Boron trifluoride Branching

Highly Branched Acids. These acids, called neoacids, are produced from highly branched olefins, carbon monoxide, and an acid catalyst such as sulfuric acid, hydrogen fluoride, or boron trifluoride. 2,2,2-Trimethylacetic acid (pivaUc acid) is made from isobutylene and neodecanoic acid is produced from propylene trimer (see Carboxylic Acids, trialkylacetic acids). 

Since 1900 other methods have been devised for producing polymethylene , including the use of boron trifluoride-diethyl ether catalysts at 0°C. Some of these methods give unbranched linear polymers, often of very high molecular weight, which are useful for comparing commercial polyethylenes which have molecules that are branched to varying extents. 

Takahashi and coworkers described the one-pot synthesis of core 2 branched oligosaccharides [236], It was found that boron trifluoride complexed with a tri-methylsilyl ether would enhance the nucleophilidty of the silyl ether. As a result, glycosylations of the 6-O-TMS modified acceptor with a glycosyl fluoride provided... 

Pentafluorocthyl iodide is of practical interest, particularly as a precursor of higher perfluoroal-kyl iodides. There are several patents for the preparation of the key compound from tetra-fluoroethene, iodine pentafluoride and iodine at 75-80 C in the presence of catalysts anti-mony(III) fluoride, titanium(lV) chloride, boron trifluoride, vanadium(V) fluoride, niobium(V) fluoride, and molybdenum(Vl) fluoride.11-13 The agents iodine monofluoride" and bromine monofluoride" can add to branched pcrfluoroalkcnes, e.g. perfluoro-2-methylbut-2-ene gives perfluoro-2-iodo-2-methylbutane.1415... 

Korshak and coworkers20 polymerized levoglucosan in p-dioxane at 80-90°, using, as the catalyst, benzenesulfonic acid or such Lewis acids as boron trifluoride, ferric chloride, or aluminum chloride. Highly branched, amorphous products having Ma 38,000-68,000 (by light-scattering) were obtained. 

Alkylphenol. Alkylphenol is a common surfactant intermediate used to produce alkylphenol ethoxylates. Phenol reacts with an olefin thermally without a catalyst but with relatively poor yields. Catalysts for the reaction include sulfuric acid p-toluene sulfonic acid (PTSA), strong acid resins, and boron trifluoride (BF3). Of these, strong acid resins and BF3 are mostly widely used for the production of surfactant-grade alkylphenols. The most common alkylphenols are octylphenol, nonylphenol, and dodecylphe-nol. Mono nonylphenol (MNP) is by far the most common hydrophobe. It is produced by the alkylation of phenol with nonene under acid conditions. All commercially produced MNP is made with nonene based on propylene trimer. Because of the skeletal rearrangements that occur during propylene oligomerization, MNP is a complex mixture of branched isomers. 

Jang [2] a Ziegler-Natta catalyst consisting of nickel naphthenate, boron trifluoride dibutylether, and triethylaluminum was used to control 1,2-branch-ing in 1,4-butadiene polymerization. 

In addition to the initiation of gaseous formaldehyde with formic acid, HCl, boron trifluoride and stannic chloride were studied and found to be more active than formic acid (Fig. 17). The rate of gaseous formaldehyde polymerization with the initiator was measured under the same conditions as the formic acid initiated polymerization by determining the decrease in pressure of formaldehyde. HCl as initiator (at about 3—4% in the mixture) caused kinetic branching, i.e. a rapid increase in the rate of polymerization. 

Allenylstannanes add to aldehydes in the presence of equimolar boron trifluoride etherate, or magnesium dibromide etherate to give homopropargyl alcohols.37 If the aldehyde has a branched alkyl group, the syn adduct is formed (equation 9-43) through... 

The simplest polyhydrocarbon, with structural element —CHi—, can be produced by the polymerization of ethylene (CH2=CH2), diazomethane (CH2N2), or a mixture of CO and H2. The polymer produced from diazomethane is called poly(methylene). It is only lightly branched. The polymerization mechanisms has not been established. A carbene mechanism has been discussed for gold as initiator. With boron trifluoride-water as initiator, on the other hand, a regular cationic polymerization with proton addition and subsequent propagation is considered ... 

Cyclopropane fatty acids behave as normal saturated fatty acids on silver ion chromatography, but react with bromine and so can be distinguished by this means [128]. They form methoxy-derivatives with boron trifluoride-methanol reagent [610], and they are converted to methyl-branched fatty acids by vigorous catalytic hydrogenation [571]. Both types of derivative can be characterized by mass spectrometry. 

For the conversion of oligosaccharides containing branched chains with 6-8 mannose rniits terminating in iV-acetylglucosamine it is reported that TMS bromide in the presence of boron trifluoride etherate and collidine provide means of obtaining the oxazoline from which bonding to spacer groups can be effected. ... 

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