Hydrogenation of vegetable oil

Margarine is made by hydrogenating cottonseed, soybean, peanut, or corn oil until the desired butter-like consistency is obtained. The product may be churned with milk and artificially colored to mimic butter s flavor and appearance. 

Hydrogenation of corn oil, and other v etabie oils, provides margarine. 

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A few fatty acids with trans double bonds (trans fatty acids) occur naturally but the major source of trans fats comes from partial hydrogenation of vegetable oils m for example the preparation of margarine However the same catalysts that catalyze the... 

Zirconium tetrafluoride [7783-64-4] is used in some fluoride-based glasses. These glasses are the first chemically and mechanically stable bulk glasses to have continuous high transparency from the near uv to the mid-k (0.3—6 -lm) (117—118). Zirconium oxide and tetrachloride have use as catalysts (119), and zirconium sulfate is used in preparing a nickel catalyst for the hydrogenation of vegetable oil. Zirconium 2-ethyIhexanoate [22464-99-9] is used with cobalt driers to replace lead compounds as driers in oil-based and alkyd paints (see Driers and metallic soaps). 

Recovery of iodine hy action of sulfur dioxide on aqueous sodium iodate Hydrogenation of vegetable oils with gaseous hydrogen Desulfurization of gases by scrubbing with aqueous ethauolamiues... 

In some applications such as catalytic hydrogenation of vegetable oils, slurry reactors, froth flotation, evaporative crystallisation, and so on, the success and efficiency of the process is directly influenced by the extent of mixing between the three phases. Despite its great industrial importance, this topic has received only limited attention. 

Nickel, Ni, is also used in alloys. It is a hard, silver-white metal used mainly for the production of stainless steel and for alloying with copper to produce cupronickels, the alloys used for nickel coins (which are about 25% Ni and 75% Cu). Nickel is also used in nicad batteries and as a catalyst, especially for the addition of hydrogen to organic compounds, as in the hydrogenation of vegetable oils (Section 18.6). 

Flash fires and explosions which frequently occurred on discharge of the hot products of catalytic hydrogenation of vegetable oils were attributed to formation of phosphine from the phosphatides present to a considerable extent in, e.g., rape-seed and linseed oils. 

The Pt-Sn complexes were studied extensively in the hydrogenation of vegetable oils to remove excessive unsaturation9. 

Hydrogenation of vegetable oils Hydrogenation is a two-step process. 

Powdered nickel metal acts as a catalyst for the hydrogenation of vegetable oils. (See the entry for hydrogen for more on hydrogenation.)... 

Haber synthesis of ammonia from N2 and H2 Hydrogenation of vegetable oils Oxidation of hydrocarbons and CO and reduc-... 

Catalytic hydrogenation of vegetable oils is widely used to form harder fats and to decrease the content of polyunsaturated fatty acyl groups. The products have a greatly increased resistance to rancidity. However, they also contain fats with trans double bonds as well as isomers with double bonds in unusual positions.251 253 Such compounds may interfere with normal fatty acid metabolism and also appear to affect serum lipoprotein levels adversely. Trans fatty acids are present in some foods. One hundred grams of butter contain 4-8 g, but hydrogenated fats often contain much more. It has been estimated that in the United States trans fatty acids account for 6-8% of total dietary fat.253... 

Hydrogenation These catalysts are used to add hydrogen to unsaturates, as in the hydrogenation of vegetable oils to form hardened oils. Most catalytic systems consist of nickel or a noble metal on a support. 

Selective and Complete Hydrogenation of Vegetable Oils and Free Fatty Acids in Supercritical Fluids... 

Figure 14.1. Reaction mechanism for the selective hydrogenation of vegetable oils (here, linoleic acid).

We have demonstrated that vegetable oils and fatty acid esters can be selectively hardened in liquid, near-critical, or supercritical C02 or propane and in mixtures thereof at temperatures between 60 °C and 120 °C and at a total pressure up to 20.0 MPa. Table 14.2 summarizes the results for the selective hydrogenation of vegetable oils in supercritical C02 in comparison with hydrogenation reactions performed in a discontinuous (i.e., batch or semibatch) stirred-tank reactor and in a continuous trickle-bed reactor. 

Catalytic Hydrogenation of Vegetable Oils Catalytic hydrogenation, used in the food industry, converts double bonds in the fatty acids of the oil triacylglycerols to —CH2—CH2—. How does this affect the physical properties of the oils ... 

Fatty acid triesters of glycerol containing the unnatural trans isomers of fatty acids. Trans fats are often formed as by-products in the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, (p. 1205)... 

CATALYTIC HYDROGENATION OF VEGETABLE OILS FOR EDIBLE FOOD PRODUCTS... 

Stearic Acid Stearic acid is obtained by hydrolysis of fat or hydrogenation of vegetable oils. Compendial stearic acid contains a mixture of stearic acid and palmitic acids. It is available as powder or crystalline solid which is white to yellowish white in color and possesses a characteristic odor. Although stearic acid is insoluble... 

A mechanical mixture of milk with beef tallow under pressure was patented in 1869 with the name oleo-margarine as an alternative for butter and pork fats. Its production grew, but it was soon superseded by the introduction of fats made by the catalytic hydrogenation of vegetable oil. Around 120 Mt/a of fats (ie., solids) and oils (ie., liquids) are produced world-wide of which ca. 10 Mt/a is margarine (known as spread in the UK), currently produced in more than 60 countries. 

Although alkene hydrogenation is one of the easiest organic reactions, the partial hydrogenation of vegetable oils presents some selectivity problems to get the desired properties. For example, while it is necessary to reduce the number of unsaturations in order to harden the oil and reduce the sensitivity to oxidation, unsaturated acids are fundamental in our diet and thus it is important to keep at least part of them. 

Much of the hydrogen that is used in industry, especially for the hydrogenation of vegetable oils and whale oil to convert them into solid fats, is produced by the reaction of iron with steam. The steam from a boiler is passed over iron filings heated to a temperature of about 600° C. The reaction that occurs is... 

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