Author Topic: P-MeO-phenol from hydroquinone: part II  (Read 16639 times)

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PolytheneSam

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Here's some more
« Reply #40 on: June 06, 2002, 01:38:00 AM »
PUB-NO:  DE003207937C1
DOCUMENT-IDENTIFIER:  DE 3207937 C1
TITLE:  Process for the preparation of 4-alkoxyphenols

PUBN-DATE: May 19, 1983

ASSIGNEE-INFORMATION:

APPL-NO:  DE03207937
APPL-DATE: March 5, 1982

PRIORITY-DATA: DE03207937A (March 5, 1982)
INT-CL_(IPC): C07C041/09
EUR-CL (EPC): C07C041/09
US-CL-CURRENT: 568/650

ABSTRACT:
A novel process for the preparation of 4-alkoxyphenols by reacting hydroquinone with an alcohol at increased temperatures in the presence of catalytic amounts of benzoquinone  and an acid is characterised in that perchloric acid is used as the acid.  This process gives 4-alkoxyphenols in high yields.  4-Alkoxyphenols are valuable intermediates, for example for the preparation of 4-alkoxyphenyl
carboxylates, which are used as liquid-crystalline compounds.

Patent DE3207937



********************************

PUB-NO:  EP000039484A1
DOCUMENT-IDENTIFIER:  EP 39484 A1
TITLE:  Process for the production of monoethers of hydroquinone  and quinol ketales as intermediates thereof.

PUBN-DATE: November 11, 1981

INVENTOR-INFORMATION:
NAME                                         COUNTRY
KELLER, REINHOLD DR                          N/A
KONZ, ELMAR DR                               N/A

ASSIGNEE-INFORMATION:
NAME                                         COUNTRY
HOECHST AG                                   DE

APPL-NO:  EP81103259
APPL-DATE: April 30, 1981

PRIORITY-DATA: DE03017393A (May 7, 1980)
INT-CL_(IPC): C07C043/23; C07C043/295 ; C07C041/18 ; C07C043/315
EUR-CL (EPC): C07C043/23; C07C043/305, C07C043/315 , C07C045/51 , C07C049/753
, C07D317/64
US-CL-CURRENT: 568/650,568/652

ABSTRACT:
Monoethers of hydroquinone  are prepared by reduction of monoketals of
p-benzoquinone,  preferably using complex hydrides of boron or aluminium, with a sulphite or molecular hydrogen in the presence of a nickel catalyst until one mole of H2/mole of p-benzoquinone  monoketal is absorbed in an inert solvent to give the corresponding quinol ketals and treatment of these with an acid.  The quinol ketals formed as intermediates here are novel compounds.

The monoethers of hydroquinone  are precursors, intermediates and final products in various subject areas.

Patent EP39484





http://www.geocities.com/dritte123/PSPF.html
The hardest thing to explain is the obvious

PolytheneSam

  • Guest
I wonder how allyl alcohol would work in a ...
« Reply #41 on: June 06, 2002, 04:01:00 AM »
I wonder how allyl alcohol would work in a reaction like this.  You probably have to use something other than H2SO4 as the dehydrating agent.  Do a Claisen rearrangement on the  hydroquinone monoallyl ether to get 2,5-dihydroxy allylbenzene, methylate it to get 2,5-dimethoxy allylbenzene and go from there.

http://www.geocities.com/dritte123/PSPF.html
The hardest thing to explain is the obvious

Rhodium

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Which phenols can be steam distilled?
« Reply #42 on: December 30, 2003, 11:03:00 PM »
Study of the steam distillation of phenolic compounds using ultraviolet spectrometry
Norwitz, George; Nataro, Nicole; Keliher, Peter N.

Anal. Chem., 58(3), 639-41 (1986)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/steam.distillation.phenolics.pdf)

Abstract
The steam distn. of 42 phenolic compds. was studied using a semimicro steam-distn. app. and UV spectrometry. In the distn., the following gave >95% recoveries: PhOH, 2-RC6H4OH (R = O2N, MeO, Br, Cl), 2,3- and 2,4-Cl2C6H3OH, 2,4,5- and 2,4,6-Cl3C6H2OH, 2,4-Br2C6H3OH, 2-, 3- and 4-cresol, 4,2-Cl(Me)C6H3OH, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-xylenol, 4-RCMe2C6H4OH (R = Me, Et), thymol and carvacrol. The percent recovery for the other phenolic compds. was as follows: 3-O2NC6H4OH, 3.7%; 4-O2NC6H4OH, 1.8%; 3-MeOC6H4OH, 31.1; 4-MeOC6H4OH, 23.2; 3-BrC6H4OH, 79.6; 4-BrC6H4OH, 67.8; 3-ClC6H4OH, 93.5; 4-ClC6H4OH, 91.6; 3,4-Cl2C6H3OH, 64.1; 2,4-(O2N)2C6H3OH, 21.2; picric acid, 0.0; 2-H2NC6H4OH, 0.1; 3-H2NC6H4OH, 0.2; 4-H2NC6H4OH, 0.1; pyrocatechol, 1.6; resorcinol, 0.4; hydroquinone (I), 0.0; pyrogallol, 0.7; and phloroglucinol, 0.1. Examg. the spectra of the undistd., distd. and residual solns. showed that the aminophenols undergo some decompn., and that I is almost completely destroyed during the distn. The important role that H bonding (intermol. and intramol.) plays in the recovery from steam distn. is examd.


armageddon

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sorry
« Reply #43 on: July 08, 2004, 10:33:00 PM »