WO2009129292A1 - Polyol esters and process for making them - Google Patents

Abstract

Produce polyol esters from natural oils or derivatives thereof by: (i) subjecting an admixture that comprises (a) a natural oil component consisting essentially of at least one hydroxylated triglyceride having at least one hydroxyl group, and a solubility parameter (a), and (b) a polyether component consisting essentially of at least one polyether polyol having a boiling point above that of glycerin and having a solubility parameter (b); wherein | (a) - (b)|, as measured on the MPa1/2 scale at most about 2 MPa1/2, to transesterification conditions using at least one transesterification catalyst; and (ii) removing sufficient glycerin to drive formation of at least one polyol ester from the polyether polyol and at least one fatty acid from the hydroxylated triglyceride. The polyol esters, whether capped or not, are characteristically homogeneous and have utility in, for instance, elastomers, coatings, adhesives, sealants, foams, functional fluids, lubricants, surfactants, wetting agents, dispersing agents, power transmission fluids, oil and gas exploration fluids, industrial and institutional cleanings, metal working fluids, and quenchants.

Description

POLYOL ESTERS AND PROCESS FOR MAKING THEM

[0001 ] This invention relates to improved methods for producing polyols and related materials from vegetable or renewable feedstocks.

[0002] Driven by a current industry-wide need to replace mineral oil-based chemical feedstocks with renewable equivalents, many attempts have been made to make polyols for polyurethane foams, lubricants, etc. from oils of natural origin, intermediate products derived therefrom and combinations thereof. One practiced approach consists of designing "hybrid" molecular structures using molecules derived from natural oils or the oils themselves on one side and petroleum-based moieties on the other. See, for example, WO 2004/020 (BASF) which teaches synthesis of polyols for flexible foams by propoxylation of Castor oil. The contribution of renewable materials, expressed as a percentage of total weight of polyols produced is, however, limited and decreases with increasing product molecular weight. In addition, this method does not yield hydroxy- (OH-) functionalities other than three (3) (glycerine's functionality).

[0003] Polyols with OH functionalities other than 3 can be made using technology claimed by The Dow Chemical Company in WO 2004/096744, WO2004/096882 and WO2004/096883. This technology essentially teaches a complex, four-step process: methanolysis, hydroformylation, hydrogenation and polymerization. The process does not integrate into a product polyol backbone any unsaturated fatty acids, whether they come from the natural oil or result from the hydrogenation step, thereby producing a mixture of chemically divergent species.

[0004] Other known processes teach transesterification of natural oils bearing natural or introduced hydroxyl groups with polyhydric alcohols (for example, DE 1604177, DD 155771 ) or reaction of epoxidized natural oils with amine components (for example, US2007/0155934). Materials produced by these processes are generally suitable for highly crosslinked thermoset polymers, but their use as polyols is limited due to excessive internal crosslinking. [0005] A simplified process has been discovered for preparation of polyol esters from natural oils or their derivatives and polyether polyols. The process is driven by removal of glycerine by distillation or evaporation. The process is suitable for one vessel with distillation or evaporation means to remove glycerine. The product is preferably sufficiently free of materials that might interfere with further use that purification beyond the initial distillation to remove glycerine is unnecessary. Thus, the need for a series of vessels, separation columns and the like is avoided.

[0006] In one aspect, this invention is a process for producing polyol esters from natural oils or derivatives thereof. The process comprises steps: (i) Subjecting an admixture that comprises (a) a natural oil component consisting essentially of at least one natural oil or derivative thereof having at least one (≥) hydroxyl group, and a solubility parameter δ(a), each such oil or derivative thereof hereinafter also referred to as "hydroxylated triglyceride"; and (b) a polyether component consisting essentially of at least one polyether polyol having a boiling point above that of glycerin and having a solubility parameter δ(b); wherein |δ(a) - δ(b)|, as measured on a MPa^1/2 scale is at most (<) 2 MPa^1/2, to transesterification conditions using at least one transesterification catalyst; and (ii) Removing sufficient glycerin to drive formation of at least one polyol ester from the polyether polyol and at least one fatty acid from the hydroxylated triglyceride.

[0007] In a second aspect, this invention includes a polyol ester comprising structural elements derived from (a) hydroxylated triglycerides having hydroxyl groups and (b) polyether polyols having a number averaged molecular weight of at least 92 Daltons, wherein (a) constitutes at least (≥) 50 weight percent (wt percent), more preferably ≥ 60 wt percent, most preferably ≥ 70 wt percent, each wt percent being based upon total polyol ester weight. The polyol esters preferably have an OH-functionality of from 3 to 8. The polyol ester may be capped such that at least one, preferably all, of the polyol ester's hydroxyl groups are capped (reacted) with an alkylene oxide or an acid group that has from two carbon atoms to 18 carbon atoms (C₂-Ci₈). [0008] The above polyol esters and capped polyol esters have utility in a variety of compositions or applications including, but not limited to elastomers, coatings, adhesives, sealants, and foams as well as functional fluids lubricants, surfactants, wetting agents, dispersing agents, power transmission fluids, oil and gas exploration fluids, industrial and institutional cleaning, metal working fluids, and quenchants.

[0009] "Initiator" means a compound having ≥ one active hydrogen group, that is, ≥ one functional group having a hydrogen atom or an atom such as oxygen, sulfur or nitrogen, which is sufficiently active to react with an alkylene oxide. Initiators include such compounds as, water, ethylene glycol, or propylene glycol, glycerol, sorbitol or combinations thereof.

[00010] "Polyether polyol" refers to a reaction product of an initiator and an alkylene oxide (for example, ethylene oxide (EO), propylene oxide (PO), or butylene oxide (BO) or a combination thereof.

[0001 1 ] "Polyol ester" means a product of a transesterification reaction between a polyether polyol and a one natural oil or derivative of a natural oil wherein an ester group linking a glycerine moiety and at least one fatty acid moiety in a hydroxylated triglyceride is replaced by an ester linkage between the oxygen of a hydroxyl group on the polyether polyol and the fatty acid moiety from the natural oil.

[00012] "Natural oil" refers to animal and vegetable oils, preferably vegetable oils. Examples of vegetable and animal oils include, but are not limited to, castor oil, soybean oil, safflower oil, linseed oil, corn oil, sunflower oil, olive oil, canola oil, sesame oil, cottonseed oil, palm oil, rapeseed oil, tung oil, fish oil, or a blend of any of these oils. For purposes of this invention, petroleum or mineral oils are distinguished from natural oils.

[00013] "Natural oil or derivative thereof" refers to a natural oil as previously discussed or any substance, compound or combination thereof chemically or physically, preferably chemically, derivable from a natural oil. [00014] "Natural oil moiety" refers to a molecule or, preferably, a part of a molecule which is derived from or derivable from a natural oil.

[00015] "Structural element" means a portion of a molecule comprising ≥ two atoms bonded to each other within that portion and ≥ one atom bonded to ≥ one atom not in that portion but in the molecule. The structural element preferably retains structural characteristics, at least structural skeleton of its chemical source.

[00016] "Renewable resource" refers to annually renewable resources such as compounds of animal and plant origin as distinguished from, for instance, petroleum or mineral oils and derivatives.

[00017] "Natural oil content," "weight contribution of renewable resource," "renewable resource content," "renewable content" "renewable" and "weight contribution from natural oil" all refer to that weight percentage of subject matter derived from plant or animal oil or fat as its origin, based on total weight of said subject matter.

[00018] "Functionality", "OH functionality", "hydroxyl functionality", or "polyol functionality" all refer to number of hydroxyl groups in a polyol unless other functional groups are particularly identified.

[00019] "Active hydrogen functionality" refers to number of active hydrogen atoms, that is, hydrogen atoms available for reaction, more reactive than the hydrogen atoms on carbon. Determine active hydrogen functionality using the Zerewitinoff test published in J. Amer. Chem. Soc. 49(1927) p3181 . A functional group having at least one active hydrogen atom is referred to as an "active hydrogen group" and include hydroxyl groups, amine groups, sulfides and combinations thereof

[00020] "Solubility parameter" refers to a property, represented by δ, used within the art of organic, physical and polymer chemistry to describe the solubility of organic compounds in other organic compounds or solvents. Calculate δ from fragment contributions published in the art (see, for example, Handbook of

Solubility Parameters and other Cohesion Parameters. Barton, A. CRC Press, Florida (1984) and Properties of Polymers: their Estimation and Correlation with Chemical Structure. Van Krevelen D.W.; Hoftyzer, PJ. Elsevier, Amsterdam, 2nd.ed. (1976).

[00021 ] "Transesterification vessel" refers to any reaction vessel in which a transesterification reaction takes place, preferably in which mixing and transesterification take place.

[00022] "Closed loop" denotes any device for conveying liquid that can be isolated from atmospheric oxygen. Exemplary closed loops include tubing, piping, connectors, or a combination thereof.

[00023] "Evaporator" denotes equipment effective for vaporizing at least one liquid, especially for separating said liquid(s) from a liquid or semi-liquid mixture. Evaporators include, for instance, falling film evaporators, rotary evaporators, vapor-liquid separators and the like as well as thin film evaporators.

[00024] "Capping agent" or "capping reagent" refers to any compound capable of reacting with a hydroxyl group such that the active hydrogen atom of the hydroxyl group is replaced by a group not having an active hydrogen atom. Exemplary and preferred capping reagents include, for instance, esters, anhydrides or carboxylic acids that lack alcohol or amine functionality. Suitable capping agents include short chain carboxylic acids, their anhydrides and their alkyl esters of wherein the carboxylic acid or derivative thereof has two to eighteen carbon atoms (C₂ -Ci₈), advantageously six to twelve carbon atoms (C₆-Ci₂), preferably six to ten carbon atoms (C₆-Ci₀), more preferably short chain carboxylic acids or short chain lower alkyl esters of C₈ and Ci₀ carboxylic acids, mixtures of two or more of such carboxylic acids or lower alkyl esters (for example, a mixture of short chain lower carboxylic acids or short chain lower alkyl esters of C₈ and Ci₀ carboxylic acids), and even more preferably one or more carboxylic acids or methyl esters of such carboxylic acids.

[00025] Number average molecular weight (Mn) is a measure of average chain length of a polymer based on monomer repeating unit units per chain and is calculated from the molecular weight distribution curve measured by gel permeation chromatography (GPC).

[00026] Weight average molecular weight (Mw) is a measure of average chain length based on a weighted average and is calculated from the molecular weight distribution curve measured by GPC.

[00027] Molecular weight distribution (MWD) or polydispersity is Mw/Mn and is a measure of the similarity of molecular weights in a sample of polymer.

[00028] References to the Periodic Table of the Elements herein refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any references to a Group or Groups shall be to the Group or Groups reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.

[00029] All percentages, preferred amounts or measurements, ranges and endpoints thereof herein are inclusive, unless otherwise specified. Numbers herein have no more precision than stated. All lists include combinations of two or more members of the list. All amounts, ratios, proportions and other measurements are by weight unless stated otherwise. All percentages refer to weight percent based on total composition according to the practice of the invention unless stated otherwise. Unless stated otherwise or recognized by those skilled in the art as otherwise impossible, steps of processes described herein are optionally carried out in sequences different from the sequence in which the steps are discussed herein.

[00030] "Comprising", synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements, material, or steps. "Consisting essentially of" indicates that in addition to specified elements, materials, or steps; unrecited elements, materials or steps are optionally present, but do not unacceptably materially affect the specified elements, materials or steps. "Consisting of" indicates that only stated elements, materials or steps are present except that unrecited elements, materials or steps may be present to an extent they have no discernible effect on the stated elements, materials or steps.

[00031 ] A hydroxylated triglyceride is suitably any triglyceride of any fatty acid or derivative thereof having ≥ one hydroxyl group (for example, ricinoleic acid). Conveniently, the triglyceride is a natural oil such as castor oil, rapeseed oil, sunflower oil, soy oil, or Kamala oil. Alternatively, the triglyceride is a derivative of a natural oil such as hydrogenated castor oil, blown castor oil, dehydrated castor oil, or a combination thereof. The natural oil is optionally reacted with other materials within the skill in the art for forming derivatives of natural oils. Derivatives of natural oils so formed include hydroxy fatty acid derivatives, fatty acids derivatives, fatty alcohols and combinations thereof.

[00032] In the above process, react a hydroxylated triglyceride with at least one polyether polyol. Polyether polyols include such compounds as a reaction product of an alkoxylating agent with an active hydrogen initiator. Preferred alkoxylating agents include C₂ to C₈ epoxides. More preferred alkoxylating agents include ethylene oxide, propylene oxide or combinations thereof, most preferably propylene oxide. Active hydrogen initiators suitable for alkoxylation include any alkoxylateable active hydrogen compound, for instance polyols, polyamines and aminoalcohols. Exemplary active hydrogen initiators include neopentylglycol; 1 ,2- propylene glycol; trimethylolpropane; pentaerythritol; sorbitol; sucrose; glycerol; alkanediols such as 1 ,6-hexanediol; 2,5-hexanediol; 1 ,4-butanediol; 1 ,4- cyclohexane diol; ethylene glycol; diethylene glycol; triethylene glycol; polytetramethyleneglycol and derivatives thereof; 9(1 )-hydroxymethyloctadecanol, 1 ,4-bishydroxymethylcyclohexane; 8,8- bis(hydroxymethyl)tricyclo[5,2,1 ,02,6]decene; dimerol alcohol (a 36 carbon diol available from Henkel Corporation); hydrogenated bisphenol; 9,9(10,10)- bishydroxymethyloctadecanol; 1 ,2,6-hexanetriol; or a combination thereof. Exemplary polyamine active hydrogen initiators include ethylene diamine; neopentyldiamine, 1 ,6-diaminohexane; bisaminomethyltricyclodecane; bisaminocyclohexane; diethylene triamine; bis-3-aminopropyl methylamine; triethylene tetraamine and bis(aminoalkyl)alkylamines. Exemplary aminoalcohols include ethanolamine, diethanolamine, and triethanolamine. Other useful active hydrogen initiators that are optionally used include polyols, polyamines or aminoalcohols described in U.S. Patent Nos. 4,216,344; 4,243,818 and 4,348,543 and British Pat. No. 1 ,043,507. Preferably, the active hydrogen initiator is selected from a group consisting of neopentylglycol, trimethylolpropane, pentaerythritol, ethoxylated pentaerythritol, propoxylated pentaerythritol, butanol, sorbitol, sucrose, glycerol, ethoxylated glycerol, propoxylated glycerol, diethanolamine, 1 ,2-propylene glycol, 1 ,6-hexanediol, 2,5-hexanediol, 1 ,4-cyclohexane diol, 1 ,4-butanediol, ethylene glycol, diethylene glycol, triethylene glycol, sucrose, bis-3-aminopropyl methylamine, propylene glycol, ethylene diamine, diethylene triamine, 9(1 )- hydroxymethyloctadecanol, 1 ,4-bishydroxymethylcyclohexane, glycerine, 8,8- bis(hydroxymethyl)thcyclo[5,2,1 ,02,6]decene, dimerol alcohol, hydrogenated bisphenol, 9,9(10,10)-bishydroxymethyloctadecanol, 1 ,2,6-hexanetriol, and combination thereof. More preferably, the active hydrogen initiator is selected from butanol, ethylene glycol, propylene glycol, glycerine, sorbitol, sucrose, alkanolamines, aromatic amines like ortho-toluene diamine or combinations thereof. Alkoxylation of an active hydrogen initiator to form a polyether initiator useful in the practice of the invention is well within the skill in the art, for instance as taught by "Chemistry And Technology of Surfactants" from Richard J. Farn, published by Blackwell Publishing, 2006 or by "Polyols for Polyurethanes" by M. Ionescu, published by Rapra Technology, 2005. Alkoxylation forms at least one polyether chain in the polyether initiator. In such polyether chains, oxide moieties (for example, ethylene oxide (EO) and propylene oxide (PO)), are optionally arranged in random, block or reverse block order.

[00033] The polyether polyol preferably has a boiling point sufficiently above that of glycerin that it does not distill out with glycerin that is removed from a reaction mixture. The polyether polyol preferably has a boiling point at process conditions of ≥ 5 degrees centigrade (⁰C), more preferably ≥ 15 °C, most preferably ≥ 30 °C higher than the boiling point of glycerine. The polyether polyol preferably has a molecular weight of ≥ 92 Daltons, more preferably ≥ 150 Daltons, most preferably ≥ 300 Daltons. While the polyether polyol is optionally very large, for instance, having a molecular weight of 12,000 Daltons, smaller polyether polyols are preferred in most instances to allow use of a larger relative weight contribution of renewable resource. To this end, the polyether polyol preferably has a molecular weight of < 1500 Daltons, more preferably < 1000 Daltons. The polyether polyol preferably has a functionality ≥ 1 , more preferably ≥ 2, most preferably ≥ 3 and, independently, preferably < 8, more preferably < 6, with more specific preferences corresponding to a preferred functionality for an intended use.

[00034] The polyether polyol or mixture thereof (polyol component b) is preferably sufficiently compatible (as determined by solubility parameters) with the hydroxylated triglyceride or combination thereof (natural oil component a) with which it is reacted in the process of the invention that they do not readily separate. Thus, the solubility parameters of the polyol component and natural oil component, as measured on the MPa^1/2 scale, differ by advantageously by < 2 MPa^1/2, preferably < 1 .5 MPa^1/2, more preferably < 1 MPa^1/2, most preferably < 0.5 MPa^1/2.

[00035] Those skilled in the art recognize that overall reactions involving a sequence of individual chemical changes, in this instance the condensation reaction of fatty acids with the hydroxyl groups of polyether polyols and with hydroxyl groups on other fatty acid moieties to form chains of fatty acid moieties on the polyether polyol, result in mixtures of individual compounds. For instance, in a reaction of a polyether triol with sufficient hydroxylated triglyceride to form a fatty acid chain of an average of 4 fatty acid units per chain on each hydroxyl group of the polyether triol, one molecule may have 4 units per chain while another molecule has one chain of 3 units and two of 4 or even 5 units. These variations in the number of structural elements and their placement and possible resulting variations in molecular weight are referred to herein as divergence in structure and its associated molecular weight distribution. Molecular weight distribution is measured by any means within the skill in the art, for instance, GPC, or liquid permeation chromatography, liquid chromatography, or high performance liquid chromatography (HPLC). Chromatograms reveal chemical composition distribution (CCD), with non-polar components eluting separate from, and usually earlier than, more polar components (for instance, polyether polyol). The CCD is an important parameter to highlight the chemical complexity of polyol esters produced and allows comparison of products made from different hydroxylated triglycerides, combined with various polyether polyols. In general, quantitative information can also be obtained for product and residual polyether polyol content.

[00036] It is well known to those skilled in the art that absolute differences in solubility parameter values of 4 Mpa^1/2or less would lead to miscible liquids whereas differences larger than 4 Mpa^1/2would give immiscible liquids. Based on this knowledge, one would expect any effect of the difference in solubility parameters between hydroxylated triglycerides and polyether polyols to manifest at differences -in an absolute sense- of less than 4 Mpa^1/2 units in solubility parameter. Surprisingly, in the practice of the current invention, smaller absolute differences in solubility parameter between triglyceride and polyether polyol component result in a more homogenous product mixture than is observed with larger absolute differences in the solubility parameters. Absolute differences greater than about 2, more particularly absolute differences greater than about 1 .5, most particularly less than about 1 , even less than about 0.5 MPa^1/2 show a tendency toward more homogenous products. It is believed that these smaller absolute differences in solubility parameters result in product mixtures much closer to ideal homogeneous character. Additionally, practice of the invention results in removal of small product molecules such as fatty acids or dimers of fatty acids not reactive with the polyether polyol, which are preferably distilled away with the glycerine. This, too, helps achieve product mixtures that are more homogenous (less chemically diverse) than those achieved by practice of other processes that would superficially appear to result in similar products. Products of the process of the invention preferably also have fewer variations in the numbers of these functional groups and structural elements (structural diversity) and associated smaller molecular weight distributions than have products of similar processes wherein the differences between solubility parameters of the polyether polyol and the hydroxylated triglyceride are greater, advantageously greater than about 2 preferably greater than about 1 .5, more preferably greater than 1 , most preferably greater than about 0.5 MPa^1/2.

[00037] Because of the homogeneity of the product of the process of the invention relative to products of somewhat analogous inventions where the solubility parameter of the polyether polyol differs from that of the natural oil component by more than the amounts preferred for practice of the present invention, steps of product purification are seldom needed after the glycerine is removed to drive the reaction. Use of other purification stages such as chromatography, ion exchange, and the like is, in fact, preferably avoided because it is unnecessary.

[00038] Although the product mixtures are relatively homogeneous, a variety of products can be obtained through practice of the process described above. For instance, variations in the relative amounts of polyether polyol component and natural oil component vary the lengths of the average fatty acid chain in the molecule, thus vary the molecular weight. Preferred amounts of polyether polyol or combination thereof relative to amounts of hydroxylated triglyceride vary according to probable use of the resulting polyol ester product. A stoichiometric ratio (ratio of equivalents, where a triglyceride has a functionality of 3) of polyether polyol to hydroxylated triglyceride is preferably ≥ 1 :1 , more preferably ≥ 1 :2, most preferably ≥ 1 :3 and independently advantageously < 1 :12, preferably < 1 :8, more preferably < 1 :6, most preferably < 1 :3. These ratios preferably result in an equivalent weight of preferably ≥ 250, more preferably ≥ 500, most preferably ≥ 750, and independently preferably < 4000, more preferably < 2000, and most preferably < 1500 with corresponding molecular weights of preferably ≥ 500 Daltons, more preferably at ≥ 1 100 Daltons, and most preferably ≥ 1875 Daltons, and independently preferably < 32,000 Daltons, more preferably < 12,000 Daltons, and most preferably < 9,000 Daltons.

[00039] A resulting polyol ester has its hydroxyl functionality determined by number of active hydrogen groups, preferably hydroxyl groups, on the hydroxylated triglyceride and polyether polyol component, stoichiometry and extent of reaction. When a stoichiometric ratio is close to one, on average, each terminal hydroxyl group on a polyether polyol is expected to esterify such that an ester is formed with one natural oil moiety. The hydroxyl functionality of the resulting polyol ester is then that of the hydroxyl functionality of the polyether polyol component, if the fatty acid units of the hydroxylated triglyceride all have a functionality of 1. Hydroxylated fatty acids having a hydroxyl functionality of greater than 1 result in greater functionalities in the product. For instance, when a trifunctional polyether polyol is reacted with castor oil at a stoichiometric ratio of 1 , the resulting polyol ester has an average hydroxyl functionality of 3 because each polyether polyol hydroxyl group is esterified with one ricinoleic acid moiety, which moiety has one hydroxyl group. When a stoichiometric excess of natural oil component is used, a polyester chain of more than one natural oil moiety forms on each hydroxyl group of the polyether polyol. Conversely, when excess polyether polyol is used, some hydroxyl groups of the polyether polyol will not be esterified but will remain as hydroxyl functional groups on the product polyol ester. The final hydroxyl functionality of the polyol ester is ≥ 2 preferably ≥ 3, and more preferably < 8, most preferably < 6, depending on the intended final use of the product. For instance, functionalities of ≥ 2, preferably ≥ 2.2 and most preferably ≥ 2.5, and independently preferably < 8, more preferably < 6 are particularly useful in making flexible foams.

[00040] Average characteristics of the polyol ester comprising structural elements derived from (a) hydroxylated triglycerides having hydroxyl groups and (b) polyether polyols having a molecular weight ≥ 92 Daltons, wherein the weight contribution of from the hydroxylated triglyceride renewable materials is ≥ 50 wt percent are also represented by Formulas A-C as follows: n3=n2 Formula A f3≥f2 Formula B

M3=(M2-f2) + (M1 -92)^*(n1/n2) Formula e wherein n is the number of moles; M is Mn, preferably as calculated from atoms in the ideal structure. EW is equivalent weight; f is hydroxyl functionality; and, in each instance, 1 represents that of the hydroxylated triglyceride, 2 that of the polyether polyol and 3 that of the product. Thus, n2 is the number of moles of polyether polyol, which according to Formula 1 is equal to the number of moles of product n3. Preferably, the product mixtures produced by practice of the process of the invention vary less from the average or fully reacted product than do products of other processes wherein the difference between solubility parameters of the hydroxylated triglyceride and the polyether polyol are greater than (>) 2 MPa^1/2. [00041 ] In the process of the invention, heat the polyether polyol, and hydroxy I ated triglyceride to a reaction temperature, for a reaction time, while under a vacuum and in the presence of an amount of a catalyst sufficient to form the polyol ester and distill off glycerin. The reaction temperature employed is, for example, a function of the reactants and catalyst as well as the pressure, but the reaction temperature is preferably ≥ 150 °C, more preferably ≥ 180 °C, most preferably ≥ 200 °C, to preferably < 250 °C, more preferably < 220 °C, and most preferably < 210 °C when the pressure is below 1 .0 millibar (mbar) (100 Pascals (Pa)). For instance, a pressure of 26 mbar (2600 Pascals) and a temperature of 182 °C are sufficient to remove vaporized high purity glycerin from a reaction mixture while leaving the product polyol ester in a liquid phase. A pressure below atmospheric is needed to assist in volatilizing the glycerin at temperatures below those that could result in deterioration of some choices of reactants. The pressure is preferably a vacuum, that is, a pressure below (<) 200 Pa, preferably < 150 Pa, more preferably < 100 Pa.

[00042] Preferably contact reactants in the presence of a transesterification catalyst. The catalyst is any catalyst within the skill in the art for use in catalyzing transesterification, preferably at the preferred temperatures previously outlined. Such catalysts include tin, titanium, zinc, cobalt, carbonate catalysts (for example, potassium carbonate (K₂CO₃), sodium carbonate (NaHCO₃), or lithium carbonate (LiCO₃)), other bases (for example, sodium hydroxide (NaOH) or potassium hydroxide (KOH)) and combinations thereof. Organometallic catalysts, particularly those of tin and titanium are preferred. The tin catalyst is optionally any tin transesterification catalyst such as those known in the art. Exemplary tin catalysts include tin (II) octanoate, tin (II) 2-ethylheptanoate, dibutyl tin (IV) dilaurate, and other tin catalysts which are similarly functionalized. Preferably the tin catalyst is tin (II) octanoate, tin (II) 2-ethylheptanoate, or dibutyl tin (IV) dilaurate or combination thereof. The titanium catalyst is optionally any titanium catalyst effective for transesterification, such as those known in the art. Exemplary titanium catalysts include titanium tetraisopropoxide, titanium tetraisobutoxide, or any appropriately functionalized titanium (IV) alkoxide. Preferably the titanium catalyst is titanium tetraisopropoxide. Among the carbonates, the lithium salt is more preferred. [00043] The amount of catalyst is preferably at least a minimum amount sufficient to effect a reaction between the polyether polyol component and natural oil component and form the polyol ester at a desirable rate. The amount of catalyst depends, for example, on the particular type of catalyst and reactants. When a tin, titanium or carbonate catalyst is employed, the amount of catalyst is advantageously ≥ 100 parts by weight per million parts by weight (ppm), preferably ≥ 250 ppm, more preferably ≥ 500 ppm, and most preferably ≥ 1000 ppm, in each case based on total weight of reactants. Considerations other than operability determine any preference for upper limits. While more is operable, even suitable, such considerations as cost of the catalyst or necessity of deactivating or removing excess indicate that, in most cases, an amount of catalyst would be preferably < 2500 ppm, more preferably < 2000 ppm, most preferably < 1500 ppm, based on total weight of reactants.

[00044] Reaction time, similarly, depends on such variables as temperature, vacuum, kind of catalyst and catalyst concentration. In most instances, the time is ≥ 10 minutes to < 24 hours. Preferably, the reaction time is ≥ 15 minutes, more preferably ≥ 30 minutes, more preferably ≥ 1 hour to preferably < 12 hours, more preferably < 9 hours and most preferably < 5 hours.

[00045] One need not use any solvent in conjunction with either the polyether polyol or the natural-oil based component because the polyether polyol is selected to be sufficiently compatible with the natural oil component in the amounts used for reaction. Avoiding use of a solvent alleviates the need for its removal and removed glycerin is sufficiently pure for subsequent use.

[00046] The polyol esters described herein may be used with any additives known in the art for production of polyurethane polymers. Such additives include blowing agents, catalysts, surfactants, cell openers, colorants, fillers, load bearing enhancement additives such as copolymer polyols, water, internal mold releases, antistatic agents, and antimicrobial agents. [00047] Preferred surfactants include those made commercially available by Crompton Corporation under trade designation L26 or other polyol pendant chains grafted with a silicone moiety.

[00048] The polyol esters described herein form polyurethane foams made with a wide range of water concentrations. Often, the water concentrations range from preferably 1 part by weight (pbw) water per hundred pbw polyol, more preferably ≥ 2 pbw water per 100 pbw polyol, most preferably ≥ 4 pbw water per 100 pbw polyol, to advantageously 10 pbw water per 100 pbw polyol, preferably < 9 pbw water per 100 pbw polyol, more preferably < 8 pbw water per 100 pbw polyol and most preferably < 6 pbw water per 100 pbw polyol.

[00049] The polyol esters described herein also particularly useful in bio- lubricants, that is, lubricants based upon renewable resources such as seed oils and vegetable oils rather than from petroleum or natural gas. Bio-lubricants are particularly important in environmentally sensitive applications such as marine, forestry or agricultural lubricants, especially because they are believed to be readily biodegrade, and appear not to harm aquatic organisms and surrounding vegetation. Bio-lubricants without or with reduced numbers of free hydroxyl groups are preferred in most situations over bio-lubricants with a greater number of free hydroxyl groups..

[00050] In some embodiments, modify the polyol ester described herein by reacting functional groups, preferably hydroxyl groups, on the polyol ester's fatty acid chain with a capping reagent to decrease the number of free hydroxyl groups. Carboxylic acid capping occurs via known esterification or transesterification reactions, for example, by using acidic or basic catalysts for esterification, and transesterification catalysts described herein for production of polyol esters for transesterification. Temperatures used for capping reactions are conveniently ≥ 70 °C, preferably ≥ 100 °C, more preferably ≥ 120 °C independently to preferably < 230 °C, more preferably < 200 °C, most preferably < 180 °C at atmospheric pressure. While capping optionally occurs simultaneously with the formation of the polyol ethers according to the practice of the invention, it preferably occurs in a separate step in order to improve product homogeneity relative to simultaneous capping.

[00051 ] The capped polyol esters described herein find use in such products as lubricants and power transmission fluids. For instance, they optionally replace at least a portion of the petroleum or mineral oils frequently used in such fluids. The capped polyol esters are also useful in or as lubricants, surfactants, wetting agents, dispersing agents, power transmission fluids, oil and gas exploration fluids, industrial and institutional cleaning, metal working fluids, quenchants and combinations thereof. In these areas of application, the polyether polyesters are useful alone or in combination with other materials such as oils, polyolefins, other functional fluids, cleaners, or lubricating materials. For instance, the polyol esters are useful with synthetic lubricants such as polyalkylene glycols (PAG), polyol ethers (POE), and poly (alpha-olefins) (PAO), and with mineral oils.

[00052] The capped polyol esters described herein have a hydroxyl percentage that is preferably ≥ 0.1 wt percent, more preferably ≥ 0.2 wt percent and, most preferably ≥ 0.3 wt percent and independently < 2 wt percent, more preferably < 1 wt percent, most preferably < 0.7 wt percent, each wt percent being based upon capped polyol ester weight as measured in accord with American Society for Testing and Materials (ASTM) D4272-94d. Achieving a hydroxyl percentage of 0 wt percent, while technically possible, is very expensive.

[00053] The polyol esters, especially the capped polyol esters, described herein also have a 12 carbon atom and higher carbon number saturated hydrocarbon content that is preferably ≥ 0 wt percent, more preferably ≥ 0.1 wt percent and, most preferably ≥ 0.2 wt percent, and independently preferably < 32 wt percent, more preferably < 10 wt percent, most preferably < 2 wt percent, each wt percent being based upon polyol ester or capped polyol ester weight, whichever is appropriate. As a general rule, a lower saturated hydrocarbon content is better than a higher saturated hydrocarbon content as composition pour point tends to increase with increasing saturated hydrocarbon content as determined by the procedures of ASTM D97. [00054] In addition, the polyol esters, especially the capped polyol esters, described herein, have a viscosity at 25 °C that is preferably ≥ 40 centipoises (cps) (0.04 Pascal second (Pa.s)), more preferably ≥ 50 cps (0.05 Pa.s), still more preferably ≥ 75 cps (0.075 Pa.s) and even more preferably ≥ 100 cps (0.1 Pa.s) independently preferably < 2000 cps (2 Pa.s), more preferably < 1500 cps (1 .5 Pa.s), still more preferably < 1000 cps (1 Pascal Pa.s), and even more preferably, < 800 cps (0.8 Pa.s). Further, the compositions have a pour point that is preferably < (lower in temperature) -10 °C, more preferably < -20 °C, still more preferably, < -25 °C and most preferably < -30 °C. Determine kinematic viscosity (KV), in centistokes (cSt) and its metric equivalent, square meters per second (m²/sec) at 40 °C and 100 °C using a Stabinger viscometer in accord with ASTM D7042. Use the KVs to calculate a viscosity index (Vl) in accord with ASTM D2270. Measure lubricant pour point in accord with ASTM D97-87.

[00055] If desired, polyol ester lubricant compositions of the present invention, whether capped as or uncapped, are optionally admixed with an amount of one or more of the seed or vegetable oils disclosed herein. When present in a lubricant composition, the amount of such seed or vegetable oils is ≥ 1 wt percent, preferably ≥ 10 wt percent and more preferably ≥ 30 wt percent, and independently < 90 wt percent, preferably < 80 wt percent, more preferably < 70 wt percent, in each instance based upon combined weight of uncapped or capped polyol ester lubricant composition and seed or vegetable oil.

[00056] The following examples illustrate, but do not limit, various aspects or embodiments of this invention. Unless stated otherwise all percentages, parts and ratios are by weight. Arabic numerals designate examples of the invention while capital letters designate comparative samples (not examples of the invention).

Examples:

[00057] Use the following materials in the examples: PE-1 is a polyether polyol having a functionality of 3, and a number averaged molecular weight of 625 Daltons. Make PE-1 by alkoxylation of glycerin with 100 wt percent ethylene oxide (EO) to a final molecular weight of 625 Daltons. PE-2 is a polyether polyol prepared by alkoxylating a glycerine initiator with 8 moles of butylene oxide (BO) per mole of initiator to a final theoretical molecular weight of

668 Daltons.

PE-3 is a capped polyether polyol prepared by endcapping PE-2 with 4 moles of

EO per mole of initiator to a final molecular weight of 844 Daltons.

PE-4 is a polyether polyol obtained by alkoxylating a glycerine initiator with 8 moles of propylene oxide (PO) per mole of initiator to a final molecular weight of 556

Daltons.

PE-5 is a capped polyether polyol prepared by alkoxylating PE-4 with 4 moles of

EO to a final molecular weight of 732 Daltons.

PE-6 is a polyether polyol obtained by alkoxylating a sorbitol initiator with 14 moles of BO per mole of initiator to a final molecular weight of 1 190 Daltons.

PE-7 is a capped polyether polyol obtained by endcapping PE-6 with 7.9 moles of

EO per mole of initiator to a final molecular weight of 1538 Daltons.

PE-8 is a polyether polyol obtained by alkoxylating a sorbitol initiator with 14 moles of PO per mole of initiator to a final molecular weight of 994 Daltons.

PE-9 is a capped polyether polyol obtained by endcapping PE-8 with 7.9 moles of

EO per mole of initiator to a final molecular weight of 1342 Daltons.

[00058] Table 1 below summarizes characteristics, including solubility parameters, for PE-1 through PE-9.

Table 1 : Physical Properties of Polyether Polyols Used in Comparative Samples and Examples

Key: EO=ethylene oxide, PO=propylene oxide, BO-butylene oxide.

Examples 1-16 and Comparative Samples A-C

[00059] For each of Comparative Samples A-C and Examples 1 -16, place castor oil (0.2 mole (163.3 g)) and 0.1 mole of one of the polyether polyols indicated in Table 2 in a stirred stainless steel reactor. Then add 0.1 wt percent to 0.5 wt percent (relative to the total weight of reactor contents) catalyst (see Table 2). Close the reactor, purge it with nitrogen, then evacuate it three times in order to remove all traces of air. Heat reactor contents with stirring (350 rpm) to 200 °C -250 °C, as indicated in Table 2, with an applied vacuum of 0.5 mbar (50 Pascal) over a time period between 9 to 17 hours, as detailed in Table 2. Separately collect a total of 30 grams (g) to 80 g of a distillation product. After the indicated time, cool reactor contents to room temperature (nominally 25 ⁵C). Treat reactor contents with a silica based filtration aid commercially available from Beaver Chemicals Ltd. under the trade designation Celite™, then separate the filtration aid and the reactor contents via filtration. In addition, analyze distillation products, which contain two liquid phases, an upper phase with a glycerin content of between 10 and 12 wt percent, and a very pure bottom phase with a glycerin content of about 99 wt percent, in each case based upon total phase weight.

[00060] Table 2 gives an overview of examples using the polyether polyols of Table 1 . In all cases, molecular weights of the polyols calculated from hydroxyl number data in Table 2 are in satisfactory agreement with GPC measurements using standard equipment. Polydispersities range from 1 .25 to 1 .40.

Examples 17-20

[00061 ] For each of Examples 17-20, replicate Example 1 using an initiator as shown in Table 2, but substitute a hydroformylated high oleic canola oil for the castor oil of Example 1 .

[00062] Prepare hydroformylated canola oil by the following procedure:

[00063] Prepare a catalyst solution in a dry box by mixing a solution of dicyclohexylphenylphosphine monosulfonate sodium salt ligand (DCHPPMS-Na) (1 17.2 g of 20 percent in N-methyl pyrrolidone (NMP), 62.269 mmol DCHPPMS- Na) with a solution of rhodium dicarbonyl acetylacetonate { Rh (acac) (CO)₂) (1 .614 g, 6.255 mmol) in NMP (389.69 g). The resulting solution contains 0.127 percent Rh, 4.610 percent DCHPPMS-Na and 95.07 percent NMP. Seal the solution under nitrogen and constant stirring. Prepare the ligand in accord with the procedure described in WO 2004-A1 -096744.

[00064] Configure a hydroformylation reactor (Parr pressure reactor, 300 cubic centimeters (cc)) with a dip tube to feed syngas (CO + H₂) to the bottom of the reactor, and further equipped with internal coils for controlled water cooling, and with addition cylinders for addition of substrate or water into the reactor under pressure. The reactor is also equipped with a high pressure cylinder (600 cc, 6000 pounds per square inch absolute (psia)/41 .4 megapascals (MPa)) for pressurization with syngas or any other gas to be fed into the reactor.

[00065] Use a nitrogen purge to clean and dry the reactor. Transfer the catalyst solution (37.0 ml), into the reactor under nitrogen, followed by addition of degassed high oleic canola oil (80.0 g; >70 percent oleic content). Purge the reactor three times with syngas (hydrogen to carbon monoxide (H₂:CO) molar ratio = 1/1 ) and then pressurize the reactor to 600 psia (4,137 kilopascals (kPa)). Stir reactor contents at 1000 revolutions per minute (rpm) with heating to 85 °C. Maintain reactor pressure at 600 psia (4137 kPa) by feeding syngas from the high pressure cylinder . Record initial pressures in the high pressure cylinder and the reactor when the temperature is stabilized at 80 °C. Reaction time is 2 hours.

[00066] Following hydroformylation step, reduce the stirring rate to 600 rpm, and lower the temperature to 65°C, and syngas pressure to 400 psia (2758 kPa). Transfer degassed deionized water (31 ml) into the substrate addition cylinder under nitrogen. Purge the cylinder three times with syngas and then pressurize it to a target pressure of 400 psia (2758 kPa). Pressurize water from the substrate cylinder into the reactor with continued stirring at 600 rpm for 15 min. Drain the resulting mixture into a bottle containing di-isopropyl ether (DIPE) (120 ml) that is preheated to 65 °C and functions as a single component low solubility extraction solvent. Place the bottle in a 65°C bath and stir its contents for 5 to 15 minutes to settle out two phases, a bottom phase and a top phase. Decant off the bottom phase (crude aqueous phase), and wash the top phase (crude organic phase) with an equal volume of water four times at 65 °C with five minutes stirring for each wash. Remove water from the resulting organic phase via evaporation to obtain an aldehyde product.

[00067] Hydrogenate the aldehyde product to its corresponding alcohol product by trickling a 25 wt percent solution of the aldehyde product in diisopropyl ether over a fixed bed of nickel catalyst supported on alumina commercially available from Sϋd-Chemie under the trade designation C46-8-03 CDS 1/16" RS Extrudate at a temperature controlled within the range of 120 to 150 °C against a stream of hydrogen gas. [00068] Table 2 shows initiators, reaction characteristics and product characteristics for Examples 17-20.

Key: ^* Comparative Sample, not an example of the invention, oct= octanoate, OMe= methoxide, f2=functιonalιty of product

Δδ=absolute difference in calculated solubility parameter between polyether polyol and triglyceride

%REN=percent by weight of renewable materials assuming all glycerine is distilled off In addition, sorbitol and glycerine are assumed to be of renewable origin

MW= molecular weight, (OH#) determined from hydroxyl number, (ideal) calculated from structural formula of ideal product

[00069] For Table 2, use composition data measured by Alberdingk-Boley, Krefelfd, Germany, as published in Bauer et.al. Proceedings 2006 UTECH Conference, Maastricht, The Netherlands to calculate a value of 18.83 MPa^1/2 for the solubility parameter of Castor oil. The hydroformylated high oleic canola oil has a calculated value of 19.13 MPa^1/2 using composition data from "Performance of trans-free vegetable oils in shortenings and deep-fat frying," Frank T. Orthoefer, Lipid Technology 17(5) (2005) p. 101 -106 with averaging of listed components to allow for the very small percentage not accounted for in the article. For the calculation, assume all unsaturation to be hydroformylated.

[00070] The data in Table 2 shows that high yields of polyol esters having high levels of renewable materials can be produced according to the practice of the invention under a variety of conditions. In each instance the molecular weight obtained for the product mixture from the measurement of the OH number (MW (OH#)) is reasonably close to the molecular weight calculated for the desired product (MW ideal) considering error inherent in laboratory scale experiments. The reason for somewhat more variation in Examples 17 and 18 is not yet determined, but the process developed for castor oil was used for the hydroformylated canola oil without optimization to facilitate comparison. Optimization of the process for canola oil derivatives is within the skill in the art.

[00071 ] Analyze products of Comparative Sample A and Examples 1 -20 using the following liquid chromatography method based on normal-phase separation on a silica gel column with amounts specified in Table 3 of cyclohexane, acetone and methanol as mobile phase. Use evaporative light scattering (ELSD) for detection. The details of the method are listed below:

Column: chromatography column commercially available from Macherey-NageL GmbH & Co. KG under the trade designation Nucleosil™ 3-100. It is a bare silica column with dimensions (4.6 x 150 mm, 3 μm particles). [00072] Eluent gradient composition: Table 3

Flow rate: 1 .0 ml/min

Temperature: 30 °C

Pressure 130 bar (13000000 Pascals)

Injection volumes: 10-20 μl_

Prepare sample solutions of natural oil polyols and related materials in cyclohexane/acetone 9:1 (volume ratio) at 1 -2 weight percent. Dissolve initiators in acetone.

Detection: ELSD (for instance, the detector commercially available from Sedere Sa,

France under the trade designation Sedex™ 55) at 38 °C and 2.0 bar (200000

Pascal) nitrogen gas.

[00073] Chromatographic analysis results of Comparative Sample A and Examples 1 -20 shows that the products of the invention (Examples 1 -20) are more homogeneous than Comparative Sample A where the difference in solubility parameters between that of the polyether polyol and the hydroxylated triglyceride is greater than 2 (See Table 2).

[00074] Examples 1 -16 use the same hydroxylated triglyceride as Comparative Sample A and are more homogeneous in that they have a main peak, sometimes with a shoulder or a small peak in a more hydrophobic area (left side of chromatograms). In contrast, the chromatogram of Comparative Sample A shows a main peak made up of many smaller overlapping peaks between 2.5 and 5 minutes and a relatively large peak at about 1 1 minutes which is absent from the other chromatograms. While the chromatograms of products of the invention usually indicate mixtures, the chromatogram of Comparative Sample A indicates many more separate compounds and much more difference in the hydrophilicity, thus functional nature, of the product in the presence of a large separate product peak at 1 1 .

Claims

WHAT IS CLAIMED:

1 . A process comprising steps:

(i) subjecting an admixture that comprises (a) a natural oil component consisting essentially of at least one hydroxylated triglyceride having at least one hydroxyl group, and a solubility parameter δ(a), and (b) a polyether component consisting essentially of at least one polyether polyol having a boiling point above that of glycerin and having a solubility parameter δ(b); wherein |δ(a) - δ(b)|, as measured on the MPa^1/2 scale at most about 2 MPa^1/2, to transesterification conditions using at least one transesterification catalyst; and

(ii) removing sufficient glycerin to drive formation of at least one polyol ester from the polyether polyol and at least one fatty acid from the hydroxylated triglyceride.

2. The process of Claim 1 , wherein each natural oil or derivative thereof is a triglyceride of at least one fatty acid or derivative of at least one fatty acid having at least one hydroxyl group.

3. The process of Claim 2 wherein the hydroxyl group is secondary.

4. The process of any of Claims 1 -3 wherein at least one fatty acid is ricinoleic acid or at least one natural oil is castor oil, Kamala oil or a combination thereof.

5. The process of any of Claims 1 -4 wherein at least one hydroxylated triglyceride comprises at least one fatty acid moiety having at least one hydroxyl group introduced at a site of unsaturation.

6. The process of any of Claims 1 -5 wherein at least one polyether polyol has a molecular weight of at least about 92 Daltons and hydroxyl functionality of at least 3 and at most 8.

7. The process of any of Claims 1 -1 1 wherein transesterification conditions include a reaction temperature of at least 150 °C and at most 250 °C at a pressure below 1 .0 mbar (100 Pascal).

8. The process of any of Claims 1 -7 wherein glycerin removal occurs at a pressure no more than 200 Pascals.

9. The process of any of Claims 1 -8 wherein the transesterification catalyst is selected from tin, titanium, zinc, cobalt, enzyme, carbonate or base catalysts or a combination thereof.

10. The process of any of Claims 1 -9 further comprising a step of reacting at least one hydroxyl group on the polyol ester with a capping reagent to produce a capped polyol ester.

1 1 . A polyol ester comprising structural elements derived from (a) hydroxylated triglycerides having hydroxyl groups and (b) polyether polyols having a molecular weight of at least 92 Daltons, wherein (a) constitutes at least 50 weight percent, based upon total polyol ester weight.

12. The polyol ester of Claim 1 1 , wherein the polyol ester has an OH- functionality of from 3 to 8.