[MVoronov]

I am not a professional chemist.
But I am debating with my friend about evolution theory. :-)
Let's say that replication - It is a process involving a molecule (the replicator), as a result of this process we'll have two or more of the same molecule.
Could you give me examples of most primitive replicators?
Sorry for my english, i'm not Englishman or American.
Thank you

[Yggdrasil]

If by a primitive replicator, you mean a simple system that is capable of replication, then a few researchers have come up with simple chemical systems that are capable of self-replication.  Gerald Joyce's group at Scripps has developed an relatively small RNA enzyme capable of self-replication (if it is given the correct substrates).  Jack Szostak's group at Harvard developed "protocells" that are capable of growing and dividing in the presence of free fatty acids.  The citations for the papers are given below, along with some articles from the popular press describing the work done in the different labs:

Lincoln and Joyce. 2009.  Self-Sustained Replication of an RNA Enzyme.  Science, 323: 1229. doi:10.1126/science.1167856
http://www.wired.com/wiredscience/2009/01/replicatingrna/

Zhu and Szostak. 2009.  Coupled Growth and Division of Model Protocell Membranes.  J. Am. Chem. Soc., 131:5705. doi:10.1021/ja900919c
http://www.wired.com/wiredscience/2008/09/biologists-on-t/

If by most primitive replicator, you mean the earliest systems capable of replication during the history of life on Earth, then scientists are not sure what these early replicators may have been.  The above articles are attempts to create something like those primitive replicators may have been, but the origin of life is still very much an open question in the sciences.

[MVoronov]

Thank you very much! 
I'll read the articles.