11. 12.

S . B . G a s h e r and L. D. Smirnov, Khim. G e t e r o t s i t d . Soed., 393 (1982). S . B . Gashev and L. D. Smirnov, Izv. Akad. SSSR, Ser. Khim., 678 (1979).

REACTIONS OF

PHASE

OF

TRANSFER

COMMUNICATION ESTER SOLID

WITH

CARBONYL

COMPOUNDS

IN

THE

PRESENCE

CATALYSTS

1 I. RE LATIONSKIPS

IN ALKYLA

I-CHLORO-3-METHYL-2-BUTENE

CARBONATES

AND

QUATERNARY

S. S. Yufit

and

I. A.

TION IN THE

AMMONIUM

OF ACE TOACETIC PRESENCE

OF

SALTS

Esikova

UDC

541.124:66.095.253:547.484.34

In the alkylation of compounds with a motile hydrogen atom under conditions of interracial c a t a l y s i s (IFC), solid alkali m e t a l c a r b o n a t e s (usually Na2CO 3 or K2CO 3) a r e used as the condensing agent [1]. However, the m e c h a n i s m of IFC f o r s o l i d / l i q u i d s y s t e m s h a s been studied v e r y little, and the role of the q u a t e r n a r y a m m o n i u m s a l t s used as c a t a l y s t s is not at all c l e a r . We have i n v e s t i g a t e d the kinetics of the r e a c t i o n of a e e t o acetic e s t e r (HA) with 1 - c h i o r o - 3 - m e t h y l - 2 - b u t e n e (prenyl chloride RX) in benzene in the p r e s e n c e of solid K2CO 3 and v a r i o u s q u a t e r n a r y a m m o n i u m s a l t s (QX): b e n z y l t r i e t h y l a m m o n i u m chloride (I), t e t r a b u t y l a m m o n i u m iodide (ID, and c e t y l t r i m e t h y l a m m o n i u m b r o m i d e (KI). EXPERIMENTAL The reactions were carried out in a thermostatted reactor (40 m I~ mounted on a high-speed rocker to provide vigorous mixing. The original acetoaeetic ester and l-chloro-3-methyl-2-butens were purified in accordance with [2]. The benzene was thoroughly purified [3] and stored over metallic Na, and was redistilled before use. The K2CO 3 was dehydrated under vacuum (24 h, 150-180~ The presence of moisture has a significant effect on the alkylation rate; the KHCO 3 was dried under vacuum at 70~ (3 h). The (1) was obtained from triethylamine and PhCH2CI [4], yield 75%, m.p. 188~ (benzene-ethanol). Products (If) and (III), grade c.p. (chemically pure), were dried in a desiccator over 3/~ molecular sieve. When HA and RX interact in the presence of K2CO 3 and QX, only monoalkylation takes place, and prenylacetoacetic ester RA is formed, COOC~H5 I

CH~

COOC~H~ I

-~ CICH~C~=C(CH3)~ -, CHCH~.CH=C(CH~).z

[

COCH8 (HA)

(RX)

i

COCHs (RA)

The c o n v e r s i o n of HA c o r r e s p o n d s exactly to the c o n v e r s i o n of RX and the f o r m a t i o n of RA. The c o u r s e of the r e a c t i o n was followed c h r o m a t o g r a p h i c a l l y . The method u s e d f o r analysis of the r e a c t i o n m i x t u r e was d e s c r i b e d in [2]. The kinetic e x p e r i m e n t s w e r e p e r f o r m e d as follows: The r e a c t o r , heated to 40~ was c h a r g e d with 5 g of the solid d e h y d r a t e d deprotonating agent a n d Q X (usually 0.001 mole); then, 25 ml of a solution of HA and RX in benzene was added, this solution containing a c e r t a i n amount of t r i d e c a n e (internal s t a n d a r d f o r GLC). The r e a c t i o n was usually continued up to 20-30% c o n v e r s i o n of HA. At c e r t a i n i n t e r v a l s , s a m p l e s of the organic l a y e r w e r e drawn off and filtered; the f i l t r a t e was analyzed by GLC without any p r e p a r a t i v e t r e a t m e n t to d e t e r mine the c o n c e n t r a t i o n s of HA, RX, and RA. The kinetic c u r v e s f o r the HA w e r e w o r k e d up integrally on coordinates of log C H A v s t i m e , and the o b s e r v e d f i r s t - o r d e r constant with r e s p e c t to HA (kH) was found. F r o m the kinetic c u r v e s of RA f o r m a t i o n , the initial r a t e s of alkylation (W 0) w e r e calculated [5]. The m e a n e r r o r of d e t e r m i n a t i o n of W 0 was -~ 10%. The r e s u l t s a r e p r e s e n t e d in Table 1. Deprotonation of HA. The deprotonation of 1.75 m o l e s / l i t e r HA in 25 ml benzene under the influence of 5 g solid KaCO 3 or Ki-ICO~ was c a r r i e d out at 40~ in the p r e s e n c e of (I) or without (I) (procedure of kinetic e x N. D. Zelinskii Institute of Organic C h e m i s t r y , Academy of Sciences of the USSR, Moscow. T r a n s l a t e d f r o m I z v e s t i y a Akademii Nauk SSSR, S e r i y a K h i m i e b e s k a y a , No. 1, pp. 47-53, J a n u a r y , 1983. Original article s u b m i t t e d April 2, 1982. 36

0568-5230/83/3201-0036507.50

9 1983 Plenum Publishing C o r p o r a t i o n

TABLE i. Allcylation of Acetoacetic and Prenylacetoacetic Esters with Prenyl Chloride (RX) in the Presence of a Solid Carbonate (5 g) in Benzene (40~ [HA] -- [RX], organic phase volume 25 ml) Cerbonate [ H A ] , moles]liter

Aeetoazetic ester

I

0,35 0,175 t,75

0.036

t,75

0,036 KHCOs 0,05 C82C03 0,0t54

t,75

1,75 1,75 t,75 Prenylacetoaeetic ester

0,87

* Carbonate

w0qo 4, moles/litero

moles

K2COa 0,036 0,036 0,036 0,036 0,036 0,036

t,75 1,75 t,75

QX

kobsOl04, sec-1

see

(i) 0,000 O,OOi 0,004 0,010 0,00t 0,00t (H) 020t

0,10

0,69

i,2/~

i,47 t,t3 0,35 0,t6

0,69 0,69

1,08

(Ill) 0,00t

t,18

(I) O,OOi

0,035

0,106

0,001

7,08

3,83

0,0154 CsiCOa

2,53

0,0077*

0,0005

L24

0,54

2.5 g.

p e t i t : e a t s is analogous to that d e s c r i b e d above). In the c o u r s e of the experiment, the HA concentration was m e a s u r e d c h r o m a t o g r a p h i c a l l y , and periodic s a m p l e s of the organic phase filtrate w e r e t i t r a t e d with a 0.01 N HC1 solution in tile p r e s e n c e of an indicator (methyl orange in the case of the KHCO3 and phenolphthalein in the case of the K2CO3). The data on the HA consumption (Fig. 1) show a linear relationship up to 90 rain when plotted on f i r s t - o r d e r r e a c t i o n coordinates, with kobs : 0.72 910 -4 sec -1. Solubility of K2CO$ and KItCO 3 in Solution of HA in Benzene. To 5 g of dried solid K2CO3 or KKCO3, was a d d e d 2 5 ml of a solution (1.75 m o l e s / l i t e r ) of acetoacetie e s t e r in benzene, in the p r e s e n c e of 0.23 g (0.001 mole) of (D and without rely (D (designated A and B, respectively). The s y s t e m was mixed vigorously for 3 h at 40~ and then filtered, and the filtrate was t i t r a t e d to determine the ions CO32-, A-, and HCO[ f o r the s y s t e m s with K2CO 3 and KHCO 3. The p r e s e n c e of COl- ions in the s y s t e m was established by a qualitative reaction with Mg 2-. The HCO[ ion does not give a qualitative reaction with Mg 2+ salts (Table 2).

DISCUSSION

OF

RESULTS

In studying the role of solid carbonates in the reaction of C-allwlation of HA in benzene in a two-phase solid/liquid system, it was established that the logarithm of the reaction rate varies linearly with the enthalpy of formation of the crystal lattice of the carbonate used as the deprotonating agent [6]. The observed effect was explained on the basis that AH ~ of the lattice enters directly into the magnitude of the free energy of activation of the reaction, since file first stage of the process, deprotonation, leads to breakdown of the salt crystal surface. The alternative mechanism, which includes homogeneous deprotonation of HA under the influ~ce of K2CO 3 dissolved in the organic phase, is rejected because of the data obtained on the solubility of potassium carbonate and bicarbonate in the acetoaeetic ester/belxzene system (Table 2). It can be seen ~at in the absence of QX, potassium bicarbonate does not dissolve in this system. The addition of 0.001 mole of (I) provides transfer of HCO 3 from the crystal surface to the bulk organic phase, which is in accord with the data of [7]. The carbonate ion could not be detected in the organic phase, even in the systems containing QCI. Thus, the transfer of CO 2into the organic phase does not take place, at least within the limits of sensitivity of the reaction with Mg2+; this is consistent with the data of [8], according to which doubly charged ions of onium salts are not transferred. The interaction of HA with solid K2CO 3 in benzene leads to the potassium derivative of HA, which par~ially dissolves in the organic phase. When I~A-ICO~ is used as the base, no consumption of HA was observed; and ac37

TABLE 2. D e t e r m i n a t i o n of Solubility of KaCO3 and KHCO 3 in Acetoacetic E s t e r / B e n z e n e S y s t e m ([HAl = 1.75 m o l e s / l i t e r , 5 g of salt) Results of titration Quantity of (I), moles

Salt

methyl orange

I phenolphthalein

g-ions/liter 0 0,00t * o 0,00t

KIICOs KHCO3

KzCO3 K~C03

0 1

0,003

0,023 0,08

* Under t h e s e conditions, the m a x i m u m possible concentration of (D in the organic p h a s e is 0.04 m o l e / l i t e r .

lg C q !,J

CAH, moles]liter

o,5

o"

,f,5 ~

4! .2

b

1,0

]

6t;

I

f~o

Fig. 1

I

t80

o

.... 6~o

~2o - " ~ .

I

2~0 ~, min Fig. 2

Fig. 1. Deprotonation of a c e t o a c e t i c e s t e r on solid K2CO S in benzene: without (D; 2) with (D 0.001 and 0.002 m o l e .

1)

Fig. 2. L i n e a r a n a m o r p h o s e s of kinetic c u r v e s f o r allwlation of a c e t o acetic e s t e r on solid c a r b o n a t e . Mole r a t i o K2CO3:HA: 1) 8.2; 2) 4.1; 3) 0.82. Mole r a t i o Cs2CO3:HA. 4) 0.35. cording to the phenolphthalein t i t r a t i o n data, the organic phase likewise did not contain the c a r b a n i o n of HA. The data f r o m t i t r a t i o n of the c a r b o n a t e s y s t e m with phenolphthalein a r e in a c c o r d with the quantity of CHO 8 and A- in the o r g a n i c p h a s e . The introduction of (I) into the s y s t e m containing HA and K2CO 3 leads to an inc r e a s e in the quantity of t h e s e ions in the organic phase as a r e s u l t of the f o r m a t i o n of new ion p a i r s with Q+ ~ H C O 3 and QA). The o b s e r v e d deviations between the r e s u l t s of t i t r a t i o n obtained f o r the carbonate s y s t e m with and without (I) (with allowance f o r the i n c r e a s e of [A-] due to the f o r m a t i o n of ion p a i r s with Q+) m a y be r e l a t e d to the change in acidity of the solution in the p r e s e n c e of the onium cation [9]. Thus, the data f r o m the t i t r i m e t r i c a n a l y s i s of the solution of HA in benzene a f t e r it is s a t u r a t e d with KHCO 3 o r K2CO 3 p r o v i d e evidence in f a v o r of the a s s u m p t i o n that t h e deprotonation of HA p r o c e e d s c~ the s u r face of the solid c a r b o n a t e . A c h a r a c t e r i s t i c f e a t u r e of the deprotonation on the solid carbonate is that the consumption of HA ends a f t e r a c o n v e r s i o n of 18% or 30% has been r e a c h e d in the r e s p e c t i v e s y s t e m s without and with (I) (see Fig. 1). The initial r a t e of HA consumption is independent of the p r e s e n c e of (D in the s y s t e m . The c o n v e r s i o n of HA is not changed if the quantity of (D is i n c r e a s e d f r o m 0.001 to 0,002 m o l e . The HA c o n sumption c u r v e s a r e identical f o r the two c a s e s .

38

A kinetic analysis of the section of the curves in Fig. 1 up until the reaction stops shows that the e x p e r i mental points for all three e x p e r i m e n t s fall s a t i s f a c t o r i l y on a s t r a i g h t line on coordinates of log [HA] vs 7; the f i r s t few points fall above the straight line. F r o m these facts we can conclude that the reaction of HA with solid K2CO 3 in benzene is d e s c r i b e d by the equation of an i r r e v e r s i b l e reaction that is f i r s t - o r d e r with r e s p e c t to HA, with kob s = 0.72 9 10 -4 see -i. In the course of this interaction, two kinetieally independent products appear: the calcium derivative of HA (KA) and an intermediate adsorption complex of HA on the K2CO3 s u r f a c e (SAK). The SAK, which is f o r m e d in the r e v e r s i b l e stage, is not c o n v e r t e d to KA, and this also leads to deviation of the f i r s t points of the kinetic curve [10]. Thus, the deprotonation p r o c e s s can be r e p r e s e n t e d by the scheme K~CO~

HA.

~ SAK

K~CO~

~ -

H A 7_:_~t~A

(i) (2)

The stoppage of the reaction of HA with solid K2CO3 can be explained on the basis that as the interaction of the original r e a c t a n t s p r o c e e d s , the active c e n t e r s on the carbonate become eompletely filled (here we cons i d e r that an active c e n t e r of the carbonate is that section of the s u r f a c e on which the deprotonatien of HA can take place). The i n c r e a s e in the c o n v e r s i o n of HA when (I) is introduced into the s y s t e m is due to the o c c u r r e n c e of exchange reactions that i n c r e a s e the accessibility of the HA to the K2CO3 s u r f a c e . Such r e a c t i o n s are KA + QC1--+ QA + KCI KHC0a + QC1--+ QHC03 + KCI KHC0a + QA QHC0a + KA AS a consequence of the exchange processes in which the onium cation Q+ takes part, bicarbonate is desorbed from the surface of the crystal lattice into the bulk organic phase, leading to the appearance of new active cenmrs on the K2CO 3 and an increase of the quantity of KA as a result of renewal of the carbonate surface. It should be noted that most of the KA that is formed is in the insoluble precipitate. Moreover, in the presence of (1) there is a partial conversion of KA to QA, resulting in an increase in the concentration of the carbanion in the organic phase (Table 2). The alkylation of HA with prenyl chloride was carried out with various mole ratios K2CO3:HA, from 0.82 to 8.2. In these experiments, equimolar quantities of HA and RXwere used. It was established that the kinetic curves obtained in these experiments are not described by the equation of a second-order reaction, but rather give linear plots on semilogarithmie coordinates of log [HA] vs T, indicating zero order with respect to RX (Fig. 2). With excess K2CO 3, kob s = 0.69 9 10 -4 sec -I does not change with decreasing equimolar concentrations of the reactants from 0.35 to 0.175 mole/liter (yield of RA in 4 h91%). With a mole ratio K2CO3:HA = 0.82 and [HA] = [RX] = 1.75 moles/liter, there is a break on the kinetic curve, with the slope of the initial section on semilegarithmic coordinates corresponding exactly to the slope of the lines obtained with excess K2CO 3. At the same time, the slope of the final section corresponds to the rate constant for HA alkylation (0.i 9 10 -4 sec -I) in the presence of KHCO 3 and the same quantity of (1). The observed break on the kinetic curve occurs at an HA conversion of 24%, close to the 30% HA conversion for stoppage of the reaction of HA deprotonation under the influence of solid K2CO 3 in the presence of (1). This means that the retardation of the alkylation is related to deactivation of the surface carbonate because of the formation of bicarbonate [6]. In all of the experiments on HA alkylation in the presence of K2CO 3 and (I), the HA consumption corresponds to the formation of RA, the order with respect to RX is zero, and the first-order rate constant of alksdation is close to the rate constant of HA deprotonation under the same conditions. Since the alkylation rate is 100 times g r e a t e r in the p r e s e n c e of a strong base, i.e., a 50~o aqueous KOH solution [2], we can a s s u m e that in the p r e s ence of solid K2CO3 and (D, the alkylation rate is limited by the deprotonation stage. At the same time, in the absence of (D, the altcylation of HA is an o r d e r of magnitude s l o w e r (Table 1). The conversion of HA under these conditions (~ 20%) is g r e a t e r than the yield of RA, which is ~10% in 5 h. This means that without f.he (D, the alkylation of the ion p a i r p r o c e e d s m o r e slowly than its formation, and hence the alkylation rate under these conditions should depend on the concentrations of both HA and RX. Analogous r e s u l t s a r e obtained if Cs2CO3 is used in place of K2CO3. A c o m p a r i s o n of the data on deprotonation and allcylation in the p r e s e n c e of K2CO3 and Cs2CO 3 without (D shows that the rate of deprotonation under the influence of Cs2CO 3 (W 0 = 5 9 10 -4 m o l e / l i t e r 9 is a l m o s t twice the rate under the influence of K2CO 3 (W0 = 2.15 • -4 m o l e / l i t e r , see). At the same time, the r a t e s of alkyiation differ by an o r d e r of magnitude (Table 1). This is consistent with the assumption that the reactivity- of ion p a i r s may 39

by an o r d e r of magnitude (Table 1). This is consistent with the a s s u m p t i o n that the r e a c t i v i t y of ion p a i r s m a y be r e l a t e d to the distance between the cation and the anion. The r a t i o s between the r a t e s of deprotonation and alkylation, both on K2CO 3 and on Cs2CO 3, a r e such as to e n s u r e that the r e a c t i o n will p r o c e e d without a limiting stage. If the s t a g e of proton a b s t r a c t i o n f r o m the HA is limiting, then n e i t h e r the nature n o r the concentration of the c a t a l y s t should change the kinetic r e l a t i o n s h i p s of the r e a c t i o n , since t h e r e is no effect on the rate of QX deprotonation. A study of the influence of the quantity of (I) in the r e a c t i o n s y s t e m shows (Table 1) that changes in the quantity of s a l t have p r a c t i c a l l y no effect on the alkylation r a t e . V a r i a t i o n of the lipophilicity of the onium c a t ion* a l s o has no effect on the p r o c e s s r a t e . The o b s e r v e d facts indicate unambiguously that the m e c h a n i s m of HA alkylation under the influence of solid K2CO 8 includes deprotonation as the limiting s t a g e . In a c c o r d with the data of [6], the alkylation of HA in the p r e s e n c e of different solid c a r b o n a t e s p r o c e e d s with a single m e c h a n i s m , and the i n c r e a s e in alkylation r a t e when the change is m a d e f r o m a w e a k e r b a s e to a s t r o n g e r is c o n s i s t e n t with the a s s u m p t i o n of the limiting role of the deprotonation stage. A change in acidity of the original s u b s t r a t e also affects the alkylation r a t e . Indeed, if in the allgylation in the p r e s e n c e of K2CO3 the HA is r e p l a c e d by its p r e n y l - s u b s t i t u t e d adduct, the p r o c e s s goes f o r w a r d f a r m o r e slowly, since its pK A is higher than f o r the HA [11]. At the s a m e t i m e , if we use a m o r e active deprotonating agent such as Cs2CO3, the alkylation of RA can be a c c o m p l i s h e d . In 25 ml of benzene in the p r e s e n c e of 0.0005 m o l e s ' o f (I) and [I~A] = [RX] = 0.87 m o l e / l i t e r with a mole r a t i o Cs2CO3:RA = 0.35, the alkylation of RA has the s a m e r e l a t i o n s h i p s as those o b s e r v e d in the alkylation of HA under conditions of a deficiency of c a r b o n a t e , and the alkylation is c h a r a c t e r i z e d by an o b s e r v e d r a t e constant f o r RA alkylation equal to 0.54 9 10 -4 sec -1. At the s a m e t i m e , kob s f o r the HA under the s a m e conditions is an o r d e r of magnitude g r e a t e r , 3.83 9 10 -4 see -1. Thus, the p r e s e n c e of a limiting stage, deprotonation, which is d e t e r m i n e d by the acidity of the s u b s t r a t e , the basieity of the deprotonating agent, and the rate of alkylation of the ion pair, leads to a change in the kinetic relationships of the process in comparison with a two-phase liquid/liquid system in which the base is a50% aqueous KOH solution [12]. Among the basic, distinctive characteristics of alkylation in a system consisting of a solid carbonate and an organic phase, we should list thehigh selectivity of the monoalkylation process and the lack of any dependence of the process rate on the alkyl halide concentration or on the quantity and nature of the catalyst. The role of QX under these conditions comes down to the formation of a new; more reactive ion pair QA, and to the transfer of the HCO~ that prevents deprotonation of the substrate from the surface of the solid phase into the bulk liquid. CONCLUSIONS i. The interaction of acetoacetic ester with l-chloro-3-methyl-2-butene in the presence of solid K2CO 3 and catalytic quantities of benzyltriethylammonium chloride leads to selective formation of the monoalkylated product, with a high yield. In order to obtain the dialkylated product, it is necessary to use a stronger deprotonating agent such as Cs2CO 3. 2. The reaction kinetics in the alkylation of acetoacetic ester on solid carbonates are determined by the presence of a limiting stage - the deprotonation of the substrate. The reaction is first-order with respect to acetoacetic ester and zero-order with respect to l-ehloro-3-methyl-2-butene. The alkylation reaction rate does not depend on the quantity of catalyst QX that is added, nor on its structure and lipophilicity. 3. The deprotonation of acetoacetie ester proceeds on the surface of the solid carbonate and is described by the equation of an irreversible first-order reaction. There is no transfer of CO~- to the organic phase, and hence no homogeneous deprotonation. The deprotonation stops after the active centers have been used up and the surface of the carbonate crystal lattice has become deactivated as a result of bicarbonate formation. 4. The role of the catalyst comes down to transfer of bicarbonate ion from the crystal surface into the bulk organic phase, leading to renewal of the carbonate surface; this increases the conversion of aeetoacetie ester. The catalyst has no effect on the deprotonation rate.

*Solubility of QX in benzene, m o l e s / l i t e r : (I) 0.3 9 10 -3, (II) 0.45 9 10 -3, (1-[I) 0.7 9 10-3; values we d e t e r m i n e d by t i t r a t i o n of the halide in a s a t u r a t e d solution of the s a l t in benzene at N20~

40

LITERATURE 1. 2. 3. 4. 5. 6. 7. 8. 9. I0. ii. 12.

CITED

W . E . K e l l e r , Compendium of P h a s e - T r a n s f e r Reactions and Related Synthetic Methods, Fluka AG, CH9470, Buchs, Switzerland (1979). I . A . E s i k o v a and S. S, Yufit, Izv. Akad. Nauk SSSR, Ser. Khim., 507 (1980). A. W e i s s b e r g e r , E. P r o s k a n e r , J . A. Riddick, and E. E. Toops, Organic Solvents, 2nd ed., Wiley, New Y o r k (1955). M. Finkelstein, R. S. P e d e r s e n , and S. D. R o s s , J. Am. Chem. Soc., 8_~1,2361 (1969). V . A . Yakovlev, Kinetics of E n z y m e C a t a l y s i s [in Russian], Nanka, Moscow (1965), p. 64. S . S . Yufit and I. A. Esikova, Dold. Akad. Nauk SSSR, 26_~5, 358 (1982). M. L i s s e l and E. V. Dehmlow, Chem. B e r . , 114, 1210 (1981). A. B r a n d s t r S m , Adv. P h y s . Org. Chem., 1_55, 267 (1977). A. BrandstrSm, Preparative Ion Pair Extraction, Apotekarsocieteten, Stockholm 0974). L.P. Hammett, Physical Organic Chemistry, 2nd ed., McGraw-Hill, New York (1970). O.A. Reutov, I. P. Beletskaya, and K. P. Butin, CH-Aeids [in Russian], Nauka, Moscow (1980), p. 37. S.S. Yufit and I. A. Esikova, Izv. Akad. Nauk SSSR, Set. Khim., 515 (1980).

REACTIONS PHASE

OF

CARBONYL

TRANSFER

COMPOUNDS

IN THE

PRESENCE

OF

CATALYSTS.

COMMUNICATION 12. ROLE OF QUATERNARY AMMONIUM CATION IN ALKYLATION OF ACETONE BY 1 - C H L O R O - 3 - M E T H Y L - 2 - B U T E N E

I. A.

Esikova

and

S. S. Yufit

UDC

541.124:541.128:66.095.253:547.284.3

We had e s t a b l i s h e d p r e v i o u s l y [1, 2] that the r a t e of alkylation of acetone (HA) by 1 - c h l o r o - 3 - m e t h y l - 2 butene (prenyl chloride RX) in a t w o - p h a s e catalytic s y s t e m is l i n e a r l y dependent on the concentration of RX in the organic p h a s e and the activity of OH- in the aqueous phase. Also, we investigated the solubility of b e n z y l t r i e t h y l a m m o n i u m chloride (TEBA-C1, QC1) in organic p h a s e s with v a r i o u s compositions [3] and its c o n v e r s i o n s under the actual conditions in acetone alkylation [2]. The w o r k we are r e p o r t i n g h e r e was a i m e d at d e t e r m i n i n g the r e a c t i o n o r d e r with r e s p e c t to acetone and investigating the influence of QC1 concentration in the organic phase and the type of solvent on the rate of acetone alkylation by prenyl chloride. EXPERIMENTAL The p r o c e d u r e s used in the kinetic studies and in the a n a l y s i s of the products, as well as the c h a r a c t e r istics of the original r e a c t a n t s , have been p r e s e n t e d in [1]. The method of Newton and G r e g o r y [4] was used in d e t e r m i n i n g the initial r a t e s (W~ of f o r m a t i o n of 2 - m e t h y l - 2 - h e p t e n - 6 - o n e (MH) in the alkylation of acetone by RX in toluene o r benzene in the p r e s e n c e of a 50% aqueous solution of NaOH and TEBA-C1. The values obtained f o r the total concentration of TEBA-C1 and TEBA-OH in the m i x t u r e s of acetone with benzene a f t e r t r e a t m e n t with the 50% aqueous caustic solution a r e p r e s e n t e d in Fig. 1. Studies of the influence of the HA c o n c e n t r a tion on W 0 w e r e p e r f o r m e d at 40~ in s y s t e m s containing 25 m l of an organic p h a s e with [RX] = 5 m o l e s / l i t e r , [HA] = 0.8-3.2 m o l e s / l i t e r , benzene, and 1 g of t r i d e c a n e (internal s t a n d a r d f o r GLC); the aqueous p h a s e c o n s i s t e d of 10 g of a 50% NaOH solution and 0.23 g of TEBA-C1. We also i n v e s t i g a t e d the influence of the T E B A - C I c o n centration on W 0 (Table 1). The influence of v a r i o u s solvents on the rate of MG f o r m a t i o n (Table 2) was i n v e s tigated at 40~ in s y s t e m s consisting of 25 ml of organic p h a s e plus an aqueous phase (5 g NaOH + 5 g H20). The concentration of acetone in the aqueous NaOH solution was d e t e r m i n e d f r o m the data of [5], which a r e d e s c r i b e d by ~he equation log [HA] = A + B . [NaOH]. The solubility of acetone in aqueous solutions of v a r i o u s concentrations is shown in Table 3. F r o m t h e s e data it follows that the solubility of AH in 50% aqueous NaOH cannot be g r e a t e r than 2 . 10 -2 m o l e / l i t e r .

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. i, pp. 53-58, January, 1983. Original article submitted April 2, 1982. 0 5 6 8 - 5 2 3 0 / 8 3 / 3 2 0 1 - 0 0 4 1 $07.50 9 1983 Plenum Publishing C o r p o r a t i o n

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