A PROCESS FOR INCREASING THE MOLECULAR WEIGHT OF POLY(ALKYLENE CARBONATE) POLYOLS

Abstract: Process for increasing the molecular weight of a poly(alkylene carbonate) polyol which comprises exposing the poly(alkylene carbonate) polyol to elevated temperatures at which dialkylene glycol, trialkylene glycol, or initiator segments, wherein the initiator has about the same or greater volatility as the dialkylene glycol or trialkylene glycol segment, are abstracted from the poly(alkylene carbonate) polyol, at a pressure wherein the dialkylene glycol, trialkylene glycol, or initiator is volatile, and removing the volatile dialkylene glycol, trialkylene glycol, or initiator from the mass of the poly(alkylene carbonate) polyol, under conditions such that the molecular weight of the poly(alkylene carbonate) polyol is increased.

Description: A PROCESS FOR INCREASING THE MOLECULAR WEIGHT OF POLY(ALKYLENE CARBONATE) POLYOLS This invention relates to a process for increasing the molecular weight of poly(alkylene carbonate) polyols. Poly(alkylene carbonate) polyols are use- ful in preparing polyurethanes, and as surfactants. Polyether polyols and polyester polyols are well-known polymers which can be further polym¬ erized with organic polyisocyanates to prepare poly¬ urethanes. Polyether polyols are prepared by the reaction of hydroxy-containing hydrocarbons, such as an aromatic or aliphatic diol, and use "epoxides" for instance, ethylene oxide and propylene oxide. Polyester polyols are prepared by the reaction of poly acids, such as adipic or terephthalic acid, or esters of polyacids, such as dimethyl adipate or dimethyl terephthalate with dihydroxy-containing hydrocarbons, such as aromatic and aliphatic diols. Some poly(alkylene carbonate) polyol properties resemble polyester polyol properties while other proper¬ ties resemble polyether polyols. It is known to prepare polycarbonates from aliphatic dihydroxyl compounds either by a process of phosgenation in which hydrogen chloride is liberated or bound by bases, such as pyridine or quinoline, or by a process of transesterification with carbonic acid esters of alcohols or phenols, preferably diphenyl- carbonate, optionally with the aid of transester- ification catalysts. In either case, it is essential to use phosgene or a mixture of carbon monoxide and chlorine as source of carbonic acid. Processes which involve the preparation and handling of phosgene are difficult and costly due to the considerable safety risks involved and the high cost of materials due to corrosion. To this are added ecological problems since either the spent air is contaminated with hydrogen chloride or the effluent water with sodium chloride. Polycarbonates produced by these methods, using dihydrocarbyl compounds, may have a functionality of less than two due to inadequate or incomplete ester- ification or transesterification which often prevents the products from forming high molecular weight polymers in subsequent reactions. Poly(alkylene carbonate) polyols can be prepared by the method illustrated by Malkemus, US 3,133,113. It is disclosed that an alkylene carbonate such as ethylene carbonate can be reacted with a glycol such as diethylene glycol in a mole ratio in the range of 1.2:1 to 2.5:1 at reduced pressure while removing ethylene glycol formed by the reaction until the reaction is complete. The catalyst employed is a mixed zinc borate-alkaline earth metal oxide catalyst. Stevens, in US 3,248,414; 3,248,415 and 3,248,416, discloses the preparation of poly(alkylene carbonate) polyols from (1) carbon dioxide and 1,2-epoxides; (2) cyclic carbonates such as ethylene carbonate; or (3) from cyclic carbonates and a 1,2-epoxide. A minor amount of a polyol is employed as an initiator. The reaction is usually conducted under pressure in the presence of a metal carbonate, metal hydroxide, trisodium phosphate or a tertiary amine. Poly(alkylene carbonate) polyols have also been prepared by polymerization of ethylene carbonates under pressure using basic catalysts and a minor amount of glycol as initiator, Buysch et al., US 4,105,641. These products are low in carbonate and high in ether groups concentration due to decomposition of the ethyl¬ ene carbonate. In Stevens' patents discussed herein- before, the patentees exposed a poly(alkylene carbonate) polyol derived from ethylene carbonate and monσethylene glycol to temperatures of 160°C at 2 mm Hg (0.27 kPa) pressure to remove unreacted ethylene carbonate. Hostetler, US 3,379,693 removed unreacted ethylene carbonate from products similar to poly(alkylene carbonate) polyols by heating them to about 130°C under 1-5 mm Hg (0.13-0.67 kPa) pressure; Maximovich, US 3,896,090 reacted ethylene carbonate with diethylene glycol and treated the reaction product under reduced pressure to remove the unreacted ethylene carbonate and diethylene glycol. Several workers have prepared poly(alkyl- ene carbonate) polyols and related materials by con¬ trolling an equilibrium between the reaction mate¬ rials of a diol and alkylene carbonate and the products of a poly(alkylene carbonate) polyol and monoethylene glycol. The reaction is controlled by the removal of monoethylene glycol. Malkemus, US 3,133,113 reacted ethylene carbonate and diethylene glycol at 125°C to 130°C under reduced pressure of 10 mm Hg (1.3 kPa) in the presence of certain catalysts with concurrent removal of monoethylene glycol as distillate. This was fol¬ lowed by removal of starting material. This pro¬ cedure is plagued by the presence of volatile ethylene carbonate which condenses as a solid throughout the system causing severe plugging and reducing ethylene carbonate conversion while mono¬ ethylene glycol is being removed. This process requires large excesses of " ethylene carbonate. Springmann et al., US 3,313,782 further studied this process under reduced pressure in the presence of catalysts and set limits on the reac¬ tion conditions; the reaction temperatures must be lower than the boiling point of the alkylene carbon- ate, but high enough to distill off the monoethyl¬ ene glycol formed. Lai et al., US 4,131,731 used staged reductions in pressure during the reaction of alkyl¬ ene carbonate with a diol, wherein the final stage was to remove monoethylene glycol. The patentees characterized their reaction conditions by stating that the alkylene carbonate must have a boiling point 4.9°C greater than monoethylene glycol. The chemistry based on the above equilibrium was improved by Buysch et al., US 4,105,641 by carry- ing out the reactions in a solvent (e.g., cumene) capable of removing monoethylene glycol as an azeo- trope with the solvent. Hereinbefore, the molecular weights of pol (alkylene carbonate) polyols from alkylene car- bonates have been controlled by either the stoichi- ometry of the reactants, that is, higher alkylene carbonate.to initiator ratios for higher molecular weights, or the removal of monoethylene glycol from the reaction mixture wherein an ethylene carbonate to initiator equivalent ratio of about 1 is used. Catalysts are used in most cases, as reaction rates are very slow in the absence of a catalyst. When high alkylene carbonate to initiator ratios are used to make higher molecular weight pol (alkylene carbonate) polyols, reaction rates drop severely as higher conversions are approached; long reac¬ tion times are required and the products are con¬ taminated by unreacted alkylene carbonate. If temperatures are increased to increase the rate, the product decomposition occurs with C0 2 loss. In the instant process, rates of molecular weight build are rapid without C0 2 loss. The choice of catalyst has an effect on the molecular weight and the CC> 2 retention of the poly(alkylene car¬ bonate) polyol. In each process the choice of the ratio of starting reactants and catalysts resulted in an upper limit on the molecular weight of the poly(alkylene carbonate) polyol which can be prepared. Furthermore, the products of such processes are of relatively low molecular weight and have a broad molecular weight range, that is, they have a high poly-dispersity index and are often contaminated with unreacted starting materi¬ als and relatively low molecular weight reaction intermediates. Furthermore, the particular reac- tant ratio and catalyst used has a significant effect on the amount of carbon dioxide moieties in the backbone of the chain. What is needed is a process for prepar¬ ing higher molecular weight poly(alkylene carbon¬ ate) polyols beyond the limitations imposed by the stoichiometry and catalyst used at reasonable reac¬ tion rates and free of low molecular weight contam¬ inants. Furthermore, what is needed is a process for making higher molecular weight poly(alkylene carbonate) polyols with a relatively low p ly- -dispersity index. What is further needed is a process which allows the preparation of poly(alkyl¬ ene carbonate) polyols with higher carbon dioxide contents. The invention is a process for increas¬ ing the molecular weight of a poly(alkylene carbon¬ ate) polyol which comprises exposing the poly(alkyl¬ ene carbonate) polyol to elevated temperatures at which dialkylene glycol, trialkylene glycol, or initiator segments, wherein the initiator has about the same or greater volatility as the dial- kylene glycol or trialkylene glycol segment, are abstracted from the poly(alkylene carbonate) polyol, at a pressure wherein the dialkylene glycol, trial¬ kylene glycol or initiator is volatile, and removing the volatile dialkylene glycol, trialkylene glycol or initiator segments from the mass of the poly(al¬ kylene carbonate) polyol, under conditions such that the molecular weight of the poly(alkylene car¬ bonate) polyol is increased. This process allows the preparation of higher molecular weight poly(alkylene carbonate) polyols at faster rates and higher purity than previously prepared in the art. Furthermore, the process allows a great deal of flexibility in the preparation of such polyols with varying degrees of molecular weight. The poly(alkylene carbonate) polyols prepared by this process generally have an increased weight percent of carbon dioxide moieties in the backbone of the polymer, and have a lower poly-dispersity index. The starting materials in the process of this invention are poly(alkylene carbonate) polyols. Such compounds include randomized polymers containing C0 2 moieties and di- and polyalkylene- oxy units. The poly(alkylene carbonate) polyols can further contain the residue of an initiator as well as unreacted starting material's and other relatively volatile reaction products. Alkylene- oxy moieties refer herein to a series of repeat- ing units which contain an alkylene group bound to an oxygen, wherein the carbons of the alkylene group can be further substituted with a hydrocar- byl moiety. Alkyleneoxy moieties can be repre¬ sented by the following formula <C T R 2 ) 2 -C(R 2 ) 2 -0} s wherein R 2 is as herei•nafter defi•ned, and s is an integer of 2 or greater; more preferably between about 2 and 10; even more preferably 2 or 4; and most preferably 2. A dialkylene glycol refers herein to 2 alkylene moieties connected by an oxy¬ gen and terminated by a hydroxyl group, wherein the alkylene moieties can be substituted with a hydrocarbyl moiety. Preferred dialkylene glycol moieties correspond to the formula HO-C(R 2 ) 2 -C(R 2 ) 2 -0-C(R 2 ) 2 -C(R 2 ) 2 -OH wherein R2 is as hereinafter defined. Examples of preferred dialkylene glycols include dipropyl- ene glycol, diethylene glycol, 1,2-dibutylene gly¬ col, 2,3-dibutylene glycol, and the like. Preferred poly(alkylene carbonate) poly¬ ols are random polymers of 0 II _(R x ) χ t-CO* tC(R A ) 2 -C(R * ) 2 0) Z H]m wherein R 1 is 3 X)_; 2 . " R is separately in each occurrence hydro¬ gen, halogen, a nitro group, a cyano group, a l-20 n y drocart> Yl group or a C , 2Q hydrocarbyl group substituted with one or more of the fol¬ lowing: a halo, cyano, nitro, thioalkyl, tert- -amino, alkoxy, aryloxy, aralkoxy, carbonyldi- oxyalkyl, carbonyldioxyaryl, carbonyldioxyar- alkyl, alkoxycarbonyl, aryloxycarbonyl, aralk- oxycarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkylsulfinyl, arylsulfinyl, aralkylsulfinyl, alkylsulfonyl, arylsulfonyl, or aralkylsulfonyl group; R 3 i.s separately in each occurrence an n valent hydrocarbon radical or hydrocarbon radical which can contain one or more hetero- atoms of 0, N or S; X is S , 0 , NH, 0 0 0 tl II II -CO- , -OCO- , or -CNH- / m is an integer of 1 or greater; n is separately in each occurrence an integer of from 1 to 25; x is 1; y is separately in each occurrence 1 to 40; and z is separately in each occurrence 1 to 100. One preferred class of poly(alkylene carbonate) polyols generally corresponds to-the formula O (R 3 X((C0) p -C(R 2 ) 2 -C(R 2 )2)q-0))mHn wherein R 2, R3, X, n and m are as previously defined; p is separately in each occurrence 0 or 1; and q is separately in each occurrence an integer of 1 or greater. In the hereinbefore defined formulas, R 2 i.s preferably hydrogen, C 1 _ 2Q alkyl, , 2Q halo- alkyl, C-,_ 2Q alkenyl or phenyl; R is more prefer¬ ably hydrogen, C__ 3 alkyl, C 2 _ 3 alkenyl, or phe¬ nyl; R is even more preferably hydrogen, methyl 2 or ethyl; R is even more preferably hydrogen or methyl, and most preferably hydrogen. R 3 is pref¬ erably an aliphatic or cycloaliphatic hydrocarbon or an aliphatic or cycloaliphatic hydrocarbon con- taining one or more oxygen, nitrogen or sulfur moi- eties; R 3 i.s more preferably a n valent alkane or cycloalkane, or a n valent alkane or cycloalkane containing one or more oxygen, nitrogen or sulfur 3 . moieties; R is even more preferably a n valent c ι_ιo a lkane or a n valent C_ _ Q alkane substi¬ tuted with one or more oxygen moieties. X is preferably S, 0 or NH; X is most preferably 0. Preferably, m is 1 to 10, more preferably 1 to 5. Preferably, n is an integer of 1-10, inclusive; more preferably 1-5, inclusive; and most prefer¬ ably 1 or 2. Preferably, q is an integer of from 1 to 1000, inclusive; and most preferably an integer of from 1 to 500, inclusive. Preferably, y is 5 to 20, and z is 20 to 50. The products of this process are poly- (alkylene carbonate) polyols with higher molecular weights than the starting pol (alkylene carbonate) polyols. The molecular weights of the poly(alkyl¬ ene carbonate) polyols prepared by this process can be any molecular weight desired which is above the starting molecular weight. Preferable molecular weights are between 500 and 10,000, with most pre¬ ferred molecular weights being between 1,000 and 8,000. The products prepared have a poly-dispersity index (M / ), either only slightly higher or in some cases even lower than the starting pol (alkyl¬ ene carbonate) polyols. Poly-dispersity indexes are known to increase with increasing molecular weight in step growth polymerization. The prod-., ucts prepared contain a higher weight percent of C0 2 in the backbone than the starting materials. Unreacted starting materials and low molecular weight reaction products produced during the preparation of the starting poly(alkylene car¬ bonate) polyols are removed. The process of this invention preferably involves exposing a poly(alkylene carbonate) polyol to elevated temperatures under reduced pressure con¬ ditions so as to cause the splitting off of a dial¬ kylene glycol moiety, a trialkylene glycol moiety and/or a moiety which, is as volatile or more vola- tile than the dialkylene glycol or trialkylene gly¬ col moiety and removing such volatile components from the reaction mass. Generally, the dialkylene glycol and/or initiator will volatilize. Depend¬ ing on the degree of rectification used, and the CO„ content, less volatile components may come off, such as the trialkylene glycols. If the pol (alkylene carbonate) polyol starting material contains no dialkylene glycol units, the trialkyl¬ ene glycol units can be removed by this process. In general, the lightest fraction which splits from the starting material will be taken off. In those embodiments wherein the poly(alkylene carbon¬ ate) polyol is a monofunctional species, that is; where the initiator has only one active hydrogen site, under certain circumstances the initiator fragment may be more volatile than the dialkylene glycol fragment and therefore will split off and be removed more readily than the dialkylene glycol portion. When the initiator is a linear C, „ alco¬ hol, the C 1 _ 8 alcohol fragment will be removed before any dialkylene glycol fragments will be removed. Where a linear C 1Q or C.. alcohol is used as the initiator, the linear C, Q or C,., alco¬ hol is about as volatile as the dialkylene glycol and therefore should come off at the same time. Wherein a linear C 12 or greater alcohol is the initiator, the dialkylene glycol is more volatile and will split off. Branched alcohol initiators have somewhat different volatilities and will be split out based on its relative volatility as com- pared to the dialkylene or trialkylene glycol fragment. The volatile component can be removed by any method known in the art. Such methods include fractional distillation, fractionation, passing an inert gas over the reaction mass so as to remove the volatile species, and any other method for removing the volatile species condensed by a water-chilled condenser as is known in the art, for example, a falling film still such as a wiped film evaporator is particularly useful. A preferred method of con¬ densing the distillate is by the use of a water- -chilled condenser. The majority of the volatile components present such as acetone and water, both introduced during catalyst removal, and dioxane, small quantities of which can be present due to decomposition, pass through the water-chilled con¬ denser under the reduced pressure conditions employed and can be condensed using a dry ice con¬ denser. The volatile species condensed by the water- -chilled condenser can be recycled to be used as ini¬ tiators for the preparation of poly(alkylene carbon- ate) polyols useful as starting materials in this process. The process of this invention takes place at any temperature at which the splitting off of the volatile segments occurs. The lower temperature limit is that temperature at which the splitting of the volatile component occurs, and the upper limit is that temperature at which the poly(alkylene carbonate) polyol undergoes decom¬ position. Preferred temperatures are between 150°C and 300°C. More preferred temperatures are between 175°C and 260°C, with between 200°C and 250°C being most preferred. Pressures used in this process are those pressures at which the dialkylene glycol or species as volatile or more volatile than dialkyl¬ ene glycol will volatilize at the temperatures used. Preferable pressures are atmospheric and subatmos- pheric, with subatmospheric pressures being more preferable. More preferable pressures are less than 300 mm Hg (40.0 kPa), even more preferably less than 100 mm Hg (13.3 kPa), even more preferably less than 50 mm Hg (6.67 kPa), and most preferably between 10 and 30 mm Hg (1.33 and 4.00 kPa). It is preferred to remove the catalysts used to prepare the pol (alkylene carbonate) polyols prior to the performance of this process, as such catalysts can result in the decomposition of the poly(alkylene car¬ bonate) polyols at the temperatures used in this process Trace amounts of such catalysts can be present without significant decomposition. The bulk of the catalyst is preferably removed prior to the advancement process. The combination of short reaction times in the presence of very low cata¬ lyst levels allows high molecular weight build with minimal decomposition. The reaction time for the process of this invention is variable depending on various factors, including temperature, pressure, and the molecular weight of the desired product. At lower pressures, and at higher temperatures, the time to achieve the desired molecular weight is lower. The process can be run for a time sufficient to give the desired molecular weight. Reaction times are rela¬ tively rapid, only a few hours are required in most cases. The process of this invention is gener¬ ally performed by exposing the poly(alkylene car¬ bonate) polyol in neat form to the processing con¬ ditions. The process can be performed in a solvent, although performing the process in neat form is preferred. Solvents useful include inert organic solvents with a boiling point above that of the dialkylene glycol, or the most volatile species. Pol (alkylene carbonate) polyol start¬ ing materials useful in this invention are pre- pared by any method known in the art, such as, the condensation of an alkylene carbonate; carbon dioxide and an alkylene oxide; or mixtures of an alkylene carbonate, an alkylene oxide and/or CO-,; with an organic compound containing one or more active hydrogen atoms (initiator) in the presence of an alkaline catalyst or metal salt of an alka¬ line compound. Examples of these poly(alkylene carbonate) polyols and methods for preparation of these polyols are contained in Maximovich, US 3,896,090; Maximovich, US 3,689,462; Springmann, US 3,313,782; Stevens, US 3,248,416; Stevens, US 3,248,415; and Stevens, US 3,248,414. An example of useful poly(alkylene car¬ bonate) polyol starting materials is represented by the following formula R 3 *X( (CO) p -C(R 2 ) 2 -C(R 2 ) 2 ) q -OH) n wherein R 2, R3, X, n, p and q are as hereinbefore defined. Alternatively, the pol (alkylene carbon¬ ate) polyols can be prepared by reacting a dialkyl carbonate or diaryl with an initiator with two or more hydroxyl moieties. See, for example, US 4,476,293 and US 4,191,705. Alkylene carbonates useful in the reac¬ tion are those which will react with the reactive hydrogen-containing functional groups. Desirable alkylene carbonates are those corresponding to the mula II 0 0 2 \ / 2 (R^) 2 -C-C-(R^) 2 wherein R 2 i.s as previously defined. Dialkyl carbonates useful in this inven¬ tion include those corresponding to the formula (R 2 ) 3 C-OCO-C(R 2 ) 3 and more preferably, 0 HC(R 2 ) 2 -C(R 2 ) 2 -OCO-C(R 2 ) 2 C(R 2 ) 2 H wherein R 2 is as previously defined. R 2 i.s preferably hydrogen, or a monova- lent C-,_ 20 alkane, C__ 20 haloalkane, C., 2Q alkene or benzene radical. R is more preferably hydro¬ gen, or a monovalent C.__ alkane, C _ 3 alkene or benzene radical. R is most preferably hydrogen, or a monovalent methane or ethane. Examples of desirable alkylene carbon¬ ates include ethylene carbonate, propylene carbon¬ ate, butylene carbonate, vinylene carbonate and phenylene carbonate. More preferred alkylene car- bonates include ethylene and propylene carbonate. Examples of preferred dialkyl carbonates include dimethyl carbonate, diethyl carbonate and dipropyl carbonate. A preferred diaryl carbonate is diphe- nyl carbonate. Epoxides useful for preparing starting materials for this invention are those which will react with C0 2 or the functional group on an organic compound wherein the functional group contains an active hydrogen so as to add an ether and carbon- ate unit to the organic compound. Desirable epoxides- include those corre¬ sponding to the formula (R 2 ) c C-(R 2 ) 2 \θ 2 wherein R 2 i.s as defined above. Among desirable epoxides are the alkyl¬ ene oxides, for instance ethylene oxide, propylene oxide, butylene oxide; epihalohydrins, such as epi- bromohydrin and epichlorohydrin; styrene oxide, vinylene oxide, cyclohexene oxide; cyclopentene oxide, cycloheptene oxide, 2,3-epoxy propylphenyl ether and tert-butyl glycidyl ether. Among pre¬ ferred epoxides are ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibro- mohydrin, styrene oxide and vinylene oxide. The organic compound containing active hydrogen atoms (the initiator) is a hydrocarbon or hydrocarbon which is substituted with one or more heteroatoms of oxygen, nitrogen or sulfur contain¬ ing between 1 and 25 functional groups containing a reactive hydrogen. Among the desirable initi¬ ators are those which correspond to the formula R 3 γXH) n . 3 wherein R , X and n are as hereinbefore defined. A functional group containing a reactive hydrogen means herein any moiety which contains a hydrogen- atom which will readily react with an alkylene carbonate, a dialkyl carbonate, diaryl carbonate or an alkylene oxide in the presence of carbon dioxide. More specifically, reactive hydrogen means herein a hydrogen linked directly to an oxy¬ gen, nitrogen or sulfur atom, such as is found in a hydroxy, non-tertiary amine, amide, mercapto or carboxyl group. The organic compounds containing active hydrogen atoms of this invention (the initiator) contain one or more of the following functional groups, hydroxyls, amines, mercaptans, carboxyls, sulfones, amides, imides, or carbonates. In addi¬ tion, the initiators may contain other groups in their backbone structure, such as, for example, sul- fones, sulfoxides, sulfides, amines, amides, ethers, esters, carbonates and the like. Among desirable initiators are polyols such as aliphatic polyether and polyester polyols, cycloaliphatic polyols, aromatic polyols and poly¬ ols which further contain oxy or ether groups; polyamines; polymercaptans; polyamides; polycar- boxylic acids; water, alkylolamines and organic compounds which contain two or more of the above- -described functional groups containing reactive hydrogens. The preferred classes are the poly¬ ols, polyamines and polymercaptans. Examples of active hydrogen-containing compounds include those described in the U.S. patents incorporated by ref¬ erence hereinbefore. Two or more initiators can be used in combination to obtain a poly(alkylene carbonate) polyol. Catalysts used in the preparation of poly- ether polyols include alkali metal hydroxides, alka¬ line earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, ammonium hydroxide and ammonium carbonate. Preferable catalysts for the reaction of an active hydrogen-containing organic compound with an alkylene carbonate, dialkyl carbonate, diaryl carbonate, alkylene oxide and carbon monoxide, or alkylene carbonate in admixture with an alkylene oxide and/or carbon dioxide include ester exchange catalysts. Among preferable catalysts are such metals as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic and cerium as well as the alkoxides thereof. Examples of other preferable catalysts are alkali metal carbonates, alkaline earth metal carbonates, ammonium carbonates, alkali metal borates, alkaline earth metal borates, ammo¬ nium borates, hydrocarbyloxy titanates, zinc borate, lead borate, zinc oxide, lead silicate, lead arsen- ate, litharge, lead carbonate, antimony trioxide, germanium dioxide, cerium trioxide and aluminum isopropoxide. Examples of other preferable cata¬ lysts include salts of organic acids of magnesium, calcium, cerium, barium, zinc and titanium, alkali metal stannates, alkaline metal stannates and ammo¬ nium stannates. Examples of borate catalysts include sodium meta-borate, sodium meta-borate tetrahydrate, sodium meta-borate dihydrate, sodium pentaborate pentahydrate, sodium tetraborate decahydrate, .sodium tetraborate pentahydrate, diammonium tetraborate tetrahydrate, ammonium hydrogen tetraborate tetra¬ hydrate, lithium ortho-dihydroborate, lithium meta- -borate, lithium tetraborate, lithium pentaborate pentahydrate, potassium meta-borate, potassium tetraborate tetrahydrate, potassium tetraborate pentahydrate, potassium pentaborate tetrahydrate, magnesium meta-borate trihydrate, magnesium dibor- ate, magnesium ortho-borate, calcium meta-borate, calcium tetraborate and strontium tetraborate tetra¬ hydrate. Examples of stannate catalysts include sodium stannate trihydrate, potassium stannate tri- hydrate, potassium stannate monohydrate, barium stan¬ nate trihydrate, and magnesium stannate trihydrate. More preferred catalysts are the alkali metal carbonates, alkaline earth metal carbonates, ammonium carbonates, alkali metal stannates, alka¬ line earth metal stannates, alkali metal borates, alkaline earth metal borates and ammonium borates. Even more preferred catalysts are alkali metal car¬ bonates, alkali metal borates and alkali metal stan¬ nates. Most preferred catalysts are potassium car¬ bonate, sodium meta-borate and sodium stannate. The choice of catalyst affects the per¬ centage of carbon dioxide units in the poly(alkyl- ene carbonate) polyol. Generally, the poly(alkyl¬ ene carbonate) polyol contains between 5 and 35 weight percent of the carbon dioxide. The use of most of the catalysts described hereinbefore results in a poly(alkylene carbonate) polyol in which about 10 percent of the units are carbon dioxide units, whereas the use of sodium meta-bor¬ ate results in about 25 percent carbon dioxide units, and the use of sodium stannate results in from 30 to 50 percent carbon dioxide units. In this context, percent means the percentage of the carbon dioxide units based on the total of the car¬ bon dioxide units and the alkyleneoxy units. A suitable amount of the catalyst is any amount which is catalytic under the reaction condi- tions. Preferable catalyst concentrations are between 0.01 and 5 percent by weight based upon the reactants, more preferably between 0.01 to 1.0 percent by weight, and most preferably between 0.05 to 0.1 percent by weight. A method of removing alkaline catalysts from polyether polyols and poly(alkylene carbonate) polyols comprises (a) dissolving a polyether polyol or a pol (alkylene carbonate) polyol in an apro- tic solvent; (b) contacting the polyether polyol or poly(alkylene carbonate) polyol solution with a sufficient amount of an adsorbent which adsorbs alkaline catalysts to adsorb the alkaline cata- lysts, at a temperature of between about -30°C and 110°C under conditions such that the adsorb¬ ent adsorbs the alkaline catalysts; and (c) physically separating the adsorb¬ ent from the polyol solution. The following examples are included for illustrative purposes only, and do not limit the scope of the invention or the claims. Unless other¬ wise stated, all parts and percentages are by weight. The molecular weights and distribution are determined by size 'exclusion chromatography on (R) Waters Ultrastyragel 1000 A and 10,000 A columns in series using tetrahydrofuran (THF) as the mobile phase and calibrated with narrow molecular weight poly(ethylene glycol) standards. Example 1 Part A: A 5:1 mole ratio of ethylene carbonate (EC)-: diethylene glycol (DEG) is heated with stirring under a nitrogen atmosphere for 7 hours at 150°C using 1.0 weight percent Na-,Sn0 3 3H_,0 as catalyst to give a 98 percent ethylene carbonate conversion; with prod¬ uct containing 23.1 weight percent carbon dioxide. Part B: The product (20 weight percent in ace¬ tone) is stirred with Florisil (1 g/10-g product) for 3 hours to remove catalyst, followed by filtra¬ tion to remove catalyst and_ concentration to remove acetone. A sample (91.3 g) is placed in a two- -necked boiling flask and several boiling stones are added. The flask is equipped with a thermom¬ eter and heating mantel and attached to a distill¬ ing apparatus connected to a vacuum source, and subjected to fractionation. The maximum pot temperature is 185°C. The pressure is maintained between 0.5 to 1.0 mm Hg (0.07 to 0.13 kPa). Distillate (24 g) is recovered (92 percent diethylene glycol and 7 percent ethylene carbonate). The residue is a light amber viscous liq- uid, with 29.0 weight percent carbon dioxide. The results are compiled in Table I. Example 2 Part A: A 10:1 mole ratio of ethylene carbonate (EC) :monoethylene glycol (MEG) is heated with stirring under a nitrogen atmosphere for 24 hours at 135°C using 1.0 weight percent Na 2 Sn0 3 3H 2 0 as catalyst to give a 100 percent ethylene carbonate conversion to a poly- (alkylene carbonate) polyol with 25.8 percent weight percent carbon dioxide. Part B: The polyol (20 weight percent in acetone) is stirred with Florisil (1 g/10-g polyol) for 2 hours to remove catalyst, followed by filtration and concen¬ tration. A sample (89.8 g) is subjected to fraction- ation at a maximum pot temperature of 194°C and' a pressure of 0.5 to 1.0 mm Hg (0.07 to 0.13 kPa). Distillate (21.2 weight percent) is recovered (3 percent monoethylene glycol, 86 percent diethylene glycol and 6 percent triethylene glycol). The residue is a light amber viscous liquid, with 32.1 weight percent carbon dioxide. The results are compiled in Table I. Example 3 Part A: A 15:1 mole ratio of ethylene carbonate (EC) :diethylene glycol (DEG) is heated with stirring under a nitrogen atmosphere for 8 hours at 150°C using 1.0 weight percent Na SnO g 3H 2 0 as catalyst to give 95.7 percent ethylene carbonate conversion to a poly- (alkylene carbonate) polyol with.21.8 weight percent carbon dioxide. Part B: The catalyst is removed as in Example 1. A sample (73.0 g) is subjected to fractionation with a maximum pot temperature of 210°C and a pressure of 0.5 to 0.8 mm Hg (0.07 to 0.11 kPa) to give a 20.7 weight percent distillate of 25 percent ethylene carbonate, 73 percent diethylene glycol and 1 percent monoethylene glycol. The residue is a light amber viscous liquid with 30.8 weight percent carbon dioxide. The results are compiled in Table I. Example 4 Part A: A 50:1 mole ratio of ethylene carbonate (EC) :monoethylene glycol (MEG)is heated with stirring under a nitrogen atmosphere for 88 hours at 135°C using 0.2 weight percent Na 2 SnO_ 3E_ 2 0 as catalyst to give 96.6 percent ethylene carbonate conversion to a poly- (alkylene carbonate) polyol with 27.6 weight percent carbon dioxide. Part B: The catalyst is removed as in Example 1. A sample (184.4 g) is subjected to fractionation with a maximum pot temperature of 210°C and a pressure of 1.3 mm Hg (0.17 kPa) to give an 8.0 weight per- cent distillate of 71.5 percent ethylene carbonate and 25.3 percent diethylene glycol. The residue ' is a light amber viscous liquid with 29.3 weight percent carbon dioxide. The results are compiled in Table I. Example 5 Part A: A 100:1 mole ratio of ethylene carbonate (EC) :monoethylene glycol (MEG) is heated with stirring under a nitrogen atmosphere for 121 hours at 135°C using 0.1 weight percent Na 2 Sn0 3 3H 2 0 as catalyst to give 92.5 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 26.9 weight per¬ cent carbon dioxide. Part B: The catalyst is removed as in Example 1. A sample (72.7 g ) is subjected to fractionation with a maximum pot temperature of 227°C and a pressure of 1.5 mm Hg (0.20 kPa) to give a 9.4 weight percent distil- lation of 46.3 percent ethylene carbonate, 36.9 percent diethylene glycol and 6.9 percent triethylene glycol. The residue is a light amber viscous liquid with 30.0 weight percent carbon dioxide. The results are compiled in Table I. Example 6 Part A: A 1:2 mole ratio of diethyl carbonate (DEC):- diethylene glycol (DEG) is heated with stirring under a nitrogen atmosphere using 1.0 weight percent Na 2 SnO_ 3H 2 0 as catalyst. The pot temperature is allowed to increase from 122°C to 187°C during which time ethanol and some diethyl carbonate are removed from the reactor by distillation. The residue is a pol (alkylene car¬ bonate) polyol which is a liquid with 27.7 weight percent carbon dioxide. Part B: The catalyst is removed as in Example 2. A sample (97.2 g) is subjected to fractionation at a maximum pot temperature of 215°C and a pressure of 0.3 to 2.0 mm Hg (0.04 to 0.27 kPa) to give a 9.5 weight percent distillate. The residue is a light amber viscous liquid with 33.4 percent carbon dioxide. The results are compiled in Table I. TABLE I Molecular Weight Data Portion of Advancement t % l Wt % 2 Tg Example Reactants Conditions Advanced Residue ' c0 ? (°C) Peak Mn Mw PDI 1A EC:DEG=5:1 No - 23.1 -57.3 526 423 756 1.786 IB 185°C/0.5-1.0 mm Yes 70.3 29.0 -24.6 4255 2146 3749 1.757 (0.07-0.13 kPa) 2A EC:MEG=10:1 No - 25.8 -47.9 1050 630 1126 1.787 2B 194°C/0.5-1.0 mm Yes 78.8 32.1 -19.3 6861 3077 5829 1.894 (0.07-0.13 kPa) 3A EC:DEG=15:1 No - 21.8 -45.1 1393 792 1449 1.830 3B 210°C/0.5-0.8 mm Yes 79.3 30.8 -23.2 6219 2840 4892 1.722 (0.07-0.11 kPa) 4A EC:MEG=50:1 No - 27.6 -34.3 3485 1636 3624 2.218 4B 210°C/1.3 mm Yes 90.2 29.3 -19.4 6219 2889 4663 1.614 (0.17 kPa) 5A EC:MEG=100:1 No - 26.9 -29.1 5126 2286 5343 2.358 5B 227°C/1.5 mm Yes 87.3 30.0 -13.9 I I I I (0.20 kPa) 6A DEG:DEC ~2 No - 27.7 -56.7 734 540 878 1.626 6B 215°C/0.3-20 mm Yes 79.2 33.4 -16.6 5646 2614 4608 1.763 (0.04-0.27 kPa) 1 Wt residue after advancement x 100 Wt PAC polyol before advancement 2 Nuclear magnetic resonance procedure using dimethyl sulfoxide as internal standard PDI stands for poly-dispersity index. TABLE IA Capillary Gas Chromatographic Analysis of Examples IB to 4B Assay ( t %) EC:Diol Example Mole Ratio Diol Advanced Dioxane MEG DEG TEG EC IB 5 DEG Yes - 0.40 - - - 2A 10 MEG No - 0..72 6.70 0.56 1.84 2B 10 MEG Yes - 0.51 - - - 3B 15 DEG Yes 0.46 4A 50 MEG No 0.20 0. 18 4.64 4B 50 MEG Yes 0.25 Example 1 shows that advancement of a 5:1 product can increase the molecular weight beyond that of a 50:1 product while reducing the poly-dispersity index (PDI). This is accomplished in only a fraction of the time required to make a 50:1 product. Example 2 shows that advancement of a 10:1 product can increase the molecular weight beyond that of a 100:1 product while reducing the poly-dispersity index. This is accomplished in only a fraction of the time required to make a 100:1 product, while remov¬ ing volatile impurities. Example 3 shows that advancement of a 15:1 product can increase the molecular weight by more than three-fold while maintaining a low poly-dispersity index. Example 4 shows that advancement of a 50:1 product can increase the molecular weight to about that of" a - 100:1 product but at greatly reduced poly-dispers¬ ity index and with removal of volatile impurities. Example 5 shows that the advancement of a 100:1 product can produce a high molecular weight, high purity product with a Tg of -13.9°C. Example 6 shows that advancement of a 2:1 DEG:DEC product can increase the molecular weight to about that of a 100:1 product but at a greatly reduced poly- -dispersity index and at much higher reaction rates. Example 7 Part A: A 10:1 mole ratio of ethylene carbonate and diethylene glycol is heated with stirring under a nitrogen atmosphere for 3 hours at 175°C using 0.5 weight percent Na 2 Sn0 3 3H 2 0 as catalyst to give 97.5 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 23.7 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (1069.6 g) is subjected to fractional distillation for 2.5 hours with a max- imum pot temperature of 237°C and a pressure of 10 mm Hg (1.3 kPa). Distillate is collected in a water-chilled condenser (~15°C) and a dry ice-isopro- panol trap (—78°C). The distillate collected * at 15°C accounts for 16.7 weight percent (179.1 g) of the sample charged and has the following assay: 0.30 percent monoethylene glycol, 1.51 percent dioxane, 10.49 percent ethylene carbonate, 76.21 percent diethylene glycol, 10.04 percent triethyl- ene glycol, 0.70 percent tetraethylene glycol and 0.05 percent water (99.4 percent total). The dis¬ tillate collected at -78°C accounts for 4.9 weight percent (51.9 g) of the sample charged and has the following assay: 60.23 percent acetone, 24.97 percent dioxane and 8.8 percent water (94.0 per- cent total). The residue is a light amber viscous liquid with 29.5 weight percent carbon dioxide, accounts for 77.4 weight percent (828.2 ' g) of the sample charged and has the properties shown in Table II. Ti-BLE II wt % t % Molecular Weight Data Advanced Residue CO ? Mn Mw PDI No _ 23.7 643 1230 1.840 Yes 77.4 29.5 2372 5463 2.303 Example 7 shows scale-up data on a pre¬ ferred method using a 10:1 product. Reaction rates are rapid; complete distillate analysis is given. Example 8 Part A: A 10:1 mole ratio of ethylene carbonate to diethylene glycol is heated with stirring under a nitrogen atmosphere for 24 hours at 135°C using 0.5 weight percent Na 2 Sn0 3 3H 2 0 as catalyst to give 91.6 percent ethylene carbonate conversion to a pol (alkylene carbonate) polyol with 21.3 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (525.8 g) is subjected to fractional distillation for 2.5 hours with a max¬ imum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Additional samples are sub¬ jected to fractional distillation to higher pot temperatures and a pressure of 10 mm Hg (1.3 kPa) The results are given in Table III. TABLE III t % t % t % Molecular Weight Data Aαvance en Conditions Advanced Residue Distillate C0 ? HMw Mn Mw PDI starting material No - - 21.3 - 655 1154 1.761 235°C/10 mm Yes 71.9 27.7 31.1 1941 1938 3958 2.042 (1.3 kPa) 249°C/10 mm Yes 71.1 28.2 29.8 2250 2113 4609 2.180 (1.3 kPa) 262°C/10 mm Yes 69.8 29.4 29.1 2770 I I I (1.3 kPa) . 275°C/10 mm Yes 67.7 30.3 25.4 3886 I I I (1.3 kPa) : I = Insoluble in tetrahydrofuran HMw = Hydroxyl molecular weight Example 8 shows the effects of final pot temperature on molecular weight build and C0 2 content. High C0 2 content is retained in the prod¬ uct even at 275°C. Example 9 Part A: A diethylene glycol initiated adduct is made from ethylene oxide and carbon dioxide at 175°C using sodium stannate trihydrate as catalyst. _ The catalyst is removed by the process described in Example 1. The residue is a poly(alkylene car¬ bonate) polyol with 17.8 weight percent carbon dioxide. Part B: A sample (516.5 g) is subjected to fractional distillation for 2.5 hours with a max¬ imum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Distillate is collected in a water- -chilled condenser (~15°C) and a dry ice-isopro- panol trap (—78°C). The distillate collected at 15°C accounts for 31.2 weight percent (161.3 g) of the sample charged and has the following assay: 0.44 percent monoethylene glycol, 0.90 percent dioxane, 6.66 percent ethylene carbonate, 73.7 percent diethylene glycol, 15.19 percent triethyl- ene glycol, 1.29 percent tetraethylene glycol and 0.02 percent water (98.2 percent total). The dis¬ tillate collected at -78°C accounts for 0.7 weight percent (3.4 g) of the sample charged and has the following assay: 2.36 percent acetone, 85.73 per¬ cent dioxane and 2.6 percent water (90.7 percent total). The residue is an amber viscous liquid with 20.9 weight percent carbon dioxide, accounts for 67.1 weight percent (346.6 g) of the sample charged and has the properties shown in Table IV. TABLE IV wt % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No 17.8 621 428 671 1.560 Yes 67.1 20.9 4365 1973 4141 2.098 Example- 9 shows- scale-up data on a- pre- - ferred method using a product made from ethylene oxide and carbon dioxide. Reaction rates are rapid to give a high molecular weight product with a rela¬ tively low poly-dispersity index (compare to 50:1 product) . Example 10 Part A: A 10:1 mole ratio of ethylene carbonate to polypropylene glycol having a molecular weight of 425 is heated with stirring under a nitrogen atmos¬ phere for 6 hours at 175°C using 0.5 weight percent sodium stannate trihydrate as catalyst to give 98 percent ethylene carbonate conversion to a poly- (alkylene carbonate) polyol with 10.8 weight percent carbon dioxide. The catalyst is removed as in Example Part B: A sample (81.8 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Dis- tillate is collected in a water-chilled condenser (~15°C) and a dry ice-isopropanol trap (—78°C). The distillate collected at 15°C accounts for 9.8 weight percent (8.0 g) of the sample charged and has the following assay: 1.02 percent monoethylene glycol, 5.40 percent ethylene carbonate, 76.9 percent dieth¬ ylene giycol and 8.13 percent triethylene glycol. The distillate collected at -78°C accounts for 2.5 weight percent (2.1 g) of the sample charged and has the following assay: 69.1 percent acetone and 24.7 percent dioxane. The residue is a light straw viscous liquid with 12.7 weight percent carbon dioxide, accounts for 86.8 weight percent (71.0 g) of the sample charged and has the properties shown in Table V. TABLE V wt % wt % MClecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No 10.8 1323 817 1562 1.91 Yes 86.8 12.7 3021 1870 3891 2.08 Example 10 shows that a polypropylene glycol of 425 molecular weight can be used as ini¬ tiator. A 10:1 product is rapidly advanced to a high molecular weight product with relatively low poly-dispersity index. Example 11 Part A: A 10:1 mole ratio of ethylene carbonate to 1,4-butanediol is heated with stirring under a nitrogen atmosphere for 7 hours at 150°C using 0.5 weight percent sodium stannate trihydrate as cata¬ lyst to give 93 percent ethylene carbonate conver- sion to a poly(alkylene carbonate) polyol with 19.3 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (92.5 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 190°C and a pressure of 10 mm Hg (1.3 kPa). Dis- tillate is collected in a water-chilled " condenser (~15°C) and a dry ice-isopropanol trap (—78°C). The distillate collected at 15°C accounts for 25.3 weight percent (23.4 g) of the sample charged and has the following assay: 0.66 percent monoethylene glycol, 17.1 percent 1,4-butanediol, 76.9 percent diethylene glycol and 0.51 percent triethylene glycol. The distillate collected at -78°C accounts for 11.1 weight percent (10.3 g) of the sample charged and has the following assay: 22.0 per- cent acetone and 23.8 percent dioxane. The resi¬ due is a light straw viscous liquid with 25.2 weight percent carbon dioxide, accounts for 52.4 weight percent (23.4 g) of the sample charged and has the properties shown in Table VI . TABLE VI wt % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No _ 19.3 258 357 489 1.37 Yes 52.4 26.2 1161 819 1332 1.63 Example 11 shows that 1,4-butanediol can be used as initiator. A 10:1 product is rapidly advanced to a much higher molecular weight product. Some of the 1,4-butanediol is present in the distillate. Example 12 Part A: A 10:1 mole ratio of ethylene carbonate to dipropylene glycol is heated with stirring under a nitrogen atmosphere for 4 hours at 175°C using 0.5 weight percent sodium stannate trihydrate as catalyst to give 100 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 14.7 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (89.5 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Dis¬ tillate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 20.2 weight percent (18.1 g) of the sample charged and has the following assay: 0.91 percent dioxane, 39.4 percent diethylene glycol, 55.8 percent dipro- pylene glycol and 0.30 percent triethylene glycol. The distillate collected in the dry ice-isopropa- nol trap accounts for 4.0 weight percent (3.6 g) of the sample charged and has the following assay: 24.2 percent acetone and 61.3 percent dioxane. The residue is a straw colored viscous liquid with 20.5 weight percent carbon dioxide, accounts for 71.5 weight percent (64.0 g) of the sample charged and has the properties shown in Table VII. TABLE VII wt % wt % Molecular- Weigh Data- Advanced Residue CO ? Peak Mn Mw PDI No _ 14.7 794 461 870 1.89 Yes 71.5 20.5 3485 1921 3817 1.99 Example 12 shows that dipropylene gly- col can be used as initiator. A 10:1 product is rapidly advanced to a molecular weight greater than a 50:1 product. Some of the dipropylene glycol is present in the distillate. Example 13 Part A: A 10:1 mole ratio of ethylene carbonate to polyester polyol (Formrex ® 11-225, a hydroxyl functional diethylene glycol adipate, MW = 500, manufactured by Witco) is heated with stirring under a nitrogen atmosphere for 3.5 hours at 175°C using 0.5 weight percent sodium stannate trihydrate as catalyst to give 97.3 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 18.7 weight percent carbon dioxide. The catalyst was removed as in Example 1. Part B: A sample (93.2 g) is subjected to fractional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Distillate is collected in a water-chilled condenser and a dry ice- • isopropanol trap. The distillate collected by the water-chilled condenser accounts for 10.8 weight percent (10.1 g) of the sample charged and has the following assay: 0.47 percent dioxane, 12.05 percent ethylene carbonate, 76.8 percent diethylene glycol and 2.85 weight percent triethylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 3.4 weight percent (3.2 g) of the sample charged and has the following assay: 85.0 percent acetone and 10.3 percent dioxane. The residue is a straw colored vis¬ cous liquid with 19.0 percent carbon dioxide, -accounts for 84.8 weight percent (79.0 g) of the sample charged and has the properties shown in Table VIII. TABLE VIII wt % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No _ 18.7 1573 1041 1841 1.77 Yes 84.8 19.0 3485 2098 4513 2.15 Example 13 shows that a polyester polyol can be used as initiator. A 10:1 product is rapidly advanced to a much higher molecular weight product. Example 14 Part A: A 10:1 mole ratio of ethylene carbonate to polyester polyol (poly(caprolactone) diol, MW = 530) is heated with stirring under a nitrogen atmosphere for 4 hours at 175°C using 0.5 weight percent sodium stannate trihydrate as catalyst to give 97.9 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 19.2 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (91.3 g) is subjected to fractional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Distillate is collected in a water-chilled condenser and a dry ice- isopropanol trap. The distillate collected by the water-chilled condenser accounts for 13.6 weight per¬ cent (12.4 g) of the sample charged and has the fol¬ lowing assay: 0.85 percent dioxane, 7.27 percent ethylene carbonate, 51.2 percent diethylene glycol and 1.42 percent triethylene glycol. The distillate col- lected in the dry ice-isopropanol trap accounts for 5.8 weight percent (5.3 g) of the sample charged and has the following assay: 89.1 percent acetone and 9.3 percent dioxane. The residue is a straw colored viscous liquid with 22.1 percent carbon dioxide, accounts for 80.0 weight percent (73.0 g) of the sample charged and has the properties shown in Table IX. TABLE IX • wt % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No _. 19.2 1968 1175 2213 1.88 Yes 80.0 22.1 6145 3033 7015 2.31 Example 14 shows that a different type of polyester, polyol .can.be used- as-άnit tor. — 10:1 product is rapidly advanced to a molecular weight much greater than a 100:1 product while maintaining a relatively low poly-dispersity index. Example 15 Part A: A 10:1 mole ratio of ethylene carbonate to N-methyldiethanolamine is heated with stirring under a nitrogen atmosphere for 5 hours at 135°C using 0.5 weight percent sodium stannate trihy¬ drate as catalyst to give poly(alkylene carbonate) polyol. The catalyst is removed as in Example 1. Part B: A sample (87.1 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 200°C and a pressure of 10 mm Hg (1.3 kPa). Dis- tillate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 36.1 weight percent (31.4 g) of the sample charged and has the following assay: 3.68 percent dioxane, 2.03 percent ethylene carbonate, 66.3 percent diethylene glycol, 7.73 percent N-methyldietha- nolamine and 4.?1 percent triethylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 12.6 weight percent (11.0 g) of the sample charged and has the following assay: 30.7 percent acetone and 38.3 percent dioxane. The residue is a dark viscous liquid, accounts for 44.3 weight percent (38.6 g) of the .sample charged and has the properties shown in Table X. TABLE X wt % Molecular Weight Data Advanced Residue Peak Mn Mw PDI No _ 264 313 573 1.83 Yes 44.3 1450 989 2242 2.27 Example 15 shows that a material con¬ taining a tertiary nitrogen in its backbone can function as initiator. A 10:1 product is rapidly advanced to a higher molecular weight product. Example 16 Part A: A 5:1 mole ratio of ethylene carbonate to thiodiethanol is heated with stirring under a nitrogen atmosphere for 6 hours at 150°C using 1.0 weight percent sodium stannate trihydrate as cata¬ lyst to give 92 percent ethylene carbonate conver¬ sion to a poly(alkylene carbonate) polyol. The catalyst is removed as in Example 1. Part B: A sample (93.4 g) is subjected to fractional distillation at a pressure of 10 mm Hg (1.3 kPa). Samples for molecular weight determination are removed at various pot temperatures up to 222°C. Distillate is collected in a water-chilled con¬ denser and a dry ice-isopropanol trap. The dis¬ tillate collected by the water-chilled condenser accounts for 44.4 weight percent (41.5 g) of the sample charged and has the following assay: 0.91 percent dioxane, 13.5 percent ethylene carbonate, 63.4 percent diethylene glycol, 11.3 percent thio¬ diethanol and 2.13 percent triethylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 11.0 weight percent (10.3 g) of the sam- pie charged and has the following assay: 5.73 per¬ cent acetone and 71.8 percent dioxane. The residue is a dark amber viscous liquid and accounts for 33.2 weight percent (31.0 g) of the sample charged. Molecular weight build as a function of pot temper- ature is given in Table XI. • TABLE XI Pot Temperature Molecular Weight Data (°C) Peak Mn Mw PDI Part A Product 419 366 583 1.59 170 1093 686 1324 1.93 195 2179 1101 2532 2.30 215 3278 1455 3767 2.59 222 1889 1048 2568 2.45 Example 16 shows that a material con¬ taining sulfur in its backbone can function as initiator. The molecular weight of a 5:1 product can be increased nearly five-fold by the process of this invention. Example 17 Part A: A 10:1 mole ratio of ethylene carbonate to aminated pol (propylene glycol) (Jeffamine D-400, Mw = 430, a product of the Jefferson Chemical Divi- sion of Texaco) is heated with stirring under a nitrogen atmosphere for 19 hours at 135°C using 0.5 weight percent sodium stannate trihydrate as catalyst to give 96 percent ethylene carbonate con¬ version to a poly(alkylene.carbonate) polyol with 11.1 percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (97.6 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 225°C and a pressure of 10 mm Hg (1.3 kPa). Dis- tillate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 17.5 weight percent (17.1 g) of the sample charged and has the following assay: 0.79 percent monoethyl- ene glycol, 11.9 percent ethylene carbonate, 81.0 percent diethylene glycol and 1.22 percent trieth¬ ylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 2.3 weight percent (2.2 g) of the sample charged and has the following assay: 74.3 percent acetone and 16.8 percent dioxane. The residue is an amber viscous liquid with 12.9 ' percent carbon dioxide;- accounts ~ for 79.7 weight percent (77.8 . g) of the sample charged and has the properties shown in Table XII. TABLE XII t % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No _ 11.1 843 708 1497 2.11 Yes 79.7 12.9 3415 1837 4861 2.65 Example 17 shows that an amino-func- tional material can be used as initiator. A 10:1 product is rapidly advanced to a much higher molec¬ ular weight product. Example 18 Part A: A 50:1 mole ratio of ethylene carbonate to diethylene glycol is heated with stirring under a nitrogen atmosphere for 45 hours at 160°C using 1.0 weight percent sodium metaborate as catalyst to give 100 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 17.8 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (105.7 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Dis- tillate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 9.6 weight percent (10.1 g) of the sample charged and has the following assay: 1.19 percent dioxane, 60.9 percent diethylene glycol, 24.8 percent tri¬ ethylene glycol and 1.05 percent tetraethylene glycol. The distillate collected in the dry ice- -isopropanol trap accounts for 4.1 weight percent (4.3 g) of the sample charged and has the follow- ing assay: 83.4 percent acetone and 3.47 percent dioxane. The residue is a very light yellow, vis¬ cous liquid with 21.0 percent carbon dioxide, accounts for 86.2 weight percent (91.2 g) of the sample charged and has the properties shown in Table XIII. TABLE XIII wt % wt % Molecular Weight Data Advancec1 Residue CO ? Peak Mn Mw PDI No 17.8 1284 754 1445 1.91 Yes 86.2 21.0 2900 1389 3184 2.29 Example 18 shows that poly(alkylene carbonate) polyols made using sodium metaborate as catalyst can be advanced to much higher molec¬ ular weight products by the process of this inven¬ tion. Example 19 Part A: A 10:1 mole ratio of ethylene carbonate to diethylene glycol is heated with stirring under a nitrogen atmosphere for 3 hours at 150°C using 1.0 weight percent potassium carbonate as catalyst to give 95 percent ethylene carbonate conversion to a poly(alkylene carbonate) polyol with 11.6 weight percent carbon dioxide. The catalyst is removed as in Example 1. Part B: A sample (102.2 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 210°C and a pressure of 10 mm Hg (1.3 kPa). Distill¬ ate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 20.3 weight percent (20.8 g) of the sample charged and has the following assay: 0.53 percent dioxane, 12.03 percent ethylene carbonate, 19.8 percent diethylene glycol, 35.3 percent triethylene gly¬ col and 7.54 percent tetraethylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 4.6 weight percent (4.7 g) of the sample charged and has the following assay: 58.8 percent acetone and 29.5 percent dioxane. The residue is an amber viscous liquid with 11.6 percent carbon dioxide, accounts for 69.8 weight percent (71.3 g) of the sample charged and has the properties ' shown in Table XIV. TABLE ; xiv-- - wt % wt % Molecular Weight Data Advanced Residue CO ? Peak Mn Mw PDI No _ 11.6 678 448 751 1.68 Yes 69.8 11.6 969 684 1089 1.59 Example 19 shows that poly(alkylene carbonate) polyols made using potassium carbon¬ ate as catalyst can be advanced to higher molecu¬ lar weight products by the process of this inven- tion. Example 20 Part A: A 5:1 mole ratio of propylene carbon¬ ate to diethylene glycol is heated with stirring under a nitrogen atmosphere for 12 hours at 175°C using 1.0 weight percent sodium stannate trihydrate as catalyst to give poly(alkylene carbonate) polyol. The catalyst is removed as in Example 1. Part B: A sample (91.3 g) is subjected to frac¬ tional distillation with a maximum pot temperature of 235°C and a pressure of 10 mm Hg (1.3 kPa). Dis¬ tillate is collected in a water-chilled condenser and a dry ice-isopropanol trap. The distillate collected by the water-chilled condenser accounts for 62.3 weight percent (56.9 g) of the sample charged and has the following assay: 0.93 percent propylene glycol, 25.6 percent propylene carbonate, 37.2 percent dipropylene glycol and 7.57 percent tri- propylene glycol. The distillate collected in the dry ice-isopropanol trap accounts for 3.6 weight percent (3.3 g) of the sample charged and has the following assay: 44.5 percent acetone and 15.9 percent dioxane. The residue is an amber viscous liquid, accounts for 32.1 weight percent (29.3 g) of the sample charged and has the properties shown in Table XV. TABLE XV wt % Molecular Weight Data Advanced Residue Peak Mn Mw PDI No _ 213 316 535 1.69 Yes 32.1 4101 1958 5294 2.70 Example 20 shows that propylene carbon¬ ate can be used to make poly(alkylene carbonate) polyols and that these polyols can be advanced to much higher molecular weights by the process of this invention. Examples 21-26 Part A: Preparation of Poly(alkylene carbonate) Polyols A-F The desired mole ratio of ethylene car- bonate and alcohol is heated with stirring under a nitrogen atmosphere in the presence of sodium stannate trihydrate (1.0 weight percent) as cata¬ lyst to a high ethylene carbonate conversion. Af¬ ter reaction is complete, the catalyst is removed by stirring the product (20 weight percent in ace¬ tone) with Florisil (1 g/10 g product) for three hours, followed by filtration and solvent removal. TABLE XVI Poly(alkylene carbonate) Polyols Reac¬ Reac¬ tion tion Temper¬ EC EC/Ini¬ Time ature Conver¬ Initiator tiator (hr) (°C) sion (%) A n-Hexanol 10 25.5 150 98.0 B n-Octanol 10 22.0 160 100.0 C n-Decanol 10 22.0 160 99.4 D n-Dodecanol 5 21.5 160 100.0 E n-Dodecanol 20 23.5 160 96.5 F n-Butanol 10 25.0 160 99.6 • Example 21 Part B: A portion of Poly(alkylene carbonate) Polyol A is placed in a two-necked, 100-ml boiling flask and several boiling stones are added. The flask is equipped with a thermometer and heating mantle and attached to a distilling apparatus connected to a vacuum source. The polyol is subjected to fractionation to give a residue of 49.1 g of a light amber viscous liquid with a 31.0 weight percent carbon dioxide (96 percent carbon dioxide retention) . Example 21 Part B: TABLE XVII Molecular Weight Data t % Peak Mn Mw Mz PDI CO, Before Fractionation 1063 507 1077 1668 2.122 26.5 After Fractionation 3539 1935 3436 5193 1.775 31.0 Example 27 shows that a poly(alkylene carbonate) polyol made using n-hexanol as initia¬ tor can be rapidly advanced to a molecular weight greater than a 50:1 product- while maintaining- a lower poly-dispersity index. Product analysis by proton nuclear magnetic resonance indicates no detect¬ able n-C 8 -C 17 moieties. Example 22 Part B: A portion of the Pol (alkylene carbonate) Polyol B is fractionated using the same equipment as in Example 21. The maximum pot temperature is 191°C at 0.7 mm Hg (0.09 kPa) pressure. The distil¬ late (17.5 g) contains 93 percent octanol, 2 per¬ cent dioxane and 4 percent diethylene glycol. The residue (63.4 g) is a light amber viscous liquid with 31.7 weight percent carbon dioxide. Example 22 Part B: TABLE XVIII Molecular Weight Data . 0 , Peak Mn Mw Mz PDI CO° Before Fractionation 785 450 889 1407 1.972 23.4 After Fractionation 3539 2092 3593 5026 1.718 31.7 There is considerable molecular weight advance¬ ment while reducing the amount of poly-dispersity. Example 22 shows that a pol (alkylene carbonate) polyol made using n-octanol as initi¬ ator can be rapidly advanced to a molecular weight of about that of a 50:1 product while maintaining a lower poly-dispersity index. Example 23 Part B: Pol (alkylene carbonate) Polyol C is fractionated using the same equipment as in Example 21. The maximum pot temperature is 193°C at 0.7 mm Hg (0.09 kPa) pressure. The distillate (12.8 g) con¬ tains 86 percent decanol, 12 percent diethylene glycol, 0.5 percent ethylene carbonate and 0.5 percent mono- ethylene glycol. The residue (59.8 g) is a light amber viscous liquid with 26.6 weight percent carbon dioxide (90 percent carbon dioxide retention). TABLE XX Molecular Weight Data . y Peak Mn Mw Mz PDI CO, Before Fractionation 1063 555 1304 4886 2.351 24.6 After Fractionation 3321 1901 3240 4751 1.704 26.6 Example 23 shows that a poly(alkylene carbonate) polyol made using n-decanol as initi- ator can be rapidly advanced to a molecular weight greater than a 50:1 product while maintaining a lower poly-dispersity index^. Nearly half of the initiator remains in the product. Example 24 A portion of Pol (alkylene carbonate) Polyol D is fractionated using the same equipment as in Example 21. The maximum pot temperature is 170°C at l.l mm Hg (0.15 kPa) pressure. The distil¬ late (11.5 g) contains 65 percent diethylene glycol, 31 percent dodecanol, and 0.5 percent monoethylene glycol. The residue (51.9 g) is a light amber vis¬ cous liquid with 20.4 weight percent carbon dioxide (100 percent carbon dioxide retention).- TABLE XXI Molecular Weight Data . 0 . Peak Mn Mw Mz PDI CO, Before Fractionation 358 329 546 764 1.657 15.7 After Fractionation 570 742 1417 5768 1.909 20.1 There is some molecular weight advancement but the majority of the initiator remains in the product. Example 25 A portion of Poly(alkylene carbonate) Polyol ~ E is fractionated using-the same- equipment-- - as in Example 21. The maximum pot temperature is 194°C at 0.8 mm Hg (0.11 kPa) pressure. The distil- late (10.6 g) contains 35 percent ethylene carbon¬ ate, 21 percent dodecanol, 41 percent diethylene glycol and 0.5 percent monoethylene glycol. The residue (81.3 g) is a light amber viscous liquid with 28.0 weight percent carbon dioxide (94 percent carbon dioxide retention) . TABLE XXII Molecular Weight Data . a/ Peak Mn Mw Mz PDI CO ? Before Fractionation 1873 685 1995 4950 2.910 25.7 After Fractionation 2950 1943 3209 4767 1.652 28.0 There is considerable molecular weight advancement while reducing the amount of poly-dispersity. How¬ ever, the majority of the initiator remains in the product. Examples 24 and 25 show that when a poly(alkylene carbonate) polyol made using n-do- decanol is used as initiator, product advancement to higher molecular weights can occur by the pro¬ cess of this invention but the majority of the initiator remains in the product. Example 26 Part B: Portions of Poly(alkylene carbonate) Polyol " F " are " fractionated "" at several different pressures. (A) At 40 mm Hg (5.3 kPa) Pressure: The sample is fractionated using the same equipment as in Example 27 above except that a 50-ml flask was used. The maximum pot tempera- ture is 198°C. The distillate (3.4 g) contains 95 percent butanol and 3 percent dioxane. The residue (33.2 g) is a light amber viscous oil with 28.8 weight percent carbon dioxide (100 percent carbon dioxide retention) . (B) At 100 mm Hg (13.3 kPa) Pressure: The sample (33.7 g) is fractionated using the same equipment as in (A) . The maximum pot tem¬ perature is 210°C. The distillate (3.1 g) contains 93 percent butanol and 5 percent dioxane. The resi¬ due (30.3 g) is a light amber viscous oil with 26.5 weight percent carbon dioxide (95 percent carbon dioxide retention). (C) At 760 mm Hg (101.3 kPa) Pressure: The sample (36.7 g) is fractionated using the same equipment as in (A). The maximum pot tem¬ perature is 253°C. The distillate (7.6 g) contains 50 percent butanol and 50 percent dioxane. The resi- due (23.7 g) is a light amber viscous oil with 26.8 weight percent carbon dioxide (69 percent carbon dioxide retention). Molecular Weight Data Peak Mn- Mw Mz PDI Before Fractionation 881 590 928 1318 1.571 253°C Pot/760 mm 1151 715 1153 1638 1.612 (101.3 kPa) 210°C Pot/100 mm 1641 866 1535 2201 1.773 (13.3 kPa) 198°C Pot/40 mm 2135 1242 2144 3022 1.725 (5.3 kPa) Molecular weight advancement occurs in each case and is higher as the fractionation pressure is reduced. Wt % %C0 2 Wt % % Butanol Conditions CO, Lost Butanol Lost Before Fractionation 25.1 - 9.38 253°C Pot/760 mm 26.8 31.1 3.29 77.3 (101.3 kPa) 210°C Pot/100 mm 26.5 5.0 3.19 69.3 (13.3 kPa) 198°C Pot/40 mm 28.8 1.00 90.6 (5.3 kPa) *No detectable loss Example 26 shows the effect of pressure on the molecular weight advancement of pol (alkyl¬ ene carbonate) polyols made using n-butanol as ini¬ tiator. As the pressure is lower, the C0 2 content and molecular weight increase while the n-butanol content in the product decreases. Example 27 Part A: An n-octanol initiated adduct is made from ethylene oxide and carbon dioxide at 150°C using sodium stannate trihydrate as catalyst. The catalyst is removed by the procedure described in Examples 21-26. The residue is a pol (alkylene car- bonate) polyol with 12.1 weight percent carbon diox¬ ide. Poly(alkylene carbonate) polyol is fractionated using the same equipment as Example 21. The maximum pot temperature is 190°C at 0.3 mm Hg (0.04 kPa) pressure. The distillate (17.8 g) contains 79 percent octanol, 1 percent monoethylene glycol and 1 percent diethylene glycol. The residue (13.9 g) is a light amber viscous liquid with 25.7 weight percent carbon dioxide. The alkanol moieties (97.2 percent) are removed by fractionation. TABLE XIX Molecular Weight Data . 0 , Peak Mn Mw Mz PDI CO, Before Fractionation 234 229 283 354 1.235 12.1 After Fractionation 4723 1878 4832 8040 2.572 25.7 There is considerable molecular weight advancement. Example 27 shows that a poly(alkylene carbonate) polyol made from ethylene oxide and carbon dioxide using n-octanol as initiator can be advanced to a high molecular weight product using the process of this invention.

Claims: 1. A process for increasing the molec¬ ular weight of a pol (alkylene carbonate) polyol which comprises exposing the poly(alkylene carbon¬ ate) polyol to elevated temperatures at which dial- kylene glycol, trialkylene glycol, or initiator segments, wherein the initiator has about the same or greater volatility as the dialkylene glycol or trialkylene glycol segment, are abstracted from the poly(alkylene ' carbonate ' ) " polyol, at a ' pressure wherein the dialkylene glycol, trialkylene glycol or initiator is volatile, and removing the vola¬ tile dialkylene glycol, trialkylene glycol or ini¬ tiator from the mass of the poly(alkylene carbon¬ ate) polyol, under conditions such that the molec- ular weight of the poly(alkylene carbonate) polyol is increased. 2. The process of Claim 1 wherein the pressure is subatmospheric. 3. The process of Claim 2 wherein the temperature is between 150°C and 300°C. 4. The process of Claim 3 wherein the pressure is 300 mm Hg (40.0 kPa) or less. 5. The process of Claim 4 wherein the poly(alkylene carbonate) polyol is a random poly- mer which corresponds to the formula [(R 1 ^C0^C(R 2 ) 2 C(R 2 ) 2 0) 2 -H] ] wherein R 1 is R 3 -(X) ; 2 R is separately in each occurrence hydro¬ gen, halogen, a nitro group, a cyano group, a C l-20 n y drocart> yl ^ group- or- " a C-^^ Q - hydrocarbyl group substituted with one or more of the fol- lowing: a halo, cyano, nitro, thioalkyl, tert- -aminό, alkoxy, aryloxy, aralkoxy, carbonyldi- oxyalkyl, carbonyldioxyaryl, carbonyldioxyar- alkyl, alkoxycarbonyl, aryloxycarbonyl, aralk- oxycarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkylsulfinyl, arylsulfinyl, aralkylsulfinyl, alkylsulfonyl, arylsulfonyl, or aralkylsulfonyl group; R 3 i.s separately in each occurrence an n valent hydrocarbon radical or hydrocarbon radical which contains one or more hetero- atoms of 0, N or S; m is an integer of 1 or greater; n is separately in each occurrence an integer of from 1 to 25; x is 1; y is separately in each occurrence 1 to 40; and z is separately in each occurrence 1 to 100. 6. The process of Claim 5 wherein R 2 i.s hydrogen, C_ 2Q alkyl, C, 20 halo- alkyl, C_ 2 „ alkenyl, or phenyl; R is an aliphatic or cycloaliphatic hydrocarbon or an aliphatic or cycloaliphatic hydrocarbon containing one or more oxygen, sulfur or nitrogen moieties; X is S, 0, or NH; m is 1 to 10, inclusive; n is an integer of 1 to 10, inclusive; y is 5 to " 20, inclusive; " and z is 20 to 50, inclusive. 7. The process of Claim 6 wherein 2 R is hydrogen, C 1 _ 3 alkyl, C 2 __ 3 alkenyl or phenyl; R 3 i•s an n valent alkane or cycloalkane or an n valent alkane or cycloalkane contain¬ ing an oxygen; sulfur or nitrogen moieties; m is 1 to 5, inclusive; and n is an integer of 1 to 5, inclusive. 8. The process of Claim 7 wherein R 2 i■s hydrogen, methyl or ethyl; R 3 i•s an n valent C_ 10 alkane; and n is 1 or 2. 9. The process of Claim 4 wherein the poly(alkylene carbonate) polyol corresponds to the formula 0 (R-W(CO) -C(R-) 2 -C(R-) 2 ) -0)) A wherein R 2 i.s separately in each occurrence hydro¬ gen, halogen, a nitro group, a cyano group, a ι-2 0 n y drocart> y 1 group or a C.,_ 20 hydrocarbyl group substituted with one or more of the fol¬ lowing: a halo, cyano, nitro, thioalkyl, tert- -amino, alkoxy, aryloxy, aralkoxy, carbonyldi- oxyalkyl, carbonyldioxyaryl, carbόnyldi ' oxyar- alkyl, alkoxycarbonyl, aryloxycarbonyl, aralk- oxycarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkylsulfinyl, arylsulfinyl, aralkylsulfinyl, alkylsulfonyl, arylsulfonyl, or aralkylsulfonyl group; R 3 i.s separately in each occurrence an n valent hydrocarbon radical or hydrocarbon radical which contains one or more hetero- atoms of 0, N or S; X is S, 0, NH, 0 0 0 II II II -CO- , -OCO- , or -CNH- m is an integer of 1 or greater; n is separately in each occurrence an integer of from 1 to 25; p is separately in each occurrence 0 or 1; and q is separately in each occurrence an integer of 1 or greater.

Inventors: HARRIS ROBERT F, HARRIS, ROBERT, F.
Applicants: DOW CHEMICAL CO, THE DOW CHEMICAL COMPANY
Application year: 1986
Main classification: C08G18
IPC codes: C08G18, C08G64