CA1257294A - Preparation of 2-propylheptanol and other alcohols - Google Patents

Abstract

AND OTHER ALCOHOLS

ABSTRACT
A preparation of a plasticizer alcohol, consisting of predominantly 2-propylheptanol, from linear butenes is described in which oxo product of the butenes is aldoled to condense n-pentaldehyde therein with very little cross-aldolization followed by hydrogenation to obtain the 2-propylheptanol with very small 2-propyl-4-methyl hexanol content. The alcohol product as phthalate ester has excellent plasticizer properties.
Also processes are described for converting other olefins to alcohols by oxo, aldol and hydrogenation reactions, with particular attention to converting hexenes obtained by propylene dimerization to C14 alcohols suitable for preparation of detergents.

Description

~L257;~:9~

PREPARATION OF 2-PRoPYLHEPTANOL
AND OTHER ALCOHOLS

The present ;nvent;on ;s concerned w;th preparing alcohols from olefin feedstock.

The present invention is further concerned with preparing ten-carbon plasticizer alcohols from substantially linear butene feedstock.

Background of the Invention Various lower olefinic stocks are available from petroleum sources, and many procedures are known for converting lower olefins to high olefins, or to higher molecular weight compounds with various functional groups. Among such procedures are catalytic dimerization procedures for con-verting propylene and butenes to heptenes andoctenes respectively and such dimers can be catalitically hydroformylated to aldehydes, which can be reduced to alcohols. Lower olefins can be hydroformylated, using rhodium, cobalt, or other catalysts, to the corresponding aldehydes.
Aldehydes in turn can be converted to higher aldehydes by the well known aldol reaction, such ~2S~Z~

as that taught in U.S. Patent 2,921,039 for con-verting n-valeraldehyde to 2-propyl-2-heptanol, and then hydrogenated to 2-propylheptanal and

2-propylheptanol. It is also known that various alcohols can be utilized to esterify phthalic acid to form useful plasticizers, e.g. 2-ethylhexanol, 2-propylheptyl alcoho!, decyl alcohols, etc. as disclosed in ~he aforesaid 2,921,089. It is also known to conduct an aldol react;on of m;xtures of normal and branched aldehydes under cond;tions which force oross aldol reaction of the branched aldehyde with the normal aldehyde, see U.S. Patent 2,~52,5O3.

Among dimerization processes ;s the Dimersol~
dimerization process for d;meriz;ng olefins using a n;ckel coordination complex and an aluminum alkyl as catalyst. The process can convert propylene to hexenes with selectivity in excess of 85~.
2û The hexenes can be converted by oxo reaction to aldehydes and then alcohols, producing heptanols.
M. Johnson has studied oxo reaction of 4-methylpen-1-ene, showing migration of the double bond during the reaction, and fairly large production of a 2-substituted aldehyde, 2,4-dimethylpentanal, along with 5 methyl-hexanol as the~main product tJ. Chem. Soc. 1963, 485).

.

. ~.2S~g~ .

Reactions of the type described characteristically produce mixtures of isomeric products. Therefore in the production of plasticizer alcohots~ distillations may be employed at an early stage to separa~e iso-meric materials. An alternative is to effect selective reaction of the isomeric materials with resulting effect upor product propert;es.
Summary of the Invention The present invention involves a process in wh;ch m;xed butenes are converted to a ten-carbon plasticizer alcohol compr;sed of at least about 80-90~o Z-propylheptanol by an oxo react;on of the butenes to obta;n amyl aldehydes with at least about 66'~ n-pentaldehyde content, followed by an aldol react;on of the aldehydes under conditions to cause substantially all of the n-pentald`ehyde to react but with incomplete conversion of branched aldehydes, and then hydrogenat;ng to produce alcohols in which the ten-carbon alcohols are comprised of at least 80-90~ 2-propylheptanol. Under the aldol conditions employed the 2-methylbutanal present does not readily condense with itself, and condenses at a comparatively slow rate with the n-pentanal, so that the 2-propyl-4-methylhexanol content (resulting from the so-called cross aldol of n-pentanal with 2-methyl-butanai) in the resulting alcohol is held to no more than about 15-2n%, often 12~' or less.
The ten-carbon alcohol mixture, after isolation from other components, is admirably suited as a plasticizer alcohol, having good plasticizing pro-perties as the phthalate diester. It approaches the excellent plasticizer properties of the 2-propyl-heptyl phthalate, as the small amount of 2-propyl-4-methylhexanol causes only a slight decline in such properties.

`` ~25~29~ .

The descr;bed procedure is advantageous in that it avoids the expense of a fractionation of difficultly separable aldehyde isomers prior to the aldol reaction, and produces an excellent plasticizer alcoh'ol in high yield by an efficient procedure from the source materials. The main s;de product, 2-methylbutanol, is in itself useful as a plasticizer alcohol. The invention utilizes selective a'ldol reaction as a step in producing a quality plasticizer alcohol without normally requiring separation of aldehyde isomers prior to aldol condensation. This contrasts with the pro-cedure used in 2-ethylhexanal manufacture in which propylene is hydroformylated to a mixture of n-butanal and 2-methylpropanal ~isobutyraldehyde), and the mixture of close boiling isomers is then carefully separated by fract;onal distillat;on in an expensive multiple tray column, so that the n-butanal can be taken forward to an aldol 'reaction.

The invention is further concerned with process in which olefins selected from those with

3 to 7 carbon atoms are converted to aldehydes w;th

4 to 8 carb'on atoms, which are then subjected to aldol condensat;on to obtain aldol products in relatively high yield for hydrogenation to alcohols having useful properties and derivative uses, with especial interest in conversion of hexenes to heptanals and to C14 alcohols for use in detergents.

~25~2g~

Detailed Description of the Invention In the production of plasticizer alcohols from olef;ns, typical procedures introduce branching into the alcohol product. The branching has a significant effect upon propert;es when the alcohols are ut;l;zed as plast;c;zers ;n the form of phthalate esters. It is therefore desirable to control the degree of branch;ng.

The present invention utilizes an oxo reaction of olefins, followed by an aldol condensation. If n-pentanal is reacted in an aldol condensation, followed by hydrogenation, 2-propylheptanol is obtained, and is well-suited as a plasticizer alcohol.
If n-pentanal is reacted in a cross-aldol reaction with 2-methylbutanal, the alcohol obtained following hydrogenation is 2-propyl-4-methyl-hexanol, which has much poorer propert;es as a plast;cizer alcohol.
It follows that a superior product can be obtained by separating n-pentanal from its ;somers prior to conducting the aldol reaction. However, iso-meric aldehydes have similar boiling points, andseparation by distillation on a commercial scale involves high caPital cost equipment with con-sequent expense together with a very substantial energy cost. In the presently described ;nvent;on there is great advantage in avoiding such a dis-tillation step.

~:~S~9~

The present invention in one part;cular aspect employs an oxo reaction of butenes to obtain a mixture of aldehydes, wh;ch is then sub~ected to an aldol reaction. The oxo reaction involves contacting substantially linear butenes with hydrogen and carbon monoxide and hydroformylation catalyst under hydroformylatic,n conditions suited to obtaining a high proportion of n-pentanal in the aldehyde product. It is desirable to have the n-pentanal to branched aldehyde ratio at least about 2.0:1, representing at least about 66.7% n-pentanal content. Aldehydes w;th 70-75~.
normal content, or even higher normal contents are desirable to the extent available from oxo reactions, poss;bly up to 85%., and will be useful for the aldol stage of the present invention.

The aldol reaction is carr;ed out ut;l;zing the usual aldol catalysts and conditions to pro-mote the aldol reaction of the n-pentanal, using elevated temperatures upwards of 60C., parti-cularly temperatures of about 90C. to 130C~, or possibly up to 150C. or higher if des;red. The reaction is operable over broad pressure ranges including pressures less than atmospher;c as well as elevated pressures, but will usually be effected at slightly elevated pressures sufficient to main-tain the reactants substantially in the liquid state.
The reaction can also conveniently be conducted at reflux. The conditions and parameters discussed and illustrated herein with respect to butenes and pentanals are in general exemplary of those for other olefins and aldehydes.

~257~

Under the aldol cond;tions employed, the n-pentanal reacts with itself to form aldol pro-duct at a rate about 15 times greater than it reacts w;th 2-methylbutanal. The aldol reaction is permitted to go to 80% or so completion so that if about 25% of the aldehyde supplied is 2-methylbutanal, about 3/4 of it will remain un-reacted, and about ~87~ of the aldol product will be that from self-condensat;on of n-pentanal. The conversion of n-pentanal to aldol product will be very high and desirably nearly complete, such as upwards of 90 or 95%.` There will be some variation with conditions and isomer content of the aldehydes utilized, but the present invention contemplates obtaining aldol product with about 80'~ to about 95~_being from the self-condensation of n-pentanal, and preferably at least 85% from self-condensation with no more than 15% of 2-propyl-4-methylhexanal being produced. In the present process, the aldol intermediate, 2-propyl-~-hydroxyl-heptanal will ordinarily be dehydrated in the aldol procedure to 2-propylheptenal. Under some conditions the immediate aldol product can be isolated, but ord;narily under the temperature conditions em-ployed herein the 2-propyl-2-heptanal is produced.
The aldol reaction can utilize strongly alkaline catalyst, such as sodium and potassium hydroxide, or sodium and potassium cyanide. The concentration of the aqueous alkali can be varied, but molar 3Q or similar concentrations of alkali metal hydro-xides can be used, and concentrations selected will generally be in the range of about 1 to 10~ by weight. The amount of aqueous alkali to aldehyde reactant can also vary, for example from about 15%

57~9~

by volume aqueous alkali up to about 75~ by volume aqueous alkali. The aldol reaction will be run for a suffic;ent time to obtain the desired degree of con~ersion, which for batch react;ons may be in the range of about 1 to about 3 hours, while in continuous reaction t;mes of less than five minutes are achievable. The reaction is stopped by per-mitting the reaction mixture to cool and separating the organic reaction phase from the aqueous alkali phase. Since the n-pentanal reacts more rapidly than its isomers, the proportion of the isomers`in the reacted aldehyde increases, and it therefore is not generally desirable to separate and recycle unreacted components to the reaction.
.
For the oxo reaction, linear butene streams are available which may have up to 70~ l-butene with the balance 2-butene. 3utene streams generally contain isobutylene also, but the isobutylene can be separated in a reaction with methanol producing methyl tertiary butyl ether, making linear butenes available which are substantially free of isobutylene.
The hydroformylation procedures described herein can be employed to obtain aldehydes with a great pre-dominance of the n-pentanal from linear butenes containing even a high proportion of 2-butene, as even 2-butene itself produces a pentanal: 2-methyl-- butanal ratio of about 2.33, and a 1:2 mixture of l-butene:2-butene produces product ratios in the range of about 2.8:1 to 3.1:1. In terms of avail-able and effective materials, it may be desirable to employ linear butene mixtures in which l-butene ~257~9~

is from 1/3 to 1/2 of the mixture; and, of course, higher proportions of l-butene could be used if available, up to 100% l-butene. It happens, however, that the amount of normal aldehyde product is not very sensitive to increases in the l-butene content in ranges above 50~.

It is important that the hydroformylation of the m;xed lin:ear butenes gives a relatively high ratio of normal aldehydes, as this contr;butes to the Teasibility of using the aldehyde mixture for an aldol reaction to obtain a fa;rly h;gh yield of 2-propylheptanal (and ult;mately 2-propylheptanol) without excess;ve 2-propyl-4-methylhexanal. The use of moderate temperatures ;n the hydroformylation contributes to obtaining about a 3:1 mixture of normal to branched aldehyde. Thus temperatures sufficient to produce an appreciable reaction rate, ranging from ~0 to 100C. or so can be used, and temperatures on up to 125 - 130C. can be employed to obtain better reaction rates. Still higher temperatures up to 15nC. or higher can be used but with a tendency to produce more branched aldehyde than des;red. To some extent high catalyst concentrations can be employed to obtain reaction rates, even at relatively low temperatures. Cobalt catalys~ is especially suited to obtain the desired high proportion of normal aldehyde. Unmodified cobalt carbonyl catalyst can conveniently be used~
Such catalyst, conventionally designated as cobalt octacarbonyl, can be provided or employed in many forms known to be useful as a hydroformylation catalyst, although it may be necessary to exercise ~257~

some choice to provide catalyst best suited to obtaining a high proportion of normal product.

The oxo stage of the reaction can be conducted urider the usual condit;ons pertaining to cobalt catalyzed hydroformylation reactions, w;th attention to the temperature conditions as described above.
Usual pressure conditions apply, such as 6.89-27.56 M Pa or up to 34~45 M Pa total pressure, with most of the pressure being from the carbon monox;de and hydrogen supplied. The carbon monoxide and hydrogen are conveniently used in 1:1 ratio and obtained from usual synthesis gas sources, but other ratios can be e~ployed in keeping with known hydroformylation practice. The reaction can be carried to the desired stage of completion in 1 to ~ hours or so on a batch basis, varying with time, temperature, pressure and catalyst concentration.

The reaction can be conveniently conducted either without a solvent or with solvents and, employing concentrations customary for homogeneous catalyst reactions, such as 2 to 10 molar or greater concentrations of the butenes in a solvent, e.g., hydrocarbon solvents such as toluene, and 0~1% to 1~ by weight, based on cobalt, of catalyst.
.
The present invention is also concerned with preparing detergent range alcohols from propylene feedstock. The detergentrange alcohols are some-what higher in carbon number than plasticizer alcohols, often having about 14 carbon atoms, but in some cases ranging from about 11 to about lo or so carbon atoms. Propylene can be dimerized to hexenes, and the hexenes can be converted to aldehydes by an oxo reaction as described herein, ~57~9~ .

and the resulting heptaldehydes can be reacted in an aldol react;on to produce aldol products which can be hydrogenated to C14 alcohols.

The described route to C14 alcohols gives an alcohol having properties suitable for use in pre-paring detergents. While the alcohols have some branching, much ot the product is mono-branched, or of a branched structure which can be bio-degraded. Thus, depending upon particular proce-dures utilized, the product may be comprised inlarge part of 2-pentylnonanol, possibly with a small fraction of 2-pentyl-4-methyloctanol. Such structures, with non-adjacent branches~ are susceptible to biodegradation.

For reactions where the ultimate product is a plasticizer, as usual in those involving aldol reactions of pentanals, there is interest in limiting cross-aldol reactions which increase chain branching. However, for other uses where branching is n-ot necessarily detrimental, some cross aldol reactions are useful as augmenting the efficient utilization of feed stock materials. Thus in a broader sense the present invention can utilize aldol reactions in which there is aldol and cross-aldol condensation of n-aldehydes along with branched aldehydes in which the br~nching is not at the 2-position, or generally including the class of alkanals except for those substituted on the 2-position. This applies to aldehydes with ~25729~
. . , 4 to 8 carbon atom~s, as obtainable from oxo reactions of C3 to C7 olefins, and applies par-t;cularly to aldehydes with 6 to ~ carbon atoms.
Thus in such aldol react;ons, crude oxo mixtures containing a number of isomers may be employed, and substantially complete reaction of all the aldehyd'es except the Z-substituted aldehydes.can be.achieved. For example, better than 95% con-version ofC~-aldehydo alkanes can be achieved, '10 while convers;on of 2-substituted aldehydes may be in the neighborhood of 25 to 30% or poss;bly even up to 50~. Thus it is feasible to use such crude oxo mixtures in aldol reactions to obtain useful products. Using oxo product in which the ~ -aldehyde alkane content may range from 60 up to near 80~ or so, aldol conversions may approach 75 to 90%, even though participation of the 2-sub-stituted aldehydes is limited, so that it is in-volved in cross-ald.ol'producing no more than 20,' of thè product.

It is possible to obtain butene streams which are substantially linear and substantially free of isobutylene, in which no more that 2~ or so of the butenes is isobutylene,'and it is advantageous to use such butene streams. However, somewhat more isobutene.can be tolerated, so long as the total of the resulting 3-methylbutanal ' ' . together with other branched aldehydes in the ~257~9 aldehydes to be reacted does not become undes;rably high. The 3-methylbutanal is more prone to react in the aldol reaction than the 2-methylbutanal isomer, so it is desirable to keep its presence to a minimum.

The hydrogenation of the enals from the aldol reaction can be conducted under the usual catalytic hydrogenation conditions for reducing olefinic bonds and aldehyde groups. The carbon-to-carbon bond reduces more rapidly and at a lower temperature than the aldehyde group, e.g. at about 90C., with cobalt on Kieselguhr catalyst at elevated hydrogen pressure. The hydrogenation will generally be carried out at 3.45-13.8 M Pa, or greater hydrogen lS pressures arid temperatures of 130 to 2ûOC. or higher, although any temperatures which are effective with a particular catalyst can be used. The stated conditions will be effective for reducing both the carbon-to-carbon bond and the aldehyde group to obtain saturated alcohol. Various other hydro-genation catalysts can be used ;ncluding platinum and platinum on carbon catalysts, copper chromite, activated nickel etc., and individual catalysts can be utilized in conjunction with other catalysts.

The present invention involves an oxo reaction, followed by an aldol reaction, and then a hydro-genation to convertenals to alcohols. For large scale operations, the oxo reaction will be con-ducted with usual provision, for separating gaseous reactants and products, and catalyst, from the aldehyde products, with recycle as appropriate.
The aldehyde product mixture will then be subjected to an aldol reaction, followed by decantation and water washing or other simple procedures to separate P25~9~

the organic product-conta;ning phase from the aqueous phase. The product phase is then hydro-genated, converting both the C5 aldehydes and C1O
enals to the corresponding alcohols. The hydro-genation is followed by a distillation to removelight erids, followed by a distillation to remove C5 alcohols. Both the C5 and Clo alcohols can then be treated in further hydrogenation polishing ope-rations to improve the alcohol quality by insuring complete hydrogenation. The ten-carbon alcohol mixture thus obtained will, as described herein, have a high content of 2-propylheptanol with only small amounts of 2-propyl-4-methylhexanol or other branched alcohols, the amounts of such materials being sufficiently small that the alcohol mixture has properties suitable for a plasticizer alcohol.

The five-carbon alcohol co-product obtained is principally 2-methylbutanol, a useful product;
historically five-carbon alcohols have more value than ten-carbon alcohols. The separation of the five-carbon from ten-carbon alcohols is readily effected by distillation in equipment constructed of inexpensive alloys such as carbon steel. Sepa-- ration at this stage is simple, comPared to the difficult separation which would be required to separate the five-carbon aldehyde isomers prior - to the aldol reaction.

As an alternate to the above procedure, it is possible to separate ~he five-carbon aldehydes by distillation from the l~-carbon enals prior to hydrogenation. For convenience of separation, distillation of the alcohols is generally preferred, and then the five-carbon components are in the form - of alcohols. However, i; the aldehydes are desired ~L2st7~

for some purpose, separation is appropriate, and th;s has the advantage of avoid;ng unnecessary hydro-gen use~

Hexenes, as produced by dimerization of propyl-ene with transition metal catalysts, as in the Dimer-sol ~ dimerization process, are characterized by being composed almost entirely of internal olefins, and a linear content generally reported as about 20~, but ranging up to 2,% or so. The main isomer present is a 2-methyl-2-pentene, along with other 2- and 4-methyl pentenes and around 6/, 2,3-dimethyl-2-butene.

The linear hexenes can be separated from the crude -dimerization product by use of a molecular sieve or other suitable procedure, and the linear hexenes alone then subjected to an oxo reaction to obtain heptanal produrts, wtth the linear content of the heptanals ranging up to 75% or more. 9ranched isomers which may be present include 2-methylhexanal, and 2-me.hylpentanal. The oxo product m;xture can be reacted in an aldol reaction, employing aldol conditions as described herein, to produce aldol products. Under the aldol conditions employed, the n-heptanal reacts with itself at a rate about 10-15 times faster than it reacts with 2-methyl-hexanal or other 2 -substituted aldehydes. Thus, when the C~ aldehydes are produced from linear hexenes, a product compound predominantly of pro-3Q duct from self-condensation of n-heptanal can be obtained by carrying out an aldol reaction of the oxo reaction product, with some control over the amount of product from 2-substituted aldehydes by controlling the amounts of conversion which is per-mitted. It may be desirable to have better than ~:~5~9~

50 or 60~ complet;on for efficient use of feed stock, and conversions of 80% or higher may at times be desirable. The reaction can be run to achieve 95%
or better conversion of the n-aldehyde to aldol product, while only about 1/4 to 1/3 or so of the 2-substituted aldehydes are usually converted to aldol product by a cross-aldol reaction. With use of appropriate control, aldol product with about 80% to say 95% from self-condensation of n-heptanal can be obtained, for example at least ~5~O from self-condensation, with no more than 15,' of cross-aldol product. Depend;ng upon the pro~
perties desired ;n the product, the degree of branching can be controlled to a considerable extent by the present process. It happens that some known detergent range alcohols have a fair degree of brancing and still have satisfactory biodegrad-abil;ty.Regardless of the desired degree of branching, there is advantage in being able to carry out an ~ 20 aldol reaction on the oxo product of the hexenes, - without need for separating branched aldehyde isomers, and obtain a useful product, particularly considering the !ow cost nature of the feed-stock and process. The process can be used to obtain a product composed of about ~5% 2-pentylnonanol and 15% 2-pentyl-4-methyl-octanol.

The oxo process can generally be utilized to achieve 90-95% yields of aldehydes. ~ith linear hexenes as reactant, selectivity to aldehydes without 2-substituents, i.e. c~-aldehydoalkanes, can be as high as 60 to 65%, but in large scale ~257~g~

operation will possibly range from 50 to 65%.

The C7 branched aldehydes which do not react in the aldol reaction can be separated from the reaction mixture for various purposes, or hydro-genated with the mixture and utilized as a C7 branched alcohol. If desired, the branched C7 alcohol can be dehydrated, and then subjected to an oxo reaction to produce an aldehyde with an additional carbon atom. Thus 2-methyl-hexanol can be converted to 2-methylhexene-l, which car, be recyc~ed to the oxo stage of the reaction pro~-cess and hydroformylated to predominantly 3-methyl-heptanal. This 3-methylheptanal, not having any substituent in the 2-position, reacts at a gobd rate in the aldol react;on. Other unreacted al-.
dehydes, such as ~,4-dimethylpentanal and 2-ethyl-pentanal9 can similarly be hydrogenated and dehydrated and recycled to be converted in the oxo stage to C~
aldehydes with no substituent in the 2-position, which will take part in the aldol reaction when recycled through that stage. This procedure to use the un-reacted C7 aldehyde results in greater conversion of the original reactants to the desired final product, rather than to a concomitant product such as C7 alcohols. Use of this recycle feature ;n the oxo-aldol process changes the product obtained from linear hexenes considerably, and can produce a product composed on a mole basis of about 40~
1-pentyl-nonanol, about 30,' Z-pentyl-5-methyl-nonanol, and about 10,' of Z-(l-methylpentyl)-S-methyl-nonanol.

~ 25~

. , ~, As ind;cated above, the linear content of proo pylene dimers.is fairly low, being around 2~% or somewhat higher. At t;mes there may be advantage in separat;ng the linear components for use in the present process, wh;le the branched materials can be used in gasol;ne with advantage to the octane rating of the gasol;ne. However, ;t has been found that the entire hexenes portion of the propylene dimerization product can, if des;red,.be utilized lQ as feedstock for the present oxo-aldol process.
The branched isomers are typified by 2-methyl-2-pentene which, whe.n subjectedto oxo reaction with cobalt catalyst, has been found to be very selectively converted to ~methyl- and 5-methylhexanals. For-tunately it has been found that cobalt catalyst, incontr.ast to rhod;um, has the effect of isomerizing the internal olefins-so.that the aldehyde group is predominantly on the end of the chain. It appears that the methyl substituent has some influence in directing the oxo reaction to obt3in a great pre-dominance of aldehydes with no substituent in the 2-pos:ition. It is very important to the use of propylene dimer in the present process, that the . oxo product is predominantly an alpha aldehydo-alkane, i.e. there is no substituen~ in the 2-position. As discussed herein, aldehydes with substituents in t-he 2-position do not readily undergo aldol reactions. Thus if the internal . hexenes were converted largely to such unreacted 3C . aldehydes, it would be very difficult to effect self-condensation of such aldehydes to a useful extent, and the use of propylene dimers in the present oxo-aldol process would be impractical.
However, as discussed herein, the oxo process with cobalt catalyst converts the hexenes largely to aldehydes which will rea~t in the aldol reaction, making hexenes, obtained from propylene dimerization, ~ ~ 57 very suitable as a feedstock for product;ng deter-gent range alcohols in accord with the present ;nvent;on.

Particular branched hexene isomers are con-verted to ~-aldehydoalkanes with very high selectivity, with 2-methyl-2-hexene selectivity of 9.2% being obta;nable. The mixture of both branched and `linear hexenes from propylene dimer-;zat;on can be converted to ~-aldehydoalkanes w;th select;v;ty such as about 78,'. Thus higher selectiv;ty to aldehydes desirable for the aldol react;on can be obta;ned by using the crude hexenes mixture for the oxo reaction, rather than only the linear hexenes. Depending upon relative value and availabil;ty of the l;near and branched hexenes, one might find advantage ;n using only the branched hexenes in the present process because of the high selectivity in the oxo process to~-aldehydes suitable for aldol reaction.

2û By use of the entire hexene cut from propylene dimerization in the oxo-aldol process, followed by hydrogenation, a C14 alcohol product can be obtained which is about 15~o 2-pentylnonanol, about 10% 2-pentyl-4-methyl-octanol, about sn,~
2-pentyl-7-methyloctanol, and about 25~/ 2(3-methylbutyl)nonanol. If branched C7 alcohol produced from unreacted aldehyde is dehydrated and recycled to the oxo stage as discussed above, a product can then be obtained which is about 10' ~0 2-pentylnonanol, about 5% 2-pentyl-4-methyloctanol, about 25% 2(4-methylpentyl)-7-methyloctanol, about 10% Z-pentyl-7-methYloctanol, and various multi-branched hexadecanols, e.g., 2(2-ethyl,3-methyl-propyl)-5-ethyl-6-methylheptanol.

~2572~

Example 1 An aldol reaction was conducted ;n a 1 liter round bottom flask equipped with stirrer, addition funnel, reflux condenser and adaptors for nitrogen flow. A 100 ml. amount of aqueous 1 molar potassium hydroxide solution was placed in the flask and heated to about 85C. n-Pentanal and 2-methylbutanal were admixed in about 3:1 ratio, after each had been puri-fied by distillation, and used for gradual addition to the reaction flask with st;rring. Over about one hour, about 300 ml was added containing 187.7 grams n-pentanal and 60.8 grams 2-methylbutanal. The reaction mixture was placed in a separatory funnel;
and the lower aqueous phase (87 grams) was separated.
The organic layer was washed four times with water, and amounted to Z13.5 grams. Gas chromatographic analysis for the starting aldehydes indicated about a 3:1 ratio of 2-methylbutanal to n-pentanal, showing that the n-pentanal had been consumed at a much higher rate in the reaction. The product contained about 70.5% of alkenal condensation product and 25.3%
of the starting aldehydes. The product had 2-propyl-heptanal in about 9:1 ratio to 2-propyl-4-methyl-hexenal.
~ .
A 110.89 gram amount of the product was utilized for hydrogenation, employing 11 grams of cobalt on Kieselguhr catalyst with 4.4. ml H20 as promoter, in a 300 ml stirred autoclave. The autoclave was pressured to 6.89 MPa with hydrogen and gradually heated, with hydrogen uptake starting at about 40C.
After one hour, the pressure had fallen to 3.31 M Pa and the autoclave was again pressured to 6.89 M Pa After two hours, with further addition of hydrogen, the pressure was 10.4 M Pa and temperature 160C.

~ ~257 :Z~ 9Li The run was contin~ed for a total of s;xt2en hours.
The measured gas uptake was in very slight excess of theory for hydrogenation of both the olefin and aldehyde groups ;n the compounds present.

The product was f;ltered through a "Celite"-(Trade--Markt filture mat to remove catalyst, a~d the mat was with-n-hexane. The n-hexane was removed under vacuum~ leav;ng 88 grams of product for d;st;llat;on_ Distillation was carr;ed out at 1333 ia w;th lô.l gram being collected at 30-100C., ~fiich gas chroma-tography ;ndicated to be 66.4% 2-methylbutan~ol, 27.5%
pentanol, and 4.1% 2-propylheptanol. An additional 38.9 grams was collected at 103.5-105C., 11.3X
2-propyl-4-methylhexanol and 87.7X 2-propylheptanol.
It can be seen that the above descr;bed procedure provtdes 2-propylheptanol ~;th only very minor adulterat;on by the aldol alcohol product of branched aldehydes. Also the 2-propylheptanol thus produced was readily separated by dist;llation from the 2-methylbutanol produced by hydrogenation of the 2-methylbutanal which d;d not undergo the aldoLcon-densat;on.

Example 2 .
n-Pentanal~ 246.3 grams, and 2-methylbutanal, - - 82.1 grams, were m;xed and util;zed for an aldol reaction, employing 100 ml of aqueous 1 molar sodium hydroxide. The aldehydes were added to the aqueous hydroxide in a flask as described in Example 1. The aldehyde addit;on took twenty minutes and the mix-ture was then refluxed, 89-~5C., for on~ hour.
Gas chromatographic analysis ;ndicated that 5~%
of the aldehydes had reacted, and the reac~;cn m;xture conta;ned 2n.7% 2-methylbutanal, 2~
.
- . .
.~.

-22- ~ 25 7 ~ 9L~
.

pentanal, 4.8% 2 propyl-4-methyl-hexenal and 37~9%
2-propyl-2-heptenal. Thus ;t ;s shown that the n-pentanal tvaleraldehyde) reacted w;th ;tself at a much faster rate than with the 2-methylbutanal, S mak;ng the 2-p~opyl-heptenal much more predom;nant as product than the 3:1 p~edominance of n-pentanal as starting aldehyde. The lo~er aqueous phase was removed and the upper organic layer was distilled under vacuum. Volatile materials, ;ncluding water, n-pentanal, 2-methylbutanal, and pentanol, ~ere - remo~ed under vacuum reach;ng 2666 Pa a total of 78 grams be;ng collected ;n cold traps~ Heat was then appl;ed and 3.88 grams collected at a head temperature of 52-~6C, 9.93 grams at 86C., 5.65 grams at 90~., and an aclditional 26.04 grams at 90C. All of the fract;ons were predom;nantly 2-propyl-2-heptenal, in the range of about 70 to 80~ uith 2-propyl-4-methyl-hexenal constituting only a small fraction of the product. The unreacted 2-methylbutanal was, as ind;cated, read;ly separated from the much h;gher bo;ling Z-propyl-2-heptenal - product.

Example 3 An aldol product m;xture was ut;l;zed ~or hydrogenat;on. The product mixture was from Z5 reaction of n-pentanal and 2-methylbutanal, w;th the latter be;ng ;n excess dur;ng much of the reaction and conta;ned about 54-~ 2-propyl-2-heptenal arld 2-propyl-4-methyl-2-hexenal ;n about 3:2 rat;o.
The hydrogenat;on was conducted w;th cobalt on kieselguhr at pressures up to about 10.3 MPa and temperatures from 125 to 160C. for three and one-half hours. The product was vacuum filtered and the filter washed with hexane wh;ch was removed by vacuum. Chromatography ;ndicated the m;xture was about 35% C5 alcohols and 60% ClQ alcohols. The ,,s~~j ~,.J' . .

~257~9~

mixture was washed with sulfuric acid d;luted with an equal amount of water, and then with water several ~imes. Distillation was then carried out using a fractionating head, obtaining 44.26 grams at 125 to 200C. at atmospheric pressure, the fraction being 74.1% 2-methyl-1-butanoland 16.3% pentanol, and slightly over 5% C10 alcohols; and then 42.35 grams at 70 to 109C. at 1330 Pa with 41.8% being 2-propyl-4-methyl-1-hexanol and 52.5" 2-propyl-1-heptanol, with less than 2~ C5 alcohols; and 16.6 grams at 109-114 C. at1330Pa with 30.4% 2-propyl-4-methyl-l-hexanol and 66.6% 2-propyl-1-heptanol.

Thus it is demonstrated that the hydrogenated aldol condensation product, v;z. 2-propyl-1-heptanol, is produced by hydrogenation of aldol reaction pro-duct and separation readily effected from hydro-genated product of unreacted aldehyde, 2-nethyl-l-butanol.
Example 4 - - 20 A mixture of butenes was hydroformylated w;th cobalt catalyst. The reaction was carr;ed out in a 300 ml st;rred autoclave in 100 ml. solution with toluene as solvent and 0.3~ by weight cobalt car-bonyl as catalyst. Utilizing a 5 molar concen-tration of butenes, with l-butene and 2-butene in 1:1 ratio and CO:H2 in 1:1 ratio, the reactor was pressured to 16.64 M Pa and heated to 100C.
and 20.77 M Pa. After 5.2 hours, all but 6%
of the olefin had reacted, producing n-pentanal sO and Z-methylbutanal in 2.0:1 ratio~ the pentanal constituting 66.~,' of the reaction mixture. The reaction rate was 2.1 gram moles per liter-hour.

~257~9~

Example 5 A hydroformylation s;milar to Example 4 was conducted utilizing a l-butene to 2-butene ratio of 1:2 and obtaining a n-pentanal to 2-methylbuta-nal ratio of 3.2 after 1 hour and 3.1 after 6-hours.
In similar procedures, the ratio was in the range of 2.8:1 to 3.1:1.

Example 6 The procedure of Example 4 was repeated but util;z;ng 2-butene as the olefin, to obtain a pentanal to methylbutanal ratio of 71:29 at 100C., and 69:31 at 110C.

Example 7 A mixture of butenes, l-butene:2-butene:iso-butylene in 1:1:2 ratio, was hydroformylated in accord with the procedure of ~xample 4, producing pentanal:2-methylbutanal:3-methylbutanal in 15:5.2:11 ratio after one hour reaction.

The hydroformylations of butenes take place at excellent rates over cobalt catalysts and with good selec~ivity to aldehydes, selectivities greater than 93% being obtainable. With butene-2 as the substrate and 0.3 wt. % cobalt, (based on cobalt metal) rates over 5 gram moles per liter-hour have been observed at 110C.
, A sample of 2-propylheptanol was used to esterify phthalic acid to obtain a plasticizer.
The plasticizer was used to plasticize polyvinyl chloride (P~C) and found to have good plasticizing properties, as compared with other plasticizers in Table 1.

~L25~:~9~

Table 1 Plasticizer * Volatility (40% in PVC) Low Temp. Flex (Tf) 1 day 6 days Di(2-propylheptyl) phathalete -40C 1.0~3~7%
Dioctyl phthalate (2-ethylhexyl) -39C3.9% 19.0-~
Diisononyl phthalate -36C 1.8%7.0-~
D;isodecyl phthalate -37C1.2% 4.2%
*Determir,ed in a standard Clash-~erg test.

It ;s recogn;zed ;n the Plast;cs Industry that the mor-e eff;cient a plast;cizer is, the lower the temperature in the Clash-Berg low temperature flexi-bility test, i.e. a Tf of -45C. indicates a far superior plasticizer than a Tf of -35C. Therefore in the above table it can be seen that the propylheptyl phthalate compares favorably, having a lower flexibi-lity temperature, as well as appreciably lower vola-tility compared to dioctyl phthalate. An additional factor which is advantageous in the product prepared by the present procedure is the fact that adulteration with branched aldehyde can be tolerated. Thus 2-propyl-4-methyl-hexyl phthalate has a low temperature flex;bility value of -31.5, and the presence of 12~, or so of this in the phthalate will only raise the low temperature flexibilityl to about -38.5. and the volatility ;s st;ll excellent. By contrast dioctyl-phthalate ould be more sensitive to adulteration by isomers as di(2-ethyl-4-methylpentyl) phthalate has a low temperature flexibility (Tf) of -30C and a very high volatility (6.7~ in 1 day test.) ~2572,~

Example 8 A phthalate plasticizer was prepar;ed by using an alcohol mixture for esterification co~posed of 85% 2-propylheptanol, 11% 2-propyl-4-methylhexanol, and 4% 2-propyl-5-methylhexanol. The alcohol mix-ture was prepared in accord with procedures describedherein, involving an aldol reaction of 75% n-pentanal, 25% 2-methylbutanal and 2% 3-methylbutanal, as obtainable from oxo reaction of butenes having a very small isobutylene content. The plasticizer with polyvinyl chloride (40% plasticizer) gave a low temperature flexibility (Tf) value of -38 to -39, 1 day volatility of 1.2% and 6-day volatility of 4.1-4.3~.

Example 9 A mixture of 709 gm of n-pentanal, 237 gm of 2-methylbutanal and 19 gm of 3-methylbutanal was added over 40 minutes with stirring, to 300 ml of 1 molar potassium hydroxide solution at 88C. After the addition was completed, the reaction mixture was maintained at 88C with stirring for a further 2 hours, at which time the n-pentanal was 96% con-- verted. The aldol product cons;sted of ~3~ 2-propyl-heptanal, 13% 2-propyl^4-methylhexenal and 4% 2-propyl-5-methylhexenal. The reaction mixture also contained 75,~ of the originally charged 2-methyl-butanal.

The reaction product was cooled a~d the organicphase was separated and hydrogenated at 160C under 10.33 M Paof hydrogen pressure ;n the presence of a cobalt on kieselguhr catalyst. The hydrogenation 30 of the enals produced the correspondino alkanols~
and the resulting mixture of C5 alcohols and Clc ~25~99~

alcohols was separated by distillation and the C10 alcohol was converted to its phthalate ester for use as a plasticizer.

Example 10 , S Dimerization of propylene over transitionmetal catalysts produces a mixture of hexenes.

The l;near hexenes in the m;xture can be se-parated and such l;near hexenes are for the most part 2-hexenes. The follow;ng pro`cedure illustrates the reaction of 2-hexenes in an oxo reac'ion, followed by an aldol reaction of the product. A sample of refinery 2-hexenes was passed through basic alumina particles for removal of oxides and 802 grams of the hexenes was placed in a 1 gallon stainless steel autoclave with 4.75 grams CO2(CO)8 catalyst. The autoclave was pressured to 16.64 M Pa with 1:1 carbon monoxide and hydrogen, and heated to 110C. The temperature was kept at about 110C for 1 hour and then rose to about 130 as the procedure was continued for about

5 hours. A 916.5 gram product was obtained, with - convers;on about 94% with about 78% selectiv;ty to C7 compounds, and 71.5% to C7 aldehydes. Chromato-graphy indicated the aldehydes were in ratio of about 29.4 n-heptanal to 16.7 2-methylhexanal to 8.5 2-ethylpentanal. A 9~7 gram amount of the product was d;stilled, with a final pot temperature of 120C. and vacuum of 400 Pa to obtain a 608 gram distillation fraction and 278 gram residue.
Chromatography indicated the fraction included C7 aldehydes in ratio 33.4 n-heptanal to 26.8 2-methyl-hexanal to 17.2 2-ethylpentanal, and minor amounts of other components. Evidently there was more loss of the normal aldehyde than the branched ones in the distillation.

~257:29~

It ;s feas;ble~to achieve a higher percentage of n-aldehyde than present in the above distillation fract;on, such as 60% or better, and therefore n-heptanal was added to the above fract;on to have a more typical aldehYde for aldol reaction, about 600 grams of the above fract;on being used with 500 grams n-heptanal. A 300 ml amount of 0.8 molar sodium hydroxide was placed ;n a reaction flask with 955 ml methanol, and the aldehydes were placed ;n an add;tion funnel. The react;on med;um was heated to about 71C., and addition was slowly started and completed in about 13 hours~ Chromatography indi-cated about 50/' completion of the reaction, with C14 aldehydes in ratio of about 23.4~ 2-pentylnon-2-enal to 8.72-~ 2-pentyl-4-methyloct-2-enal to 1.4%
2-pentyl-4-ethylhept-2-enal. Several C7 aldehydes were also present in the ratio of 22.9 heptanal to 8.5 2-methylhexanal to 5.3 2-ethylpentanal.

The aldol condensation product was hydro-genated over a cobalt/kieselguhr catalyst, using 131 grams catalyst w;th 1336 grams of the conden-sation product. The materials were ma;ntained at about 160 C. and 10.43 M Pa of hydrogen for about two hours when react;on appeared complete.
Reaction conditions were maintained for an additional 4.5 hours. Analys;s indicated about 99% completion of the hydrogenation. The product conta;ned 2-pentyl-nonanol ;n about 18.4 to 7~2 ratio to a mixture of 2-pentyl-5-methyl-octanol and 2-pentyl-4-ethyl-heptanol and large amounts of C7 alcohols from the unreacted aldehyde, being hep~anol in a 2?.5 to 16.3 ratio to a m;xture of 2-methylhexanol and 2-ethylpentanol The product was fractionated ~25,~2~

by dist;llation, with a 280 gram fraction being obtained at 110-115C. at 266 Pa from 1180 grams of hydrogenation product. The fraction was in large predominance composed of C14 alcohols.

Example 11 A mixture of hexenes produced by the DimersolR
dimerization process was utilized as olefln reactant.
The crude hexene cut from the dimerization was used, and had the distribution of linear and branched 10~ hexenes ~ypical of such material. A 1029 gram amount of the hexenes was used in a 3.8 liter autoclave with

6.04 grams catalyst, Co2(C0)8, 0.02 weight %. Per-oxides had been removed from the hexenes by treat-ment on a basic alumina column. The autoclave was taken-to reaction conditions with 1:1 C0/H2 and maintained at 110C. and 18.0 M Pa for 9 hours, with 80~ of theoretical gas uptake, and then con-tinued overnight. Chromatography indicated high conversion to C7 aldehydes, with minor amounts of residual hexenes. A 1360 gram amount of the pro-duct was subjected to distillation, with a 797 gram fraction being obtained at pot temperatures of 60 ; to 97C. as the vacuum dropped from 11.97 K Pa to .66 K Pa. Chromatography indicated a high proport;on of C7 aldehydes with a very small amount of C6 olefins.

A 792 gram amount of the above aldehyde fraction was utilized in an aldol reaction, adding the aldehyde material from an addition funnel to a reaction flask containing 564 grams methanol and 250.9 grams 0.8 molar sodium hydroxide. The addition took about 6 hours, with stirring at about 500 rpm and temperature at 72-73 C. The reaction mixture was then refluxed for 1.5 hours.

12~729~

Analysis of a sample indicated only about 1 part aldol product to 3 parts aldehyde, on a mole basis.
The reaction was continued at reflux overnight, giving 1 part aldol product to about 2.6 parts S aldehyde reactant. During the reaction it was observed that the reaction mixture had a large upper phase and a smaller lower phase, indicating that methanol was not very effective in promoting miscibility and reaction, possibly because of the rel-atively long chain length of C7 aldehydes. Chro-matography showed a fair amount of the C14 aldol product, including 2-pentylnonenal, and a large amount of unreacted C7 aldehydes.

The above aldol product was subjected to further aldol reaction, after removing the methanol to employ different conditions; A 552 gram amount of the aldol-condensate, 55.6 area percent C7 aldehydes and 31.5 area percent C14 enals, was placed in an addition funnel and added to a reaction ,lask containing 163 grams 0.8M ~aOH and 3&~ grams 2,5-hexanediol. Addition was complete after 45 minutes, with temperature maintained at 100C.
with agitation of the reaction mixture. The reaction mixture was then refluxed at 100 C for 1.75 hours. The reaction m;xture separated into upper and lower phases of about equal weight. The conversion had been improved in that the ratio o;
C14 enals to C7 aldehydes ;n the product (upper phase) was now about 1.7 to 1.

A 515 gram amount of the product was subjected to hydrogenation, employing 51.65 grams cobalt/
kieselguhr catalyst and 160C., about 10.98 M Pa hydrogen. Approximately 549 grams of pro-duct was recovered. The conversion of C14 enals to C14 saturated alcohols was about 90%, with about 10% found as unsaturated alcohols. The product was ~257:29~
.

filtered to remove catalyst, and the filtrate was distilled. The process produced several C14 alcohols in very substantial amounts, with a number of others in very small amounts. Several C7 alcohols from unreacted aldehyde were also present in substantial amount.
.
The examples of procedures for converting propylene dimers, via oxo, aldol and hydrogenation, to C14 alcohols, illustrate that the-reaction is feasible, although conditions in the procedures are not optim;zed and results better than those reported can be ach;eved by appropriate determination of cond;t;ons. In the procedures it was found that a co solvent, wh;ch can be referred to as a phase transfer solvent, such as a hexane diol, resulted in higher conversion in the aldol reaction than was - obtained by the use of-methanol. The diol apparently aids by providing greater solubility of the aldehyde reactants in catalyst-containing phase, thereby permitting more complete reaction. Other diols exhibi~ing appreciable solubility for both the reactants-and aqueous catlyst system are expected to be similarly useful, and appropriate usage of such systems should make it possible to greatly exceed the 63-b or so conversion obtained above, particularly when the aldehyde reactants contain very high proportions of aldehydes free of 2-sub-stitution, as can be obtained by oxo reaction of the complete hexenes mixture obtained by propylene dimerization.

The hexenes product from a Dimersol~
dimerization refinery product was analyzed and found to nave the following distribution.

~5729~

. Hexene Distribution - % (100% Basis) 2,3-dimethyl-2-butene 6.4 2-methyl-2-pentene 39.2 trans-4-methyl-2-pentene 15.9 cis-~-methyl-2-pentene 2.9 2-methyl-1-pentene 5.0 2,3-dimethyl-1-butene+4-methyl pentene1.7 trans-2-hexe~e 16.5 ~
trans-3-he~e~e 5.8 ~ 2~.9 cis.3 ~ cis 2-hexene . 5.6 ~
l-hexene 1~0 J

~L25~29-~

' Dimersol~dimer;zation process product and various hexene components thereof were reacted in an oxo variation over cobalt catalyst generally as described in Examples herein. The prod~uct d;s-tribution obtained are reported in Table 2 below,along with the reaction temperatures and times.
The D-Mixture ;n the table ;s the m;xture of all the hexenes obtained in the D;mersol dimerization process. The part;cular aldehydes are ;dentified below the table by key to Roman numerals w;th the aldehyde group in all cases ;n the l-pos;t;on.
The % aldolable product as reported ;ncludes all aldehyde products except those w;th 2-substituents.
.

~25729~

* -34-o o~ ~ o 1-- 1~ ~ U~ O O U~

I o oo 1~ ~o ~ o~
H ¦ O O O O O--N t_ L L.

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~_ H I_Ul 00 ` 1~ W
H 00000 1 O` O I I I W ~ 11 ~ c~ ~1 ~ o u~ o o o o c c c c W H O~ Lr~) Lrl ~ ~ r~) C~ _ Q ~ Q Q
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C C C C C C C C
0 ~ w ~
V i~ V ~ ~ X X C
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W ~ >~
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CJ ~ r ~ r r QJ I I ~ ~
x x ~ V ~ Q, r ~ N1~ ~1 x ~ - _ E E E r-- 1111 1111 11 N ~`J. ~ ~It--H ~1--1 ~L~257;~9~

It will be noted that, desp;te the branching in the dimerization product mixture, very high selectivi.ies to "aldolable" aldehydes are obtained, such as better than 75%. The result is even more pronounced when ;ndividual branched olefins are reacted, even when the methyl branches are located on an unsaturated carbon atom. Use of a catalyst which permits migration of the double bond, as the . cobalt catalysts herein, is essential to this result.

One of the components found in the dimerization product mixture, 2,3-dimethyl-2-butene~ is relatively unreactive in the oxo reaction, so, if desired the reaction can be effected to leave it unreacted.

With further regard to the aldehydes obtained by oxo reaction of propylene dimerization product, one of the isomers present in large amount is 3-methylhexanal. This aldehyde reacts readily in the aldol condensation. Moreover, in cross-aldol with n-heptanal, it appears to exhibit a very strong ' preference for the condensation to occur on the 2-carbon of the normal aldehyde, i.e. to produce 2-pentyl-5-methyloctanal, rather than Z(l-methyl-butyl)nonanal~ The latter compound, having adjacent methyl substituents, might be more resistant to bio-degradation when converted to a detergent alcohol.
The S-methylhexanal, also obta;ned ;n substantial amounts, apparently reacts readily in an aldol reaction to give su;table product.

~25i729~

.

The Dimersol ~ dimerization process has been referred to in various publications, e.g. see "How First Dimersol is Working" by Benedek et al, Hydro-carbon Processing, May 1~0, Page 143; also Chauvin et al, "The IFP Dimerso ~ Process for the Dimerization of C3 and C4 Clefinic Cuts", Advances in Petrochemical Technology, presented at American Institute of Chemical Engineers~ April 13, 1976, Kansas City, Missouri The combination of the Dimersol ~ dimerization process, oxo process, aldol and hydrogenation provides a very efficient route from propylenes to detergent range alcohols. One of the known routes to such alcohols rel;es upon ol;gomerization of ethylene to obtain higher molecular weight materials which are then subjected to an oxo reaction. The presently proposed route is in many respects more efficient and economical than those involving ethylene oligomerization, as propylene costs less than ethyl-ene, and the reactions involved using dimerization, oxo and aldol are more straight forward than an oligomerization which can produce a broad mixture of products and require extensive equipment and proceciures to direct it to suitable product. As discussed hereinabove, the mixture of isomers obtained from a dim!erization can be carried through the oxo, aldol and hydrogenation reàctions to obtain high overall conversions and yields, despite the presence of extensive branching in the materials.
It is fortunate to find that a high proportion of the materials are capable of taking part sequentially in all of the required reactions, and in particular that the aldehyde failing to react in the aldol reaction, because of 2-substitution, is at a comparatively low level.

~;~57~

It has also been found that pentenes can be hydroformylated to hexanals, and the hexanals condensed in an aldol reaction and hydrogenated to form 12-carbon alcohols, in a manner similar to S such react;ons wlth the hexenes.

The processes herein can employ various olefins as star~ing material and the conditions of the various oxo, aldol etc. stages as described for butenes are generally applicable to the pro-cesses employing hexenes or other olefins as starting material. With particular reference tothe oxo stage, it will be noted that cobalt catalyst is employed with the hexenes in order to promote migration of the olefinic bond and high selectivity to des;red aldehyde isomers, such catalysts being for example Co2(C0)8 which may be equivalent to HCo(C0)4 under reaction conditions, and HC(C03) (Phosphine ligand).

The C14 or other detergent range alcohols produced by the present process can be readily converted to detergents by known procedures. Thus non-ionic detergents are prepared by reaction with ethylene oxide to have a desired number of ethoxyl groups, e.g. 6 to 10 or 12 or so. These, or other ethoxylated alcohol, possibly with 2 to 3 ethoxyl groups can be reacted to form an alcohol ether sulfate, having a sulfate anionic end group with a sodium ot other cation. The alcohols can also be reacted to prepare sulfate derivatives. The detergents thus prepared will have the requisite hydrophobic groups for detergent properties~ More-over, the structures are such as to pro~ide bio-degradability, in that the structures are acyclic ~L 2X 7 ;~: 9 L3~

alkyl groups which are essentially free of any tertiary carbon groups and in which branching on adjacent carbon atoms is absent or at a very low level. The common 2-branching characteristic of aldol product, with or without various addit~onal methyl or other lower alkyl branches in non-adjacent positions, is not expected to have any important effect on the biodegradable nature of the compounds. An alcohol ether sulfate prepared from 2-pentylnonanol has been described as bio-degradable by Cranland et al, Surfactant Congress No. 4, Vol. 1, page 93 (1967). Also Kravetz et al, Proceed;ngs of the American Oil Chemists' Society, 69th annual meeting, May, 1978, St. Lou;s, Mo., concluded that variation of branching from 45% to 75% linear had noappreciable effect on`biodegradation rates of primary alcohol ethoxylates, and make reference to 58% branching giving biodegradation at rates not appreciably different from zero branching.
It is further of interest that Farnesol, a natural alcohol with branching, degrades somewhat slower than a straight chain alcohol, but still degrades at a rate sufficient to meet stringent biodegrada-- bility requirements. Farnesol is a 15 carbon alcohol ~5 with methyl branches at the 3, 7 and 11 positions.

~25~9~
--39~

Example 12 A freshly distilled sample of 2-pentene was hydroformylated in a~00 ~nl autoclave, employing 0.41 gram Co(CO~8 catalyst with 65.84 grams pentene.
A 1:1 mixture of CO/H2 was used, with in;t;al charge to 10.43 M Pa and heating to 120C.
and 20.67 M Pa with agitation at lO00 rpm. Gas-uptake was observed, as the pressure was increased to 20.67 M Pa. After about 2 hours, an 83 gram pro-duct was obtained. Chromatography showed a small residual amount of pentene and C6 aldehydes in the ratio of 61.1 hexanal to 2~.9 2-methylpentana to 10.0 2-ethylbutanal. An aldehyde sample was provided to have aldehydes in the same ratio, using 189.1 grams hexanal, 89.9 grams 2-methyl-pentanal, and 31 grams 2-ethylbutanal, and placed in an addition funnel for addition to 110 ml of 0.8 M NaOH in a round bottom flask equiPped with a mechanical stirrer. Heating was begun and addition was started after about 15 minutes and continued as reflux started around 91C. Addition was completed in about 4n minutes. Stirring was continued for an hour, but without further heating, and a sample was taken. Analysis indicated partial reaction. The reaction mixture was heated to 95C.
for an additional 1 1/2 hours. Upper and lower phases of the reaction mixture were separated, and the upper phase was analyzed. The analysis indicated better than 25~ conversion ta C12 enal, nearly all being 2-butyloctenal, and large amounts of unreacted C6 aldehydes, the major part of which was branched aldehydes. The aldehyde mixture can readily be hydrogenated to the corresponding alcoh Q 1 S .

- ~25~ 9-~

-4~-Exemple 13 An aldol procedure was carr;ed out as in Example 12, except that the amount of water was increased ten fold~ The same amount of ~laOH was present, although now in much more dilute solution.
Because of the large volume, less e,fective stirring was ach;eved. After a two hour reaction, analys;s ;nd;cated substantial convers;on to C12 enals, al-though somewhat lower than in Example iZ~

Example 14 An aldol reaction was carried out as ;n Example 12, employing 6.1 to 2.9 to 1 ratio of hexanal to 2-methylpentanal to 2-ethylbutanal, the total amount being 31n grams. The branched aldehydes were placed in a flask with 110 ml of 0.8 M ~laOH, and tetrabutylammonium chloride in an amount molecularly equ;valent to the ~laOH. The tetrabutyl-ammon;um chlor;de serves as a phase transfer catalyst. The reaction flask was heated to reflux and addition was started. The addition continued for about 6 hours with reflux temperatures (pot) from 90-95C. The mixture was cooled and separated into two phases. Analys;s of the upper phase showed better than 75,' convers;on to C12 enals, about half of wh;ch was 2-butyloctenal, and the rema;nderma;nly a m;xture of 2-butyl-4-ethyl-heptenal and 2-butyl-4-ethylhexenal. In the un-reacted C6 aldehydes present, the branched aldehydes were in greater amount than the hexanal. The reaction ~0 can be directed .o produce a higher percentage of product from the n-hexanal by adding the aldehydes ~25~

together, rather than adding the n-aldehyde to the branched aldehydes in the reaction mixture as in the foregoing procedure. The phase transfer catalyst was effective in improving conversion in this pro-cedure, but use of co-solvents, such as methanol or diols, may be more practical for large scale con-tinuous operations. The use of hexanediol has been shown effective for aldol reaction of heptanals herein, and can similarly be used with hexanals.

It will be noted that the alcohols produced from both the pentenes and hexenes feedtocks are in-tended for use as detergent range alcohols. The considerat;ons here;n as to reaction conditions and various parameters of the oxo and aldol reactions as described for the hexenes and resulting C7 aldehydes also are in general applicable to the pent-enes and resulting C6 aldehydes. The C12 alcohols produced from the reactions starting with pentenes will have the hydrophobic groups such alcohols provide in detergents, and the groups will have a degree of branching similar to that of C14 alcohols from hexenes.
It is feasible to substantially avoid presence of branches on adjacent carbon atoms. In one particular aspect the present invention is directed to a process of preparing alcohols from an oxo reaGtion with olefins selected from those having 5 to 6 carbon atoms, or mixtures thereof, to obtain aldehydes ` having 6 to 7 carbon atoms, comprising high amounts of ~-aldehydoalkanes, and effect;ng aldol convers;on 3n with limited participation of 2-substituted aldehyde to obtain aldol product, which is then hydrogenated to C12 or C14 alcohols havins properties valuable for use ;n detergents.

Claims (36)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process of preparing aldol products which comprises conducting an oxo reaction with olefins selected from those having from 5 to 7 carbon atoms to obtain aldehydes having from 6 to 8 carbon atoms and comprised of at least 50%
.alpha. -aldehydoalkanes and subjecting the aldehydes to an aldol reaction to cause good conversion of the aldehydes to aldol product but with that produced from cross-aldol of 2-substituted aldehydes constituting no more than 20% of the product.

2. The process of Claim 1 in which the aldehydes have .alpha.-aldehydoalkane content of from about 60 to about 80%
and the conversions of aldehyde to aldol product are in the range of about 75% to about 90%.

3. The process of Claim 1 in which the conversion of aldehyde other than 2-substituted aldehyde in the aldol reaction is at least about 95%.

4. The process of Claim 1 in which the oxo reaction is conducted with hydrogen and carbon monoxide at temperatures in the range of 80 to 150°C and pressures sufficient to maintain catalyst stability but not over 34.5 M Pa and the aldol reaction is conducted in aqueous alkaline medium at temperatures of 60 to 150°C.

5. The process of Claim 4 in which a cobalt catalyst is employed for the oxo reaction.

6. The process of Claim 1 in which the olefin is pentene.

7. The process of Claim 4 in which the oxo process is conducted at 6.89 to 27.56 M Pa in the presence of cobalt catalyst, and the aldol reaction is conducted at about 90° to about 130°C.

8. The process of Claim 4 in which the olefins are pentenes.

9. The process of Claim 1 in which the olefins are hexenes.

10. The process of Claim 9 in which the oxo reaction is conducted with a hexene mixture comprised mainly of methylpentenes with no more than 30% linear hexenes, and obtaining C7 aldehydes with less than 30% 2-substituted aldehydes, subjecting the aldehydes to an aldol reaction to obtain aldol product with conversion of at least 70%.

11. The process of Claim 10 in which no more than one-third of the 2-substituted aldehydes are converted to aldol product.

12. The process of Claim 10 in which the hexene mixture comprises substantially the hexenes mixture from a dimerization of propylene over a nickel and aluminum alkyl catalyst.

13. The process of Claim 9 in which more than 75% of the C14 aldol product has double branching but has practically no branches located on adjacent carbon atoms.

14. The process of Claim 9 in which the oxo reaction is conducted with cobalt catalyst and hydrogen and carbon monoxide at temperatures in the range of 80° to 150°C and pressures sufficient to maintain catalyst stability but not over 34.5 M Pa and the aldol reaction is conducted in aqueous alkaline medium at temperatures of 60° to 150°C.

15. The process of Claim 10 in which substantially linear hexenes are separated from a propylene dimerization mixture and subjected to an oxo reaction to obtain better than 50% selectivity to .alpha.-aldehydoalkanes and subjecting the oxo reaction product to an aldol reaction to produce an aldol product with no more than about 15% content from cross aldol of 2-substituted aldehydes.

16. The process of Claim 15 in which the aldol reaction is conducted in aqueous alkaline medium at temperatures of 60° to 150°C.

17. The process of Claim 15 in which a C7 aldehyde mixture comprising at least 50% methylhexanals but no more than 30% of 2-substituted aldehydes is subjected to an aldol reaction with strong alkaline catalyst to effect high conversion of the methylhexanals to aldol product but with no more than one-half of the 2-substituted aldehydes being converted to aldol product.

18. The process of Claim 1 further comprising hydrogenating the aldol product to obtain alcohols.

19. The process of Claim 7 further comprising hydrogenating the aldol product to obtain alcohols.

20. The process of Claim 8 further comprising hydrogenating the aldol product to obtain alcohols.

21. The process of Claim 19 in which the hexene mixture comprises substantially the hexenes mixture from a dimerization of propylene over a nickel and aluminum alkyl catalyst.

22. The process of Claim 20 in which more than 75%
of the C14 alcohol product has double branching but has practically no branches located on adjacent carbon atoms.

23. The process of Claim 19 in which the oxo reaction is conducted with cobalt catalyst and hydrogen and carbon monoxide at temperatures in the range of 80° to 150°C
and pressures sufficient to maintain catalyst stability but not over 34.5 M Pa and the aldol reaction is conducted in aqueous alkaline medium at temperatures of 60°C to 150°C.

24. The process of Claim 20 in which substantially linear hexenes are separated from a propylene dimerization mixture and subjected to an oxo reaction to obtain better than 50% selectivity to .alpha.-aldehydoalkanes and subjecting the oxo reaction product to an aldol reaction to produce an aldol product with no more than about 15% content from cross aldol of 2-substituted aldehydes.

25. The process of Claim 14 further comprising hydrogenating the aldol product to obtain alcohols in which the product contains at least 85% 2-pentylnonanol and no more than about 15% 2-pentyl-4-methyloctanol.

26. The process of Claim 16 further comprising hydrogenating the aldol product to obtain alcohols.

27. The aldol product produced in accordance with Claim 1, 2 or 3.

28. The aldol product produced in accordance with Claim 4, 5 or 6.

29. The aldol product produced in accordance with Claim 7, 8 or 9.

30. The aldol product produced in accordance with Claim 10, 11 or 12.

31. The aldol product produced in accordance with Claim 13 or 14.

32. The aldol product produced in accordance with Claim 15, 16 or 17.

33. The alcohols obtained in accordance with Claim 18, 19 or 20.

34. The alcohols obtained in accordance with Claim 21, 22 or 23.

35. The alcohols obtained in accordance with Claim 24, 25 or 26.

36. A mixture comprising the products of Claim 1 and 2.