A history of innovation

Our roots go all the way back to 1814 when Johann Daniel Riedel, a pharmacist, began making pharmaceutical products in Berlin.

1861	1861 Eugen de Haën, a chemist, acquires a laboratory for inorganic chemicals and starts to make high-purity salts and oxides in Hanover-List.
1902	The de Haën company moves to Seelze. The product range is focused on inorganic chemicals.
1928	The two companies merged forming the "Riedel-de Haën Aktiengesellschaft". Since then the company has advanced to become one of the world's most acknowledged manufacturers of high grade chemicals. The product range includes high purity hydrofluoric acids, technical preservatives, fluorescent pigments, photographic dyes and - last not least - laboratory chemicals.
1948	1948 Riedel-de Haën main office moves to Seelze.
1955	1955 Casella AG acquires 75% stake in Riedel-de Haën.
1970	1970 Hoechst AG acquires Cassella AG.
1995	1995 Hoechst sells Riedel-de Haën to AlliedSignal Inc., headquartered in Morristown, New Jersey, USA.
1996	1996 The laboratory chemicals business is spun off as RdH Laborchemikalien GmbH & Co. KG. This firm remains a joint-venture company formed by AlliedSignal Inc. and Sigma-Aldrich, an American maker of laboratory chemicals until March 1999.
1997	The assets of Riedel-de Haën AG were transferred to AlliedSignal Specialty Chemicals GmbH, which changed its name to Riedel-de Haen GmbH.
1998	1998 Troy Chemicals, an American company, acquires the Technical Preservative Materials Division.
1999	1999 AlliedSignal Inc. and Honeywell Inc. merge and form new firm: Honeywell. A few months thereafter Riedel-de Haën GmbH is renamed Honeywell Specialty Chemicals Seelze GmbH.
2001	Riedel-de-Haën AG, is reactivated to serve Honeywell customers under the well known brand name for inorganic fine chemicals.