Neo-acids

The boric and sulfuric acids are recycled to a HBF solution by reaction with CaF2. As a strong acid, fluoroboric acid is frequently used as an acid catalyst, eg, in synthesizing mixed polyol esters (29). This process provides an inexpensive route to confectioner s hard-butter compositions which are substitutes for cocoa butter in chocolate candies (see Chocolate and cocoa). Epichlorohydrin is polymerized in the presence of HBF for eventual conversion to polyglycidyl ethers (30) (see Chlorohydrins). A more concentrated solution, 61—71% HBF, catalyzes the addition of CO and water to olefins under pressure to form neo acids (31) (see Carboxylic acids). 

Neo acids are prepared from selected olefins using carbon monoxide and acid catalyst (4) (see Carboxylic Acids, trialkylacetic acids). 2-EthyIhexanoic acid is manufactured by an aldol condensation of butyraldehyde followed by an oxidation of the resulting aldehyde (5). Isopalmitic acid [4669-02-7] is probably made by an aldol reaction of octanal. 

Trialkylacetic acids have been produced commercially siace the early 1960s, ia the United States by Exxon and ia Europe by Shell, and have been marketed as neo acids (Exxon) or as Versatic Acids (Shell). The principal commercial products are the acid and the C q acid (neodecanoic acid, or Versatic 10), although smaller quantities of other carbon numbers, such as C, C, and C, are also produced. 

Health and Safety Factors. The C q trialkylacetic acids have toxicities similar to those for other neo acids oral LD q in rats is 2.0 g/kg, and dermal LD q in rabbits is 3.16 g/kg. 

Shell has claimed that the Koch reaction to make Koch neo-acids can be carried out with a CIER, instead of concentrated sulphuric acid (Eqn. (8)). 

This synthesis gives rise to carboxylic acids formed on tertiary carbon atoms, so called neo-acids [15], and i( takes place in stronj y acidic conditions in two stages ... 

Commercial petrochemical processes using syngas or carbon monoxide are based on four principal classes of reactions phosgenation, Reppe chemistry, hydroformylations, and Koch carbonylations. Phosgenation is a key step in the manufacture of polyurethanes, polycarbonates, and monoisocyanates. Reppe chemistry is the basis for acetic acid and acetic anhydride production as well as formic acid and methyl methacrylate synthesis. Hydroformylations utilize syngas in the oxo synthesis to make a wide variety of aldehydes and long-chain alcohols. The fourth class of reactions are Koch carbonylations. Koch carbonylations are used commercially to produce neo acids which are specialty products that serve markets similar to 0X0 alcohols. 

Koch carbonylations use strong acid catalysts to react olefins with carbon monoxide and water to form branched isomers of carboxylic acids. Neo acids produced by Exxon Chemical and Versatic acids produced by Shell Chemical are examples of commercial processes utilizing Koch carbonylation chemistry [9]. 

Neo Acids. Neo acids are actually not made by the 0x0 process but are products of Koch carbonylation. They are frequently included with the family of 0x0 chemicals because their end use products serve similar markets. For instance, pivaloyl chloride made from neo pentanoic acid is used as a precursor for several herbicides, pesticides, and pharmaceutical products. Neodecanoic acids are used as drying agents for paint and as a heat stabilizer for PVC. Latex paint additives are made from vinyl and glycidyl esters which are derived from neodecanoic acid. 

Exxon is the only producer of neo acids in the United States and Shell is the sole producer in Western Europe. Shell markets neo acids under the trade name Versatic Acids. 

Reppe reactions are the formation of carboxylic acids from olefins by reaction with carbon monoxide and water utilizing a metal carbonyl catalyst. The same reactants combine to form carboxylic acids in the presence of an acid catalyst. These acid catalyzed reactions are known as Koch Carbonyla-tion reactions. Commercial processes utilizing this route are the DuPont process for glycolic acid from carbon monoxide and formaldehyde and the carbonylation of olefins to neo acids practiced by Exxon and Shell. 

Shell produces C, to C, carboxylic acids marketed under the trade name Versatic acids. Exxon carbonylates propylene oligomers to produce neo acids. The derivatives and markets for these products are described in this chapter under the section on oxo chemicals. 

Petroleum coke, 41, 42, 68 Petroleum refining, 199, 206 Pharmaceuticals aniline, 202 1, 4 butanediol, 205 Cll-ClSoxo alcohols, 264 formic acid, 242 neo acids, 263 propionaldebyde, 260 pyridine, 160... 

The carbonylation of olefins, by using such strong acids such as H2SO4, H3PO4-BF3, or HF-SbFs (superacids or magic acids) as catalysts, is known as the Koch synthesis. It 3delds predominantly branched isomers of carboxylic acids Neo acids (Exxon) and Versatic acids (Shell). The economic importance of these products is far less than that of the compovmds obtained by Reppe reactions (85,86). 

Another plant licensed by H. Koch to Enjay Chemical Co. in Baton Rouge, USA, came onstream in 1965. This plant is designed to make the so-called Neo-acids (branched C5-, C7- and CjQ-acids) with a capacity of 4500 tons per year. As catalyst BF3/2H2O is used [796, 1002]. 

Hydrolytic stability - Hydrolysis of esters to giye acids and alcohols is a facile reaction and can proceed at elevated temperatures in the presence of water. Hydrolysis of ester generates acid that can be very corrosive to metal components and can catalyze the base stock decomposition process. Therefore, hydrolytic stability of esters is an important issue. Much work has been carried out to improve the hydrolytic stability by varying the composition of acids and alcohols. Generally, esters made from aromatic acids or from more sterically hindered acids, such as 2-alkyl substituted acids or neo-acids, have improved hydrolytic stabilities. Proper branching of the acids protect the carbonyl ester function from the detrimental attack of water. The presence of impurity, such as trace acid or metal, can catalyze the decomposition and hydrolysis of ester. Compared to PAO or alkylaromatic base stocks, ester hydrolysis is always an issue of concern in many lubrication applications. 

---