A recent attempt to replace a string within double quotes “string value” while using sed resulted in much trial and error. A quick Internet search revealed a working answer.  It is here for my reference.

I wanted to replace “this value” with “that one” in a file, we’ll call testfile.  According to multiple sources, the sed command allows the use of other characters instead of /.

sed 's#"this value"#"that one"#g' testfile

This also works.

sed 's/\"this value\"/\"that one\"/g' testfile

Usually the man pages are useful, but for sed, the info pages are more informative.  Below is the relevant selection for this article around line 107.

info sed

Source(s)
http://stackoverflow.com/questions/7517632/how-do-i-escape-double-and-single-quotes-in-sed-bash
http://www.commandlinefu.com/commands/view/2889/sed-using-colons-as-separators-instead-of-forward-slashes