Ascorbic acid vc

PSM was purchased from Tianhua Ecological Agriculture Development Co., Ltd. in October 2019. Hydrogen peroxide 30% was obtained from Tianli Chemical Reagent Co., Ltd. Salicylic acid was purchased from Baishi Chemical Co., Ltd. Ferric sulfate, ascorbic acid (Vc), and acetic acid were purchased from Xilong Chemical Co., Ltd. Hydrochloric acid and sulfuric acid were obtained from the Beijing Chemical Factory. Ethanol, ethyl acetate, sodium nitrite, and sodium hydroxide were purchased from Beilian Fine Chemicals Co., Ltd. DPPH and ABTS were obtained from Fuyang Manlin Biotechnology Co., Ltd. Chitosan and sodium alginate were purchased from Sinopharm Chemical Reagent Co., Ltd. Calcium carbonate was purchased from Fuchen Chemical Reagent Factory. Calcium chloride was obtained from Yongsheng Fine Chemical Co., Ltd. Potassium persulfate was purchased from Shengao Chemical Reagent Co., Ltd. Rutin was purchased from Nanjing Aoduofuni Biotechnology Co., Ltd. Aluminum nitrate was purchased from Chengdu Cologne Chemical Co., Ltd. AB‐8 MR was purchased from Guangfu Fine Chemical Research Institute. Water was purified by the Milli‐Q system (UPH‐II‐20T; Ulupure).

Waterlogged archaeological pine wood (Pinus massoniana) were cut into blocks of 10 mm (longitudinal), ×5 mm (tangential) and ×5 mm (radial) approximately in size. The archaeological wood used was obtained from the Nanhai One shipwreck lying on the bottom of South China Sea for around 800 years with a maximum moisture content of around 529%. These sample were desalinated before the treatment. However, the indissoluble salts including calcium sulfate and ferrous sulfide can be hardly removed from the samples. Anisole(99%), copper(II) bromide(Cu(II)Br₂, 99%) from Macklin Biochemical, 2-bromoisobutyryl bromide (BIBB, 98%) from Bide Pharmatech, N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA, 98%), 2-Bromo-2-methylpropanoic acid (97%) from D&B Biotech, pyridine (99%), Ascorbic acid (Vc, 99%) from Xilong Scientific, ethanol (AR) and dichloromethane (CH2Cl2) from Tongguang Fine Chemicals were used directly without purification. Butyl methacrylate (97% with 10 ppm MEHQ) and styrene (99.5%) were purchased from Aladdin and purified through an alkaline aluminum oxide column to eliminate inhibitors before use.