imidazole production, UPR, ecoinvent 3.6, Undefined

ISIC4 categories:
C:Manufacturing/20:Manufacture of chemicals and chemical products/201:Manufacture of basic chemicals, fertilizers and nitrogen compounds, plastics and synthetic rubber in primary forms/2011:Manufacture of basic chemicals
GLO - Global
Reference year: 2010 - 2010

Location: GLO - Global
The process “imidazole, at plant, GLO" is modelled for the production of imidazole from glyoxal. Raw materials are modelled with a stoechiometric calculation. Emissions are estimated. Energy consumptions, infrastructure and transports are calculated with standard values.
Imidazole (C3H4N2; CAS 288-32-4) is a white or pale yellow solid. Of the many known methods for producing imidazoles, only the following are of industrial importance.

The Radziszewski Reaction
In the generally applicable Radziszewski reaction, a 1,2-dicarbonyl compound is condensed with an aldehyde and ammonia in a molar ratio of 1 : 1 : 2, respectively. Replacement of a molar equivalent of ammonia with a primary amine leads to the corresponding 1-substituted imidazoles.
The reaction is usually carried out in water or a water – alcohol mixture at 50 – 100 °C. Work-up may involve the usual processes (e.g., distillation, extraction, and crystallization). Distillation leads to imidazole with a purity > 99 %. The yield is generally 60 – 85 %.

Dehydrogenation of Δ2-Imidazolines
Δ2-Imidazolines can be obtained by several routes from 1,2-diamino compounds and carboxylic acid derivatives:
1. by reaction of a diamine with a carboxylic acid over an acidic heterogeneous catalyst (e.g., alumina – phosphoric acid) in the gas phase;
2. by reaction of a diamine with a carboxylic acid nitrile in the presence of sulfur or copper salts in the liquid phase; or
3. by preparation of diformyl derivatives from a diamine and formic acid esters, followed by conversion to imidazoline in the gas phase at 200 – 350 °C over a heterogeneous catalyst (e.g., zinc oxide – alumina).
The Δ2-imidazoline is then dehydrogenated in the gas phase over a precious metal at ca. 300 °C or on alumina – zinc oxide at 400 – 500 °C. In some cases this synthesis gives even better yields than the Radziszewski reaction (e.g., for 2-aryl-substituted imidazoles).

The imidazole ring is a constituent of several important natural products, including purine, histamine, histidine, and nucleic acids. Therefore, the bulk of imidazole produced is used in the preparation of biologically active compounds like herbicides and pharmaceuticals.
Frischknecht R., Jungbluth N., Althaus H.-J., Doka G., Dones R., Heck T., Hellweg S., Hischier R., Nemecek T., Rebitzer G. and Spielmann M. (2007) Overview and Methodology. Final report ecoinvent v2.0 No. 1. Swiss Centre for Life Cycle Inventories, Dübendorf, CH, retrieved from:

Gendorf (2000) Umwelterklärung 2000, Werk Gendorf. Werk Gendorf, Burgkirchen as pdf-File under:

Klaus Ebel, Hermann Koehler, Armin O. Gamer, Rudolf Jäckh: Imidazole and Derivatives. Published online 2000. In: Ullmann's Encyclopedia of Industrial Chemistry, Seventh Edition, 2004 Electronic Release (ed. Fiedler E., Grossmann G., Kersebohm D., Weiss G. and Witte C.). 7 th Electronic Release Edition. Wiley InterScience, New York, Online-Version under: DOI: 10.1002/14356007.a13_661

Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.


Radziszewski reaction

Process type
Supported nomenclature
ecoinvent 3.6
LCI modeling approach
Before modeling
Multifunctional modeling
Aggregation type
Data provider
Review status
For sale

ecoinvent EULA