## 1 Introduction
Converting alcohols from gasoline additives to bio-oil refining reagents, which end up in the fuel, does not change their ultimate caloric contribution for fuel use. Olefin mixtures can be used. So, although olefins are consumed that may have other uses, olefins or olefin mixtures, whatever is cheaper, can be applied. For example, cheaper olefin mixtures can be obtained by pyrolysis of waste polyolefin base plastics. The total caloric content of the combined olefin and alcohol reagents remain within the refined upgraded products together with all of the original caloric content of the raw bio-oil. However, olefin/alcohol acid-catalyzed upgrading will not, and is not intended, to produce \"drop in\" fuels for use in gasoline or most diesel motors. Furthermore, the product is not primarily intended for subsequent feeding into refinery processes to make gasoline due to its considerable oxygen content. But the oxygenated products can be blended with petroleum fuels or biodiesel liquids and might have promise for application in low temperature/high compression diesel engines requiring low cetane number fuels someday. In our earlier work, undesirable catalyst deactivation [18] and decomposition [17,19] occurred during these upgrading processes due to bio-oil's complex composition, especially with substantial amounts of water present. A goal of this work is to develop and apply a more highly active catalyst with good hydrothermal stability for this process. A second goal is to more fully elucidate the complex competing reaction pathways involved in the acid-catalyzed refining of bio-oil with olefins plus alcohols. Bio-oil upgrading is exceptionally complex. This is because bio-oils are composed of a wide variety of oxygenated compounds (more than 300) and its chemical composition is feedstock and pyrolysis process dependent. However, all reported bio-oils are poorly defined mixtures of carboxylic acids, alcohols, aldehydes, esters, ketones, sugars or anhydrosugars, phenolic compounds, furans, water, a few cyclic hydrocarbons and multifunctional compounds such as hydroxyacetaldehyde, hydroxyacetic acid, hydroxyacetone, _etc_. [7]. Model compounds and their mixtures are often first employed to study the reaction steps involved in bio-oil upgrading processes [10,12,13]. For this work, we have selected phenol, water, acetic acid, acetaldehyde hydroxyacetone, d-glucose and 2-hydroxymethylfuran as typical bio-oil components and mixed them as a synthetic bio-oil. This composition contains a better representation of the types of compounds involved in the many reactions competing during refining and has allowed a more complete understanding of the reaction paths. Solid acid catalyzed reactions of 1-octene/1-butanol with this synthetic bio-oil were investigated in the liquid phase, respectively, over Dowex50 WX2 (DX2), Amberlyst15 (A15), Amberlyst36 (A36), Cs\({}_{2.5}\)H\({}_{0.5}\)PW\({}_{12}\)O\({}_{40}\) (an insoluble acidic heteropoly acid salt) and silica sulfuric acid (SSA) catalysts. All of these catalysts are reported water-tolerant strong acids. A short preliminary communication in Bioresource Technology [22] on this effort has appeared. The full study is reported here. SSA is a superior proton source compared with many acidic solid supports, such as styrene/divinylbenzene sulfonic acid resins and Nafion-H [23]. SSA exhibited good activity and stability in preliminary catalytic upgrading of model bio-oils by simultaneous reactions with 1-butanol and 1-octene [22]. Reaction pathways were proposed, but, more systematic research was needed to examine upgrading feasibility and elucidate the complicated reaction mechanism. Thus, various olefins and alcohols are investigated in reactions with phenol/water (1:1) mixtures in this paper. Also, reactions of 1-octene with phenol, phenol/water, phenol/water/acetic acid, phenol/water/1-butanol, phenol/water/2-hydroxymethylfuran, phenol/water/d-glucose, phenol/water/hydroxyacetone and phenol/water/acetic acid/1-butanol are reported here.