Date of Award

12-2014

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Advisor

Barbara J.W. Cole

Second Committee Member

Raymond C. Fort, Jr.

Third Committee Member

Douglas J. Gardner

Abstract

Formaldehyde (CH2O), is a colorless, flammable, and strong-smelling pungent gas which is used to make resins for household products such as composite wood products, paper products, coatings, plastics, synthetic fibers and textile finishes. It is also commonly used as a preservative in medical laboratories, mortuaries, and some consumer products, including some hair straightening products. Formaldehyde was classified as a human carcinogen and ubiquitous environmental contaminant by the U.S. Department of Health and Human Services as well as the US National Toxicology Program (FEMA 2008; EPA, 2011). There is sufficient evidence from human studies showing that high levels of formaldehyde exposure can increase the risk of nasopharyngeal cancer, sinonasal cancer, and myeloid leukemia. In response to the recent contaminant classifications, regulatory limits for formaldehyde emissions have been reduced. Formaldehyde emissions from wood have long been linked to composite manufacture and handling. Recent reports from environmental agencies suggest that CH2O emanates from wood itself before being processed (Schafer and Roffael, 2000). The mechanism by which it might be produced in or by “native” wood has not been established. This investigation focused on the determination of the formaldehyde source in wood using simple yet highly sensitive methods of 2,4,6-trichlorophenylhydrazine (TCPH) with GS/MS analysis to detect levels of the compound as low as ng/g O.D. wood. At room temperature, formaldehyde is emitted from “native” wood at very low levels (5-50 ng/g O.D. wood). Over time, emissions decrease from the loss of moisture in the wood. Formaldehyde is generated at elevated temperatures, especially above 150 °C, and continues to diffuse from wood after generation even when no longer under heat treatment. Mechanistically, formaldehyde is generated from each wood component but at different levels. Elevated temperature experiments as well as enthalpy AH calculations suggest that formaldehyde is produced by fragmentation of lignin and to a lesser extent by degradation of carbohydrates.

Share