Amines in steam humidification systems

James Stroud <stroud [at] mail__utexas__edu> writes:

>If anyone has information or experience regarding the effects on
>collections that may result from the use of amines in direct steam
>humidification systems, we would be grateful to hear them.

In 1996/97, under contract to Indiana University Art Museum (IUAM)
supported by a grant  (Analyzing the Effect of an Indoor Pollutant
on Traditional Easel Paintings) from the National Center for
Preservation Technology and Training (NCPTT), I analyzed 74 samples
from 21 paintings from IUAM thought to be affected by
diethylaminoethanol (DEAE) contamination introduced into the
atmosphere by live steam humidification, in order to determine if
the paintings were damaged by the DEAE.  Two Reports of Results were
written and are available from NCPTT
(<URL:http://www.ncptt.nps.gov>).

    1.  Williams, R.Scott, Canadian Conservation Institute.
        Analyzing the Effect of Diethylaminoethanol, an Indoor Air
        Pollutant, on Traditional Easel Paintings-Phase 1 Report:
        Analytical Procedures for DEAE in DEAE [diethylaminoethanol]
        Contaminated Paintings.
        Natchitoches, Louisiana: NCPTT. 1998. (22 pp; appendices).
        [PTT Publications No. 1998-16].

        This report describes analytical procedures for detecting
        the presence and effects of diethylaminoethanol on
        paintings.

    2.  Williams, R.Scott, Canadian Conservation Institute.
        Analyzing the Effect of Diethylaminoethanol, an Indoor Air
        Pollutant, on Traditional Easel Paintings-Phase 2 Report:
        Infrared Spectroscopic Analysis of Varnish and Paint Samples
        from IUAM Paintings for the Presence of DEAE.
        Natchitoches, Louisiana: NCPTT. 1998.  (15 pp). PTT
        Publications No. 1998-17]

        This study is based on analytical procedures developed in
        Phase 1 of the DEAE analysis project  The report presents
        infrared spectroscopic analysis of varnish and paint samples
        from paintings for the presence of diethylaminoethanol, an
        indoor air pollutant, in an effort to analyze the effects of
        DEAE and conservation treatments on DEAE-contaminated
        paintings.

I have summarized below the results for painting and model compound
samples. Details are in the NCPTT reports.

A. Summary of Results of IR spectroscopic analysis of painting
samples

    1.  FTIR analysis was performed on 74 samples from 21 paintings
        from IUAM.  Most painting samples has several components or
        layers, and all were analyzed.  More than 500 spectra were
        collected for these components, and interpreted to identify
        the chemical composition of these components.

    2.  Model compounds to represent the major organic components of
        paintings were exposed to various concentrations of DEAE and
        the products of reaction were analyzed.

    3.  Studies on the model compounds showed that DEAE can react
        with the acidic components of paintings, in particular with
        the resin acids in natural resin varnishes, and free fatty
        carboxylic acid in drying oils.  However, DEAE does not
        react with carboxylic esters of glycerol, and therefore is
        unlikely to react with the triglyceride esters that comprise
        the major component of drying oils.

    4.  DEAE reaction products, specifically DEAE carboxylate soap,
        was tentatively identified in only one painting, "Peinture"
        by Soulages. It was found in the ground layer, but in no
        other layers, including an acidic oil layer on the surface,
        where the potential for reaction is greatest.

    5.  Small amounts of oxalate compounds, perhaps calcium oxalate,
        were detected in several paintings.  One source of oxalic
        acid and its salts is metabolic by products from molds,
        fungus, and algae.

    6.  The analyses reported here indicate that the IUAM paintings
        have not been damaged by reaction with DEAE.

B. Detailed summary of results of FTIR analysis of products of
reaction of DEAE with model compounds

    1.  DEAE reacted only with the acidic components of model
        compounds.  DEAE produced DEAE resinates from dammar by
        reacting with the resin acids in dammar, DEAE soaps by
        reacting with carboxylic acids (myristic, palmitic and
        stearic acid) and the acid components (fatty acids) in
        linseed stand oil and trilinolenin.

    2.  Ammonia and morpholine reacted with carboxylic acids in a
        similar way to produce ammonium and morpholine carboxylate
        soaps.

    3.  DEAE did not react with esters including tripalmitin and
        tristearin and methyl stearate.

    4.  DEAE did not react with metal soaps including aluminum,
        calcium, sodium or zinc stearate.

    5.  The amount of reaction of DEAE with model compounds
        decreased with the concentration of the DEAE.

    6.  In vapors above 10000 ppm DEAE in water solution, dammar,
        copal, and all acids liquefied and the IR showed DEAE soaps.
        The methyl and glycerol esters, and metal soaps did not
        react (nor did they react when exposed to 100% DEAE vapors
        in a hanging drop apparatus).

    7.  In vapours above 400 ppm DEAE in water solution, DEAE soaps
        were formed from myristic acid, and to a lesser extent from
        palmitic acid.  The myristic acid liquefied, whereas the
        palmitic acid was only "moistened".  Stearic acid looked
        unchanged and did not show DEAE soap in its spectrum.  This
        suggests that the reaction may depend on crystallinity,
        being least favored for the most crystalline stearic acid.

    8.  Dammar did not react with vapours above 400 ppm DEAE in
        water solution.

    9.  The DEAE appears to react with resin and carboxylic acids in
        a straightforward acid-base neutralization reaction to
        produce a DEAE salt (DEAE resinate or DEAE carboxylate
        soap).

    10. DEAE does not hydrolyse or saponify triglyceride ester.
        DEAE will not damage oil paint media by this reaction.

    11. DEAE does not enter into ion exchange reactions with metal
        soaps to replace the metal ion by DEAE ion.

R. Scott Williams
Senior Conservation Scientist (Chemist)
Conservation Processes and Materials Research
Canadian Conservation Institute
1030 Innes Road
Ottawa, Ontario, Canada K1A 0M5
613-998-3721
Fax: 613-998-4721,



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                  Conservation DistList Instance 14:43
                 Distributed: Tuesday, February 6, 2001
                       Message Id: cdl-14-43-001
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