal aluminate in step (c) be about 1:2 .+-. 10 mole % 
and that the slurry in step (d) contains 80 to 99% by weight of the 
precipitate from step (a) and 1 to 20% by weight of the slurry from step 
(c). 
The catalyst described in the preceding paragraph cannot be delineated by a 
simple formula since the chemical nature and identity of the products 
obtained in each one of the steps cannot be rigorously identified. In one 
preferred form the catalyst is prepared by first interacting in step (a) a 
stoichiometric amount of a water-soluble magnesium salt, such as, 
magnesium nitrate dissolved in water with a stoichiometric amount of 
sodium hydroxide in water. A simplistic view of this reaction would 
involve the interaction of one mole of magnesium nitrate with 2 mols of 
sodium hydroxide in water to produce 1 mole of "magnesium hydroxide" 
precipitate and 2 mols of sodium nitrate. However, the precipitate is 
believed to comprise a complex of magnesium oxides and hydroxides and not 
solely Mg(OH).sub.2. 
In the next step of the preferred catalyst preparation, additional 
magnesium nitrate as an aqueous solution is mixed the slurry from step (a) 
forming a second slurry followed by the treatment of this slurry with 
sodium aluminate. The slurry arising at this step is even more complex 
containing probably some form of magnesium-aluminum hydroxides and oxides. 
The washing of this slurry removes any residual water-soluble salts, such 
as, magnesium nitrate and sodium nitrate. This slurry when treated with a 
water-soluble lithium salt, such as, lithium chloride has the effect of 
doping or modifying the complex mixture of magnesium-aluminum hydroxides 
and oxides in an unknown manner. When isolated and dried however this 
product is found to exhibit catalytic properties startlingly superior to 
the material from step (d) which contains no lithium ion. X-ray analysis 
of this lithium doped product reveals an amorphous structure clearly 
demonstrating that the product is not a crystalline product, such as, 
magnesium aluminate or its naturally occurring mineral counterpart, 
"spinel". While it is not clear what the exact morphology of this catalyst 
is, the lithium ions present are chemically bound and not merely 
agglomerated since they remain in the catalyst after the water washing. 
While not wishing to be bound by any theory or scientific explanation, it 
is submitted that the lithium undergoes some type of ion exchange reaction 
with the surface of the complex of magnesium-aluminum hydroxides and 
oxides. 
Zinc ion is also effective for the doping of the magnesium-aluminum 
hydroxides and oxides complex in place of lithium ion. Again, the 
mechanism of the unexpected advantages accompanying this doping operation 
is not known. However, as in the case of lithium, it is also speculated 
that some type of ion exchange reaction takes place since the zinc ions 
are not removed by a washing step. 
The catalysts of this invention are also characterized by the following 
physical properties: a pore volume of about 0.20 to about 0.50 cc./g., 
preferably about 0.32 to 0.36 cc./g., a surface area of about 20 to about 
400 meters.sup.2 /g., preferably about 50 to 100 meters.sup.2 /g., and a 
bulk density of about 0.70 to about 0.90 cc./g., preferably about 0.8 to 
0.9 cc./g. Another distinction between the catalysts of this invention and 
those of the prior art lies in the fact that the instant catalysts are not 
subjected in their preparation of temperatures of above about 400.degree. 
C. which is generally the case for the preparation of compounds such as 
magnesium-aluminate (spinel). The latter are used in the electronic 
industry as insulators or semi-conductors. 
The commercial demand for mesityl oxide and isophorone makes it desirable 
that the product ratio of mesityl oxide to isophorone be less than about 1 
otherwise excess mesityl oxide has to be recycled to the operating unit. 
Conventional catalysts presently in use, such as, calcium hydroxide 
produce mesityl oxide:isophorone ratios of two to about five which is 
undesirable from an economic standpoint. The catalysts of this invention 
as shown in the FIGURE afford these desirable mesityl oxide:isophorone 
weight ratios at reasonable acetone conversion levels. This product ratio 
can also be modified by merely adjusting the acetone conversion. 
Another unexpected property of the catalysts of this invention is the fact 
that while water depresses the reaction rate somewhat it also increases 
the reaction efficiency of converting acetone to isophorone and mesityl 
oxide which suppressing the formation of undesirable by-products. 
The preferred temperature range for converting acetone to mesityl oxide and 
isophorone using the catalysts of this invention lies in the range of 
about 250.degree. to about 350.degree. C. with a more preferred range 
lying in the range of about 280.degree. to about 320.degree. C. 
Pressure is not narrowly critical but pressures of about 1 to about 5 
atmospheres are preferred. If desired the conversion of acetone with the 
catalysts of this invention can be effected at atmospheric and below as 
well as higher superatmospheric pressures. 
The feed rate of acetone is not narrowly critical but it is preferred for 
efficient operations to range between about 20 and 140 pounds of acetone 
per/hour/foot.sup.3 of catalyst. This corresponds to an hourly vapor space 
velocity of about 90 to about 700 cubic feet of gaseous acetone per cubic 
foot of catalyst per hour. At about 300.degree. C. and 3 atmospheres, the 
preferred contact time is about 5 to about 40 seconds. 
It is preferred to hold percent conversion of acetone in the range of about 
7 to about 30 percent by weight. 
The life of the catalysts of this invention is surprisingly long and is in 
excess of about 7000 hours for the efficient conversion of acetone. An 
unexpected attribute of these catalysts is the fact that their life can be 
extended further by regeneration consisting of heating the catalyst in the 
presence of air or oxygen at a temperature in the range of about 
250.degree. to 350.degree. C. thereby burning off any adhering polymer and 
non-volatile by-products. Surprisingly the regenerated catalyst is as 
efficient and in many cases more efficient than the original catalyst. 
The terms conversion and efficiency of the acetone conversion are used in 
this invention as defined below: 
##EQU1## 
Where: A = Total Acetone equivalents fed 
B = total Acetone in product 
Mso = total Equivalents of acetone in the mesityl oxide product 
I = total equivalents of acetone in the isophorone product. 
The term "Acetone Equivalent" is one for acetone, two for mesityl oxide and 
three for isophorone for purposes of this disclosure. It simply accounts 
for each mole of acetone fed to the reactor whether in reacted or 
unreacted form. 
While the highest efficiencies are obtained by using an anhydrous acetone 
feed having a purity of 99 percent or greater, this invention can be used 
with acetone having a purity as low as about 70 percent by weight with the 
balance being mesityl oxide, water and other materials, such as, 
isopropanol, hexanes, and the like. 
The conversion of acetone to mesityl oxide and isophorone according to this 
invention is preferably carried out over a fixed catalyst bed. 
The catalysts of this invention do not require a support. They can be 
pelleted, extruded or shaped into any desired form. However, if desired 
they can also be formulated to be carried on an inert material. 
The testing of these catalyst compositions was carried out by two methods. 
The first involved the use of a pulse reactor-gas chromatographic 
combination which yields rapid and semi-quantitative data. This was used 
principally as a screening tool to detect highly active catalysts for 
subsequent testing. Also the reaction chemistry and other features were 
examined by this technique. The second method was a one-inch i.d. pilot 
plant reactor. In this latter device long term testing was carried out. 
The initial screening operations used in the discovery of this catalyst 
system were effected by means a pulse reactor consisting of a modified 
Hewlett-Packard Model 5750-B gas chromatograph. The gas chromatograph 
separation column was 10 feet long and 1/8 inch in diameter packed with 20 
percent Carbowax 20M (Trademark of Union Carbide Corporation for 
polyethylene glycol having a formula molecular weight range of about 
18,000 to 19,000) on Chromosorb T (a polytetrafluoroethylene support sold 
by Johns-Manville Co.). 
The programming schedule was 50.degree. to 100.degree. C. at 8.degree./min. 
Detection was by fid (flame ionization detection) although the less 
sensitive tc (thermal conductivity) mode can also be used. The detector 
temperature was 300.degree. C. Peak integration was carried out by an 
electronic coulometer. 
The injection port kept at 300.degree. C. was 1/4 inch i.d. into which a 
2mm o.d. glass liner filled with catalyst (about 0.1 to 0.2 g.) was 
inserted. Specially cut silicone rubber septa prevented gases from 
by-passing this glass catalyst holder. 
In the general procedure six 25 .mu.liter fractions of acetone were 
initially injected into the catalyst bed. These injections were carried 
out in rapid succession; after this the catalyst in the separation column 
was cleared of all reaction products by sweeping helium through for about 
2 hours. After this two 2 .mu.liter injections of acetone were used to 
measure the initial catalyst activity. 
The pilot plant reactor is described below: 
ONE-INCH PILOT PLANT REACTOR 
This device consists of a 1 inch i.d. pipe (300 cm long) made of 304 
stainless steel. The bottom 165 cm contained about 1 liter of catalyst. A 
1/4 inch thermocouple well went through the center of this catalyst bed. 
In it were 6 thermocouples, equally spaced. Readings were a multipoint 
recorder. On each end of the catalyst bed was a glass wool plug (.about.7 
cm) and a Carpenter 20 "Neva-Clog" screen. Before the catalyst bed was a 
120 cm preheat section of 1/4 inch glass balls. Acetone liquid was pumped 
with a reciprocating plunger pump into a tubular heat exchanger (2 
ft..sup.2 surface area, steam heated, 190 psi) and then directly onto the 
glass bead section. Vapor flow was in a downward direction. Heating was by 
3/4 inch-high temperature glass fiber insulated tapes which were 
controlled by temperature controllers. The reactor pressure was controlled 
with appropriate valves. Following this was a 2 ft..sup.2 heat exchanger. 
Weights (in and out) were on 100 kg. balances (.+-.25 g.). Usually the 
material balance was within 2%. Gas formation--invariably nil--could be 
checked with a wet test meter. 
Data from this pilot plant reactor can be quantitatively related to plant 
scale operations. 
ANALYTICAL METHODS 
Water was determined by Karl Fischer titration or by using thermal 
conductivity detection. The reaction crudes were analyzed by gas 
chromatography. Area-wt. % correlations were established using synthetic 
known samples. 
Typical pulse-reactor results are presented later. They were calculated 
from the pulse reactor-gas chromatographic runs carried out by the above 
procedure. Calcium hydroxide, a commonly using heterogeneous catalyst from 
acetone aldol condensations, was added as a reference but was relatively 
inactive. 
The activity of each catalyst can be inferred from the recovered acetone 
percentage. The smaller this number the more acetone is converted, the 
more active the catalyst is. 
The term "active hydrogen-containing organic compounds" as used herein 
includes those having the group --C--H adjacent to a aldehydic or ketonic 
carbonyl group, a nitro group, a cyano group and other electron 
withdrawing groups such as those present in quaternary salts. 
Preferred active hydrogen containing organic carbonyl compounds which are 
susceptible to aldol condensation using the catalysts of this invention 
include aliphatic aldehydes, such as, formaldehyde in conjunction with 
other active hydrogen containing compounds, acetaldehyde, n-butyraldehyde 
and the like, aliphatic ketones such as methyl ethyl ketone, methyl 
isobutyl ketone, diethyl ketone, and the like, cycloaliphatic ketones, 
such as, cyclohexanone, as well as acetone. 
The above described catalysts unexpectedly demonstrate selective reactivity 
even for such closely related aliphatic aldehydes as n-butyraldehyde and 
its isomer isobutyraldehyde. It was demonstrated that n-butyraldehyde 
reacted over 8 times faster than isobutyraldehyde in an aldol condensation 
using these catalysts.

The invention is further described in the examples which follow. All parts 
and percentages are by weight unless otherwise specified. 
EXAMPLE 1 
Lithium Ion Doped Catalyst Preparation 
A solution of 1440 g. of magnesium nitrate, Mg(NO.sub.3).sub.2. 6H.sub.2 O 
in 8 liters of distilled water was charged to a stainless steel 5 gallon 
reactor equipped with a mechanical stirrer and addition funnel. A solution 
of 421 grams of sodium hydroxide, NaOH, in 4 liters of distilled water was 
then added dropwise over a period of about 4 hours with good stirring. The 
pH of the contents of the reactor was about 9 to 10. A white precipitate 
or slurry formed during this step. There was next added 50 grams of 
Mg(NO.sub.3).sub.2. 6H.sub.2 O to the slurry with continued stirring 
followed by the slow addition of a solution of 32.0 grams of NaAlO.sub.2 
in 1100 ml. of distilled water over a two hour period. The pH of the 
resultant slurry was about 8. 
After standing overnight the slurry was filtered and the filter cake 
carefully washed three times with 1.5 liters of distilled water. The wet 
cake weighed 639.8 grams and had a solids content of 47.5% (determined on 
an aliquot portion dried at 100.degree. C./30 mm. for 24 hours in a vacuum 
oven). 
Fifty grams of the wet cake was doped with lithium ions by re-slurring, in 
a solution containing 0.5 grams of LiNO.sub.3 dissolved in 500 ml. of 
distilled water, for four hours followed by filtration and drying of the 
filter cake in a vacuum oven at 100.degree. C./30 mm. for 24 hours. 
EXAMPLE 2 
Zinc Ion Doped Catalyst Preparation 
Example 1 was repeated with the exception that the doping step was carried 
out by re-slurrying 50.0 grams of the wek cake in a solution containing 
1.0 grams of Zn(NO.sub.3).sub.2.6H.sub.2 O for 4 hours followed by 
filtration and drying of the filter cake in a vacuum oven at 100.degree. 
C./30 mm. for 24 hours. 
EXAMPLE 3 
Testing of Lithium and Zinc Ion Doped Catalysts 
The pulse-gas chromatographic technique described supra was used for 
testing the catalysts prepared as in Examples 1 and 2 and compared with a 
Control A which was identical to the Example 1 catalyst except that no 
doping with lithium or zinc ions was used. The results are presented in 
Table 1. 
TABLE 1 
______________________________________ 
Unconverted 
Mesityl Isophorone 
Other 
Catalyst 
Acetone, % Oxide, % % Products, % 
______________________________________ 
Control A 
10.0 0.8 31.5 57.7 .sup.(1) 
Example 1 
8.9 1.9 40.0 49.2 .sup.(2) 
Example 2 
16.6 1.4 33.2 48.8 .sup.(2) 
______________________________________ 
##STR1## 
##STR2## 
EXAMPLE 4 
Pilot Plant Reactor Evaluation of Lithium Ion Doped Catalysts 
Acetone (99% pure) was fed to the 1 inch .times. 10 foot pilot plant 
reactor described supra which was packed with a 1/8 inch pelleted, lithium 
doped catalyst prepared as in Example 1. The elemental analysis of this 
catalyst indicated the following composition: 
C, 2.41% (due to a graphite lubricant for pelleting) 
Al, 3.49% 
Mg, 47.47% 
S, 0.03% 
cl, 0.32% 
Li, 0.05% 
This catalyst had the following physical properties: 
______________________________________ 
Pellet crush strength 6 lbs. 
Pore volume 0.32 cc./g. 
Surface area 115 m.sup.2 /g. 
(After heating to 350.degree. C.) 
Bulk density 0.86 g./cc. 
______________________________________ 
The feed rate of the acetone above was 44 lbs./ft..sup.3 of catalyst/hr. at 
300.degree. C./40 psi. 
About 18.4% of the acetone was converted into isophorone and mesityl oxide 
at an efficiency of 85.4%. The concentration of mesityl oxide and 
isophorone in the product stream was 5.6 and 7.8% respectively, 
representing a mesityl oxide/isophorone product ratio of 0.72. These data 
are delineated in Table 2 along with six other runs made at different 
operating conditions of feed rate and pressure with temperature held 
constant at 300.degree. C. 
TABLE 2 
__________________________________________________________________________ 
1" .times. 10' PILOT PLANT REACTOR RESULTS 
Mesityl 
Mesityl Oxide Total Acetone 
Efficiency to 
Oxide 
Isophorone 
Isophorone 
Conversion 
Mesityl Oxide + Isophorone 
Operating Conditions 
(wt. %) 
(wt. %) 
(wt. %) 
(%) (%) (.degree. C)/psi/lbs. 
__________________________________________________________________________ 
5.6 7.8 .72 18.4 85.4 300/40/44 
5.6 10.9 .5 23.8 81.7 300/40/22 
5.0 5.0 1.0 13.8 84.8 300/40/66 
4.4 3.8 1.9 10.2 94.2 300/40/132 
4.8 19.6 .24 36.8 76.4 350/40/22 
6.2 9.0 .71 21.4 87.3 300/40/44 
3.9 7.0 .55 15.6 81.4 300/0/44 
__________________________________________________________________________ 
EXAMPLE 5 
An Alternate Lithium Ion Doped Catalyst Preparation 
To a solution of 149 g. of magnesium nitrate, Mg(NO.sub.3).sub.2.6H.sub.2 
O, in 1 liter of distilled water was added over a 30 minute period with 
stirring a solution of 42.1 g. of sodium hydroxide in 400 ml. of distilled 
water. A white precipitate appeared at once which was slurried in the 
aqueous medium. To this slurry was added a solution of 3.2 g. of sodium 
aluminate, NaAlO.sub.2, in 110 ml. of distilled water. The pH after the 
addition of the sodium aluminate was complete was 8-9. After standing 
overnight the reaction mixture was filtered and the filter cake washed 
with three 500 ml portions of distilled water. The filter cake was 
contacted overnight with 500 ml of water in which 0.1 g. of lithium 
nitrate, LiNO.sub.3 had been dissolved. The slurry which resulted was 
filtered and the filter cake dried at 100.degree. C. for 18 hours under a 
vacuum of 30 mm Hg. The yield of white solid catalyst was 29.3 grams. 
EXAMPLE 6 
Lithium Ion Doped Catalyst Preparation 
To 149 g. of Mg(NO.sub.3).sub.2.6H.sub.2 0 in one liter of distilled water 
was addd a solution of 42.1 g. of NaOH, 3.2 g. of NaAlO.sub.2 in 500 ml. 
of distilled water slowly over a period of 30 minutes. A precipitate 
appeared at once and the pH at the end of the addition was 8-9. The 
precipitate was filtered and washed three times with 500 ml of distilled 
water. The precipitate was then contacted with a solution consisting of 
0.1 grams of LiNO.sub.3 in 500 ml of distilled water. The so-treated 
precipitate was dried at 100.degree. C. for 18 hours under a vacuum of 30 
mm Hg. The dried catalyst amounted to 31.8 grams. 
EXAMPLE 7 
Lithium Ion Doped Catalyst Preparation 
To a solution of 140 grams of Mg(NO.sub.3).sub.2.6H.sub.2 O and 15.3 grams 
of Al(NO.sub.3).sub.2.9H.sub.2 O in one liter of distilled water was added 
a solution of 43.7 grams of NaOH in 500 ml of distilled water slowly over 
a 30 minute period with stirring. The pH at the end of the addition was 
8-9. The precipitate which appeared was filtered and washed three times 
with 500 ml portions of distilled water. The filter cake was redispersed 
in 500 ml of distilled water containing 0.1 grams of LiNO.sub.3 and left 
to stand overnight. It was then filtered, dried at 100.degree. C. for 18 
hours under a vacuum of 30 mm Hg. The yield of dry catalyst was 29.0 
grams. 
EXAMPLE 8 
Lithium Ion Doped Catalyst Preparation 
To a solution of 43.7 grams of NaOH in 500 ml. of distilled water was added 
a solution of 149 g. of Mg(NO.sub.3).sub.2.6H.sub.2 O and 15.3 grams of 
Al(NO.sub.3).sub.3.9H.sub.2 O in 1 liter of distilled water slowly over a 
30 minute period with good stirring. At the end of this time the pH of the 
mixture was 8-9. The precipitate which formed was filtered and washed 
three times with 500 ml. portions of distilled water. The filter cake was 
redispersed in 500 ml. of distilled water containing 0.1 g. of LiNO.sub.3. 
The product was filtered and dried at 100.degree. C. for 18 hours under a 
vacuum of 30 mm Hg. The yield of catalyst was 30.9 grams. 
EXAMPLE 9 
Catalyst Evaluations 
The catalyst preparation described in Examples 5, 6, 7 and 8 were evaluated 
in the pulse-gas chromatographic technique described supra using two micro 
liters of acetone as the active hydrogen containing organic carbonyl 
compound. The results are delineated in Table 3. 
EXAMPLE 10 
Pilot Plant Reactor Evaluation of Lithium Ion Doped Catalysts with 
Aliphatic Aldehydes 
The pilot plant reactor described in Example 4 was packed with 1091 g. of 
the catalyst which was described in Example 1. The particles were sized to 
a diameter of 0.4-2.4 millimeters. The reactor was heated to 280.degree. 
C. at a pressure of 40 psig while pumping at 50:50 (weight) mixture of 
n-butyraldehyde and isobutyraldehyde at a rate of about 700 grams per 
hour. Gas chromatographic analysis and material balance shows the 
following results: 
Percent in n-butyraldehyde reacted = 51.0 
Percent isobutyraldehyde reacted = 6.0 
TABLE 3 
__________________________________________________________________________ 
UNCONVERTED 
MESITYL 
ISOPHORONE, 
OTHER PRODUCTS 
CATALYST 
ACETONE, % 
OXIDE WT. 
% ISOXYLITONES.sup.(a) 
TETRALONES.sup.(b) 
__________________________________________________________________________ 
Exp. 5 18.2 3.3 32.3 5.6 36.6 
6 57.7 6.4 31.0 0.8 2.7 
7 27.1 2.6 39.8 2.7 17.6 
8 77.9 13.8 5.1 0 0 
__________________________________________________________________________ 
##STR3## 
##STR4## 
The efficiency of the catalyst evaluated herein depends upon the 
specificity with which n-butyraldehyde condensed with itself to form 
2-ethylhexenealdehyde rather than with isobutyraldehyde to form a 
corresponding isomer. It was found that the efficiency of the former 
reaction to form 2-ethylhexenealdehyde was 65.9 percent as opposed to an 
efficiency of 11.0 percent for the condensation of n-butyraldehyde with 
isobutyraldehyde to form that dimer. The efficiency of forming a trimmer 
of 3 n-butyraldehyde units was 19.6 percent. Therefore the total reaction 
efficiency was 93.8 percent. This evaluation demonstrates that the 
catalyst evaluated herein discriminates in favor if an n-butyraldehyde 
plus n-butyraldehyde condensation in preference to isobutyraldehyde plus 
n-butyraldehyde or isobutyraldehyde plug isobutyraldehyde condensation by 
almost an order to magnitude. 
EXAMPLE 11 
Evaluation of Lithium Ion Doped Catalysts with Anhydrous Acetaldehyde 
The lithium doped catalyst described in Example 1 was shaped into 1/8 inch 
pellets and 145 grams packed into a stainless steel pipe reactor having 
the dimensions 1 .times. 12 inches followed by a condenser and receiver. 
At 40 psi and 280.degree. C. about 90 grams per hour of anhydrous acid 
acetaldehyde was pumped through this arrangement. Gas chromatographic 
analysis showed that 67.2 percent of acetaldehyde was recovered, 25.6 
percent of the dimer 
##STR5## 
was produced and 7.2 percent of the trimer 
##STR6## 
was produced. 
EXAMPLE 12 
Evaluation of Lithium Doped Catalyst with Cyclohexanone 
Using the equipment described in Example 11, ninety grams per hour of 
cyclohexanone feed was passed through the reactor at 40 psi and 
280.degree. C. Gas chromatographic analysis showed the product consisted 
of 85.3 percent of cyclohexanone and 12.3 percent of a mixture of dimers 
having the structural formulae shown below: 
##STR7## 
Although the invention has been described in its preferred forms with a 
certain degree of particularity, it is understood that the present 
invention disclosure has been made only by way of example and that 
numerous changes can be made without departing from the spirit and the 
scope of the invention.