US 20100168472A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2010/0168472 A1 Bogan, JR. et al. (43) Pub. Date: Jul. 1, 2010

(54) PROCESS FOR PRODUCTION OF ACROLEN Publication Classification FROM GLYCEROL (51) Int. Cl. (76) Inventors: Leonard Edward Bogan, JR., CD7C5L/6 (2006.01) Lansdale, PA (US); Mark Anthony C07C 45/29 (2006.01) Silvano, New Hope, PA (US) (52) U.S. Cl...... 562/532:568/.486 (57) ABSTRACT Correspondence Address: The present invention relates to a process for producing ROHMAND HAAS COMPANY acrolein by liquid phase dehydration of glycerol by preparing PATENT DEPARTMENT a mixture of a catalyst Suspended in an organic solvent com 1OONDEPENDENCE MALL WEST prising one or more vinyl polymers and glycerol; and then PHILADELPHIA, PA 19106-2399 (US) mixing and heating the mixture to between 150° C. and 350° C. to dehydrate the glycerol and form acrolein. The vinyl (21) Appl. No.: 12/592, 182 polymers are selected from the group consisting of polyole fins, polystyrene, and mixtures thereof. The polyolefins may (22) Filed: Nov. 20, 2009 be polyethylene, polypropylene, polybutylene, polyisobuty lene, polyisoprene, polypentene, or mixtures thereof. The Related U.S. Application Data acrolein may be subjected to vapor phase oxidation in the (60) Provisional application No. 61/203.554, filed on Dec. presence of a catalyst, Such as a mixed metal oxide, to pro 24, 2008. duce acrylic acid. US 2010/01 68472 A1 Jul. 1, 2010

PROCESS FOR PRODUCTION OF ACROLEN erol, the selectivity of the reaction to acrolein and the service FROM GLYCEROL life of the catalyst are appreciably reduced at higher concen trations, and a glycerol concentration of between 10 and 25% by weight glycerol is recommended. 0001. This invention claims priority to U.S. Provisional 0007 International Patent Application Publication WO Application No. 61/203.554 filed Dec. 24, 2008. 2006/092272 describes the dehydration of 0.1-90% glycerol solution to acrolein followed by the vapor-phase oxidation of FIELD OF THE INVENTION acrolein to AA. The dehydration is carried out using catalysts having a Hammett acidity H of +2 to -3 for liquid-phase 0002 The present invention relates to a process for the reactions, and -3 to -8.2 for gas-phase. While this patent liquid phase dehydration of glycerol to produce acrolein and application discusses liquid phase dehydration of glycerol to acrylic acid. acrolein, no mention is made of an organic solvent. 0008 U.S. Pat. No. 2,558,520 provides a process for liquid BACKGROUND OF THE INVENTION phase dehydration of glycerol to acrolein over a Supported 0003 Acrylic acid (AA) is currently made commercially acidic or anhydrous phosphorous-based catalyst, using par by the two-step catalytic oxidation of propylene. More recent, affin (alkane) hydrocarbons as a solvent. It is acknowledged but not-yet-commercial technology exists for its manufacture that a small portion of the paraffin solvent distills over with by the catalytic oxidation of propane. Propylene is a petro the acrolein product. leum derivative, and its price reflects the growing scarcity and 0009 Japanese Unexamined Patent Application Publica rising price of oil. Propane, derived from oil or natural gas tion JP 2006-290815 describes the liquid phase dehydration liquids, makes a convenient fuel, and its price has risen as it of glycerol using a solid acid catalyst having a Hammett has been used as a Substitute for petroleum fuels in energy acidity H between +3.3 and -5.6 in a solvent. This applica production. Both propylene and propane are non-renewable tion provides working examples using potassium bisulfate as resources. It is desirable to find a renewable feedstock for the the catalyst, and solvents include alkanes and paraffin wax. manufacture of acrylic acid. 0010. The present invention addresses the aforesaid prob 0004. A diesel fuel can be made from renewable materials lems by using a melt of one or more vinyl polymers of suitable by transesterification of natural fats and oils. Transesterifica molecular weight as the liquid solvent. The reaction proceeds tion with methanol yields fatty acid methyl esters, also known as with alkane or paraffin wax, but without distillation of as FAME or biodiesel, and glycerol. The amount of glycerol solvent with the acrolein product. Thus, the aforesaid prob produced in this way has already outstripped demand, and the lems with product separation, Solvent recycle, and yield loss amount of this “waste’ glycerol is projected to increase. It is are obviated. Also, a more concentrated aqueous glycerol desirable to find a use for this glycerol. Glycerol is also Solution (i.e., greater than about 20% by weight glycerol) may available as a by-product of hydrolysis of various oils and be used as the feed to this process. fats, as well as from waste fluids in Soap production. 0005. The dehydration of glycerol to acrolein, in either SUMMARY OF THE INVENTION vapor or liquid phase, is well-known. A variety of acids have been used to catalyze this reaction, including mineral acids, 0011. The present invention provides a process for pro potassium bisulfate, Zeolites, Nafion composites, and modi ducing acrolein by liquid phase dehydration of glycerol, com fied zirconias. See, e.g., U.S. Pat. No. 2,042.224, U.S. Pat. prising: a) preparing a mixture of i) a catalyst Suspended in an No. 2,558,520, U.S. Pat. No. 5,387,720 and U.S. Patent Pub organic solvent comprising one or more vinyl polymers; and lication US2006/092272. In processes for liquid phase dehy ii) glycerol; and then b) mixing and heating said mixture to dration of glycerol, the catalyst can be suspended in an between 110° C. and 350° C. to dehydrate the glycerol and organic liquid, Such as an alkane or a mixture of alkanes (e.g., form acrolein. The glycerol may comprise 40% to 100% by hexadecane or paraffin wax). In Such liquid phase processes, weight glycerol, with the balance being water, based upon the some of the solvent distills and is separated from the water total weight of the glycerol. The one or more vinyl polymers into the acroleinproduct, necessitating separation and recycle are selected from the group consisting of polyolefins and of the solvent. Not only does this complicate the process and polystyrenes. add cost to it, but since acrolein has some solubility in the 0012. This mixture may also include a polymerization Solvent, Some acrolein is lost in this process. Also, it is known inhibitor which may be selected from the group consisting of that acrolein is highly reactive at elevated temperatures Such benzoquinone (“BQ), 4-hydroxy-TEMPO (“4HT), phe as those used during dehydration of glycerol and, therefore, nothiazine (“PTZ'), hydroquinone (“HQ'), methyl hydro prolonged exposure to the heat of the reaction mixture will quinone (“MeHQ'), copper metal, and mixtures thereof. result in losses of the desired acrolein product. Thus, prompt 0013 The catalyst is selected from the group consisting of removal of the acrolein product from the reaction mixture is bisulfate salts, pyrosulfate salts, and mixtures thereof, for important to maximize acrolein yields. example, potassium bisulfate, potassium pyrosulfate, and 0006. The vapor phase reaction is generally most selective mixtures thereof. when carried out in the presence of a large quantity of water, 0014. The one or more vinyl polymers has a viscosity of no e.g., aqueous solutions containing 20% or less by weight greater than about 12 Pa's at the reaction temperature and may glycerol. As the fraction of glycerol in the feed is increased, be selected, for example, from the group consisting of poly side reactions forming glycerol ether dimers and oligomers olefins, polystyrenes, and mixtures thereof. Suitable polyole occur with greater frequency, lowering the overall acrolein fins may be for example, without limitation, polyethylene, yield. Dehydration of an aqueous solution of glycerol having polypropylene, polybutylene, polyisobutylene, polyisoprene, a glycerol concentration of only 20% would require a rela polypentene, etc. tively large reactor for a given productivity, increasing both 0015 The present invention also provides a process for capital and operating expenses. Additionally, it is mentioned producing acrylic acid from glycerol, comprising: a) liquid in U.S. Pat. No. 5,387,720 that, while dehydration occurs phase dehydration of glycerol to produce acrolein by the using aqueous glycerol of greater than 40% by weight glyc process according to claim 1; and b) vapor phase oxidation of US 2010/01 68472 A1 Jul. 1, 2010 said acrolein to produce acrylic acid. The of vapor phase times referred to as “disacryl’) is formed. The only practical oxidation of the acrolein may be performed in the presence of means to prevent this is to remove the acrolein product from a mixed metal oxide catalyst. heat or convert it, e.g., to acrylic acid, as quickly as possible. To facilitate distillation and removal of the acrolein product DETAILED DESCRIPTION OF THE INVENTION from the heated reaction mixture, the reaction vessel may be sparged with air or nitrogen. If other solvents, such as paraffin 0016 Generally, the present invention comprises dehydra wax or lower alkanes, are used, it has been found that Such tion of glycerol to acrolein and is performed in a liquid-phase sparging tends to cause more of the solvent to distill over with process, using a salt of a Sulfate, pyrosulfate, or bisulfate as the acrolein product. Use of vinyl polymers as the solvent is catalyst Suspended in an organic solvent comprising one or beneficial in view of this issue since essentially none of the more vinyl polymers. vinyl polymer solvent distills over with the acrolein product 0017 For example, bisulfate and pyrosulfate salts of even when sparging is employed during the dehydration reac Group 1A elements (e.g., lithium, Sodium, potassium, etc.) tion. are useful catalysts for this dehydration reaction. It has been found that potassium bisulfate, potassium pyrosulfate, and 0023 The liquid phase dehydration of glycerol to acrylic mixtures thereof, perform particularly well as the catalyst. acid may be performed in any vessel Suitable for containing, 0018 Useful vinyl polymers include polyolefins (such as heating and distilling the liquid reaction mixture comprising polyethylene, polypropylene, polybutylene, polyisobutylene, glycerol, catalyst and vinyl polymer Solvent. For example, polyisoprene, polypentene, etc.), polystyrenes, and mixtures without limitation, a continuous stirred tank reactor (CSTR) thereof. Out of the polyolefins, polyethylene and polypropy or a wiped film evaporator (WFE, also known as a thin-film lene were found to be particularly suitable for use as the vinyl wiping still), or even an extruder, may be readily used to polymer Solvent. The organic solvent may comprise a single perform the aforedescribed dehydration and distillation a type of vinyl polymer or a mixture of more than one type of catalytic distillation type of vessel. vinyl polymer. Furthermore, the vinyl polymer, or mixture of 0024. Where the liquid phase dehydration of glycerol is vinyl polymers, should be less volatile than paraffin wax, for performed in accordance with the present invention in an example having a boiling point, at atmospheric pressure, of extruder, a Suitable extruder may have a generally cylindrical greater than 400° C. However, a solvent that has a suitably barrel with a feed port at one end, an extrusion outlet at an low vapor pressure may be too viscous to perform well as a opposite end thereof, and an addition port and a vent port reaction medium for the liquid phase dehydration reaction of intermediate the inlet and extrusion outlet. The addition port glycerol to acrolein. Thus, it is recommended, for example, is typically intermediate the inlet and the vent port, with the that the viscosity of the vinyl polymer, or mixture of vinyl extrusion outlet farthest downstream of all. In practice, one or polymers, at reaction temperature, be up to about 12.0 Pascal more vinyl polymers (solvent) and the selected catalyst are seconds (Pas), for example, without limitation, up to about provided to the feed port and pass through the barrel of the 5.0 Pa S. extruder. The glycerol is introduced through the addition port 0019. The glycerol may comprise between 10% and 100% and acrolein is removed through a vent port. Since the product glycerol by weight, with the balance being water, based on the Acrolein is Volatile, removal via the vent port is practical and total weight of the glycerol. For example, without limitation, efficient. The extruded vinyl polymer leaving the extrusion the glycerol concentration may be between 20% and 100%, or port may be recycled to the feed port of the extruder. between 40% and 100%, or between 50% and 100%, or even 0025 Since the difference between the boiling points of between 50% and 85%, by weight, based on the total weight glycerol (280°C.) and acrolein (53°C.) is so large, the liquid of the glycerol Solution. phase dehydration may be conducted at a relatively low tem 0020. The organic solvent is a liquid comprising a melt of perature which allows continuous distillation of the acrolein one, or a mixture of more than one, type of vinyl polymer. The product. For example, the glycerol, catalyst and vinyl poly melt of one or more vinyl polymers is heated to typically a mer Solvent are mixed and maintained at a reaction tempera temperature somewhere between 100° C. and 150° C. to form ture between 150° C. and 350° C., such as between 200° C. a melt prior to addition of the glycerol. It is possible for the and 300° C., or even between 220° C. and 280° C. Viscosity of the vinyl polymer melt to be too high, resulting in 0026. The liquid phase dehydration of glycerol to produce a reaction mixture that is too viscous to allow the dehydration acrolein may also be performed under reduced pressure. Such reaction to proceed efficiently. It is known that polyolefins as at 700 mm Hg (0.92 atm), to facilitate distillation and will degrade to polyolefins of lower molecular weight and removal of the acrolein and shift the reaction toward acrolein lower viscosity when heated. Thus, in cases where one or production. more polyolefins are used, the polyolefin melt may be heated 0027. Additionally, one or more polymerization inhibitors prior to addition of the glycerol thereto, to degrade the poly may be included in the glycerol-catalyst-solvent mixture to olefin(s) until the viscosity of the melt is reduced sufficiently prevent polymerization of the acrolein product. Furthermore, to permit the dehydration reaction to proceed. The polyolefin it has been observed that the vinyl polymer solvent degrades can then be stabilized against degradation by addition of a at elevated temperatures such as those employed for this radical inhibitor. dehydration process. Thus, inhibitors may be useful to pre 0021. The concentration of catalyst used should be vent or minimize losses of the vinyl polymers through deg between 1% and 40% by weight, catalyst based on the poly radation. Suitable polymerization inhibitors include one or olefin solvent, such as between 1% and 30% by weight, or more of the following: hydroquinone (HQ): 4-methoxyphe between 5% and 20%, or between 6% and 20% by weight, or nol (MEHQ): 4-ethoxyphenol 4-propoxyphenol; 4-butox even between 10% and 15% by weight, based on the polyole yphenol, 4-heptoxyphenol; hydroquinone monobenzylether; fin solvent. 1,2-dihydroxybenzene: 2-methoxyphenol; 2.5-dichlorohyd 0022. Acrolein is a very reactive molecule and, if not roquinone; 2,5-di-tert-butylhydroquinone, 2-acetylhydro quickly chilled or converted to acrylic acid, it can readily quinone; hydroquinone monobenzoate, 1,4-dimercaptoben react with alcohols to formaldols, or with itself to form vinyl Zene; 1,2-dimercaptobenzene, 2,3,5-trimethylhydroquinone; or Diels-Alder addition products. If this addition reaction is 4-aminophenol; 2-aminophenol, 2-N,N-dimethylaminophe permitted to go unchecked, an intractable, black Solid (some nol; 2-mercaptophenol, 4-mercaptophenol; catechol US 2010/01 68472 A1 Jul. 1, 2010

monobutylether, 4-ethylaminophenol; 2.3-dihydroxyac Mo, V, Cu, W, Sb, A, G, Y and O, wherea is 12, b is 0.5-12, c etophenone; pyrogallol-1,2-dimethylether, 2-methylthiophe is less than or equal to 6, d is 0.2-10, e is positive and less than nol; t-butyl catechol; di-tert-butylnitroxide; di-tert-amylni or equal to 10; fis 0-0.5; g is 0-1; his positive and less than 6: troxide; 2.2.6.6-tetramethyl-piperidinyloxy. 4-hydroxy-2.2, and X is a positive numerical value determined by the oxida 6,6-tetramethyl-piperidinyloxy. 4-oxo-2.2.6.6-tetramethyl tion state of the other elements. piperidinyloxy; 4-dimethylamino-2,2.6.6-tetramethyl 0032. Another suitable molybdenum-vanadium based piperidinyloxy; 4-amino-2.2.6.6-tetramethyl mixed metal oxide suitable for oxidation of acrolein to acrylic piperidinyloxy; 4-ethanoloxy-2.2.6.6-tetramethyl acid is represented by the following empirical formula: piperidinyloxy; 2.2.5.5-tetramethyl-pyrrolidinyloxy; 3-amino-2.2.5.5-tetramethyl-pyrrolidinyloxy; 2.2.5.5-tet MoV.W.CuX,Y, ramethyl-1-Oxa-3-azacyclopentyl-3-oxy; 2.2.5.5-tetram wherein X is at least one element selected from the group ethyl-3-pyrrolinyl-1-oxy-3-carboxylic acid; 2.2.3,3,5,5,6,6- consisting of zirconium and titanium, Y is at least one element octamethyl-1,4-diazacyclohexyl-1,4-dioxy; salts of selected from the group consisting of magnesium, calcium, 4-nitrosophenolate; 2-nitrosophenol, 4-nitrosophenol; cop strontium, and barium, and the Subscripts a, b, c, d, e, and fare per metal; copper dimethyldithiocarbamate; copper dieth such that, when a is 12, b=1 to 14, 0

0037 Specific applications of the process of the present traps. Glycerol conversion was 92.7%, acrolein yield was invention will now be described in the context of the follow 71.1%, carbon accountability was 86.7%, and mass account ing comparative and working examples, the parameters and ability was 99.5%. results of which are listed in Table 1 below. Working Example 3 Examples 0042. The same procedure was followed as in Working Comparative Example 1 Example 2, except that the solvent was a polypropylene (PP. Aldrich, M. 19600, M., 5400, viscosity=23 P at 190° C.). Glycerol conversion was 63.5%, acrolein yield was 33.7%, 0038. In a four-neck, round-bottom flask equipped with carbon accountability was 74.8%, and mass accountability stirrer, Dean-Stark trap with condenser, and above-surface was 99.2%. feed inlet, heated 13.75 g high-density polyethylene (Aldrich, MFI 42 g/10 min at 190° C./2.16 kg) and 3.0 g potassium bisulfate to 240° C. at a controlled pressure of 700 mm Hg, Working Example 4 with stirring. The mixture was too viscous for reliable stir 0043. The same procedure was followed as in Working r1ng. Example 2, except that the solvent was a polypropylene (PP. Aldrich, M 14000, M, 3700, viscosity=10 P at 190° C.). Comparative Example 2 Glycerol conversion was 76.8%, acrolein yield was 43.4%, carbon accountability was 71.5%, and mass accountability 0039. In a four-neck, round-bottom flask equipped with was 98.9%. stirrer, Dean-Stark trap with condenser, and above-surface feed inlet, heated 13.75g polyethylene (Aldrich, weight aver Working Example 5 age molecular weight, “M”, 4000, number average molecu lar weight, “M,”, 1700, viscosity=0.15 Pa's at 125° C.) and 0044) The same procedure was followed as in Working 3.0g potassium bisulfate to 240° C. at a controlled pressure of Example 2, except that the solvent was an isotactic polypro 700 mm Hg, with stirring. At a rate of 8.0 ml/hr, added 33.53 pylene (PP. Aldrich, M. 12000, M 5000, viscosity=6.0 Pat g of a 50% by weight (“w/w’) solution of glycerol in water to 190° C.). Glycerol conversion was 90.6%, acrolein yield was the flask. A significant amount of solvent distilled over in the 71.7%, carbon accountability was 88.5%, and mass account condenser with the acrolein product. ability was 98.6%. Working Example 1 Comparative Example 3 0045. The same procedure was followed as in Working 0040. In a four-neck, round-bottom flask equipped with Example 2, except that the solvent was a perfluoropolyether stirrer, Dean-Stark trap with condenser, air inlet (flow rate (Fomblin Y 06/6). Glycerol conversion was 95.7%, acrolein 19.8 standard cubic centimeters, “sccm), and sub-surface yield was 47.3%, carbonaccountability was 58.7%, and mass feed inlet, heated 19.9 g linear low-density polyethylene (LL accountability was 98.9%. Some solvent (or solvent decom DPE, Aldrich, weight average molecular weight, “M”. position product) distilled over with product. 35000, number average molecular weight, “M,”, 7700, vis cosity=78 Pat 150° C., MFI 2250 g/10 min at 190° C./2.16 Comparative Example 4 kg) and 3.0 g potassium bisulfate to 240° C. at a controlled pressure of 700 mm Hg, with stirring. The side arm leading to 0046. The same procedure was followed as in Compara the Dean-Stark trap was insulated. At a rate of 5.0 ml/hr, tive Example 2, except that the solvent was a paraffin wax added 27.32 g of an 80% w/w solution of glycerol in water (Aldrich, m.p. 73-80° C.), as described in JP 2006-290815A. containing 1000 parts per million (ppm) 4-hydroxy-2.2.6, Glycerol conversion was 99.4%, acrolein yield was only 6-tetramethylpiperidinyloxy (“4HT”) and 1000 ppm benzo 32.1%, carbon accountability was 39.5%, and mass account quinone (BQ) to the flask. No solids collected in the con ability was 82.2%. A large amount of solvent distilled with denser or any of the traps. Glycerol conversion was 97.1%, the products. acrolein yield was 73.2%, carbon accountability was 87.9%, and mass accountability was 99.8%. Working Example 6 Working Example 2 0047. The same procedure was followed as in Working Example 2, except that the solvent was a polypropylene (Me 0041. In a four-neck, round-bottom flask equipped with tocene 650Y, LyondellBasell, MFI 1800 g/10 min (a) 230° stirrer, Dean-Stark trap with condenser, air inlet (flow rate C./2.16 kg), the pressure was atmospheric, and the tempera 23.3 sccm), and sub-surface feed inlet, heated 101.3 g linear ture was 265° C. Glycerol conversion was 97.5%, acrolein low-density polyethylene (LLDPE, Aldrich, M 15000, M. yield was 72.8%, carbonaccountability was 89.8%, and mass 5500, viscosity=37.2 P at 150° C.) and 15.4 g potassium accountability was 99.2%. bisulfate to 240° C. at a controlled pressure of 700 mm Hg, with stirring. The side arm leading to the Dean-Stark trap was Working Example 7 insulated. At a rate of 25.7 ml/hr, added 128.05 g of an 80% w/w solution of glycerol in water containing 1000 ppm 4-hy 0048. The same procedure was followed as in Working droxy-TEMPO (4HT) and 1000 ppm benzoquinone (BQ) to Example 8, except that the solvent was a polypropylene (Me the flask. No solids collected in the condenser or any of the tocene 650X, LyondellBasell, MFI 1200 g/10 min (a) 230° US 2010/01 68472 A1 Jul. 1, 2010

C./2.16 kg). Glycerol conversion was 97.4%, acrolein yield Working Example 11 was 68.9%, carbon accountability was 84.2%, and mass accountability was 98.4%. Reaction in Extruder Working Example 8 0053. In a twin screw counter-rotating extruder (e.g. 0.8" 0049. The same procedure was followed as in Working Welding Engineers twin screw extruder, or Werner-Pfleiderer Example 8, except that the solvent was a polypropylene ZDS-L 28) set up with a feed port for introducing polymer in (PP3746G, Exxon-Mobil, MFI 1500 g/10 min (a) 230° C./2. 16 kg). Glycerol conversion was 98.1%, acrolein yield was Solid form Such as granule, pellet, or powder, an addition port 68.8%, carbon accountability was 73.7%, and mass account orports for introducing glycerol or acqueous glycerol Solution ability was 98.8%. (10-99% w/w glycerol) at elevated pressure, an extruder bar rel heated electrically or with oil in five (1-10) separate Zones, Working Example 9 a die which serves as the exit port for the polymer, and a vent 0050. The same procedure was followed as in Working port orports operated at Substantially atmospheric pressure or Example 8, except that the solvent was a polypropylene under vacuum and located in the last Zone, a mixture of 15% (PP3546G, Exxon-Mobil, MFI 1200 g/10 min (a) 230° C./2. w/w (0.1-50%) potassium bisulfate (or similar) catalyst, 1000 16 kg). Glycerol conversion was 99.3%, acrolein yield was 68.7%, carbon accountability was 82.0%, and mass account ppm benzoquinone (or other, Suitable inhibitor), and ability was 99.3%. Metocene 650Y polypropylene (or other appropriate polyole fin or polystyrene) is introduced via the feed port. Comparative Example 5 0054 Glyceroloraqueous glycerol solution (10-99% w/w 0051. The same procedure was followed as in Working glycerol) is introduced into the extruder barrel via an addition Example 2, except that the solvent was a polyethylene (LL port located just after (downstream of) a non-flighted Screw DPE, DNDA1082, Dow Chemical, MFI 140 g/10 min (a) section (compounder) which forms a vapor seal which keeps 190° C./2.16 kg). The run could not be completed because the the glycerol reagent from going back toward the feed port. solvent was too thick. The unreacted reagent as well as the Volatile products and Working Example 10 by-products of the reactor are removed at the vent. The mix ture of polymer and catalyst leaves the extruder through the 0052. The same procedure was followed as in Working Example 2, except that the solvent was a polystyrene (Poly outlet port, or die, in melt form, and can be recycled either in sciences, catalogue. no. 23637, MW 800-5000). Glycerol melt form or after cooling and granulating or palletizing, to conversion was 88.9%, acrolein yield was 69.0%, carbon the feed port. The following Table 2 provides suitable extru accountability was 89.2%, and mass accountability was sion process parameters in accordance with the present inven 97.7%. tion.

TABLE 1. Summary of Solvent characterization and performance

MFI MFI glycerol acrolein parallel plate (g 10 min) (g 10 min) conversion yield Viscosity (Pa S Example Polymer visc.ftemp. (190° C./2.16 kg) (230° C./2.16 kg) (%) (%) 220° C. 240° C. 260° C. Comp. 1 polyethylene 42 too viscous 132.6 98.4 73.7 Comp. 2 polyethylene 1.5 P.125 C. distills 1 polyethylene 78 P.150° C. 2250 97.1 73.2 1.67 1.23 O.88 2 polyethylene 37.2 P.150° C. 92.7 71.1 0.73 O.49 O.36 3 polypropylene 23 P 190° C. 63.5 33.7 1.06 O.74 O48 4 polypropylene 1OP190° C. 76.8 43.4 O.47 O.31 O.23 5 polypropylene 6.O.P.190° C. 90.6 71.7 O.30 O.23 O.19 6 polypropylene 1800 97.5 72.8 3.91 2.57 1.29 7 polypropylene 1200 97.4 68.9 6.03 3.94 2.49 8 polypropylene 1SOO 98.1 68.8 7.97 4.90 4.04 9 polypropylene 1200 99.3 68.7 1145 7.17 4.74 10 polystyrene 88.9 69.0 Comp. 4 perfluoropolyether 95.7 47.3 Comp. 5 polyethylene 140 too viscous 27.62 1937 14.25 US 2010/01 68472 A1 Jul. 1, 2010

TABLE 2 Polymer feed glycerol glycerol feed extruder avg. barrel glycerol acrolein rate (gmin) concentration rate (g/min) rpm temp. (C.) conversion (%) yield (%) 50 8O 1 3OO 260 10-100 10-100 O.OS-SO 100-SOO 200-350

We claim: 7. The process of claim 6, wherein each of the one or more 1. A process for producing acrolein by liquid phase dehy vinyl polymers is selected from the group consisting of poly dration of glycerol, comprising: ethylene, polypropylene, polystyrene, and mixtures thereof. a) preparing a mixture of i) a catalyst Suspended in an organic solvent comprising 8. The process of claim 1, wherein said mixture is heated to one or more vinyl polymers; and a temperature between 220° C. and 280° C. ii) glycerol; and 9. The process of claim 1, wherein the step of preparing a b) mixing and heating said mixture to between 150° C. and mixture further comprises adding polymerization inhibitor to 350° C. to dehydrate the glycerol and form acrolein. the catalyst and organic solvent, wherein said polymerization 2. The process of claim 1, wherein the glycerol comprises inhibitor comprises at least one compound selected from the 40% to 100% by weight glycerol, with the balance being group consisting of benzoquinone (“BQ), 4-hydroxy water, based upon the total weight of the glycerol. TEMPO (“4HT”), phenothiazine (“PTZ'), hydroquinone 3. The process of claim 1, wherein the catalyst is selected (“HQ), methylhydroquinone (“MeHQ'), copper metal, and from the group consisting of bisulfate salts, pyrosulfate salts, mixtures thereof. and mixtures thereof. 10. A process for producing acrylic acid from glycerol, 4. The process of claim 4, wherein the catalyst is selected comprising: from the group consisting of potassium bisulfate, potassium pyrosulfate, and mixtures thereof. a) liquid phase dehydration of glycerol to produce acrolein 5. The process of claim 1, wherein the organic solvent has by the process according to claim 1; and a viscosity of no greater than 12.0 Pas, at reaction tempera b) vaporphase oxidation of said acroleinto produce acrylic ture. acid. 6. The process of claim 1, wherein each of the one or more 11. The process of claim 10, wherein step b), the of vapor vinyl polymers is selected from the group consisting of poly phase oxidation of said acrolein to produce acrylic acid is ethylene, polypropylene, polybutylene, polyisobutylene, performed in the presence of a mixed metal oxide catalyst. polyisoprene, polypentene, polystyrene, and mixtures thereof. c c c c c