May 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
using the same gages, was compared for pure gasoline and for a very dilute jelly prepared from the same gasoline. The rate of flow was measured by weighing the discharge over a timed interval in order to avoid any uncertainty inherent in volumetric measurements. The gages were attached to sleeves silver-soldered over a 1/16-inch clean hole drilled in the pipe wall, thus avoiding any inch, and the disturbance of the flow. The pipe diameter was consistency of the jelly was estimated a t 20 grams Gardner. The results obtained are shown in Figure 3, along with the calculated line according t o Fanning's correlation. The pressure drop for gasoline was found to be more than that calculated, but both the experimental and the calculated values for pure gasoline are definitely higher than those for the jelly a t flow rates above 2 gallons per minute. The difference between the calculated and experimental values for pure gasoline is probably due to uncertainties introduced by pipe irregularities and roughness. The difference between the experimental curves for the gasoline and the jelly involves no calculations or assumptions. On a purely experimental basis this is the rather paradoxical case of a thickened, jellified fluid offering less resistance to flow than the unthickened liquid from which it was prepared (5). The viscosity of jellies is known always to decrease a t high rates of shear, presumably because of the breaking of bonds between colloidal particles a t a faster rate than they can reform. The
1019
limit of this process, however, cannot be expected to give a viscosity lower than that of the pure liquid. The explanation must, therefore, lie in a different mode of flow of the jelly and of the gasoline. The flow of gasoline ia turbulent, but no information is available about the flow of the jelly. A less turbulent, more streamlined flow of the jelly could reduce the pressure drop even while the viscosity remains much higher. Whether this is indeed the case, and whether the same paradoxical behavior is shown by other jellies, remains t o be investigated fully. LITERATURE CITED
(1) Carver, E. K., and Van Wazer, J. R., J . Phys. & Colloid Chem., 51, 751 (1947). (2) Eastman Kodak Co., Monthly Progress Report, November 1944. (3) Fieser, L. F., Harris, G. C., Hershberg, E. B., Morgans, M., Novello, F. C., and Putman, S. T., IND. ENG.CHEM.,38, 768
(1946). (4) Mysels, K. J., Ibid., 41, 1436 (1949). ( 5 ) Mysels, K. J., U. S. Patent 2,492.173 (1949). (6) Wood, G. F., Kissan, H. H., and Garner, F. H., J . Inst. Petroleum, 33, 73 (1947). RECEIVED for review August 11, 1953. ACCEPTED January 7, 1954. Work was conducted in 1945 a t Edgewood Arsenal incidental t o a joint Chemical Warfare Service and National Defense Research Committee program of evaluating flame throwers. Reported in part in the B.S. thesis of Walter Harte and John Thompson.
Sodium-Promoted Condensation of Organic Halides and Carbonyl Compounds CHARLES E. FRANK' AND WALTER E. FOSTER2 Applied Science Research Laboratory, University of Cincinnati, Cincinnati 21, Ohio
T"
1 sodium-promoted condensation of organic halides and carbonyl compounds has received relatively little attention, largely because of the great convenience and versatility of the analogous Grignard reaction. hiorton and Stevens (f1) demonstrated this reaction in 1931, obtaining better than 90% yields of triphenylmethanol (triphenylcarbinol) from the condensation of chlorobenzene and ethyl benzoate with sodium. Other reactions of this type in which sodium was found effective have included the synthesis of highly branched alcohols unobtainable by the Grignard condensation-for example, Bartlett and Schneider ( d ) obtained 3-fert-butyl-2,2,4,4-tetramethyl-3-pentanol(tritert-butylcarbinol) by the reaction of tert-butyl chloride, methyl pivalate, and sodium sand. Cadwallader, Fookson, Mears, and Howard ( 3 ) extended this condensation t o include additional examples of branched halides, esters, and ketones.
PROCEDURE
The ease of handling and high reactivity of the finely divided sodium dispersions recently described ( 5 , 6 ) prompted the present investigation of the usefulness and limitations of sodium in the halide-carbonyl condensation. In most of this work, as in that of Cadwallader et al., the halide and carbonyl compound were added concurrently to the solvent-sodium mixture. B y this procedure, 1 Present address, Research Division, Sational Distillers Products Corp., Cincinnati, Ohio. * Present address, Ethyl Corp., Baton Rouge 1, La.
illustrated below, neither the organosodium intermediate nor the carbonyl compound is present in any substantial concentration, and side reactions are reduced to a minimum. A 1-liter round-bottomed flask was fitted with a mercurysealed stirrer, a dropping funnel, a thermometer extending into the reaction mixture, a nitrogen inlet tube, and a reflux condenser vented through a cold trap and oil bubbler. After purging with nitrogen, 200 ml. of dry iso-octane (2,2,4-trimethyl pentane), 25.4 grams of a 50% dispersion of sodium in dibutyl ether (0.55 gram atom of sodium), and a few crystals of benzophenone (to activate the sodium) were added. Benzyl chloride (3.2 grams) in 30 ml. of iso-octane then was added at 25' to 30" C. over a 20minute period; there was no evidence of reaction a t this point. A solution of 28.5 grams of benzyl chloride (0.25 gram-mole total) and 14.5 grams of acetone (0.25 ram-mole) in 240 ml. of iso-octane was added dropwise over a 3-tour period. At the beginning of this addition, the mixture began darkening and heat was evolved. The flask then was cooled to about '5 and the reaction was completed a t this temperature. The mixture was quenched under a nitrogen atmosphere by the dropwise addition of 100 ml. of water while the temperature was held a t 10" to 20" C. Chloride titration of the aqueous layer showed that 98% of the benzyl chloride had reacted. The oil layer was washed, dried, and fractionated to obtain 12.4 grams of toluene (27%) and 31.8 rams of 2-benzyl-2-propanol (42.5%). The higher boiling resifue (20%) comprised acetone self-condensation products and a small amount of dibenzyl. The reaction of benzyl chloride and acetone was studied in some detail to observe the effects of temperature, solvent, and other reaction variables. Increase in the reaction temperature
INDUSTRIAL AND ENGINEERING CHEMISTRY
1020
2-
Chloride Benil>-1Reacted, 2yo propanol
Reaction Reactants, x o l e Temp., C. Chloride Acetone
Soh-ent Biityi ether d
Benzene
Ph-CH2C1 50 50 50 50 5
Iso-octane
-25
5
2Na
+ CH3COCHa
0 25 0 2:
-+
0.23
0.25
0,: 0 25
0 25 0 25 0 25 0.25
0 25 0.25 0 25 0 25
- -
High boiling Ketone= Toluene residue
Ph-CH2C(CHsj20Sa
100 100 02 93 88
25 PI 18 3 $4 40
Y8 '4 2 S o rpaction
4- XaClb 1 4 1.2 6 0 1 0 0 7
-
:; 11 42 31 27
31 4
18 5 12
11
PhCHz CHsCOCHa PhSa PliCHnSa PIi(.'II?C(CHa)~OSa 0 25 0.23 94 2: 0 .. 9 Toluene 25 e -40 0.23 0.25 98 32 0 13 a Ketone product distilling with 2-benzyl-2-propanol, probably benzylacctone. b Benzyl chloride and acetone added simultaneously t o 0.55 gram-atom of dispersed sodium; bene>-l chloride addition,led acetone by 10% except as noted. c Benzyl chloride and acetone added together from the start. d Acetone addition led benzyl chloride by 10%. e Reaction mixture was carbonated a t end of reaction t o t r a p any iinreacted phenyl or benzylsodir~in. Seither benzoic or phenylacetic acid was obtained. Ph-C1
+ 2Na
Vol. 46, No. 5
of the particular halide and carbonyl compound employed, as indicated in the next section. .4n additional factor is the particle size and r e a c t i v i t y- of t h e freshness-i.e., sodium dispersion. Dispersions having an average particle size of 5 to 15 microns vere employed in this work. These were prepared by means of B high-speed Dispersator stirring head ( 6 ) . Such dispersions retain high reactivity for several months if protected from the air. However, since even brief exposures to the atmosphere tend to deactivate t,he surface of the sodium particles, optimum results ai^ obtained with freshly prepared dispersions. SCOPE OF THE REACTIOZ
Metalation of the carbonvl conipound, as evidenced by reduction of {lie organusodium intermediate to the hydrocarbon, was found to be the major limitation t o the scope of the condensation. The relative amountfi of metalation and carbonyl addition are a function of the reactirity of the alpha-hydrogen in thc carbon)-1 compound, and of the reactivit,y of the organic radica! in the organosodium intermediate. I n ease of metalation by RNa, CHjCHO>CH3COCH,>(CH~)&HC€I~COCH2CII(CII,h>(CH,j2CHCOCH(~H~)z>CH3COOEt;this is in accordance n-ith expectations on the basis of ease of carbanion formation ( I ) . In tcndencj- toward metalation of the carbonxl compounds, the listing te,t-but).l>isopropyl>aniyl>pheii).l>benzyl is in line iyith a reduction in reactivity with increasing stability of the carbanion. Complete experimental verification of this was not obtained, however, because of the tendency of secondary and tertiary halides to dehydrohalogenate. The above generalizations are illustrated in Table 11,which lists tlie yields of alcohol (addition product) and hydrocarbon (a measure of the metalation obtained) for the various pairs of reactants. The yields of alcohol range from 7 2 7 , (from benzyl chloride and et,hyl acetate) to 0% (from the secondary and tertiary chlorides). In some instances-for example, with benzyl chloride and ethyl acetate-the carbonyl compound facilitates reaction of the halide; this is in accord with the observation of Rartlett and Schneider regarding the teit-but'yl
to 50" favored the metalation reaction slightly; decrease in the temperature to -23' stopped the reaction completely. -4 change t o dibutyl ether solvent lowered the yield of carbinol to 2555, vhile the higher boiling by-products increased to about KI~~ Addition . of 2 moles of acetone increased the metalation reaction (over 60% t,oluenc), while the yield of carbinol dropped to 21%. These results are summarized in Table I. In general, a small amount of the halide was added first to initiate reaction, and accordingly, the formation of the organosodium compound rvas slightly ahead of the carbonyl condensation throughout. The reverse procedure, involving the preliminary addition of 10% of t,he ketone, also was investigated for the benzyl chlorideacetone reaction. I n this case only 52% of t'he benzyl chloride reacted a t 50" C. ; t,he crude alcohol contained a considerable quantity of carbonyl (by hydroxylamine hydrochloride titration), probably henzylacet,one resulting from the condeiisation of benzyl chloride a-ith sodioacetone. An alkrnative route t o 2-benzyl-2-propanol also was investigated; this involved the formation of phenylsodium from chlorobenzene, the metalation of toluene to benzylsodium, and the addition of acetone to the benzylsodium. The maximum yield of alcohol (based on the chloride) was 327,. Since the metalation step itself was shown to proceed in almost yuantitative yield (by carbonation to phenylacetic acid), the preparation of alcohol by t'he tF$-o-step procedurewasnot so satisfactoryas by the o n e - s t e p p r o c e s s . TABLE11. YIELDSO F ALCOHOL D D I T I O S PRoDCC'd .4TD HYDROCARBON (kIETAL.4TION However, this alternative proI'RO~VCT) IS S O ~ I ~ - ~ : - ~ ' R OCo ~ ~ OENSATIOSS TJ:I) OF CHLORIDES WITH CARBONYL COMPOUXDS cedure may be of value in Carbonyl Compound those instances where the desired halide is relatively dif(:>CH),CO( CHa)-CH:I~CO ficult to obtain. The use of Chloride CH3COOCnHs CHz (CH:)GO CHsCHzCHO this type of metalation (essenCsHsCHzCl 72% alcohol 65% alcohol 59% alcohol 4 2 v alcohol 16% alcohol tially the r e a c t i o n of the 14% toluene FO% toluene 3.5% toliiene 27% toluene 6070 toluene CsHsCI S o alcohol& J S % alcohol . . , .... sodium salt of a weak acid 74m0 benzene 50% benzene .. . .... n-Amyl Cl 23Yo alcohol Alcohol lorn 1 2 0 ; alcohol .... .. , with a stronger acid) has been 75% pentane 66% pentane 6:3% pentane .... .... CHI frequently described in the literature ( 4 , 10). \H--Clb S o alcohol fjC/0 alcohol .. . l i o alcohol .... > l a % C3 >2c7, c3 > 7 % Cs / In general, t h e o p t i m u m Hydrocarbon Hydrocarbon Hydrocarbon
__-_.
CHs
yields of alcohol (by the concurrent react,ion of halide and carbonyl compound) were obtained by condueting the reaction at the minimum wmperature required t80 suetain it. This is partly a function
CHa
\ /
CHr--C-Cl CHa
N O alooliol 87% C4 Hydrocarbon0
Chlorobenzene-ethyl acetate pair gave a pecnliarly ~ l ~ p g reaction i~h wIiicli failed t o proceed smoothly io several attempts. Accordingly, these data are not consiatent with rhe rest of the sable. 6 Owing to low boiling,points of propane and propyiene, accurate yields of Cs hydrocarbon were not, obtained. C With tert-butyl chloride hydrocarbon was rnostly isobutylene f r o m deliydrohalopenation. Q
I N D U S T R I A L AND E N G I N E E R I N G C H E M I S T R Y
day 1954
r
d
'0 0,
x
4
i
-
1021
chloride-methyl pivalate condensation. On the other hand, the reactivity of chlorobenzene is greatly reduced by the concurrent addition of the ester; here satisfactory condensation could be obtained only by preforming the phenylsodium. Benzyl chloride and paraformaldehyde also failed to condense in the presence of sodium; the only product obtained on heating the mixture was dibenzyl. Table I11 summarizes the various reactions investigated and products prepared. Two of these products, 2,6-dimethyl-4-benzyl-4-heptanol and 2-methyl-4-isobutyl-4nonanol, have not been reported pi eviously. The procedure described is an effective, one-step method for preparing alcohols from certain organic halides and carbonyl compounds. Side reactions which most seriously limit the scope of the condensation are metalation of the carbonyl compound (with reduction of the organosodium intermediate), and dehydrohalogenation of the alkyl halide. -4spreviously shown, the best yields may be expected with carbonyl compounds containing no alpha-hydrogen atoms-e.g., pivalic acid esters ( 9 ) , benzoic acid esters (11)-and with halides incapable of dehydrohalogenation-e g , benzyl chloride, chlorobenzene. However, by the present procedure, satisfactory yields also may be obtained from normal aliphatic esteis and ketones when halides such as benzyl (ahloride are employed. Where a product may be prepared hy either the Grignard or sodium condensation, the latter has a liulnber of practical advantages, including ease of reaction with 1elatively inert compounds such as chlorobenzene, the possibility of employing metalation as a route to the organosodium intermediate, and the use of hydrocarbon solvents instead of diethyl ether.
i
ACKNOWLEDGMENT
N u) 3 A
m, ri i
o
This work was done under a fellowship supported by the A'ational Distillers Froducts Corp.; the authors are grateful to the corporation for sponsoring this research and for permission to publish these results.
m
? ?
- 2
LITERATURE CITED
(1) Alexander, E. R., "Ionic Organic Reactions," p. 127, New York,
John Wiley &. Sons, 1950. (2) Bartlett, P. D., and Schneider, A., J . Am. Chem. Soc., 67, 141 (1945). (3) Cadwallader, E. A., Fookson, A., hiears, T. W., and Howard, F. L., J. Research Natl. Bur. Standards, 41, 111 (1948). (4) Conant, J. B., and Wheland, G. W., J . Am. Chem. Soc., 54, 1212 (1932). (5) Frampton, 0. D., and Nobis, J. F., 1x0. ERG.,CHEM.,45, 404 11 11.52) ,_"__,.
,
I
(6) Hansley, V. L., Ibid., 43, 1759 (1951). (7) Heilbron, I. M., "Dictionary of Organic Compounds," Vol. f, p. 897, New York, Oxford University Press, 1943. (8) Lagerev, S. P., Trudy Uzbelcskogo Gosudarst. Univ., 6, 71 (1936). (9) Levy, J., and Tabart, A., Bull. SDC. chim. France, 49, 1776 (1931). (10) Morton, A. A., Chem. Revs., 35, 1 (1944). (11) Morton, A. A., and Stevens, J. R., J. Am. Chem. Soc., 53, 2244 (1931). (12) hlurat, M., and Amouroux, G., Bull. SOC. chirn. France, 15, 159 (1914). (13) Nesmeyanov, A. N., and Sazonova, V. A , , BUZZ. acad. sci. U.R.S.S., Classe sei. chim., 1941, 499. (14) Stas, J., Bull. soc. chim. Belg., 35, 379 (1926). (15) Whitmore, F. C., and Williams, F. E., J . Am. Chem. Soc., 55, 408 (1933). RECEIVED for review May 18, 1953. ACCEPTEDJanuary 21, 1954. the thesis of W. E. Foster submitted in partial fulfillment of the requirements for the Ph.D. degree at the University of Cincinnati.
Abstracted from
