THF Oligomers with other than OH End-Groups

There are three ways of introducing the desired end-groups into polyTHF, namely by initiation, chain transfer or termination. 

Initiation with acid chlorides complexed with metal halides (or silver salts) has been used 17), e.g.  

Some other salts, e.g. (CfiH5)3C SbF (formed in situ), resulted predominantly in H transfer or proton elimination 19). These facts have been rationalized (Adv. Polymer Sci. 37, 1980 Sect. 3.2.1) when we discussed factors influencing the relative proportions of initiation by direct addition. These factors include first of all the ability of the second THF molecule to add to the oxonium ion formed by reaction between THF and the initiating carbenium ion (preformed or transient). Steric hindrance, like that observed in oxonium ions formed by triphenylcarbenium ions and THF, is 

The macromolecules formed initially carry at one end an OH group and at the other end an OAc group. The OH end-groups are subsequently converted into OAc groups with Ac and protonic acid is regenerated. 

Oligomers prepared by Heitz with acrylic anhydride (60 % conversion, bulk process) had Mns ranging from 450 to 400 and functionalities from 1.8 to 2. 

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