Emigration to US 1830

[Sallie Hobbs]

My ancestor, Johan Friderich Chrane, emigrated from Copenhagen to Philadelphia in 1830, via Homburg.
His family was in Chariton County, Missouri, by 1840.

Today I found several biographical sketches of a famous Danish-American, Peter Lassen, who emigrated in 1831 from Copenhagen to Boston, and spent 8 or 9 years in Chariton County, Missouri. Some of the bios state that Lassen spent some time in Philadelphia.

And some of the Lassen bios state that Lassen had "permission from the King" to emigrate. So I am wondering if there was some sort of request that had to be completed, and if there would be records of the requests that have been preserved somewhere?

I do have a copy of the passenger list for Johan F. and his family. I am looking for something that might say why he was leaving Denmark.

Many thanks in advance,
Sallie Hobbs