## 1 Introduction  
Bohemite [AlO(OH)] is an aluminum oxy-hydroxide present naturally in the bauxite ores, along with diaspore (AlOOH) and gibbsite [Al(OH)\({}_{3}\)]. Pseudo-boehmite is a poorly crystallized boehmite [1, 2], consisting of Al(O,OH)\({}_{6}\) octahedral layers, and used as a catalyst or catalyst support in several processes [3, 4, 5].  
One of the most important applications of the boehmite is as precursor to obtain \(\gamma\)-Al\({}_{2}\)O\({}_{3}\). After partial dehydroxylation from 300 to 550 \({}^{\circ}\)C, boehmite is converted to \(\gamma\)-Al\({}_{2}\)O\({}_{3}\)[2, 6]. Among the aluminas, \(\gamma\)-Al\({}_{2}\)O\({}_{3}\) nd \(\eta\)-Al\({}_{2}\)O\({}_{3}\) are important as catalyst supports, due to their highly effective contact area, high thermal stability, and surface acidity susceptible to be controlled.  
It is possible to obtain the pseudoboehmite (PB) synthetically depending on the characteristics of the synthesis method employed. It has been reported the synthesis by a sol-gel method with and without catalyst [7], the atrane method [8] and low-cost approaches to synthesize PB with high surface area and broad pore size distribution. Moreover, previous reports have been focused on acid neutralization by using sodium aluminate as Al source [9], the hydrolysis of aluminum alkoxides [10] and a modified cation-anion double hydrolysis method by using water glass as the pore-expanding agent.  
The aim of this work is to show the capability of this adsorbent to separate a paraffins mixture of n-C5-C9 using the inverse gas chromatography (IGC). The IGC is a technique for obtaining information on the physico-chemical characteristics of the solid surface under flow conditions and its fundamentals are well explained in several publications [11; 12]. Briefly, this technique is to investigate the ability of a porous material to separate a mixture of compounds by placing the porous solid in a packed column, which is crossed by the flow of the carrier gas and the mixture. At the end of the column, the mixture is analysed using a chromatographic detector. This technique is able to make the study at several carrier gas flows and temperatures. It provides information about the interactions between gases and vapors with solid surfaces as diverse as alumina [13], chromia [14; 15], polymer fabrics [16], biopolymers [17], nanomaterials [12], hexacyanocobaltates [18], zeolites [19]. The possible use of a Cuban mineral, in its natural and modified state, for the separation of hydrocarbons components and C5-C9 \(n\)-paraffin mixture has been studied too [20; 21]. It has been used in phenolic resin-carbon molecular sieve membranes for C\({}_{3}\)H\({}_{6}\)/C\({}_{3}\)H\({}_{8}\) gas separation [22] and zeolite membranes [23].  
Boehmite has been used to obtain a nanostructured alumina with excellent mechanical crush strength [24], to prepare spherical silicalite/\(\gamma\)-Al\({}_{2}\)O\({}_{3}\) granules with high crush strength and good sorption properties for SO\({}_{2}\)[25]. And, to the best of our knowledge, no references about the use of synthetic bohemite in the adsorption and separation of hydrocarbons mixtures were found. For these reasons, the aim of this work was to study the behavior of a synthetic boehmite in the adsorption and separation of C5-C9 paraffin mixture by IGC. Moreover, it is going to be used the [PERSON]'s two term equation to describe the performance of gas adsorption in this adsorbent, which has not been described yet.