The English is ‘ a lot of the money that … ‘ - a reference to a quantity of a specific known ‘item/thing’, not of a thing in general. 

The translation in French also will be specific. Therefore in this and similar specific use cases, the definite article is correct (contracted as appropriate) and changes the meaning.

Mostly when talking about quantities of something, the following noun is ‘general’ and in those cases the definite article is not used in French, and ‘beaucoup de/d’ is always ‘beaucoup de/d’. 

For example, ‘ J’ai utilsé beaucoup d’ail dans ma recette ‘ compared to ‘ J’ai utilisé beaucoup de l’ail qui était dans le bac ‘

See links for further discussion. 

https://www.thoughtco.com/beaucoup-des-french-mistake-1369443 

http://www.forum.french-linguistics.co.uk/forum/topics/de-instead-of-du-de-la-des