Moisture Exclusion Efficiency

The reduction in EMC as a result of wood modification is sometimes reported in terms of a parameter referred to as the Moisture Exclusion Efficiency (MEE), which is defined as follows ... 

The moisture excluding efficiency of coatings decreases rapidly with time, relative humidity cycling, and weathering exposure. When cyclic or weathering tests are extended for periods of a year or more moisture exclusion is practically eliminated. 

Analysis of Reagent Purity H NMR (CDCls) may contain 1-5%of (4R, tra s)-2,2-dimethyl-a,ot,ot, ot -tetraphenyl-l,3-di-oxolane-4,5-dimethanol (but does not affect its efficiency). Preparative Methods see Trichloro(cyclopentadienyl)titanium. Handling, Storage, and Precautions the dry solid must be stored under exclusion of moisture and UV at rt (brown, tightly sealed bottle). It can, however, be handled quickly in the open, e.g. for weighing. Reactions should be carried out in dry equipment and with absolute solvents under argon or N2. 

In 2011 the same research group described another efficient application of dicarbo Q lic acids 63 in the asymmetric inverse-electron-demand 1,3-dipolar cycloaddition (lED 1,3-DC) of C//-cyclic azomethine imines with t-butyl vinyl ether or vinylogous aza-enamines (synthesized from enals) (Scheme 24.23). This latter reaction, carried out without exclusion of moisture and air, gave cycloadducts regioisomeric to the products observed in the normal-electron-demand 1,3-dipolar cycloaddition (NED 1,3-DC) catalysed by Ti/binolate starting from the enals and for this reason the authors introduced the concept of lED umpolung 1,3-DC. 

A soln. of biphenyl in anhydrous ether added with exclusion of air and moisture to refluxing liq. NH3, then Li-wire added to the stirred suspension, after 15 min. gaseous methyl bromide introduced so that the soln. is decolorized in ca. 1 min. 3-methyl-3-phenyl-l,4-cyclohexadiene (Y 93%) dissolved in didilorethane, solid trityl fluoroborate added, and refluxed 10 min. 2-methylbiphenyl (Y 98%). - This is an efficient method for the specific alkylation of ar. ring systems. F. e. s. D. F. Lindow and R. G. Harvey, Am. Soc. 93, 3786 (1971). 

The catalytic enantioselective fluorination of oxindoles by using a BINAP-palladium catalyst also proceeded highly efficiently without exclusion of air and moisture to give the corresponding fluorinated oxindoles in good yields with high-to-excellent enantioselectivities (up to 96%... 

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