Int.J.Curr.Microbiol.App.Sci (2014) 3(9) 211-223 ISSN: 2319-7706 Volume 3 Number 9 (2014) pp. 211-223 http://www.ijcmas.com Original Research Article The dichlorocyclopropanation of 3-methyl-1-cyclohexene and 4-vinyl-1- cyclohexene using water soluble multi-site phase transfer catalyst-A kinetic study K.Shanmugam* and E.Kannadasan Deptartment of Chemistry, Government Arts College, Chidambaram, TamilNadu, India *Corresponding author A B S T R A C T The present study focuses the attention towards the utility of multi-site phase K e y w o r d s transfer catalyst (MPTC), is demonstrated by studying hydroxide-ion initiated reaction like dichlorocarbene addition to olefins. The formation of the product was Multi-site phase monitored by GLC.Dichlorocyclopropanation of 3-methyl-1-cyclohexene and 4- transfer catalysts, vinyl-1-cyclohexene catalysed by multi-site phase transfer catalyst carried out in Dichlorocyclopro biphasic medium under pseudo-first-order conditions by keeping aqueous sodium panation, hydroxide and chloroform in excess. The effect of various experimental parameters 3-methyl-1- on the rate of the reaction has been studied. Also thermodynamic parameters such cyclohexene;4- as S#, G# and H# were evaluated; based on the experimental results, a suitable vinyl-1- mechanism is proposed.It also deals in greater detail on the kinetic aspects of cyclohexene, Kinetics chosen reactions. An attempt has been made to compare the ability of MPTC-1 with MPTC-II and single-site PTC for dichlorocarbeneaddition to olefins like 3- methyl-l-cyclohexene and 4-vinyl-l-cyclohexene. Introduction The reaction of chloroform with strong to be generated in, or transferred to the bases to generate synthetically useful organic phase, where its reaction with 3- dichlorocarbene normally requires methyl-l-cyclohexene is much greater than anhydrous conditions to avoid its rapid with water addition of dichlorocarbene to 3- hydrolysis (Reeves et al., 1976). Thus methyl-l-cyclohexene gave only normal addition of chloroform to a mixture of 3- dichlorocyclopropane product. Makosza and methyl-l-cyclohexene and aqueous 25% Bialecka (1977) formulated the mechanism sodium hydroxide solution gives 60-70% of the olefin (cyclohexene) yield in the presence of a phase transfer dichlorocyclopropanation under phase catalyst such as tridecyl methyl ammonium transfer conditions as reaction of CHCl3 chloride or benzyl triethyl ammonium with OH- at the aqueous organic phase chloride. The remarkable increase in yield of boundary, from where it is then taken in to the dechlorocarbene adduct reflects the the organic phase by the quaternary cation. ability of the quaternary salt to cause :CCl2 Soluble phase transfer catalysts for 211 Int.J.Curr.Microbiol.App.Sci (2014) 3(9) 211-223 dichlorocarbene addition to cyclohexene bicyclo[4.1.0]-heptane derivatives by the with concentrated aqueous sodium addition of dichlorocarbene to 3-methyl-l- hydroxide as the base were first reported by cyclohexene; the method involves the von Doering et al., 1980 and were reaction of 3-methyl-l-cyclohexene with investigated in detail by Makosza, 1978. The chloroform in the presence of concentrated phase transfer catalyzed dichlorocarbene aqueous solution of sodium hydroxide addition reaction of 3-methyl-l-cyclohexene (15%w/w) and catalytic amount of MPTC-I. was thought to proceed by rate-limiting The reaction proceeds exothermically when generation of the dichlorocarbene and the reagents are mixed at 500C and the hydroxide ion at the aqueous / organic yields of the product obtained by this interface. method are very high usually about 100%, within one hour with no excess of the 3- The reaction of chloroform with 4-vinyl-l- methyl-l-cyclohexene required. The ratio of cyclohexene (Starks and Napier, 1976) in 3-methyl-l-cyclohexene to chloroform the presence of sodium hydroxide gives an applied is 1: 10 in volume, depending on the excellent yield of a product C9H12Cl2which availability of the olefin. In a similar way, contains the bicyclo [4.1.0] heptane the addition of dichlorocarbene with 4- (norcarane) skeleton. In the early work, we vinyl-1-cyclohexene yielded 100% product have observed that dichlorocarbene addition within one hour under PTC conditions. reaction was carried out with excess of 3- methyl-l-cyclohexene; dichloronorcarane The dichlorocarbene addition with 3-methyl- product was obtained in a yield of about l-cyclohexene and with 4-vinyl-l- 63% under single-site PTC conditions. The cyclohexene were chosen to investigate the present detailed investigation of this reaction kinetic aspects using the new, water-soluble permitted us to develop a new method for multi-site phase transfer catalyst (MPTC- the preparation of 7,7 dichloro-3-methyl- I). CH3 H3C MPTC-I (0.1 mol%) Cl CHCl3, 15% NaOH, 500rpm, 500C Cl 7,7'-dichloro-3-methyl-bicyclo[4.1.0]-heptane (Scheme-1) MPTC(0.1 mol%) Cl CHCl , 15% NaOH, 3 Cl 500rpm, 500C 7,7'-dichloro-4-vinyl-bicyclo[4.1.0]-heptane (Scheme-2) Dichlorocarbine addition to 3-methyl-l-cyclohexene and 4-vinyl-l-cyclohexene under PTC conditions 212 Int.J.Curr.Microbiol.App.Sci (2014) 3(9) 211-223 The kinetic experiments for the 89%. This reaction was also carried out by dichlorocarbene addition to 3-methyl-l- Winberg et al, 2007, using 50% aqueous cyclohexene and 4-vinyl-l-cyclohexene sodium hydroxide and catalytic amount of (schemes 1, 2) were conducted under bi- TEBA (PTC) and obtained 72% yield of the phase conditions with excess of aqueous norcarane product, 7, 7 dichlorobicylo sodium hydroxide and chloroform under [4.1.0]-heptane.In the present study, the rate pseudo first order conditions. The reaction constant is dependent on the stirring speed was studied at a stirring speed of 500rpm in up to 500rpm and maintains constancy the temperature range 40-600C. Before the beyond the limit. The reaction is carried out kinetic run was started, the catalyst was in aqueous medium; the anion exchange conditioned with aqueous sodium hydroxide equilibrium between the anions in the and chloroform for 10 minutes. The aqueous phase and those associated with substrate, 3-methyl-l-cyclohexene/4-vinyl-l- quaternary salt in the organic phase was cyclohexene preheated at the appropriate very relative to the organic phase temperature, was added to the reaction transformation reaction. The mass transfer mixture. The samples were collected from across the interface is regarded as evident the organic layer at regular intervals of time. from Fig. 1 at low stirring speed. At The kinetics of dichlorocarbene was agitation level 500rpm, anion exchange followed by estimating the formation of two equilibrium is very fast relative to the different norcarane products namely 7,7 - reaction and the substrate consumption rate dichloro-3-methyl-bicyclo[4.1.0]-heptane becomes independent of the stirring rate as and 7,7 dichloro-4-vinyl-bicyclo[4.1.0]- observed by Makoszaet al, 1975,, in the heptane using gas chromatographic study of dichlorocarbene addition to technique. The effect of various cyclohexene catalyzed by triethyl benzyl experimental parameters such as stirring ammonium chloride (TEBA) under PTC speed, substrate concentration, sodium conditions. Doering, Wawrzyniewicz and hydroxide concentration and temperature on Jawdosiak, 1985 reported independently a the reaction rate constants were studied. The similar observation that reflected kinetic kinetics was measured up to 30% of the control by chemical reaction in which [Q+X] formation of the product. is at a steady-state concentration. Below 500rpm the requirement for sufficiently Effect of Stirring Speed rapid mass transfer of the reacting anion is not met and diffusion controlled kinetics is The effect of varying stirring speed on the observed. rate of dichlorocarbene to 3-methyl-l- cyclohexene and 4-vinyl-l-cyclohexene was Hence the independence of the reaction rate studied in the range 100-800 rpm. From the constants on the stirring speed above plots of log(a-x) versus time, the pseudo- 500rpm in the present study is indicative of first order rate constants were evaluated. A extrication mechanism. The behavior is in plot of kobs against stirring speed is shown in short contrast to reactions operative through Fig. 1 (Table1). Balakrishnan et al,2005, had interfacial mechanism, where the reaction documented the kinetic studies of rate is directly proportional to the stirring dichlorocarbene addition to cyclohexene speed. using aqueous sodium hydroxide and chloroform catalyzed by polymer supported Parham, 1983, reported the continuous phase transfer catalyst, obtained an yield of increase in the rate of dichlorocarbene 213 Int.J.Curr.Microbiol.App.Sci (2014) 3(9) 211-223 addition even up to stirring speeds of Effect of catalyst amount 1200rpm. It has also been reported that the rate of an interfacial reaction is proportional The amount of catalyst was varied from to the stirring speed in the range of 600 to 0.05-0.25 mol% for the dichlorocarbene 1400rpm.The interfacial area per unit addition to 3-methyl-l-cyclohexene and 4- volume of dispersion increased linearly with vinyl-l-cyclohexene (based on the substrate increasing speed till a stage is reached where amount) and the experiments were there is no significant increase in the conducted using 15% w/w aqueous NaOH interfacial area per unit volume of dispersion solution. The pseudo first order rate with the corresponding increase in the constants are calculated from the plots of log speed. Thus increasing the stirring speed [a-x] versus time. The rate constants are changes the particle size of the dispersed dependent on the amount of catalyst used in phase.Above certain stirring speed each reaction.The increase in rate constants (500rpm), the particle size does not change. is attributed to the increase in the number of The constancy of the rate constants is active sites. Control experiments were observed not because the process is performed and no product was detected even necessarily reaction rate limited but because after 2 hours of the reaction.