Code:
# cat tst
a,b,'jklfds','a,b,a,c','f','g','c','c,d'
a,b,'jklfds','a,b,a,c','f','g','c','c,d'
# awk '{OFS=NR%2?",":"#";$1=$1}1' RS="\'" FS=, ORS="\'" tst
a,b,'jklfds','a#b#a#c','f','g','c','c#d'
a,b,'jklfds','a#b#a#c','f','g','c','c#d'
'# awk '{OFS=NR%2?",":"Xox9870563xoX";$1=$1}1' RS="\'" FS=, ORS="\'" tst
a,b,'jklfds','aXox9870563xoXbXox9870563xoXaXox9870563xoXc','f','g','c','cXox9870563xoXd'
a,b,'jklfds','aXox9870563xoXbXox9870563xoXaXox9870563xoXc','f','g','c','cXox9870563xoXd'
'#