Patent GB-772243-A (GB)
Title: Novel industrial products derived from the mono urethanes of glycols and processes for the manufacture thereof
IPC: C07C271/06
Filed: 1951-12-31
Abstract: The invention comprises products obtained by treating monourethanes of glycols with an aldehyde.  The nature of the products varies with the conditions of reaction and the relative proportions of aldehyde and urethane employed (see Group IV (b)). When the treatment is carried out at elevated temperature using one mol. of aldehyde per mol. of the urethane, condensation occurs with elimination of water and formation of polymeric products the degree of polymerization depending on the operating conditions, speed of dehydration and catalyst employed (if any). When a non-substituted urethane and an aldehyde RCHO is employed the products are of the type <FORM:0772243/IV(a)/1> wherein n is O or an integer.  These products are capable of again fixing aldehyde groups with elimination of water so that it is possible to condense up to 3 mol. of aldehyde upon 2 mol. of unsubstituted urethane.  When the urethane is mono-substituted on the nitrogen atom, i.e. is of the type NHR1COOR3OH, the polymeric products are of the type <FORM:0772243/IV(a)/2> wherein n is an integer.  R and R1 in the above formul  are monovalent alkyl, arylalkyl, aryl, or alicyclic hydrocarbon radicals (R may also be a hydrogen atom), and R3 represents an alkylene radical.  The dimer from the condensation of formaldehyde with the unsubstituted urethane of glycol is soluble in the cold in water and alcohol, the trimer is soluble in water but insoluble in alcohol, whilst the more highly polymerized products are hard resins insoluble in all the usual solvents.  If acetaldehyde is used instead of formaldehyde the products are not hard resins but coloured viscous materials.  The urethanes of propylene glycol react much more readily with formaldehyde than do those of ethylene glycol and when a catalyst is present the product is a solid insoluble resin but by operating without a catalyst a soft and relatively soluble product may be obtained. In examples: (1) a 1 : 1 molar mixture of the N-ethyl urethane of glycol and formaldehyde (in the form of trioxymethylene) is heated in a benzene medium in the presence of a small amount of maleic acid as catalyst with removal of water by azeotropic distillation to form a yellow product having a molecular weight corresponding to a value of n equal to 4 in formula II above. After further heating of the product under vacuum at 90 DEG  C. for several hours the molecular weight increases to a value corresponding to a value of n equal to 7; (2) as in (1) except that the N-benzyl urethane of glycol is used, the product being a sticky viscous resin; (3) as in (1) except that the monourethane of propylene glycol is used, formic acid is used as catalyst, and a slight excess of formaldehyde (in the form of trioxymethylene) is employed.  The benzenic layer yields a residue which after heating under vacuum to a constant weight forms a white resin insoluble in the usual solvents except for a slight solubility in tetrachlorethane; (4) as in (3) except that the catalyst is omitted, the product in this case being a tetramer which is slightly soluble in water or alcohol and insoluble in benzene, nitrobenzene, and dibromethane. Mixed condensations may also be carried out by using mixtures of substituted and unsubstituted urethanes, e.g. by treating a mixture of the unsubstituted urethane and the N-ethylurethane of glycol with formaldehyde in the proportion of 1.5 mol. of formaldehyde to one of the unsubstituted urethane and 1 mol. of formaldehyde to one of the ethylurethane improved resins are obtained.ALSO:The invention comprises the products obtained by reacting mono-urethanes of glycols with an aldehyde.  The nature of the products varies with the conditions of reaction and the relative proportions of aldehyde and urethane employed and the treatment may be carried out with or without the aid of heat and in an aqueous or anhydrous medium.  When the treatment is carried out at or below room temperature condensation occurs generally without elimination of water but when operating at elevated temperature elimination of water occurs to form alkylene diurethanes or acetals or polymeric compounds which may be resinous (see Group IV (a)).  The treatment is generally effected in the presence of a small amount of a mineral acid or organic acid as catalyst but when the reaction is very vigorous the catalyst may be dispensed with.  When one mol. of aldehyde (RCHO) is treated with one mol. of urethane (NHR1COOR3OH) at or below room temperature reaction occurs to form products of the formula RCH(OH).NR1COOR3OH wherein R and R1 are hydrogen atoms or monovalent alkyl, aralkyl, aryl or alicyclic hydrocarbon radicals (R1 may also be a hydroxyalkyl radical) and R3 is an alkylene radical.  When the urethane is disubstituted on the nitrogen atom, i.e. is of the type R1R2NCOOR3OH, a hemiacetal compound of the type R1R2N.COOR3OCH(OH)R is formed wherein R2 is an organic radical as defined above for R1.  When two mols. of aldehyde are employed per mol. of the unsubstituted or monosubstituted urethane the products are of the formula <FORM:0772243/IV(b)/1> <FORM:0772243/IV(b)/2> respectively.  When three mols. of aldehyde are used per mol. of unsubstituted urethane products of the formula <FORM:0772243/IV(b)/3> are formed.  The reaction at or below room temperature may be carried out by simple mixing of the reactants, conveniently in aqueous solution and in the presence of an acid catalyst, e.g. hydrochloric acid, and then allowing the mixture to stand for several hours.  When the reaction is carried out at elevated temperature using one mol. of aldehyde to two mols. of urethane, the product obtained is of the formula <FORM:0772243/IV(b)/4> wherein R and R1 are hydrogen atoms or an organic radical as defined above.  An asymmetrical product may be obtained by reacting with one urethane at normal temperature and then heating the product with a differently substituted urethane.  When the urethane is disubstituted on the nitrogen atom an acetal of the structure <FORM:0772243/IV(b)/5> wherein R1 and R2 are organic radicals as defined above for R1 is obtained.  These reactions may be effected in an aqueous medium or in an anhydrous solvent, preferably one capable of entraining water azeotropically.  A dehydration catalyst such as an organic acid or anhydride, a mineral acid or a dehydrating salt may also be present.  When one mol. of aldehyde is condensed upon one mol. of the urethane polymers are formed, the degree of polymerization of which depends on the operating conditions such as temperature, speed of dehydration and nature of the catalyst. In examples: (1) the N-methylol urethane of ethylene glycol CH2OH.NH.COOCH2CH2OH is obtained by adding hydrochloric acid to a 1 : 1 molar mixture of the unsubstituted monourethane of ethylene glycol and formalin, cooling to maintain the temperature at about 20 DEG  to 25 DEG  C. and then allowing the mixture to stand for about 10 hours. Other compounds which may be obtained in an analogous manner are those having the formul : <FORM:0772243/IV(b)/6> and <FORM:0772243/IV(b)/7> (2) a derivative of the formula (CH3)2N.COOCH2CH2OCH2OH is obtained by reacting a 1 : 1 molar mixture of the N-dimethyl urethane of glycol and formalin by a procedure as in (1); (3) hydrochloric acid is added to a mixture of the monourethane of ethylene glycol (1 mol.) and formalin ( 1/2 mol.) and the mixture is allowed to stand for 12 hours to form a mixture of the N-methylol urethane and the urethane which is then heated under vacuum to 130 DEG  to 140 DEG  C. to form the N,N1-methylenediurethane of the formula CH2(NHCOOCH2CH2OH)2; (4) the benzylidene N,N1-diurethane of the formula C6H5 CH(NHCOOCH2CH2OH)2 is obtained by refluxing a mixture of the monourethane of glycol (1 mol.) and benzaldehyde ( 1/2 mol.) in benzene in the presence of benzenesulphonic acid; (5) the N,N1-methylenediurethane of propylene glycol-CH2(NHCOOCH-(CH3)CH2OH)2 is obtained from the monourethane of propylene glycol (1 mol.) and formalin ( 1/2 mol. formaldehyde+slight excess); (6) the methylene N,N1-diethyl-N,N1-diurethane of propylene glycol-CH2(N(C2H5).COOCH(CH3)-CH2OH) 2 is obtained from the N-ethyl urethane of propylene glycol and trioxymethylene, the reaction being carried out in the presence of benzene and maleic acid; (7) as in (6) except that the N-monoethanol urethane of propylene glycol is used to yield the correspondingly substituted diurethane.  Other compounds obtainable in a similar manner are those of the formula: CH3CH(NHCOOCH2CH2OH)2 CH2(N(C2H5)COOCH2CH2OH)2 CH2(N(CH2CH2OH).COOCH2CH2OH)2 <FORM:0772243/IV(b)/8> the latter being obtained by the action of formalin on the ethylene diurethane of ethylene glycol.  The products of the preceding examples may be used as intermediates in the plastic and pharmaceutical industries or as varnishes, glues or artificial textiles.  Examples are also given for the production of polymeric products from N-ethyl-(and N-benzyl-) urethane of glycol acid formaldehyde (in the form of trioxymethylene), and from the monourethane of propylene glycol and formaldehyde (in the form of trioxymethylene) (see Group IV (a)).