# US 9,433,924 B2 · Metaloxide—ZrO2 catalysts for the esterification and transesterification of free fatty acids and triglycerides to obtain bio-diesel

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- Number: US 9,433,924 B2
- Document ID: US9433924B2
- Status: Granted
- Kind: B2
- Application number: 13/508,738
- Filed: 2010-11-08
- Published: 2012-11-08
- Granted: 2016-09-06
- Earliest claimed: 2009-11-09
- Assignees: Wayne State University
- Applicants: Manhoe Kim; Steven O. Salley; K. Y. Simon Ng
- Inventors: Manhoe Kim; Steven O. Salley; K. Y. Simon Ng
- Web page: https://patentgrep.com/patent/US9433924B2

## CPC

- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 23/002: {Mixed oxides other than spinels, e.g. perovskite}
- B01J 23/06: of zinc, cadmium or mercury
- B01J 23/10: of rare earths
- B01J 23/80: with zinc, cadmium or mercury
- B01J 37/031: {Precipitation}
- B01J 37/036: {to form a gel or a cogel}
- C11C 3/003: {by esterification of fatty acids with alcohols (C11C3/02 takes precedence)}
- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- C10G 2300/1003: Waste materials
- C10G 2300/1011: Biomass
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02P 30/20: using bio-feedstock
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C11C: FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Mixed metal oxide catalysts (ZnO, CeO, La2O3, NiO, Al203, Si02, TiO2, Nd2O3, Yb2O3, or any combination of these) supported on zirconia (ZrO2) or hydrous zirconia are provided. These mixed metal oxide catalysts can be prepared via coprecipitation, impregnation, or sol-gel methods from metal salt precursors with/without a Zirconium salt precursor. Metal oxides/ZrO2 catalyzes both esterification and transesterification of oil containing free fatty acids in one batch or in single stage. In particular, these mixed metal oxides supported or added on zirconium oxide exhibit good activity and selectivity for esterification and transesterification. The low acid strength of this catalyst can avoid undesirable side reaction such as alcohol dehydration or cracking of fatty acids. Metal oxides/ZrO2 catalysts are not sensitive to any water generated from esterification. Thus, esterification does not require a water free condition or the presence of excess methanol to occur when using the mixed metal oxide catalyst. The FAME yield obtained with metal oxides/ZrO2 is higher than that obtained with homogeneous sulfuric acid catalyst. Metal oxides/ZrO2 catalasts can be prepared as strong pellets and in various shapes for use directly in a flow reactor. Furthermore, the pellet has a strong resistance toward dissolution to aqueous or oil phases.

## Claims

### Claim 1

A heterogeneous catalyst system for use in facilitating esterification or transesterification reactions in an acidic chemical stream, the catalyst system comprising:
ZnO and one or more metal oxides selected from the group of SiO2, TiO2, Nd2O3, Yb2O3, CeOx, La2O3, or mixtures thereof; and
an oxide support; the support being ZrO2, hydrous ZrO2, or a mixture thereof;
wherein the mixed metal oxides and the oxide support interact such that the metal oxide is chemically stable and has durability in an acidic chemical stream.

### Claim 2 (depends on 1)

The catalyst system of claim 1, wherein the catalyst system is one selected from the group of ZnO—SiO2/ZrO2, ZnO—TiO2/ZrO2, ZnO—Nd2O3/ZrO2, ZnO—Yb2O3/ZrO2, ZnO—TiO2—Nd2O3, ZnO—SiO2—Yb2O3/ZrO2, ZnO—SiO2—TiO2—Yb2O3/ZrO2, ZnO—SiO2—TiO2—Nd2O3/ZrO2, and ZnO—SiO2—TiO2—Yb2O3—Nd2O3/ZrO2.

### Claim 3 (depends on 1)

The heterogeneous catalyst system of claim 1, wherein the catalyst system comprises SiO2, and has an integrity of over 99.9% after 5 days in a feed stream of oleic acid and methanol at a temperature of 170° C.