US2649473A

US2649473A - Substituted carbamic acid esters as surface active agents

Info

Publication number: US2649473A
Application number: US203207A
Authority: US
Inventors: Joseph A Chenicek
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1950-12-28
Filing date: 1950-12-28
Publication date: 1953-08-18
Anticipated expiration: 1970-08-18

Description

Patented Aug. 18, 1953 SUBSTITUTED CARBAMIC ACID ESTERS AS SURFACE ACTIVE AGENTS Joseph A. Chenicek, Bensenville, Ill., assignor to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application December 28, 1950,

1 Claim.

This invention relates to certain non-ionic compounds useful as surface active agents and detergents and to an operable process for their manufacture. More specifically, the invention concerns certain N-aliphatic substituted carbamic acid esters of specific structure containing a hydrophilic group and a hydrophobic radical having such mutual effect in solution that the hydrophilic and hydrophobic properties substantially balance each other, as requisite to micelle formation and surface activity.

It is Well known and widely recognized in the detergent art that the capacity of a particular compound to act as a surface active agent or a detergent in solution with an appropriate solvent depends upon the ability of the compound when dissolved in a solvent miscible therewith to orient itself in solution to form micellar aggregates in which the hydrophobic portion of one molecule aligns itself with the hydrophobic portion of another molecule of the same compound in solution, the hydrophilic portions of the several molecules in the micelle (usually at least several hundred in number) likewise becoming aligned in adjacent positions to form an aggregate of a large number of such molecules, which as a unit is referred to as a micelle. The products of the present invention are novel applications of the theory of detergency in which the hydrophilic group is a poly-oxyalkylene chain of sufficient length to provide a radical having hydrophilic properties and the hydrophobic portion comprises a long-chain aliphatic alkyl group of sufficient length to impart a degree of water repellency to the molecule of detergent sufficient in eiiect to balance the hydrophilic properties of the molecule and provide that critical internal balance between the hydrophilic and hydrophobic portions requisite to detergency. The respective alkyl and poly-oxyalkylene chain are substituents of a carbamic acid ester which serves as the structural foundation for the detergent molecule.

In one of its embodiments, the present invention concerns a non-ionic detergent comprising a compound having the empirical structural formula:

R o ZlI-HOZ' wherein Z is selected from the group consisting of (OR) H and R" and Z is selected from the remaining member of said group, R is an alkylene group containing from 2 to about 5 carbon atoms per group, R is selected from the Serial No. 203,207

group consisting of hydrogen, alkyl and substituted alkyl, R." is an aliphatic alkyl group containing from about 8 to about 25 carbon atoms per group, and x is a whole number having a value of from about 2 to about 25.

Another embodiment of the invention concerns a process for the production of a surface active agent which comprises condensing a substituted amine containing at least one and not more than two N-substituents selected from the group consisting of (--OR)OI-l and R, with a halocarbonic acid ester containing an alkoxy radical selected from the group consisting of (OR)OH and OR. wherein a: is a whole number having a value of from 2 to about 25, R is an alkylene group containing from 2 to 5 carbon atoms per group and R is an alkyl group containing from about 6 to about 25 carbon atoms per group, said process being further characterized in that not more than one (OR) 10H group and not more than one B group is present in the same molecule of surface active agent.

Still another embodiment of this invention relates to a process for the production of a nonionic surface active agent comprising an N-substituted carbamic acid ester in which the N -substituent is an aliphatic organic radical, which comprises condensing a di-alkyl amine with a poly-oxyalkylene glycol ester of chloroformic acid, said di-alkyl-amine being further characterized in that one of the N-alkyl substituents is an aliphatic hydrocarbon group containing from 8 to about 25 carbon atoms per alkyl group and the other of the N-alkyl substituents of said di-alkyl-amine is an aliphatic hydrocarbon group containing from 1 to about 5 carbon atoms per molecule, and said glycol ester of chloroformic acid is further characterized in that said polyoxy-alkylene glycol ester contains from about 2 to about 25 oxyethylene groups per molecule.

A further embodiment of the invention, relating to one of the preferred species of the present non-ionic surface active agents, concerns a compound represented by the empirical formula:

wherein R, is an ethylene group, a: is a whole number having a value of from about 10 to about 15, R." is an aliphatic alkyl group containing from about 12 to about 18 carbon atoms per group, and R is an alkyl group containing from 1 to 5 carbon atoms per group.

The surface active and Wetting agents of the present invention, some of which act as detergents in aqueous or non-aqueous solutions, are considered broadly as a species of the generic class of compounds characterized as N-substituted carbamic acid esters of aliphatic alcohols and the specific series of compounds herein specified as surface actiye agents are represented by the empirical formulae:

and

wherein R, in both the above (1) and (2) series of compounds is an alkylene group containing from 2 to 5 carbon atoms per group, R is selected from the group consisting of hydrogen, alkyl and substituted alkyl groups, B," is an aliphatic alkyl group containing from 8 to about carbon atoms per group, and 1': is a whole number having a value of from 2 to about 25. In each case, the B group acts as the hydrophobic portion of the molecule while the remaining portion of the molecule, and particularly the polyalkylene glycol chain, acts in the capacity of the hydrophilic portion, each portion balancing the effect of the other by the proper selection of the component alkyl and polyoxyalkylene groups present in the molecular structure.

The above series of surface active products may be prepared by any convenient means available which produce compounds of the indicated structure. A readily available method of manufacture, generally preferred for the preparation of the present products, comprises condensing an ester of a haloformic acid with a poly-substituted amine at reaction conditions resulting in a metathasis-type of reaction between the halogen atom of the haloformic acid ester and a hydrogen atom or alkyl group of the poly-substituted amine, the reaction liberating the corresponding hydrogen halide or alkyl halide and forming a carbamic acid ester as the primary condensation product.

The products of the present series of surface active agents represented by Formula 1, above, and herein designated as an N-polyoxyalkylenesubstituted oarbamic acid ester of an aliphatic alcohol are prepared by means of a reaction involving at least two stages, the number of stages required depending upon the reactants available as starting materials. The reaction mechanism involved in their preparation involves essentially the condensation of an N-polyoxyalkylene substituted amine with a haloformic acid ester of a long chain alcohol. Since not generally available in prepared form, the amine reactant is synthesized prior to the primary condensation reaction by reacting an amine such as ammonia, a mono-alkylamine or dialkylamine with a polyoxyalkylene glycol or alkylene oxide containing from 2 to 5 carbon atoms per alkylene group, the glycol reactant and the reaction conditions being selected to form an amine containing an hydroxypolyoxyalkylene substituent having at least 2, up to about 25 alkylene groups per molecule. The reaction is a condensation-type mechanism and is carried out at temperatures of from about 10 to about 100 0., preferably from about to about 80 C., and desirably in the presence of an acid-actin catalyst, present in the reaction mixture in an amount more than sufiicient to neutralize the amine reactant. Superatmospheric pressures are generally desirable in this reaction to maintain the reaction mixture substantially in liquid phase during the course of the condensation reaction, particularly when the reactants are volatile at the temperatures utilized in the condensation reaction. A preferred means for effecting the reaction comprises bubbling the alkylene oxide in its gaseous form into a quantity of the ammonia, monoor dialkylamine maintained in liquid form at the desired reactiontemper-ature and at superatmospheric pressures, if required, to maintain liquid phase conditions. Suitable catalysts for the condensation reaction include the strong mineral acids, such as hydrochloric, sulfuric, and phosphoric acids, certain inorganic acid-acting materials, such as the normally acidic alumina-silica composites, a composite of silica and phosphoric acid, known generally in the art as a solid phosphoric acid catalyst and other materials well known as acidacting substances. It is to be noted that when utilizing a mono-allrylamine in the preparation of the hydroxy-p.olyoxyalkylene-substituted amine, and when suitable reaction conditions are selected which tend to enhance the condensation of more than one poly-oxyalkylene group with the amine, a dior tri-polyoxyalkylene substituted amine may be prepared which may be preferred for the manufacture of highly watersoluble surface active agents and detergents. The formation of the di-(polyoxyalkylene)-sub stituted amine is generally favored at relatively high reaction temperatures, whereas the preferred mono-(polyoxyalkylene) -substituted amine condensation product is formed by the condensation of an alkylene oxide or a polyalkylene glycol with a di-alkylamine under re action conditions generally less severe (at temperatures, for example, of from about 0 to about C.) than for the preparation of the poly- (polyoxyalkylene) s ubstituted amines.

lhe allrylene oxides and the polyoxyallzylene glycols utilizable in the condensation reaction with the mono-v or diallgylamine to form the corresponding'N-substituted polyoxyalkylene amines are selected from the abicve reactants in which the alkylene group contains from 2 to about 5 carbon atoms per allrylene group, including such alkylene oxides as ethylene-oxide, a propyleneoxide (such as trimethylene oxide or methylethylene oxide), a butylene oxide (such as isobutylene oxide), and amylene oxide and such polyoxyalkylene glycols as polyethylene glycol, polypropylene glycol, a polybutylene glycol, and a polyamylene glycol. Since the polyoxyalkylene groups in the molecular structure of the present detergents and wetting agents constitute the hydrophilic portion of the molecule, it is evident that for the final product to be water-soluble, the number of water-solubilizing polyoxyalkylene groups present in the compound, relative to the size and effect of the hydrophobic group, must predominate; for the preparation of such watersoluble products, therefore, the total molecular weight of the polyalkylene glycol must be large and the number of oxyalkylene groups per molecule must also be relatively large. Thus, the shorter the chain length of the alkylene group of the polyoxyalkylene radical, the greater is the water-solubilizing capacity of the radical for a given molecular weight, and therefore, the polyethylene and polypropylene glyools are the preferred polyalkylene glycol reactants. The number of oxyalkylene units per molecule of polyalkylene glycol reactant is preferably at least 5 and is desirably from about to about for the polyethylene and polypropylene glycols.

For the production of relatively water-insoluble surface active agents and detergents, on the other hand, products which may be utilized in non-aqueous systems, for example, the polyalkylene glycol or polyalkylene oxide utilizable in the condensation reaction with the amine is preferably selected from the polypropylene, polybutylene and polyamylene species, the solubility of the ultimate product tending to decrease as the chain length of the alkylene group increases beyond 2 carbon atoms, although low molecular weight polyethylene glycols, generally containing less than about 5 oxyethylene units per molecule, do not contain a sufficient number of watersolubilizing oxyalkylene groups to produce a water-soluble product and the latter polyethylene glycols, therefore, may be utilized when a product soluble in organic solvents, but relatively insoluble in water, is preferred.

The primary condensation of the N-polyoxyalkyleneamine, prepared as indicated above in a preliminary stage of the process, and an alkylhaloformate takes place in accordance with a reaction mechanism in which an alkyl group or hydrogen atom substituent on the amino nitrogen atom is replaced by the carbonic acid ester radical through the displacement of the halogen atom of the haloformate ester and the liberation of hydrogen halide or alkylhalide from the reaction via the resulting condensation. Since in the Series (1) compounds of this invention the alkoxy group of the formate ester contains the hydrophobic alkyl group essential for detergency of the ultimate product, the chain length of the alkoxy group must be suflicient to impart hydrophobic properties to the alkoxy radical; it has been found that such hydrophobic properties sufiioient to balance the hydrophilic properties of the polyoxyalkylene group, are present in alkoxy radicals containing from about 8 to about carbon atoms per group. Suitable alkyl haloformates or alcohol esters of haloformic acid utilizable in the condensation reaction, therefore, include the bromo-, chloro, and iodoformates of such typical alcohols as octanol (including the nand iso-octyl alcohols, undecanol, decanol (lauryl alcohol), dodecanol, pentadecanol, octadecanol, eicosanol and pentaeicosanol. the compounds of the above series which are particularly preferred because of their ready availability and relative cheapness are the chloro-substituted formic acid esters, such as octylchloroformate (also called octyl-chlorocarbonate), n-dodecylchloroformate, pentadecylchloroformate, and homologous alkylchloroformates containing from 8 to about 25 carbon atoms per alkoxy group. These reactants may be derived from any suitable source, one method of preparing the chloroformic acid esters being the reaction between carbonylchloride (phosgene) and the corresponding aliphatic alcohol desired for the ester, such as n-octanol, decanol, dodecanol, etc. The higher molecular weight alcohols, such as eicosanol and alcohols containing up to about 25 carbon atoms per molecule may be prepared by hydrolysis of the corresponding olefins or they may be separated from the products formed in the reaction of carbon monoxide and hydrogen.

The reaction between the polyoxyalkylene-substituted amine and the haloformic acid ester may be readily effected by merely heating the amine and the alkyl haloformate, for example,

Among at temperatures of from about 10 to about 120 preferably from about 20 to about 100 C. and may be more efiicaciously effected, with resulting greater yield, by heating the reactants in the presence of a basic catalyst or absorbent of the liberated by product alkyl-halide and/ or hydrogen halide. Typical of the substances which promote the condensation reaction are such alkaline compounds as the alkali and alkaline earth metal-oxides, carbonates, hydroxides, mono-basic-oxyhalides, etc. such as sodium and potassium hydroxides, calcium and magnesium carbonates, oxides and hydroxides, barium oxide, barium carbonate, calcium oxychloride, organic bases, such as the tertiary amines, including pyridine, quinoline, tributylamine, etc. and such absorbents as of silica gel or alumina gel particles, activated carbon, etc. One of the preferred procedures, representative of the above described methods for condensing the alkyl haloformate and the polyoxyalkylene-substituted amine reactants, comprises condensing the reactants at a temperature of from about to about C. in the presence of magnesium hydroxide for a reaction period of from about one hour to about six hours and thereafter separating the desired condensation product as a bottoms fraction after distillation of the uncondensed reactants from the reaction mixture.

The species of detergent and surface active agent comprising the compounds of Series (2) herein provided and designated as N-alkyl substituted carbamic acid esters of polyoxyalkylene glycols, in general have the empirical formula:

wherein R. is an alkylene group containing from 2 to about 5 carbon atoms per group, at is a whole number having a value of from 2 to about 25, R is a substituent selected from the group consisting of hydrogen, alkyl, and substituted alkyl containing from 1 to about 5 carbon atoms per group, and R" is a long chain aliphatic alkyl group containing from about 8 to about 25 carbon atoms per group. These products are prepared by the condensation of a long chain monoor dialkylamine with a chloroformic acid ester of a polyalkylene glycol. Utilizing either monoor dialkylamines as reactants, these reactants contain one and only one long chain alkyl radical containing from about 8 to about 25 carbon atoms per group and when a dialkylamine is utilized as the reactant, the other alkyl substituents, in addition to the long chain alkyl group, contains not more than about 5 carbon atoms per group. Typical representative monoand dialkylamines utilizable as reactants in the condensation with the chloroformic acid esters include such compounds as mono-octylamine, amyloctylamine, nonylmethylamine, dodecylmethylamine, octadecylethylamine, eicosanylbutylamine, pentacosanylamine, and others within the general group defined above. As heretofore indicated, the Water-solubility of the ultimate product is directly proportional to the chain length of the hydrocarbon radical attached to the carbamic acid portion of the final detergent product and the hydrophobic tendency of such group can only be counterbalanced in the product by the choice of a suitable hydrophilic hydroxy polyoxyalkylene group present in the molecular structure of the carbamic acid ester product. It is evident that the choice of the various substituents in the structure of the present esters to form products hav- M 20 about? restaurateur: v. ruju ti e vl-la ee.uum euu uwsthul ene groups ,rnolecul f bly trorn a out 11.1 iur ua r ulsuula uish u uti ized lone lyco ura .i'ela- 10 to about 15 per rnolec the formateester. ,l f a hi L a y u i r pulu lfiiluuu lu to 'form th e er :uu a e i ql the p y alk eu eruu m st. tively larger number per mlecule,'f0r exampl 25 per e ul t rodu u we ent p od c Ihawmeue is for the preparationpf a pr ct u in a u u tu or ani rsulvsut The r par t n c th i ermediate 19 1???" f ma es e .q the p y th lene 2 fected by reactingthe? ,pplyalkylene gy ol in which the .alkylen groupfcorrta iri s trorr'l 52 to about 5 c o ia uuislue ler uuw th lu rlu uu chloride (phosgene), .utilifng about egui lar pro on -9 o -an. n. alu e le ruu rustu ma a t am. auoutlatuahqu tuku'ulu lu is h ussed. situ by reacting carbonyl chloride with an alkylene oxide containing from 2 to 5 carbon atoms per alkylene groupinagnolecular ratio of the reactants which will forrn the ester of the desired molecular weight containing a suilicient numb of l u ur h sr usre uuuhul required for -the prod uct ;to have detergency. When ut i n 't l y uu po epu. e etiuu to form'the es'tenthe molecular ratio o f gler e oxide to carbonyl chloride :is determined by' the number of oxyalkylene units desired in the "final productand-may vary'frorn 2 to about idrnol ecular ratios of the respective reactants. When utilizing a polyalkylen'e glycol, normally 'n l' r id condition, the carbonyl chloride may be rnerely bubbled into-the-liqui5i-glycol at a ternper :ure

Of-fr0m aboutdp toabout 66 c. untila e of carbonyl chloride per -moleofpdlyalkylene glycol fibasedun t a e a Wheele Wei h o the glyools -containeclin the rnixture subiect ed to reaction) have undergone 1 reaction. When the ester is prepared by reaction of ana-lkyler eoxde, such .as ethylene oxide, with carbonylc de, the reaction proceeds at temperatures of gfrorn about 10 toabout 190 (7., preferably f:r orr about toabout50 C., and maybe eflected at superatmospheric pressures, "if desired, to prov sentially-liquid ph ase'conditions. the type ofreaetion,;the alkylene gggideis continuous... ly led into-the reaction mixture a the co; sationproceeds until the resultinghalggen stituted "formic-acid ester of the correspo polyalkylene glycol-contains the desired number of oxyalkylene groups per'r rrolecul e, irrithi the range ofdrom tojaboutper n ole le reaction snay also be conducted cqrrtirru feeding-the alkylene; oxide into a tower with -a suitable solid packing at r l, $11

l z fliu e ar ic e rings, --etc., while the carbonylchlgride re ac nt is--fed --into the opposite end of the react9r. he

u t uutu i u th su .uu allir i Quits 8 flow rates of the respective reactants being ad justed to provide the proper residence timeof the ester in the packed reactor as the alkylene oxide condenses with th 16 Y I-Q EIQQP .Q 3 ester chain vand continues to add to the end of the polyoxyalkylene glycol portion of the ester. The muuruutiuu b t ihul eeuu bs tu eu fOIIlIi C acid ester of the polyalkyleneglycol and the lon'gchain mono or dialkylamine tor rrn the corresponding li alkylesubstituted carbarnic acid ester of the ,polyalkyleneiglycol m y be accomplished at reaction nd t uns.esuen ie lrs ui lar to the rea tioneo d t ous ,ma" ai fih h condensation of 'the' 'alkylhaloforrnate yvith the p lyoxyalkylen a in as h r iuabore described- Thus, the condensation reactionproceeds at t tip rature ofiroru abou 0.t about 5 .Qrr irabl from about 20 to abou lw and th con ion s furth -m b fi e "rice of an alkalineior basic substance or abs ent for the hydrogen halide iiberateddurinstl a, Q1 densation reaction. {is heretofore indicated such alkaline substances are preferahly selected irorn the alkali and alkaline earth metal oxides; cariua e and .h drosid s, the forganict rtia y amines, and suitable absorbent's include such por us subs ances as activate c r rti e of silica gel, alunrina gel particles, etc, the reaction mixture containing the absorbent ,or alkaline substance being preferably stirred to of; feet intimatecontact between the reactants and alkaline substance or absorbent. IFollowingcompletion of the reaction, the.ungonverted reaotants, such as the long chain alkylarr ine and/Ior the haloformate may be remoy dfrom the desired condens rqduut by. di u l f u and ,l x e tion procedures with suitabl.blventsrfor the unreacted tartin mater a s o a ,combmati n' of suchprocedures maybe e rr'ir'aloyegi.- l v The p o u t o th re ent inven ip acharw rmed .eeus ell .Nrisut ti t i r a ac d est r .u luiuu'u al oho iu m the po yo a len lyco Q amate species a i the polyoxyalkyleneamine carb'am ate species herein provided are. nqrniallyliguid products of low melting point, wax-like rnaterials be either ,soluble in aqueous solutionslor alter,- natively, soluble in organic solvents;ldeperiding upon the structure of the respective compounds, as hereinbefore indicated. The :compoi'inds are substantially neutral, that is, they have'la pH in aqueous solution of about 7, and hence ,do not irritate the skin of animals, particularly human skin, when utilized as an aqueous Idetergent. The species of productprovidedherein are mutually compatible in ,admixture vvith leach otherand may be iurthermore combined in T admixture wit t t-tr. a id an o h ui J non-ionic detergents. The present .cfarb'amic acid esters being .llon-ionic when dissolved "in aqueous solution are .not afiected vloy alkaline earth metal ionsdissolvedin watersuch aslcalcium andmagnesium ionsin-hard Water. There.- fore they do not for m a curd QrIscum whendi'ssolved in such hard wat ers,, as is tyDicaLfor-crtain ionic detergents, such asthe fatty acidsoaps. The water-soluble, detergent products of this invention are normallylefiectiv e inconcentiajtions of from about 0.1 to abou t 0.5% inaque ous so'liition, although higher, concentrations' naylbe ,required in deterging operations'in.which= metresent detergent is required to lemu lsifyla large quantity of greaseorother oleagino famine. h pr n inve t is u the un se th es eq to specifi emhudimeu 'h p ti A product possessingdetergent properties and having the structure of an N-alkyl carbamic acid ester of a polyalkylene glycol is prepared by the condensation of a chloroformicacid .ester of a polyalkylene glycol. (a polyoxyalkylene chloroformate) with an N-alkylamine. The reactants utilized in the condensation reaction are dodecylmethylamine and the polyoxyethylene glycol ester of chloroformic acid in whichthepolyoxyethylene chain contains an average of about oxyethylene groups per ester radical. The dodecylmethylamine may be prepared in a preliminary reaction by the condensation of sodium methylamide with dodecylchloride at a temperature of from about to about C. in a closed pressure autoclave in which the pressureisincreased to about -10-atmospheres with'methylamine. In the preparation of the reactants, methylamine in excess is led as a gas into the pressure autoclave containing ,..finely. divided particlesof sodium which are heated to a temperature of about 80 C. '.as the reactor is rotated. The mixture is thereafter cooled to a temperature of 30 C. to liquefy the methylamine and thereafter dodecylchloride formed by the hydrochlorination of dodecylene is admitted into the autoclave and the reactor heated to a temperature of about 20 C., which increases to about 30 C. in the ensuing exothermic reaction. The excess methylamine is removed from the reaction heating the autoclave to distill off the low boiling methylamine. The desired dodecylmethylamine in the form of its hydrochloride salt, may be recovered from the reaction mixture by extraction with dilute hydrochloric acid solution.

The polyalkylene glycol ester of chloroformic acid in which the ester contains an average of about 15 polyoxyethylene groups per molecule is prepared by reacting carbonyl chloride with a mixture of polyethylene glycols having an average of about 15 polyoxyethylene groups per molecule. The reaction is effected by bubbling the carbonyl chloride into the glycol maintained at a temperature of about 30 C. The addition of carbonyl chloride is continued as the reaction mixture is rapidly stirred until approximately a molar equivalent of the carbonyl halide has reacted, the molar ratio being based on the average molecular weight of the polyethylene glycols contained in the glycol mixture.

The chloroformic acid ester of the polyethylene glycol is condensed with the above prepared dodecylmethylamine by mixing approximately equimolar proportions of the reactants and heating the mixture with rapid stirring to a temperature of about 80 C., and in the presence of soda-lime which absorbs the liberated hydrogen chloride. The product is a viscous liquid, soluble in water but only slightly soluble in aromatic hydrocarbons, such as benzene. Other compounds containing both 1onger and shorter chain length alkyl groups attached to the nitrogen atom of the resulting carbamic acid ester product and containing both shorter and longer chain polyoxyethylene groups in the alkoxy group of the formic acid ester radical when tested for detergency in an aqueous solution by the standard Launder-O-Meter procedure, have somewhat l s r t rsencies than the above N-dodecyl 10 carbamic acid ester ofthe polyalkylene glycol containing an average of about 15 polyoxyethylene groups per molecule. As the chain length of the N-alkyl group increases, the products tend to. be less soluble in water and more soluble in organic solvents; the opposite tendency in general holds true as the chain length of the polyoxyalkalene group increases. All products in which the N-alkyl group contains at least 8 and not more than about 25 carbon atoms per group and products containing at least 2, up to about 25 alkylene groups per polyoxyalkylene radical of the carbamic acid ester have surface active properties.

Example II A detergent product having the structure of an N-polyoxyalkylene carbamic acid ester of an aliphatic alcohol is prepared by the condensation of a haloformic acid ester of an aliphatic alcoholwith an N-substituted amine in which at least one and not more than two of the substituent groups is a polyoxyalkylene radical and the other N-substituent is an alkyl group.

. The polyoxyalkylene-substituted amine reactant. may be prepared by the reaction of a secondary amine with an alkylene oxide a condensation reaction conditions. In the present series of compounds, ethylene oxide is utilized in the reaction to form the polyoxyalkylene chain and various secondary amines are utilized in the condensation to compare the effect of the length of the polyoxyalkylene group and the chain length of the alkyl substituents in the structure of the secondary amine on the detergency of the ultimate product. The preparation of the amines is illustrated by the condensation of ethylene oxide with amylmethylamine in which the condensation is continued until an average of approximately 12 oxyethylene groups are present in the polyoxyethylene chain. The condensation is effected by introducing the ethylene oxide into the amine contained in a stirred pressure autoclave until the polyoxyethylene chain contains the desired number of oxyethylene units. The reaction is effected at a temperature of 50 C. and at a pressure of 40 atmospheres in the presence of a small quantity (about 10 grams per grams of reactants) of pyridine. The mixture is stirred as the reaction proceeds and is allowed to continued until about 12 moles of ethylene oxide have condensed to form the polyoxyalkylene, generally within a reaction period of from about 30 minutes. The polyoxyalkylene group may also be introduced into the structure of the amine as a substituent thereof by reacting the amylmethylamine with a polyethylene glycol containing an average of about 12 oxyethylene groups per molecule, the reaction being carried out at a temperature of about 50 C. and is also promoted in the presence of pyridine.

The condensation of the polyoxyethyleneamylmethylamine and ethylchloroformate to form the detersive carbamic acid ester is obtained by heating the reactants in equimolar proportions at a temperature of about 60 C. in the presence of two molar proportions of calcium hydroxide in aqueous suspension. The reaction mixture is thoroughly stirred to obtain an intimate dispersion of the reactants and the lime suspension, thereby obtaining maximum conversion to the desired end product. The product is a viscous liquid which when dissolved in an aqueous solution and shaken foams profusely and has a detergency approximately equivalent to that of a fatty acid soap, such as sodium-laurate.

The product is water-soluble in alluseful'proportions normally utilized deterging opera- 'per polyoxyethylene' substituent on the nitrogen atom of" the: carbamic acid ester and containing at least 8 but not more than about 25'. carbon atoms per alkoxy group of the formic acid ester have surface active properties, some of which are merely Wetting agents and others having. detersive properties. The solubility of the products in Water tends to decrease as the number of carbon atoms in the alkoxy radical increases without a simultaneous increase in the number of oxyethylenegroups in the polyoxyethylene chain. Conversely, the solubility of the product in water and its insolubil'ity in organic solvents; such as hydrocarbons, increases as the number of polyoxyethylene units per molecul'eincreases and the number of carbon atoms in the alkoxy group of the carbamic acid ester decreases.

1 2 Iclainrasmyinventiom A compoundt having the empiricalstructural formula:

z-n t r-oz' wherein Z- is" selected from the groupconsisting of -(OR)-xOH* and R3 and Z is selected from the other member of said group, R is an alkylene group'- containingfrom" 2" to 5' carbon atoms per group; R2 is selected from the group consisting of hydrogen-and alkyl' containing from 1 to about 5' carbon atoms per alkyI',"R"' is an aliphatic alkyi group containing from S te about 25 carbon atoms per group; and a wholenumberhaving a value of from aroma-0111525.

JOSEPH A. CHENICEK.

Refer-aides: the? file: of. this patent UNITED" STATES PATENTS Number. Name; Date 2,191,479- Mcigs.--....a.; Apr. 16,.1940

FQREIGN"PA FENTS Number Country Date 1.277740 Great Britain a. June 12,- 1919 8101463 France a -c Dec.. 28,. 1936 697,730 Germany Oct 30,1940