complicated sentence

"Order of magnitude" is a scientific term. If two numbers differ by one order of magnitude, one is about 10 times larger than the other. If they differ by two orders of magnitude, they differ by a factor of about 100, and so on. Two numbers of the same order of magnitude have roughly the same scale: the larger value is less than ten times the smaller value.

"Several" means "more than two but not many", so if the the large surfactant molecules are several orders of magnitude larger than any disperse dye molecule, then they are at least 100 times larger, and maybe 1000 times or 10000 times larger, so you could say "very much larger", but in scientific writing it is better to be as precise as you can.

Tes nailed it. Sentences very understandable as writtten.

Yea Neo but you gotta give Ahmed credit for his determination and persistence

Shouldn't that be "larger than any dispersed dye molecule"?

Possibly not

... a byproduct of the Kraft-(?)paper-making process, are used extensively. ...molecules, several orders of magnitude... any disperse-dye molecule,.. large dye-pigment particle....

The "which are" being redundant
Hyphens often used in compound adjectives

Apparently not Tes

https://www.google.com/?gws_rd=ssl#q=disperse+dye+molecules

But I gotta admit Tes that I had the same reaction

Yup. I asked my wife, who does batik and tie dyeing, and she said "Yes, disperse dyes, I use them all the time."

Aha thanks Tes. Then it needs the hyphen doesn't it