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.