DE1176123B - Process for the production of carbamic acid esters of ª ‡ -glycerine ethers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Cl .: C 07 c;

C07d

German KL: 12 ο -17/01

Number: 1176 123

File number: R 21801IV b / 12 ο

Filing date: September 3, 1957

Opening day: August 20, 1964

The invention relates to a process for the preparation of carbamic acid esters of% glycerol ethers general formula

RO CH ₂ -CHOH CH ₂ -O-CO NH ₂ in which R represents an optionally monosubstituted phenyl group, an optionally substituted cycloalkyl group or a heterocyclic group. Such carbamic acid esters of glycerol ethers are used as plasticizers for plastics and as intermediates in the synthesis of plastics, but also as intermediates in the manufacture of pharmaceuticals, e.g. B. So-tolyloxy ^ -oxypropyl carbamate (U.S. Patent 2,609,386) and related S-aryloxy ^ -oxypropyl carbamates such as 3-alkoxyphenoxy-2-oxy-propyl carbamate (British Patent 789,283 and Swiss Patent 334848) are useful.

It has already been proposed, such carbamic acid ester by treating a substituted Glycerin of the formula

R - O - CH ₂ - CHOH - CH ₂ OH

with 1 mole of phosgene to form a compound of the general formula

R - O - CH ₂ - CHOH - CH ₂ - O - CO - Cl

to obtain, the latter being converted into the monocarbamic acid ester on treatment with ammonia became.

Another method consists in treating a substituted glycerol with phosgene under conditions which form a cyclic carbonate of the general formula

R - O - CH ₂ - CH - CH ₂ - O - CO - O

lead, in which case the carbonate is reacted with liquid ammonia under pressure and Monocarbamic acid esters obtained with approximately 50% overall yield based on the glyceral alcohol will. The phosgene used must, however, because of its highly corrosive effect and because of it Toxicity must be handled with extreme care. For the production of carbamic acid esters of the formula

R - O - CH ₂ - CHOH - CH ₂ - O - CO - NH ₂ would recommend a known process according to which cyclic carbonates are produced from glycols by transesterification with diethyl carbonate, which are then converted into carbamic acid esters by treatment with ammonia can. Process for the preparation of carbamic acid esters of α-glycerol ethers

Applicant:

A. H. Robins Company, Inc., Richmond, Va.

(V. St. A.)

Representative:

Dr. G. W. Lotterhos

and Dr.-Ing. H. W. Lotterhos, patent attorneys,

Frankfurt / M., Annastr. 19th

Named as inventor:

Manuel Mannheim Baizer, Union, N. J.

(V.St. A.)

Claimed priority:

V. St. v. America January 22, 1957 (635 091)

In such a procedure, the cyclic carbonate with ammonia would become the desired one primary carbamic acid esters of the formula

R - O - CH ₂ - CHOH - CH ₂ - O - CO - NH ₂

arise, however considerable amounts of the undesired secondary carbamic acid ester would be produced the formula

R —O —CH, -CH;

CH ₉ OH

O - CO - NH ₂

form, so that finally a difficult to work up mixture of desired primary carbamic acid ester and undesired secondary carbamic acid ester is present. However, such a procedure would still have the disadvantage that after separation of the primary carbamic acid ester from the secondary carbamic acid ester from the secondary carbamic acid ester, only the glycerol ether can be recovered by saponification of this carbamic acid ester, and the diethyl carbonate used for the formation of the secondary carbamic acid ester would be lost. A process for the preparation of carbamic acid esters of glycerol of the general formula R - O - CH ₂ - CHOH - CH ₂ - O - CO - NH _{2 was} found, after which mainly only the desired one

409 657/475

3 4

primary carbamic acid ester is obtained and not The nature of the substituent R in the carbamic acid

converted starting materials again recovered esters of glycerol of the general formula

can be. The method according to the invention is “ _unu

characterized in that a glycerol ether of the K - U - CH ₂ -CHÜH - CH ₂ -ü - CO - NH ₂ formula 5 is not of particular importance for the

β Q cpj CHOH CH OH carrying out the method according to the invention,

^{2 2} and this substituent is only intended to meet the condition in which R has the above meaning, with diethyl, not to participate in the transesterification and carbonate in the presence of an amount of a water which is sufficient for the catalytic effect also not to be lytic with the transesterification catalysts react. The substituent R denotes a given free, non-volatile, basic transesterification catalyst if monosubstituted phenyl group, e.g. B. a sators is heated until essentially alkyl, alkoxy, halogen or nitrophenyl group by transesterification, an ester of the formula lent an optionally substituted cycloalkyl group

τ? π γη γηπη γη π rn er u ^{or a} heterocyclic group, ζ. B. a pyridyl - ^K ~ ^υ - <~ « ₂ - CHUH - CH 2 - U - CU - UC ₂ H _{5 15 or a thienyl radical}

next to little cyclic! Carbonate of the formula the substituents R only have a single ring system

R η γη_γη_γη_π rn - n pointing groups preferred, as for such groups

κ u cn ₂ ci-i Cn ₂ u cu u containing carbamic acid esters of glycerol already

Possible uses are given.

was formed that the transesterification thereupon by 20 As transesterification catalysts can also be used in the Addition of acidic reacting, those for the transesterification framework of the process according to the invention catalyst-destroying compounds, such as. B. transesterification reactions known catalysts ver ammonium chloride or diluted acids. As such catalysts are metal will, that the ester mixture obtained in this way alcoholates, in particular alcoholates of potassium, with ammonia to the mixture of the carbamic acid esters 25 sodium, aluminum, lithium, suitable, wherein is implemented and that, if appropriate, the alcoholates obtained can be used that essentially the primary carbamic acid ester by heating metals, for example from in addition to a little of the secondary carbamic acid ester, potassium, sodium, aluminum, lithium, in heated Form the reaction mixture contained by crystallization from glycerine.

a solvent is separated. In the context of this 30 According to the invention, advantageously un-

The method according to the invention is about 1 mole of glycerol ether with about 3 moles from the fact

Benefited from the fact that the primary alcohol group of the diethyl carbonate was implemented. With such an over-

Glycerin ethers of the formula shot at diethyl carbonate, based on glycerin

D r \ ru rnnu ru nu ^äther ' ^the transesterification takes place very quickly. It can

^K - ^υ ~~ ^CH 2 - «-HUH - CH ₂ UH _{35 but also with about only} ι Moi diethyl carbonate

Reacts faster with the diethyl carbonate than that worked per mole of glycerol ether and already secondary alcohol group of this glycerol ether, with an excess of only 2 moles of diethyl carbonate, is given by the possibility of the transesterification based on glycerol ether, with practical use abort at a point in time at which results are expected in the Reactable. Even with one essentially only the desired excess of more than 3 mol of diethyl carbonate per mix formed primary carbamic acid esters. After the mole of glycerol ether, the termination according to the invention runs the transesterification can get out of the reaction process without any problems, only a larger overmixture brings about the unreacted diethyl carbonate excess diethyl carbonate again disadvantages in the together with the work-up of the reaction mixture that became free during the transesterification, there Ethyl alcohol is distilled off and recovered. 45 a large excess of diethyl carbonate distilled off The reaction mixture does not have to be converted.

Glycerine ether of the formula If the transesterification is carried out with heating of the

action mixture is made, so the

K u CH ₂ Chuh CH ₂ UH _{from the} R _ea ktionsgemisch evaporating liquid can easily back from the reaction mixture 50 possibilities are fractionated so that the are in the other pleasures after the primary carbonate transesterification formed and the transesterification reaction of formula decline influencing ethyl alcohol from the

RO PH ΓΗΠΗ ΓΗ π cn new reaction mixture can be removed. KU-CH ₂ -CHUh-CH ₂ -U-CU-UC ₂ H ₅ The carbonic acid formed during the transesterification

with ammonia to the primary carbamic acid ester 55 ester can with aqueous ammonia or with in the formula one against ammonia and the reaction

R η γη γηπη γη η rn μη mixed inert solvent, preferably ethyl- ^K ~ ^υ - ^CHa - <~ ^HUH -CH ₂ -U-CU-NH _{2 alcohol] j} isopropyl alcohol, benzene or toluene, was reacted. The thus recovered released anhydrous ammonia to the desired starting materials can be converted to the production of further primary carbamic acid esters, using secondary carbamic acid esters, so the reaction, expediently with stirring, so that the process according to the invention is carried out based on room temperature. If aqueous ammonia was used for both starting materials used, an almost quantitative transesterification of the primary carbonic acid ester with tative yield of the desired primary carbamine-ammonia, acidic ester can still be made possible within the scope of a 65 after dehydration of the reaction mixture of the crude charge when carrying out batchwise the Ver - Primary carbamic acid esters of glycerol from a driving only with yields in the order of magnitude of solvents, such as. B. benzene, toluene, isopropyl-25% is to be expected. alcohol or ethyl acetate.

When using anhydrous ammonia dissolved in isopropyl alcohol to convert the primary Carbonic acid ester is converted into the desired primary carbamic acid ester after the reaction has ended the excess ammonia is driven off by boiling the reaction mixture, the reaction mixture is decolorized with charcoal, filtered and then cooled, whereupon the crude primary carbamic acid ester of glycerol crystallizes out immediately from the mixture. The primary carbamic acid ester of glycerol can be purified further by recrystallization be made.

The method according to the invention is explained in more detail below using an exemplary embodiment.

example

0.7 g of sodium methylate were added to 49.5 g of molten 3- (o-methoxyphenoxy) -l, 2-propanediol and then 32.5 g of diethyl carbonate. The mixture was heated to reflux for approximately 30 minutes after which time 0.75 g of ammonium chloride was added. The mixture was then cooled to room temperature and stirred for 16 hours with a solution of 8.5 g of ammonia in 160 cm ^{3 of} isopropyl alcohol. Then the mixture was cleaned while hot over charcoal and filtered. The cooled filtrate gave 19 g of the crude product and, after recrystallization, 16 g of the pure 3- (o-methoxyphenoxy) -2-oxy-propyl carbamate with a melting point of 93 to 95 ° C.

Claims (3)

Patent claims: 1. Process for the preparation of carbamic acid esters of a-glycerine ethers of the general formula RO CH ₂ CHOH CH ₂ O CO NH ₂ in which R is an optionally monosubstituted phenyl group, an optionally substituted one Represents a cycloalkyl group or a heterocyclic group, characterized in that a glycerin ether of the formula R - O - CH ₂ - CHOH - CH ₂ OH with diethyl carbonate in the presence of an amount sufficient only for the catalytic effect an anhydrous, non-volatile, basic transesterification catalyst is heated until transesterification essentially an ester of the formula RO CH ₂ CHOH CH ₂ O CO OC ₂ H _{5 in} addition to a little cyclic carbonate of the formula R - O - CH ₂ - CH - CH, - O - CO - O was formed that the transesterification then by adding acidic reacting, the transesterification catalyst destructive compounds, such as B. ammonium chloride or dilute acids canceled is that the ester mixture obtained in this way with ammonia to the mixture of Carbamic acid ester is reacted and that optionally the obtained, essentially the primary carbamic acid ester in addition to a little of the secondary carbamic acid ester containing reaction mixture is separated by crystallization from a solvent. 2. The method according to claim 1, characterized in that about 3 moles of diethyl carbonate per Moles of glycerol ether are used. 3. The method according to claim 1 or 2, characterized in that the glycerol ether is 3- (o-methoxy-phenoxy) -l, 2-propanediol or 3- (o-tolyloxy) -1,2-propanediol is used. Considered publications:
U.S. Patent No. 2,627,524;
British Patent No. 689,705;
Comptes rendus hebd., 238, pp. 108, 109 (1954). 409 657/475 8.64 © Bundesdruckerei Berlin