Exercise 2 Choose the most suitable tense

1. I can’t understand what he sees in her! If anyone treats / will treat / treated me like that, I am / will be / would be extremely angry.

2. Why didn’t you tell me? – If you told / had told me, I had / would have helped you.

3. Let me give some advice. If you smoked / would smoke / had smoked less, you didn’t feel / wouldn’t feel / wouldn’t have felt tired

4. We have a suggestion to make. How do you feel / wouldyoufeel if we offered / wouldoffer / had offered you the job of assistant manager.

5. A cheque is all right, but I’d rather you pay / paid me cash

6. I wish Peter doesn’t live / didn’t live / wouldn’t live so far away from the town center. We’ll have to take a taxi.

7. I’m sure your letter hasn’t arrived yet. If it came / had come, I’m sure I noticed / hadnoticed / would have noticed it.

READING

1 Read the text “Acetylation ”

In many chemical modification reactions the hydroxyl groups play the leading role. Esters are formed by the reaction of wood with carboxylic acids or anhydrides. Most studied and reported by dozens of authors is the acetylation of solid wood, wood fibres, chips, veneers etc. with acetic anhydride. In Europe, at Chalmers University (Sweden) efforts are focusing on the use microwave technology for fast heating during the treatment, while SHR Timber Research (the Netherlands) has developed a method to overcome the problem of the residual by-product acetic acid, a process now coming in the full scaling-up phase.

From a chemical reaction point of view, acetylation of wood with uncatalyzed acetic anhydride is relatively simple. Acetylation processes of wood have been described already in the beginning of the 20^th century. Research efforts since the late 80's and in the 90's have led to the scaling up of the acetylation process. The process basically consists of an impregnation step followed by heating up to start the exothermic reaction (at approximately 70 °C). After the reaction the mixture of acetic acid and acetic anhydride is removed from the wood. A post treatment process removes the residual acetic acid.

Acetylation with uncatalysed acetic anhydride has been studied extensively and has shown to be one of the most promising methods for improvement of technical properties of wood products. During the reaction of the wood with acetic anhydride, hydroxyl groups of the cell wall polymers are converted into acetyl groups. The principle was proven initially at laboratory scale. After some years of work, a pilot plant (2500 litres with 0.6 m3 wood capacity per batch) was built by Acetyleer Kennis BV (AKBV) in 1999 in the Netherlands. Since the establishment of the pilot plant, SHR Timber Research has conducted several experiments and results indicate good potential for the commercial acetylation of wood.

The construction of a 20000m3 full-scale production plant has started. The company that will bring acetylated wood to the market is called Titan Wood. Their aim is to provide an economic acetylation system and a range of products that exceeds the wood industry's expectations in terms of quality and performance. The biological durability class is always in class I at WPG levels of over 20 %, dimensional stabilization is 75% or more, strength properties are not influenced by the treatment (except a slight increase in hardness), the material is UV-stable and paint tests have shown remarkably good results. Termites do not prefer the material (choice test) but can eat it although not digest it.

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