VALUABLE PERFUMERY MATERIAL: SIMPLE PROCESS OF PREPARATION OF METHYL ISOEUGENOL USING CHEAP CATALYST RATHER THAN EXPENSIVE Ru(acac)3

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Clove Essential OilMain Components• Eugenol• Caryophyllene

Minor Components20 chemicals incl• Isoeugenol• Methyl eugenol• Methyl isoeugenol

Price of Eugenol & Caryophyllene & Derivatives

Vigon International, East Stroudberg, PA, USANo Compound Price

1kg5kg 10kg 50kg 200kg

1 Minyak cengkeh (Clove leaf oil)

2 Eugenol $117 $52 $38 $36 $323 Isoeugenol $170 $80 $60 $56 $504 Eugenyl acetate $185 $95 $75 $71 $655 Isoeugenyl acetate $184 $94 $74 $70$6 Methyl eugenol $150 $85 $72 $69 $657 Methyl isoeugenol $190 $100 $80 $76 $708 Benzyl eugenol $611 $521 $5019 Dihydroeugenol $147 $82 $68 $66 $6210 Caryophyllene11 Caryophyllene oxide12 Caryophyllene acetate $147 $82 $68 $66 $6213 Caryophyllene formate

Price:

• Clove Leaf Oil is the raw material used for synthesis of the above compounds U$12 – U$15/Kg (Indonesian companies such as Indesso Aroma, Djasula Wangi, Nusaroma)

Catalysts reported in literature used for Preparation of Isoeugenol/Methyl Isoeugenol:

• Ru 3(CO)12 U$168.99/g• Ru (acac)3 U$121.98/g• RhCl3 U$357.03 /g

Structure:

• Eugenol• Methyl Eugenol• Isoeugenol• Methyl Isoeugenol

Eugenol

OH

OCH3

CH2CH=CH2

Methyl Eugenol OCH3

OCH3

CH2CH=CH2

Isoeugenol

OH

OCH3

CH=CHCH2

Methyl Isoeugenol

OCH3

OCH3

CH=CHCH2

Existing Methods for Preparation of Isoeugenol /Methyl Isoeugenol from

Eugenol/Methyl Eugenol

1. Base catalyzed isomerisation.(1,2)

KOH + Eugenol/methyl eugenol is reacted at high T&P to produce isoeugenol/methyl isoeugenol plus tarry side products.

Disadvantage : -KOH ~ 2 x weight of eugenols -The mixture is viscous - Tarry side products 7%

2.Transition metal compounds catalyzed process.(3,4)

US Patent 4,138,411 : Ru compound used as catalyst 0,01%-0,1% weight of eugenol/methyl eugenol

Disadvantage : Price Ru compound U$168.99/g Tarry side product min 7%

.GB patent 1,489,451 : RhCl3 as catalyst 0.01%-0,1% weight of eugenol/methyl- eugenol

Disadvantage : Price RhCl3 = U$357.03 /g 7% Tarry side products

Multi national Companies that produce these aromatic chemicals are : Firmenich SA International Flavor & Fragrance Givaudan Rhone-Poulenck SA

3. Metal hydrotalcite isomerisation (5,7)

The conversion to isoeugenol/methyl isoeugenol is not industrially feasible at 70%

4. Base catalyzed isomerisation using microwave heating(6)

The conversion is about 98% with shorter reaction time but the amount of base used is very high, 2.2 x weight of eugenols.Therefore combined with expensive equipment,this method is non-feasible for industry.

Scope of the work :

The work relates to a cheap method to produce methyl isoeugenol using a different catalyst which cost less than 1 % of the method that is being used by the industry with the new method produces no any waste tarry side product.

Catalyst:• Ru 3(CO)12 U$168.99/g• Ru (acac)3 U$121.98/g• RhCl3 U$357.03/g• New Catalyst U$4.10/kg

Procedure:

100 g methyl eugenol and 0.1 g new catalyst are placed in a 2 liter spherical flask equipped with a thermometer, stirrer system and a reflux condenser with the contents are then heated to reflux for 5 hours. The reaction mixture is then distilled and analysed using gas liquid chromatography.

THE NEW CATALYST VS THE PRESENTLY USED METHOD IN INDUSTRY

no New catalyst

Ru(acac)3catalyst

TIME(hours)

TEMP( ° C )

%Unreacted Eugenol

Tarry product( % )

Information

1 - 0.01% 7 160 0.8 7 The expensive catalyst lose some of its catalytic power after the reaction as it is embedded in the tarry side product and therefore some must be added for new reaction

2 1% - 5 144 - 145 0.6 0 After the distillation of the product, the catalyst can be reused.Purity as checked using GC consists of trans product of 97.9% and cis product of 1.76%

References

1. A.J. Hubert and H. Reimlinger, Synthesis 97, 1969

2. G. V. Salmoria, E. C. Dall’Oglio and Z.Zucco, Synth. Commun., 27, 4335, 1997

3. L. Givaudan, GB Patent 1 489 451

4. P. Gandilhon, US Patent 4 138 411

5. D. Kishore and S. Kannan, Appl. Catalysis A, 270, 2004

6. L. N. Thach and C. R. Strauss, J. Chem., 38, 76, 2000

7. G.M. Jinesh, C.A. Antonyraj and S.Kannan, Catalysis Today, 141, 176,2009