Process for the preparation of substituted cyclohexanes.

The invention concerns a procedure for the production of new a-Hydroxyalkyl-4-t-alkyl-eyclohexane (defined as down), the Sandelholznoten exhibits and than smelling materials to be used k6nnen.

Like many other well-known natural substances, which are fibre h6chst valuable smelling off particularly clinging verffigen, aueh the eastIndian Sandelholz61 the Zuf illigkeiten the natural substances ausges5 set. The Parffimeuren it places itself to a broad use of this material would act-see against that it only in beschr nktem measure and at high price course inglich ist.

It was missing nieht at attempts to replace to Sandelholz61 dutch synthetisehe substitutes. Although it admits is the fact that rzund flat steel bar-Santalol represent those components of the Sandelholz61s, which answer-borrowed ffir the gewfinschten Rieehstoffeigensehaften is, is so far zugiinglich in no commercially attractive procedure these two alcohols. Therefore it is logically that each substance, the fibre Sandelholz) leigenschaften verffigt and on a 6konomischen the way course is inglich, immediately the attention of the Paffiimeure, which are interested in Sandelholz61substituten, on sees will pull, invention in accordance with eats manufactured new a-Hydroxyalkyl-4-t-alkylcyclohexane points the formula:

R3 GH I where - alkyl radicals, R2 methyl or Athyl represent g 1 and RA c1 _3 and the sum total of the carbon atoms in g 1 does not iibersteigt + R2 + R3 6, auf.

617,648 the new connections I is received invention in accordance with ss by the fact that one a connection of the formulas R H R or or g 1 g 1 RI lla lib II C where g 1, R2 and R3 above meaning to possess, hydriert.

The new connections Iund the ben6tigten raw materials k6nnen from the appropriate t-Alkylbenzolen or 4-t-Alkylcyclohexanen on different ways, as this is graphically represented in the following, to be thus received. The Zwisehenprodukte aufgefiihrten in the Reaktionssehema is k iuflich or k6nnen according to actually well-known methods manufactured werden.

Friedel Crafts RI R j, K ondakov 'IE g 1 0 2 g 1 617,648 R3. , 0 - IIa I! - I--R2 RI RI Hydr.

-1--'R2 2 RI g 1 lib RI = c1 _z-Alkyl R2 = CH3 -, C2 Hs-- R3 = c1 _3 - alkyl R +R2 +R3 6C R4 = H, CH3 -, C2 HsMe = left, well, K in accordance with eat reaction way A can a t-Alkylbenzol after Friedel Crafts be alkanoyliert, whereby a reaction mixture will receive, which essentially consists of the 4-t-Alkylalkanoylbenzol IIa. This Keton can on that using a suitable catalyst to the gewiinschten alcohol I hydrogenated werden.

In accordance with eat reaction way B the 4-t-Alkylcyclohexanon with a suitable Acetylid, R4 - C=CMe [R4 = H, CHa, CzHs, ME = left, well or K] to the appropriate thynylalkohol one converts, which is iibergefiihrt on that dutch the well-known Rupeumlagerung (i.e. under the influence yon Ameisensiiure) into the appropriate Alkanoylcyclohexen Ilc. This 4-t-Alkyl-l-alkanoylcyclohexen can on that in a more einoder two-stage procedure for the gewfinschten alcohol I hydrogenated werden.

Gemiiss reaction way C is iibergefiihrt the 4-t-Alkylcyclohexanon into the 4-t-Alkylcyclohexen, by first one reduces and one dehydratisiert on that. The received Olefin can be iJbergefiihrt on that under Beniitzung of the well-known Kondakov reaction into a reaction mixture, the 4-t-A1kyl-l-alkanoylcyclohexan Ilc enthiilt; this Cyclohexen can as above erw ihnt into the gewiinschten alcohol I tibergefiihrt werden.

As ihnt above erw, the alcohols of the available invention on different ways are zugiinglich. Many thereby the ben6tigten I-Alkanoyl-4-t-alkylbenzole, I-Alkanoyl-4-t-alkylcyclohexene and 1-Alkanoyl-4-t-alkylcyclohexane, which find thereby as intermediate products use, are well-known or k6nnen according to actually well-known methods, for example as in the reaction pattern to be ausgefiihrt, represented. For example the 1-Acetyl-4-t-butylcyelohexen is yon M.S.

Newman et al., J. to. Chem. Soc. 82, 4098 (1960) described, and the 4-t-Butylacetophenon is finally from J.C.

Butler et al., J. to. Chem. Soc., 76, 1906 (I954) described worden.

Gemiiss method A is reduced the I-Alkanoyl-4-t-alkylbenzol vorzugswcise using a Rhodiumoder of ruthenium catalyst. These catalysts gewiihrleisten a minimum of Hydrogenolyse.

The conditions bezi, iglich catalyst, L6sungsmittel, reaction temperature, hydrogen printing and response time (although this Gr6ssen probably unabh ingig from each other is not) are regarded as nichtkritiseh. It is however preferential using a 5%-Rhodium-auf-Aluminium-Katalysator in quantities from 0,5 to 10 Gew,% of the assigned Ketons. The hydrogenation is durchgefiihrt zweckm issigerweise at temperatures between 25 and 60° C and with DriJcken between 30 and 300 psi (I psi = 0,068atm.).

The use of a L6sungsmittels is fakultativ. The hydrogenation can be durchgefiihrt demgemiiss with or without L6sungsmittel. As L6sungsmittel for example ethanol, Essigsiiure, pentane etc. come into consideration. The data bezi, iglich catalyst quantity, temperature range, pressure and Lfsungsmittel serve only for the illustration and are not as limitation the invention regarded werden.

Alternatively the hydrogenation of the Ketons can take place in two stages, whereby first the Carbonylgruppe is reduced to a group of alcohols. Kfnnen methods use find, which admits is (for example use of NaBH4, LiA1H4, normal catalytic reduction etc.), on that can hydrogenation of the resulting benzyle alcohol take place, whereby, as erw ihnt above, a rhodium catalyst use finden'kann.

In accordance with eat methods B and C of the reaction pattern can the 1-Alkanoyl-4-t-alkylcyclohexen to the new alcohol I using different methods, which flit the hydrogenation of A, flat steel bar-ungesiittigten Ketonen to alcohols admits is, be durchgefiihrt. It can find for example a two-stage procedure use, whereby first one of the two unges ittigten connections is hydrogenated. Preferentially however the 1-Alkanoyl-4-t-alkylcyclohexen is in a 1-Stufen-Verfahren into the gewiinsehten alcohol tiberzuftihren.

The conditions fiir the 1-Stufen-Verfahren catalyst, LiSsungsmittel, reaction temperature, hydrogen printing and response time seem beztiglich to be not critical (the parameters are probably from each other abhiingig nevertheless). There is a row yon catalysts well-known, with those A, flat steel bar-unges ittigte Ketone into gesiittigte alcohols to be iibergefiihrt k inside, it is this platinum, palladium, Raney nickel, rhodium, ruthenium usw.

Preferably using konomischen Raney nickel one works, since thereby the cis lsomere of the gewiinschten alcohol fibre-rapid-finalproves to the by far iiberwiegenden Tell, for example to 60 to 85%, anf illt. A separation of the 1 (A-Hydroxy ithyl) - 4-t-butylcyclohexans into cisund trans isomers showed n imlich that the so much erwiinschte Sandelholznote of this connection essentially zurfickzuffihren on the content of cis Isomerem in the connection is. With this Veffahren the conditions are not beziiglich temperature, L Ssungsmittel, pressure and catalyst quantity kritisch.

The catalyst in a quantity, which corresponds ungef their to 5 to 15% of the used Ketons, is preferred eingesetzt.

The preferential temperature range is from 80 to 120° C, and the preferential pressure range lies between 60 and 600 psi. L6sungsmittel can be used, which however not is compelling. If solehe L6sungsmittel is used, such are preferably used with low steam pressure. Again the indicated conditions are beziiglich temperature, Druek and catalyst quantity illustratively and are to be understood as not-limiting, because it was shown that also conditions, which lie far outside of the indicated ranges are used still k6nnen. How erw it ihnt in front must be held that the fact that using Raney nickel as catalyst the cis isomers of the reaction product in the 1] is present berschuss, when iiberraschend is iiberraschend regarded. In the case of use of the other hydrogenation methods results a niimlich fiblicherweise reaction mixture, which consists in equal parts out cisund of trans Isomerem. In the case of use yon Raney nickel betriigt the appropriate Verhiiltnis ungefiihr 2-3 to 1.

The new connections of the available invention k6nnen as smelling materials use find, for example in Parfums, soaps and other toilet articles. They are in particular, although not exclusive, as substitutes or partial substitutes fiir natfirliches Sandelholz 51 geeignet.

This fact is not usserst iiberraschend, since it concerns with the connections of the formula I, which is monocyclisch, connections, strukturm issig with the well-known aund flat steel bar-Santalol relationship aufweisen.

Furthermore it must be ihnt in this connection erw that the connections of the formula 1, where R3 = H do not exhibit, 617,648 Sandelholznoten and gernchsmiissig with the available new connections iiberhaupt in no way competes k6nnen.

Furthermore it was stated that all connections of the formula 1 exhibit the Sandelholznote. However the note at ausgepr the igtesten and most intensive is imlich in the low homologous ones of the series, n in the 1 (A-Hydroxy ithyl) - 4-t-butylcyclohexan; it takes off in the mass, as the molecular weight of the further connections of the formula 1 rises. This rise can come on Vergr6sserung of the hydroxyalkyl part or the t-alkyl group. Generally homologous, which exhibit more than carbon atoms, verfiigen (under standard conditions) groove still fibre one weak Sandelholzgeruch.<br iiusserst/> As ausgeftihrt already in front, is in case of the 1 (A-Hydroxy ithyl) - 4-t-butylcyclohexans the cis lsomere bevorzugt.

The new connections I k6nnen that in accordance with eat with Parfum61en, concentrates and others in the Paffiimerie used chemicals to be mixed, in order to lend to the developing formulations Sandelholznoten. The most important use is based on it, in mentioned formulations the natfirliche Sandelholz 51 totally or partly too ersetzen.

The following examples serve the invention for the illustration. They reflect preferential aspects of the invention and are in no way limiting laid out werden.

If differently does not note, the temperatures are indicated in ° C. The infrared gangs are indicated in em-i. The NMR spectra were taken up to Chloroform-d1, the signals in 6-Einheiten relative to TMS (O, O indicated), the molecular weights became mass spectroscopic ermittelt.

For analysis purposes became methods also by gas chromatography verwendet.

Example 1 l (ct-Hydroxyiithyl) - 4-t-butylcyclohexan from 1-Acetyl4-t-butylcyclohexen A. two-stage procedure a L6sung of 70 g (0.39 mol) 1-Acetyl-4-t-butylcyclohexen in 200 ml *thanol is hydrogenated using 0,5 g %igem palladium on charcoal in a Parrbombe with elnero pressure of 50 psi hydrogen printing. After absorption of the theoretical quantity (0.39 mol) hydrogen the reaction is distilled broken off, which filters reaction mixture, concentrated and under decreased pressure, whereby a mixture yon cisund trans-l-Acetyl-4-t-butylcyclohexan in the Verh iltnis about 1: ] anfiillt: 64.6 g (yield 91%), Sdp.

64 to 92° C (8 mmHg); Mg: 182 (ms); in accordance with eat NMR is no Vinylwasserstoff vorhanden.

A L6sung of 30 g (0.16 mol) of this 1: 1-Gemisehes of cisund trans-l-Acetyl-4-t-butylcyclohexan in 30 ml water-free ether is given to water-free ether drop by drop to a geriihrtem mixture yon 4 g lithium aluminum hydride in 200 ml. After addition the mixture under Rtickfluss is heated up, abgekiihlt 5 hours and shifted drop by drop with ges ittigter Ammoniumchloridl Ssung, until a clear itherische layer results. The mixture is washed on that, dried, concentrated and distilled filtered, with 10%iger sodium caustic solution and with water. It results a 1: 1-Gemisch yon cisund trans l (z-Hydroxyfithyl) - 4-tbutylcyelohexan: 25 g (yield 83.3%); Sdp. 75 to 85°C (2 mmHg); Mg: 184; NMR: no absorption between 2.0 to 2.2 (acetyl methyl H); 3330 (hydroxyl).

B. Classification procedure using Raney nickel and a L6sungsmittel a mixture yon 353 g (2.0 mol) 1-Acetyl-4-t-butylcyclohexen, 100 ml n-butanol nnd 35 g Raney nickel (activate by repeated washing with methanol) becomes! 00° C 617,648 with a hydrogen printing of 300 psi hydrogenates. The reaction is broken off, as soon as the absorption of hydrogen aufh6rt (taken up hydrogen quantity: 3.1 mol, 78% of the theoretical quantity). The catalyst is removed dureh filtration and replaced for through fresh catalyst. The reaction is fortgeffihrt, until also still the remaining 0.9 mole hydrogen is verbraueht. After filtration and removing the LiSsungsmittels a mixture of l (A-Hydroxyiithyl) results - to 4-t-butylcyclohexan, 77% ice lsomeres and 23% trans lsomeres.

C. classification procedures using Raney nickel without L6sungsmittel a mixture yon 200 g (1.11 mol) 1-Acetyl-4-t-butylcyclohexen and 20 g Raney nickel (dureh repeated washing with methanol activated) is hydrogenated with 100° C and a hydrogen printing yon 300 psi, until the absorption of hydrogen aufh6rt (2.2 mol hydrogen). Sew filtration results a raw product, which to 64% from that cis lsomeren and 36% from that trans lsomeren yon 1 (A-Hydroxyiithyl) - 4-t-butylcyclohexan exists. A pollution (l-Acetyl-4-t-butylcyclohexan) cannot determined werden.

Example 2 cis l (A-Hydroxy ithyl) - 4-t-butylcyclohexan and transl (A-Hydroxy ithyl) - 4-t-butylcyclohexan in accordance with eat example 1A manufactured mixture of cisund trans-l-Acetyl-4-t-butylcyclohexan by means of vacuum distillation into the individual components isolated, whereby a nest Faus Drehbandkolonne is benfitzt, the physikalisehen constants of the two lsomeren are the following:

eis-l-Acetyl-4-t-butyleyclohexan: Mg: 182 (ms); Sdp. 84 to 86°C (8 mmHg); 0,80 (9H, S, t-Butyl H), 2.12 (3H S, Aeetylmethyl H); IR 1710, 1365, 1355, 1175, 1140.

trans-l-Acetyl-4-t-butyleyclohexan: Mg: 182 (ms); Sdp.

92 to 93°C (8 mmHg); NMR 0.85 (9H, S, t-Butyl H), 2.10 (3 H, S, Aeetylmethyl H); IR 1710, 1365, 1250, 1168.

The ice lsomere becomes in a Lssung yon Natriumearbonat in w issrigem methanol a 90:10% - Gemiseh yon trans: eis-I-Aeetyl-4-t-hutylcyclohexan epimerisiert. The spectral data of this mixture are in wesentliehen those of the pure trans lsomeren.

Each of the two 1-Acetyl-4-t-butylcyelohexanisomeren is reduced now using lithium aluminum hydride to the entspreehenden alcohols (see aueh example 1A). The physikalisehen constants of the two lsomeren are the following:

hurrying (A-Hydroxyiithyl) - 4-t-butylcyelohexan: Mg: 184 (ms); Sdp. 75 to 77°C (2 mmHg); NMR 0.85 (9H, S, t-Butyl H); 1,0 to 1.8 (13H, M, methyl D at 1,22, J = 6 cycles per second), 3.93 (1H, M, ha to OH); IR 3330, 1365, 1240, 1235, 1065, 935, 880.

trans1 - (A-Hydro×y ithyl) - 4-t-butyleyclohexan: Mg: 184 (ms); Sdp. 80 to 85° C (2 mmHg); NMR 0.85 (9H, S, t-Butyl H), 1.0 to 1.8 (13H, M, with methyl D at 1,16, J = 6.5 cycles per second), 3.53 (l H, M, ha to OH); IR 3340, 1365, 1235, 1150, 1068, 950, 930, 900, 880.

The erwiinschte Sandelholznote of the 1 (A-Hydroxy ithyl) - 4-t-butyleyelohexans is iehlich head the content of cis lsomerem zuzusehreiben.

Example 3 cisund trans1 (x-Hydroxyiithyl) - 4-t-butylcyclohexan from 4-t-Butylacetophenon a mixture of 17,6 g (0.10 mol) 4-t-Butylacetophenon, 1.3 g 5 CAigem rhodium on alumina, few drops E.ssigsiiure and 10 ml absolute methanol is hydrogenated in a Parrbombe with a hydrogen printing of 50 psi at room temperature. The reaction broke, sew-sewing that the absorption of hydrogen off aufgehiSrt. In accordance with eat analysis by gas chromatography consists the reaction product u 8% of l-Acetyl-4-t-butylcyclohexan; the catalyst is enffernt by means of filtration and the above Procedere is repeated, until again AufhiSren of the absorption of hydrogen is determined. The Gemiseh is filtered, concentrated under decreased Drunk and to a 1: 1-Gemisch cisund of the trans-1 (A-Hydroxy ithyl) - 4-t-butylcyclohexans distills, yield 91% (16.8 g). The spectral data are descriptive the same, as them under example 1 sind.

Above result is also received, if as L6sungsmittel of vinegar iure, ethanol or pentane is used or if as catalyst 5% rhodium on activated charcoal or if with 60° Coder with 30 psi pressure hydrogenates wird.

Furthermore the same result is received, if 1 (A-Hydroxyiithyl) - 4-t-butylbenzol in place of yon 4-t-Butylacetophenon hydrogenates wird.

In order small quantities of 1-Aeetyl-4-t-butylcyclohexan from 0, a vacuum distillation can be taken to the primiiren reaction mixture to enffernen to assistance. This Procedere arranged see more einfaeher than a repetitive Hydrierung.

BeispieI 4 cisund trans l (1-Hydro×ypropyl) - 4-t-butylcyclohexan to a mixture yon 24 g (1.0 mol) Magnesiumsp inen and 100 ml water-free) kthy] more iither are given 109 g (1.0 mol) to bromine ithan. The resuItierende mixture is held 2 hours with Rfickflusstemperatur. It follows now addition so from 109 g (0.9 mol) 1-Formyl-4-t-butylcyclohexan, drop by drop within I hour. After finished Mugabe the mixture is held, abgekiihlt 4 hours under Riiekfluss, given on that to 100 ml a mixture yon ges ittigter Ammoniumchloridl 5sung and ice. The mixture is extracted with Ather a5 (3 × 100 ml) and the excerpt is washed, dried, concentrated and distilled with water. It results a 1: 1Gemisch yon cisund trans l (1-HydroxypropyI) - 4-t-butylcyclohexan: 116 g (yield 66%); Sdp. 89 to 95° C (1 mmHg); Mg: 198 (ms); NMR 0.85 (12H, S, methyl H), 3.1 to 3.9 (1H, broadly H) ct; IR 3350, 1364, 970.

Example cisand trans l (A-Hydroxy ithyl) - 4-t-amylcyclohexan A. 1-Acetyl-4-t-amylcyelohexen to a geriihrten mixture of 46 g Lithiumacetylid in 200 ml benzene are given to 4t-Amyleyclohexanon within 3 hours of 84.0 g (0.5 mol). After finished Mugabe rtihrt one the mixture 1 hour further, adds on that to 500 ml water drop by drop and hilt the reaction mixture 1 hour with Riickflusstemperatur. One kiihlt off, separates the layers and extracts the w issrige layer with more lather. The combined organic phases are dried, filtered washed with water, fibre magnesium sulfate and restricted under decreased pressure. A distillation of the remaining {) Is fiihrt too cisund trans-4-t-Amyl-1-iithynylcyclohexanol: 49.8 g (51% yield), Sdp. 103 to 104°C (0.5 to 1.0 mmHg); NMR 2.48 (1 H, S, 3, thynyl H), 0.78 (9H, methyl H); IR 3380, 3300, 1064 cm-1.

A LiSsung of 24,0 g (0.12 mol) cisund trans-4-tAmyl-lithynylcyclohexanol and 75 ml 90%iger Ameisens iure is held 2 hours with Rfickflusstemperatur. The L6sung is abgekiihlt, admitted drop by drop to 10% ige caustic soda solution in the upper shot and extracted on that the mixture with Ether. The itherische Lssung is washed with water, filtered fibre magnesium sulfate getroeknet and restricted under reduced pressure. Dureh distillation of to-tick-lasting Ols one wins 1-Acetyl-4-t-amylcyclohexen: 13.2 g (yield 55%); Sdp. 63 to 64°C (0.1 mmHg); Mg: 194 (ms); NMR 6.93 (I H, broadly, Vinyl H), 2.25 (3H, S, acetyl methyl), 0.82 (9H, methyl H); 1R 1662, 1639, 1385, 1248, 1068, 964, 907 cm B. cisund trans l (A-Hydroxyathyl) - 4-t-amylcyclohexan s in accordance with eat procedures of the example 1A becomes from 1-Acetyl-4t-amylcyclohexen a mixture yon cisund trans l (A-Hydroxy ithyl) - 4-t-amylcyclohexan won. The yield betr igt %. This concerns a mixture cisund trans lsomeren in the Verh iltnis 1: 1; Sdp. 89 to 94°C (1 mmHg); Mg: lo 198 (ms); NMR 1.20 (0,5H, D, J = 6 cycles per second, methyl A to OH in cis isomers), 1.15 (0,5H, D, J = 6.5 cycles per second, methyl A to OH in trans isomers), 0.77 (9H, sharply, methyl H); IR 3360, 1455, 1070, 935 cm-1.

Example 6 use yon cisund trans l (A-Hydroxy ithyl) - 4-tbutylcyclohexan in Sandelholzkompositionen Cisund trans l (A-Hydroxy ithyl) - 4-t-butylcyclohexan (connection A) Sandelholzkompositionen can assigned werden.

with Effolg as effective component yon Parts by weight connection A 200 Sandela (Polycycli alcohol product with Sandelholznote) 700 Amyris61 Amerikan. Zedemholz61 10000 by addition of the connection A to above formulation one erhfilt a Composition with a soft, butterigen Sandelholznote, as she can be observed in natiirlichem SandelholzS1. Due to this excellent characteristic the connection A knows Sandelholznoten on purely synthetic basis with success use with the production yon finden.

The above and iihnlichen formulations can do the connection A in concentrations yon about 10 to 60 Gew, % added werden.

Example 7 use of hSherer similar ones in Sandelholzkompositionen the above effect knows also by use yon cisund trans l (1-Hydroxypropyl) - 4-t-butylcyclohexan, cisund trans i (1-Hydroxy-2-methylprop-l-yl) - 4-t-butylcyclohexan and cisund trans l (1-Hydroxy ithyl) - 4-t-amylcyclohexan in the type of formulation of the example 6 to be obtained. However the effect is more cher schw than with the connection A of the example 6 erreichte.

Benzylpropionat Bergamotte (natiirl.) Methylphenylcarbinylacetat Linalool, C ur Ylang bourbon specially; , - Methylionon jasmine (synthetic) to ethyl flat steel bar (p-tert. - butylphenyl) - per pion aldehyde p-tert. - Butylcyclohexylacetat Vetiverylacetat 3,7-Dimethyl-7-octenol 1,1,4,4-Tetramethyl-6-iithyl-7-acetyl1,2,3,4-tetrahydronaphthalin Undecalacton, 10% in Dipropylenglykol 617,648 22 14 14 100 97 97 56 56 1000 in the above formulation is obtained by addition by approximately to 30% the connection A a erwtinschter rounding effect; the smell of the composition becomes enriches and more softly, it corresponds to the Sandelholz51 natiirlichem by the addition yon reached. Fiir special effects knows the Ver2s connection A gewiinschtenfalls also used in hSherer quantity werden.

Example 8 use of cisund trans-1 (A-Hydroxy thyl) - 4-tbutylcyclohexan (connection A) in a holzig blumigen composition of the SandelholzSleffekt of the connection A can be obtained also in ss the following holzig blumigen composition:

Parts by weight 300 21 connection A Amylzimtaldehyd aldehyde C-12 (Lauryl), in % Dipropylenglykol example 9 use of the connection A in holzigen compositions of parts by weight connection A 280 orange ones liquid (A-Methylnaphthylketon) Limonen 38 Linalool 66 Linalylacetat 95 benzyle acetate 7-Methylionon 152 p-test-Butylcyclohexylacetat 114 Vetiverylacetat 115 Coumarin 1,1,4,4-Tetramethyl-6-iithyl-7-acetyl1,2,3,4-tetrahydron aphth alin aldehyde C-12, 10% in Dipropylenglykol 4 Undecalacton, 10% in Dipropylenglykol 6 Diphenyloxid Diphenylmethan IOOO the smell effect obtained with the connection A, that corresponds to that by addition yon Sandelholz61 to be reached k6nnte: besides to the composition K6rper is lent, which becomes and enriches a holzige character more fully, and becomes a erwtinschter rounding effect erzielt.

) hnliche effects k6nnen also by means of concentrations yon less than 28% to be reached, for example with only 14%. Ffir special purposes to obtain i.e. around special effects can be proportioned the connection A in addition, still more hSher (than 28%).