The solid state acyl shift of diglycerides: An electron diffraction study

The progress of the solid state acyl shift of 1,2-diglycerides to 1,3-diglycerides is followed at room temperature in single dipalmitin microcrystals by electron diffraction. The β′form, rather than the α-form of the 1,2-isomer, transforms to the 1,3 product. The β′ form packs in the monoclinic paraffin fashion, i.e. the O_⊥ methylene subcell and a chain tilt of 27° about the long subcell axis. After the isomerization, the chain tilt (14° to surface normal) occurs around the $\text{b}{}_{\mathrm{<mtext>S</mtext>}}{}^1$ axis of the resultant T_∥ methylene subcell.